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A Citizens' Guideto Understanding and Monitoring Lakes and -Streams

by Joy P. Michaud

Edited by Marcy Brooks McAuliffe

Illustrated by Sandra Noel

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Produced through funding from thePublic Involvement and Education Project,

Financed by proceeds from theWashington State Centennial Clean Water Fund,

and administered by thePuget Sound Water Quality Authority.

Reprinting financed by proceeds from theFreshwater Aquatic Weeds Account, and

administered by the Department of Ecology.

Text Copyright 1991, Joy P. MichaudIllustrations Copyright 1991, Sandra Noel

To obtain a copy of this document, please contact The Department of Ecology Publications Office at(206) 407-7472 and ask for publication # 94-149. (After January 15, 1995, call (360) 407-7472.)

If you have special accommodation needs, please contact Kitty Gillespie (206) 407-6540, or(206) 407-6006, Telecommunications Device for the Deaf (TDD). (After January 15, 1995, call(360) 407-6006.)

Printed on Recycled Paper with Vegetable-based Inks

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Table of Contents

A Word from the Author v

Acknowledgements vi

Introduction vii

CHAPTER ONE – Who Cares About Monitoring? 1

Different Monitoring Strategies 1Who Monitors What in Puget Sound? 2The Advantages of Citizen Monitoring 4Concerns About Citizen Monitoring 4The Value of Your Efforts 5

CHAPTER TWO – Lakes 6

The Physical Character of Lakes 8Lake Water Quality Parameters 9A Typical Lake Monitoring Program 20Example Lake Monitoring Strategies 22How to Report and Analyze Lake Water Quality Data 23

CHAPTER THREE – Streams 26

The Physical Character of Streams 28Stream Water Quality Parameters 29Pollutant Concentrations Versus Pollutant Loading 37Developing a Stream Monitoring Program 38How to Report and Analyze Stream Water Quality Data 42

CHAPTER FOUR – From the Field to the Lab 45

What Makes Good Data? 45Ground Rules 47Collecting the Sample 48Sampling and Measurement Methods 49

CHAPTER FIVE – Getting a Handle On Hydrology 59

Measuring Stream Flow 59Using a Staff Gage 63Forming a Stage/Discharge Relationship 64Calculating Pollutant Loads 65

Resources and References 66

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A Word from the Author

When I first decided to take up the studyof fresh waters, I envisioned spendinghours along the banks of scenic, gurglingbrooks and north country lakes. Imaginenow my first sampling event. A cheesefactor’s waste system had failed and ahuge quantity of waste had been releasedto a small creek. Our mission was towalk the length of the creek collectingdead fish carcasses, which we placedinto large plastic bags and carried overour backs. Every half-mile we stoppedto collect a water sample. The creekbottom and any protruding sticks orrocks were covered with long, graystrands of algae. The water itself was amilky-gray. It was a still, hot summerday and the odor of rotting fish incombination with the algae added a quiteunpleasant aspect to the occasion.

Since that day I’ve been onsampling expeditions to numerous lakesand streams. Yet, these many years laterI still distinctly remember Scotch Creek.I remember its many curves, its fewpools, and a particularly nice sectionwhere it flowed through a meadow andhad neat, undercut, grassy banksperfectly designed for the needs andwhims of brook trout.

The point is, no matter how many lakesor streams I sample or how spoiled theircondition, I maintain a personal interestin each. Each had its own character andleft a separate impression on mymemory. This is one of the great untoldbenefits of monitoring - it is not anexperience that should be saved for aselect few professionals.

Don’t be put off by those of uswho know the technical jargon and makeit all sound incredibly complex and over-whelming. And don’t be frustrated byother people’s views of the value of yourefforts. Lakes and streams belong to allof us, and we are all equally responsiblefor their protection.

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Acknowledgements

Ibis work was funded through a PublicInformation and Education (PIE) grantfrom the Puget Sound Water QualityAuthority. That really means the work -was funded through our tax dollars.Before that could happen, the citizens ofPuget Sound had to be dedicated enoughto protecting water quality to pay theprice. Chances are if you are interestedenough in water quality to pick up thisguide and read this acknowledgement,you are likely one of those who has sup-ported water quality protection efforts.And you deserve acknowledgement forthis effort.

A number of people volunteeredtheir time and expertise to review thefirst draft of this guide. These peopleprovided excellent comments and ideaswithin a demanding time schedule.These people were: Jean Jacoby, astream and lake ecologist employed byKCM consultants; Dave Hallock and JoeJoy, Water Quality Specialists with theWashington Department of Ecology;Emily Garlich a school teacher with theCity of Shelton; and Ellen Gray with theSnohomish County Council and thePilchuck Audubon Society.

Claire Dyckman, formerly with thePuget Sound Water Quality Authority,was the catalyst who recognized theneed for a guide such as this andencouraged its funding.

Sandy Marvinney produced thelayout using desktop publishingsoftware. She and Sandra Noel, thegraphic artist and designer, workedtogether to produce a handsome,readable document out of the paperscraps and floppy disks sent to them.They worked hard and long to create thisdocument within a short time and stillmanaged the last minute changes withtheir usual calm and proficiency. MarcyMcAuliffe provided ideas and creativesuggestions in addition to rewritingsentences and paragraphs, correctingpunctuation errors and all the other tasksof a technical editor.

Last, thanks to -Sally, Jack, andJean who listened to me, commiseratedwith me, and encouraged me on themany occasions when either one or allthree were necessary.

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IntroductionThe intent of this guide is to introducecitizens in the Puget Sound area to lakeand stream water quality monitoring.The first chapter provides backgroundinformation on who does monitoring inthe Puget Sound region and why, andthen describes some of the advantagesand pitfalls of citizen monitoring.Because lakes and streams are verydifferent systems, and because mostreaders will be interested in monitoringone or the other, each is describedseparately; Chapter Two covers lakes,Chapter Three covers streams. Each ofthese chapters contains an introductionto lake or stream ecology then describesdifferent water quality measurementsand why they are important. ChapterFour provides the necessary practicalinformation on how to collect thesamples and make the water qualitymeasurements, or at least prepare thesamples for later analysis. The lastchapter describes how to take streamflow measurements, which can be animportant part of both lake and streamstudies.

As with all introductions to verycomplex subjects, one of the mostdifficult aspects of producing this guidewas deciding how much information wasenough and how much was too much.For each topic discussed, somecompromise had to be reached. Somereaders will find the guide too detailedand others not detailed enough.Furthermore, by necessity the guidecontains many generalizations that bytheir very nature must then be wrong orinaccurate some of the time. Still, it is agood start. If you find the information istoo detailed in places, skip over it. Ifyou need more information, refer to theresources and references list included atthe end of this guide.

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Chapter One

Who CaresAboutMonitoring?Is there a lake or stream that isespecially important to you? Perhapsone near your home, or where youplayed as a child. Do you wonderwhether it is being properly protectedagainst pollution? Have you noticedany changes in it and wonderedwhether they were a sign ofpollution? Are you concerned aboutwater pollution, yet feel you don’tunderstand enough about it to help?Having a clean, dependable watersupply is important to almost everyaspect of our lives, yet often we feelas though there is little we can do tohelp protect this essential resource.There are things you can do -- one isto become involved in a localvolunteer monitoring program.

Before describing how lakesand streams work - which is integralto understanding how, where, when,and what to monitor - it will help tounderstand the different types ofmonitoring programs and knowabout who is doing what in terms ofwater quality monitoring in the PugetSound area.

Water quality monitoring cantake on many forms. The traditionalmethod of water quality monitoring,where water samples are collectedand analyzed, is the most common.There are other methods forassessing water quality. There is atype of visual monitoring, wherepeople follow the shoreline and notesuch things as the condition of thebank, presence of shorelinevegetation, composition of thestream or lake bottom, and otherphysical characteristics that can beused to predict possible water qualityproblems. An increasingly popularmethod involves recording theabundance and diversity of insectsand other organisms. Since these

organisms each have different levelsof tolerance to pollution, the numberand type present can tell a great dealabout the quality of the water.These two methods are indirect, orqualitative, ways of assessing waterquality. They provide valuableinformation, are less costly than thetraditional method, and can be easilysuited to citizen monitoringprograms. Although this guidedescribes the traditional method ofwater quality monitoring, much ofthe information presented is gearedtoward understanding how lakes andstreams function. This informationwill be beneficial no matter whattype of monitoring program isundertaken.

DifferentMonitoringStrategiesSome of the terms you may hear todescribe traditional water qualitymonitoring program arereconnaissance surveys, baselinesurveys, routine investigations,intensive surveys, ambientmonitoring, and compliancemonitoring. Each survey typereflects different objectives on thepart of the investigator. A few of themajor categories are described hereto provide a general understanding ofhow they may differ.

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Ambient MonitoringThe purpose of an ambientmonitoring program is to describeexisting conditions or long-termtrends in water quality. Many waterquality parameters are influenced bythe change of seasons or by short-term weather patterns. In order todistinguish between short-term“blips” in the data and actual waterquality trends, the parameters need tobe measured at consistent intervalsover a long period of time. Conse-quently, an ambient monitoringprogram usually will involve themonitoring of a few parameters on aroutine basis (every 2 weeks ormonthly) over a number of years.This type of monitoring lends itselfwell to citizen monitoring efforts.Citizens are permanently on hand,often have easy access to themonitoring sites, and are knowledge-able about the project area.

Baseline MonitoringThe purpose of baseline monitoring,as you may have guessed, is todescribe baseline conditions in a lakeor stream. Baseline conditions arethose which exist before some eventthat affects water quality occurs,such as development in thewatershed or addition of an industrialdischarge. Comparing data collectedbefore and after an event is one wayof assessing its impact on waterquality.

It is a fact of human nature thatvery little monitoring occurs in waterbodies before there has been disturb-ance of some kind. Of course,another fact of life is that as thepopulation continues to grow, ourlakes and streams will be furtheraffected. A baseline study on analready polluted stream still providesinformation; in 10 years, you can seewhether the stream is more pollutedor -- because of citizen involvementand watershed protection efforts --less polluted.

Good baseline information isscarce, so there is ample opportunityfor citizens to initiate monitoringprograms of this type. If your locallake or stream appears to be in goodshape, now might be the best time tobegin a baseline monitoring program.

Compliance MonitoringMonitoring designed to assesswhether specific standards orrequirements are being met is calledcompliance or regulatory monitoring.All of the surface waters inWashington State have beenclassified by the Department ofEcology as Class AA, A, B, or C.Each of these classes has a differentset of water quality standards.Monitoring surface waters todetermine whether they meet theirassigned standards is consideredcompliance monitoring.

NOTE: Although the purposeof an ambient monitoring programmay be to look for long-term waterquality trends, the data can bereviewed at any time to determinewhether the water body meets itsdesignated class standards, and socould also be considered compliancemonitoring.

Compliance monitoring ismore commonly used in reference topermit investigations. All industrialor municipal discharges to waters ofthe state must meet specificstandards as defined in their NationalPollutant Discharge EliminationSystem (NPDES) permits. Thedischargers themselves must monitortheir own effluents to ensure they aremeeting their permit requirements.In Washington State, the Departmentof Ecology also is required toperform periodic monitoring of thesame discharges to ensure permitrequirements are met. Due to thelegal aspects associated with thistype of monitoring, such as potentialfines and lawsuits, compliancemonitoring is not well suited forcitizen monitoring.

Who Monitors Whatin Puget SoundMany people wrongly believe thatsomeone somewhere knows abouttheir particular lake or stream, and iswatching out for it. This is not thecase. Most lakes and streams are notmonitored on any regular basis, if atall. There is ample opportunity andneed for citizens to choose a localtarget and begin their own programs-- with or without the involvement ofan agency or organization. Some ofthe agency programs are describedhere to provide an idea of thediversity and extent of water qualitymonitoring in Washington State.

Puget Sound WaterQuality AuthorityThe Puget Sound Water QualityAuthority is responsible for imple-mentation of the Puget Sound Ambi-ent Monitoring Program (PSAMP).This program consists of collectionof data on sediments, biologicalpopulations (e.g., fish and marinemammals), and habitats in additionto water quality type data. Monitor-ing by citizens is a required elementof the PSAMP program and is sup-ported through the Public Involve-ment and Education (PIE) Fund.

Washington Department ofEcologyThe Department of Ecology’sprimary responsibility is to protectthe waters of the State of Washing-ton. Consequently, this agency doesmost of the water quality monitoringin the State. Its surface water sampl-ing programs are described below.

❑ Ambient Monitoring Program:This is a long-term program ofyear-round monitoring. Stationsare primarily located at the mouthsof major rivers throughoutWashington and at a number of keylocations in Puget Sound and in afew coastal bays. Currently, 80freshwater and 35 marine waterstations are monitored.

❑ Compliance MonitoringProgram: The purpose of thisprogram is to ensure that permitholders meet their NPDESpermit requirements. Theemphasis is on direct sampling ofthe discharge (effluent), butsome sampling also is done inthe lake, stream, or marine waterto which the effluent isdischarged. Most discharges arelocated in developed -- urban orindustrial -- sections of largerrivers and streams, consequent-ly, compliance monitoring also isconcentrated in these areas.

❑ Investigative Studies: Everyyear a number of lakes andstreams or portions of streamsare selected for short-terminvestigations that may last fromone week to one year. These,too, occur primarily in waterswhere there are suspectedproblems. Typically 10 to 15 ofthese investigations occur eachyear.

❑ Lake Monitoring: Citizenvolunteer organizationsthroughout Washington Statemonitor their lakes during thesummer months. In 1990,Ecology staff collected samplesat 25 of these lakes twicebetween May and September.The samples were analyzed for awide range of parameters. Thelake program also includesmonitoring of 11 lakes in theCascade mountain range that aresensitive to acid rain.

With the exception of the lakesprogram, the Department of Ecologyitself does not utilize citizenvolunteers in many of its efforts.However, the department providesthe major source of funding to localgovernments and others whopromote the use of citizen volunteers.

Washington Department ofHealthThe Department of Health (previ-ously Department of Social andHealth Services, DSHS) is responsi-ble for monitoring bays and inlets inPuget Sound where shellfish arecollected for commercial or privateuse. Shellfish harvesting is allowedonly in waters that meet stringentfederal water quality standards. It isthe agency’s responsibility to enforcethese standards.

Another component of thesampling program is monitoring theoccurrence of paralytic shellfishpoisoning (PSP). This requiresanalysis of shellfish tissue. Citizenvolunteers are assisting in thismonitoring program by collectingshellfish samples from beachesthroughout Puget Sound.

Local GovernmentLocal governments have becomeincreasingly involved in waterquality monitoring efforts. Somelocal governments have extensiveprograms that have been in existencefor years, while others have smaller,newer programs. Program size issomewhat related to population size,but also is influenced by availabilityof funding, the sources of pollutionof most concern, and the priorities oflocal communities and electedofficials. Consequently, there is awide diversity in the monitoringprograms and the degree to whichcitizens are involved.

TribesMost of the Puget Sound Tribes areintensively involved in water qualityissues. This involvement oftenentails some monitoring efforts. Asis the case with local governments,the extent of water qualitymonitoring varies a good dealbetween tribes, as does the use ofcitizen volunteers.

SAjitpmomedBiea

WatershedManagement PlansDevelopment of watershedmanagement plans is one of therequirements for implement-ation of the Puget Sound WaterQuality Authority’s PugetSound Plan. The watershedplans are formulated by acommittee of local residents forprotection of their watershed.The idea is that by involvinglocal residents the plans willhave local support, will betailored to the particular water-shed, and will be more likely tooffer realistic solutions toproblems. Further, by partici-pating in the planning process, agroup of residents will becomehighly informed about waterquality issues. Each of theplans must include a strategyfor water quality monitoring.Many of the plans developed todate describe monitoringprograms that use citizenvolunteers. These plans arebeing implemented throughlocal government, tribes,Conservation Districts, andother organizations throughgrants from the Department ofEcology. Becoming a memberof one of these WatershedManagement Committees is oneof the best existing means tobecome involved in local issues.

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choolsn increasing number of elementary,

unior, and senior high schoolsnclude environmental studies inheir curriculum, and many of theserograms cover water qualityonitoring. Monitoring sites are

ften located close to the schools;onitoring may occur as a one-time

vent each school year, or may beone throughout the school year.esides being educational, the

nformation collected can be useful,specially if the same site is selectednd monitored year after year.

EnvironmentalOrganizations andCitizen Protection GroupsEnvironmental organizations such asthe National Audubon Society andthe Sierra Club are becomingincreasingly involved in waterquality monitoring. Their localchapters provide a good network forpromoting citizen involvementprojects such as volunteer waterquality monitoring programs. Manycitizen groups also have formed toprotect select areas. Some localexamples include Citizens to SavePuget Sound, Friends of the Snoho-mish Delta, and Save Lake Samma-mish. Many of these organizationsand groups may not currently beinvolved in any monitoring projects,but provide an excellent launchingpoint for such projects.

The Advantages ofCitizen MonitoringThe most tangible benefits of citizenmonitoring relate to convenience andexpense. Sampling programs arealways expensive. Costs are incurredduring sample collection, analysis,and data interpretation. Althoughsome citizen monitoring programsinvolve all three tasks, most focus onsample collection. Citizens whosehomes are adjacent to a lake orstream or within its watershed areavailable to do routine sampling, tobe the daily eyes and ears for thewatershed, and to do extra monitor-ing during periods of concern.

For example, stream orwatershed investigations usually areenhanced by storm event information-- that is, data collected while a stormis in progress. Even something assimple as documenting the height ofthe stream during a storm can behelpful. Since storm events cannotbe scheduled ahead of time, it maybe difficult for agency staff to obtainthese data. Citizens living near thestream are often more able to collectthis valuable information.

From a long-range perspective,the advantage of citizen monitoring

is that it promotes development of acitizenry that is not only educatedabout water quality issues but alsopersonally involved and committed.These people become strong advo-cates for water quality protectionprograms.

You may find that the greatestbenefit is personal satisfaction andenthusiasm. Most of us have child-hood memories of a certain lake orstream we played in. Chances are westill place a high personal value onthat lake or stream. This same type ofpersonal interest develops when youbecome involved in monitoring. Onceyou have muddied your boots in thewater, collected a few samples, andtaken some notes, the stream is nolonger something you drive over onthe way to work, and the lake is nolonger just a place to fish or ski. Theyare instead familiar, interesting, com-plex, and integral parts of your life.

ConcernsAboutCitizenMonitoringAlthough citizens havetaken on smallmonitoring roles for anumber of years, it was only recentlythat their involvement becamewidespread. With this growth hascome bigger roles and more intenseinterest in government actions. Inthe end, this citizen participation canhave nothing but a positive effect onour ability to protect water quality.But in the meantime, a few problemshave arisen, mainly concerningdifferences in expectations betweengovernment agencies and citizenmonitoring groups.

From an agency perspective,citizen monitoring programs can be avaluable asset to their overallsampling program, a source ofunpredictable uncontrollableworkload, or both. By its verynature, citizen monitoring producesan active citizenry that is more likelyto make phone calls, write letters,

and demand action. While thisadvocacy is one of greatest benefitsof citizen monitoring, it also putsresponding agencies in a dilemmasince they usually do not have theresources to respond immediately tothe additional demands. This, inturn, causes frustration and disap-pointment on the part of the citizens.

A second concern is associatedwith agency treatment of the datacollected by citizens. Unless the datacollected by citizens can meet thesame standards and were collectedand analyzed by the same proce-dures as those used by the agency,the citizens’ data set will be treateddifferently. As discussed in thefollowing chapters, there is a myriadof procedures for collecting andanalyzing samples. The procedureselected is dependent upon samplingobjectives, expertise, availableequipment, and, of course, money.

The procedure used determines thequality of the data collected. If lessexacting procedures are used, theresultant data are not bad oruseless, just of lesser quality.

An Analogy ...You may own a dog with many mixedbloodlines -- a mutt. You may claimthat he is the world’s best dog, thesmartest, friendliest, cutest dog ever.And he may be. But, this is a relativecomparison. Your dog is the “best”given what you expect and desire in adog. Someone else may think the“best” dog can only be a purebred witha shelf full of trophies. Both views areright, the problem is that the objectivesare different, so different criteria areused. It doesn’t matter which criteriaare used until the dogs meet. If youmix a mutt with a purebred, you get amutt -- never a purebred. The same istrue for monitoring data. A data setcollected using less stringent methodsmay meet its objectives just as well asa data set collected using the mostexpensive personnel and equipmentavailable meets its objectives.However, once you have mixed thetwo data sets, the quality of theresultant set is defined by the set thatmeets the less stringent standards.

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The answers to thesequestions will determine the typeof monitoring program youdesign, the data quality required,the people who need to beinvolved, and their level ofinvolvement. If your goal hasless to do with water qualityassessment than with convincingagencies or politicians to make achange, then keep the monitoringsimple and concentrate yourefforts in the political arena.

Once you have determinedyour objectives and expectationsfor the project, be sure everyoneinvolved knows what they are.

Data sources that are not directlycomparable because of differences inprocedures cannot be treated equallyin scientific investigations.

These concerns can bealleviated by making yourmonitoring objectives very clear atthe onset. What is the purpose ofyour study? What do you want toknow? What do you hope toaccomplish? What would you likethe final outcome to be?

How will the data be used byyou or your group? Will you want topresent the data to an agency or deci-sion makers? Who will interpret thedata? What are you expecting fromagencies or other organizations?What are you expecting from localpoliticians and decision makers?

If you are expecting agencyinvolvement or hoping that anagency will at least, look at the datafor you (not a small task) then letthem know. Ask for their assistance.Be sure the other citizens alsounderstand the objectives. Beprepared to remind everyonefrequently of what the objectives are.It’s exciting to collect data ordiscover new problems, but easy toforget that your chosen sampling oranalysis procedures place limits onthe use of your data.

The Value ofYour Efforts

acceptance of your data by an agencyor organization does not necessarilygive it any more credibility. And itcertainly doesn’t guarantee that thedata will be used to make decisionsor take actions. It is just as valuableto monitor for the purpose oflearning about a stream or lake as itis to monitor for the purpose ofidentifying problems and demandingchange.

Last, the role of citizenmonitoring is changing. Throughoutthe country, citizens are taking onmore responsibility for monitoringand protecting their environment.They are biting off bigger and morecomplex chunks as they see the needfor their involvement increase. Therole of volunteers is destined tobecome an increasingly valuablecomponent of future environmentalmonitoring projects.

Do not let all this information aboutdata quality, analysis techniques,and agency support deter you. It isprovided to help alleviate frustra-tions and misunderstandings. Thepoint is, citizen volunteers cancollect high quality data, but it isexpensive, requires a strongtraining program, and may not do abetter job of meeting yourmonitoring objectives.

Remember, if data collectedby you or your group are notaccepted in the same way as datacollected by professionals, it isNOT because citizens collected it,but because of the procedures andmethods used. Further, the

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Chapter Two

LakesLakesLakesLakesLakes are great. They provide somuch in the way of recreation. Visitone on a hot summer day; fishing,boating, and swimming are just a fewof the activities you are likely to see.Lakes and their shorelines alsoprovide important wildlife habitat, forboth aquatic and terrestrial animals.Lakes even help protect water quality.Eroded sediments, debris, and otherpollutants washed from watershedsare deposited in lakes by inflowingstreams so that outflowing streamsoften carry less of these pollutants.

Eventually lakes fill in with thematerial carried to them by thestreams. Even without humaninfluence, a once deep, clear lake willbecome shallow, weed filled, andgreen from algae. Over time, it willbecome a pond, then a marsh, andfinally a forest. This natural agingprocess in lakes – which is actuallybased on increased growth andproductivity – is call eutrophication.

Plankton(zooplankton

andphytoplankton

PhotosynthesisThe first step in the foodchain, where plantsconvert sunlight intochemical energy andorganic matter.

RespirationThe process used by bothplants and animals whereoxygen is used tobreakdown food andcreate energy.

DecompositonChemically causedbreakdown of food andorganic matter bydecomposers – occurswith and without oxygen.

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ProducersOrganisms that build uporganic matter.

Primary ProducersAlgae (microscopic)Plants (macroscopic)

SecondaryProducers

ZooplanktonPlant eating fish

We even have terms to describe therelative age and productive state of alake. A young lake, with lowproductivity, is termed oligotrophic,a middle-aged lake is mesotrophic,and an older lake that is highlyenriched is called eutrophic.Normally, this aging process takeshundreds to thousands of years. Inlakes affected by human actions, thechanges can occur more quickly –-sometimes change that wouldnormally take centuries occurs overone person’s lifetime.

Lake water quality monitoringcan be used to determine the age orlevel of enrichment of a lake, and thedegree to which it has been affectedby development. This chapterprovides introductory information onlake characteristics and their effectson some typical lake samplingparameters, along with guidelines onhow to design a lake monitoring planand how to analyze and interpret thedata you have collected.

ConsumersOrganisms that breakdown organic matter.

Detritus EatersSnailsInsectsWorms

DecomposersBacteriaFungi

BenthicMicroorganisms(bacteria and fungi)

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The PhysicalCharacter ofLakesNo two lakes are exactly alike. They maydiffer in size, depth, number and size ofinflowing and outflowing streams, andshoreline configuration. Each of thesephysical factors in turn influences the lakecharacter. Some characteristics affectedinclude the species of fish in the lake, thelikelihood the shoreline will be weedcovered or that algae will turn the lakegreen in the summer, and whether the lakewater is warm enough for swimming orsuitable as a drinking water source.Physical factors also influence decisionsabout sampling locations, water qualitymonitoring parameters, and how tointerpret the data collected.

Lake DepthIn a deep lake, water near the surface may bevery different physically, chemically, andbiologically from water near the bottom. Thetop portion of the lake is mixed by the windand warmed by the sun. Because of theavailable light and warmer temperatures,many organisms live there. The moreorganisms there are photosynthesizing,breathing, eating, and growing, the higher thegrowth rate or productivity. The bottomportion of a deep lake receives little or nolight. The water is colder; it is not mixed bywind; and decay of dead organic matter,called decomposition, is the main physical,biological, and chemical activity.

A shallow lake is more likely to behomogeneous – the same from top tobottom. The water is well mixed by wind,and physical characteristics such astemperature and oxygen vary little withdepth. Because sunlight reaches all theway to the lake bottom, photosynthesis andgrowth occur throughout the water column.As in a deep lake, decomposition in ashallow lake is higher near the bottom thanthe top for the simple reason that whenplants and animals die they sink. It also islikely that a larger portion of the water in ashallow lake is influenced by sunlight, andthat photosynthesis and growth areproportionately higher.

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Lake SizeLakes range in size from little morethan ponds to reservoirs over 50 mileslong. As you can imagine, a pond anda reservoir are quite different systems.Although there are few hard and fastrules that govern lake size compari-sons, the size does affect a number ofimportant relationships. Someexamples are the ratio of lake surfacearea to miles of shoreline, thepercentage of the total water volumethat is influenced by sunlight, and theratio of the size of the watershed tosize of the lake. These relationshipsaffect how lakes function. A smalllake with a greater ration of shorelineto water volume may be moresusceptible to damage from shorelineor watershed activities.

Inflowsand OutflowsThe size and number of inflowing andoutflowing streams in a lakedetermine how long it takes for a dropof water entering a lake to leave it – aprocess called flushing. Some lakesflush in days while other take years.You may know of a lake that isactually just a widening in the river,where the inflowing streamconstitutes a large portion of the totallake volume. Such a lake flushesrelatively rapidly. In other lakes, theinflow is not even visible; all of itcomes from groundwater seeps andprecipitation. In the former case,quality of the incoming water is thesingle most important factorinfluencing lake water quality. In thelatter case, internal lake processes andgroundwater determine water quality.In terms of pollution, the more rapidlythe lake flushes the better becausepollutants are flushed from the lakebefore they can cause too muchdamage. A more rapidly flushinglake also may respond sooner topollution control activities in thewatershed.

ShorelineConfigurationAnother important lake characteristic isthe shape of the shoreline. Shallowbays and inlets tend to be warmer andmore productive than other parts of alake. A lake with many of thesefeatures will be different than, say, abowl-shaped lake with a smooth, roundshoreline. This difference becomesimportant when setting up a monitoringplan. In the latter case, one mid-lakesampling station may adequatelyrepresent the lake. In a lake stronglyinfluenced by shallow bays or inlets,water quality is likely to be greatlyaffected by location, and multiplesampling stations probably will benecessary.

Lake WaterQualityParametersThe parameters that are most frequentlytested in lake water are discussed in thissection. These include temperature,dissolved oxygen, pH, Secchi diskdepth, nutrients, total suspected solidsand turbidity, chloraphyll a, and fecalcoliform bacteria. For each parameter,you will learn why it is important, whymeasured values differ over time, andhow pollution could affect the measure-ment. Since most of these parametersare related to each other, the relation-ship is described twice, once under thediscussion of each parameter. Forexample, there is a relationship betweentemperature and dissolved oxygen.This relationship is described in boththe discussion on temperature and thediscussion on dissolved oxygen. If youfind it difficult to understand thediscussion under one parameter, moveon to the next; with luck you will findthe next discussion helps clarify thefirst. Chapter Four describes thedifferent methods for analysis of eachparameter.

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TemperatureWhy Is It Important?Temperature exerts a major influenceon biological activity and growth. To apoint, the higher the water temperature,the greater the biological activity. Tern-perature also governs the kinds oforganisms that can live in your lake.Fish, insects, zooplankton, phyto-plankton, and other aquatic species allhave a preferred temperature range. Astemperatures get too far above or belowthis preferred range, the number ofindividuals of the species decreasesuntil finally there are none.

Temperature is also importantbecause of its influence on waterchemistry. The rate of chemicalreactions generally increases at highertemperature, which in turn affectsbiological activity. An importantexample of the effects of temperatureon water chemistry is its impact onoxygen. Warm water holds lessoxygen than cool water, so it may besaturated with oxygen but still notcontain enough for survival of aquaticlife. Some compounds are also moretoxic to aquatic life at highertemperatures.

Reasons forNatural VariationThe most obvious reason fortemperature change in lakes is thechange in seasonal air temperature.Daily variation also may occur,especially in the surface layers, whichare warmed during the day and cooledat night.

In deeper lakes during summer,the water separates into layers ofdistinctly different temperature. Thisprocess is called thermalstratification. The surface water iswarmed by the sun, but the bottom ofthe lake remains cold. You may haveexperienced this difference whendiving into a lake. Once the strati-fication develops, it tends to persistuntil the air temperature cools again infall. Because the layers don’t mix,they develop different physical andchemical characteristics. Forexample, dissolved oxygen concen-tration, pH, nutrient concentrations,and species of aquatic life in the upperlayer can be quite different from thosein the lower layer. It is almost likehaving two separate lakes.

When the surface water coolsagain in the fall to about the sametemperature as the lower water, thestratification is lost and the layersmix. This process is called fallturnover. (A similar process also mayoccur during the spring as coldersurface waters warm to the tempera-ture of bottom waters and the lakemixes. This is called spring turnover.)The lake mixing associated with aturnover often corresponds with alarge increase in turbidity. Watch forthis change in your lake this fall.

Because the sun can heat a greaterproportion of the water in a shallowlake than in a deep lake, a shallowlake may warm up faster and to ahigher temperature. Lake temperaturealso is affected by the size andtemperature of inflows (e.g., a glacialfed stream of springs or a lowlandcreek) and by how quickly waterflushes through the lake. Even ashallow lake may remain cool if fedby a comparatively large, cold stream.

Expected Impactof PollutionThermal pollution (artificially hightemperatures) almost always occurs asa result of discharge of municipal orindustrial effluents. Except in verylarge lakes, it is rare to have aneffluent discharge. In urban areas,runoff that flows over hot asphalt andconcrete pavement before entering alake will be artificially heated andcould cause lake warming, although inmost cases this impact is too small tobe measured. Consequently, direct,measurable thermal pollution is notcommon. However, since streams andrivers constitute a major source offlow to some lakes, these lakes maybe indirectly impacted by thermalpollution via inflows,

Temperature is reported'indegrees on the Celsius temperaturescale (oC). There is no numericalState water quality standard for laketemperatures. The standard readsthere will be “no measurable changefrom natural conditions.” Tempera-tures for three Western Washingtonlakes are shown below to provide

State Water QualityStandardsWater Quality standards havebeen established for all surfacewaters in Washington State. Alllakes are grouped together in oneclass – Lake Class – and mustmeet the requirements set forthfor this class by the WashingtonAdministrative Code (WAC)173-201-045. The State standardis described for each parameterdiscussed in this chapter.

Temperature (oC) Measured in the Top Layer (Epilimnion) andBottom Layer (Hypolimnion) of Three Western Washington Lakes

In June and September 1989.

SummitLake

BlackmanLake

BlackLake

Top Bot Top Bot Top BotJune 19.7 7.5 21.4 11.8 23.0 13.6September 20.0 8.0 19.1 15.9 21.1 17.2

Revised from: Brower, C. and W. Kendra. Water Quality Survey of 25 “citizen-Volunteer” Lakes from Washington State. Olympia, WA. Washington Departmentof Ecology, March 1990.

examples of the range you may expectto measure. The three lakes shownrepresent an oligotrophic lake(Summit Lake, Thurston Co.), amesotrophic lake (Blackmans Lake,Snohomish Co.) and a eutrophic lake(Black Lake, Thurston Co.). Thesesame lakes are used throughout thischapter to provide values forcomparison purposes.

Dissolved OxygenWhy Is It Important?Like terrestrial animals, fish and otheraquatic organisms need oxygen tolive. As water moves past their gills(or other breathing apparatus),microscopic bubbles of oxygen gas inthe water, called dissolved oxygen(DO), are transferred from the waterto their blood. Like any other gasdiffusion process, the transfer isefficient only above certainconcentrations. In other words,oxygen can be present in the water,but at too low a concentration tosustain aquatic life. Oxygen also isneeded for many chemical reactionsthat are important to lake functioning.

Reasons forNatural VariationOxygen is produced during photosyn-thesis and consumed during respira-tion and decomposition. Because itrequires light, photosynthesis occursonly during daylight hours.Respiration and decomposition, on theother hand, occur 24 hours a day.This difference alone can account forlarge daily variations in DOconcentrations. During the night,when photosynthesis cannot counter-balance the loss of oxygen throughrespiration and decomposition, DOconcentrations steadily decline. Theyare lowest just before dawn, whenphotosynthesis resumes.

Other sources of oxygen includethe air and inflowing streams.Oxygen concentrations are muchhigher in air, which is about 21percent oxygen, than in water, whichis a tiny fraction of 1 percent oxygen.Where the air and water meet, thistremendous difference in concentra-tion causes oxygen molecules in theair to dissolve into the water. Moreoxygen dissolves into water whenwind stirs the water, as the wavescreate more surface area, morediffusion can occur. A similar processhappens when you add sugar to a cupof coffee - the sugar dissolves. Itdissolves more quickly, however,when you stir the coffee. Rivers andstreams also deliver oxygen to lakes,especially if they are turbulent andthus well aerated when they reach thelake. Consequently, natural variationof DO concentration in lakes is alsocaused by weather and changes ininflowing streams (e.g., higher, moreturbulent flow during winter months).

Another physical process thataffects DO concentrations is therelationship between water tempera-ture and gas saturation. Cold watercan hold more gas -- that is DO -- thanwarmer water. Warmer waterbecomes “saturated” more easily withoxygen. As water becomes warmer itcan hold less and less DO. So, duringthe summer months or in the warmertop portion of a lake, the total amountof oxygen present may be limited bytemperature.

tionlakeoccuwhephois grwhedecolakeplenpracthe by tmaythe

Putting the Squeeze on Fish . . .Mid-summer, when strong thermalstratification develops in a lake, maybe a very hard time for fish. Waternear the surface of the lake – theepilimnion – is too warm for them,while water near the bottom – thehypolimnion – has too little oxygen.Conditions may become especiallyserious during a spate of hot, calmweather, resulting in the loss of manyfish. You may have heard aboutsummertime fish kills in local lakesthat likely result from this problem.

The Relationship BetweenTemperature andOxygen Solubility

Temperature(oC)

OxygenSolubility

(mg/L) 0 14.6 5 12.8 10 11.3 15 10.2 20 9.2 25 8.6100 boiling 0

11

Dissolved oxygen concentra-s may change dramatically with depth. Oxygen productionrs in the top portion of a lake,re sunlight drives the engines oftosynthesis. Oxygen consumptioneatest near the bottom of a lake,re sunken organic mattermposes. In deeper, stratified,s, this difference may be acute --ty of oxygen near the top buttically none near the bottom: Iflake is shallow and easily mixedhe wind, the DO concentration be fairly , consistent throughoutwater column.

12

Seasonal changes also affectdissolved oxygen concentrations.Warmer temperatures during summerspeed up the rates of photosynthesisand decomposition. When all theplants die at the end of the growingseason, their decomposition results inheavy oxygen consumption otherseasonal events, such as changes inlake water levels, volume of inflowsand outflows, and presence of icecover, also cause natural variation inDO concentrations.

Expected Impactof PollutionTo the degree that pollution contri-butes oxygen-demanding organicmatter (like sewage or lawn clippings)or nutrients that stimulate growth oforganic matter, pollution causes adecrease in average DO concen-trations. If the organic matter isformed in the lake, for example byalgae growth, at least some oxygen is

produced during growth to offset theeventual loss of oxygen duringdecomposition. However, in lakeswhere a large portion of the organicmatter is brought in from outside thelake, the balance between oxygenproduction and oxygen consumptionbecomes skewed and low DO maybecome even more of a problem.

pHWhy Is It ImportantThe pH of a sample of water is ameasure of the concentration ofhydrogen ions. The term pH wasderived from the manner in which thehydrogen ion concentration iscalculated – it is the negativelogarithm of the hydrogen ion (H+)concentration. What this means tothose of us who are not mathema-ticians is that at higher pH, there arefewer free hydrogen ions, and that achange of one pH unit reflects atenfold change in the concentration ofthe hydrogen ion. For example, thereare 10 times as many hydrogen ionsavailable at a pH of 7 than at a pH of8. The pH scale ranges from 0 to 14.A pH of 7 is considered to be neutral.Substances with pH less than 7 areacidic; substances with pH greaterthan 7 are basic.

Dissolved Oxygen Concentrations (mg/L) Measured in theTop Layer (Epilimnion) and Bottom layer (Hypolimnion)

of Three Lakes in June and September 1989.

SummitLake

BlackmanLake

BlackLake

Top Bot Top Bot Top BotJune 9.7 6.3 10.3 0.4 9.8 2.0September 11.8 1.6 8.9 0.2 __ 0.1

13

The pH of water determines thesolubility (amount that can bedissolved in the water) and biologicalavailability (amount that can beutilized by aquatic life) of chemicalconstituents such as nutrients(phosphorus, nitrogen, and carbon)and heavy metals (lead, copper,cadmium, etc.). For example, inaddition to affecting how much andwhat form of phosphorus is mostabundant in the water, pH alsodetermines whether aquatic life canuse it. In the case of heavy metals, thedegree to which they are solubledetermines their toxicity. Metals tendto be more toxic at lower pH becausethey are more soluble.

Reasons forNatural VariationPhotosynthesis uses up hydrogenmolecules, which causes theconcentration of hydrogen ions todecrease and therefore the pH toincrease. For this reason, pH may behigher during daylight hours andduring the growing season, whenphotosynthesis is at a maximum.Respiration and decompositionprocesses lower pH. Like dissolvedoxygen concentrations, pH maychange with depth in a lake, due againto changes in photosynthesis and otherchemical reactions.

Fortunately, lake water iscomplex; it is full of chemical “shockabsorbers” that prevent major changesin pH. Small or localized changes inpH are quickly modified by variouschemical reactions, so little or nochange may be measured. This abilityto resist change in pH is calledbuffering capacity. Not only does thebuffering capacity control would-belocalized changes in pH, it controlsthe overall range of pH change undernatural conditions. The pH scale maygo from 0 to 14, but the pH of naturalwaters hovers between 6.5 and 8.5.

Expected Impactof PollutionWhen pollution results in higherproductivity (e.g., from increasedtemperature or excess nutrients), pHlevels increase, as allowed by thebuffering capacity of the lake.Although these small changes in pHare not likely to have a direct impacton aquatic life, they greatly influencethe availability and solubility of allchemical forms in the lake and mayaggravate nutrient problems. Forexample, a change in pH may increasethe solubility of phosphorus, makingit more available for plant growth andresulting in a greater long-termdemand for dissolved oxygen.

Values for pH are reported instandard pH units, usually to one ortwo decimal places depending uponthe accuracy of the equipment used.Since pH represents the negativelogarithm of a number, it is notmathematically correct to calculatesimple averages or other summarystatistics. Instead, pH should bereported as a median and range ofvalues. There is no numerical Statewater quality standard for pH in lakes.The standard reads there will be “nomeasurable change from naturalconditions.” (A pH of 5-6 or lowerhas been found to be directly toxic tofish, according to the EPA.)

Generally, during the summermonths in the upper portion of aproductive or eutrophic lake, pH willrange between 7.5 and 8.5. In the

bottom of the lake or in lessproductive lakes, pH will be lower,6.5 to 7.5 perhaps. This is a verygeneral statement to provide anexample of the differences you mightmeasure.

Secchi Disk DepthWhy Is It Important?A Secchi disk is a circular platedivided into quarters paintedalternately black and white. The diskis attached to a rope and lowered intothe water until it is no longer visible.Secchi disk depth, then, is a measureof water clarity. Higher Secchireadings mean more rope was let outbefore the disk disappeared from sightand indicates clearer water. Lowerreadings indicate turbid or coloredwater. Clear water lets light penetratemore deeply into the lake than doesmurky water. This light allowsphotosynthesis to occur and oxygen tobe produced. The rule of thumb isthat light can penetrate to a depth of1.7 times the Secchi disk depth.

Clarity is affected by algae, soilparticles, and other materialssuspended in the water. However,Secchi disk depth is primarily used asan indicator of algal abundance andgeneral lake productivity. Although itis only an indicator, Secchi disk depthis the simplest and one of the mosteffective tools for estimating a lake’sproductivity.

Reasons for NaturalVariationSecchi disk readings vary seasonallywith changes in photosynthesis and,therefore, algal growth. In most lakes,Secchi disk readings begin to decreasein the spring, with warmertemperature and increased growth,and continue decreasing until algalgrowth peaks in the summer. Ascooler weather sets in and growthdecreases, Secchi disk readingsincrease again. (However, coolerweather often means more wind. In ashallow lake, the improved clarityfrom decreased algal growth may be

The Case of Acid RainAs important exception to thebuffering of pH changes in lakes isthe case of lakes affected by acidrain. Lakes that have received toomuch rain with a low pH (acidrain), lose their buffering capacity.At a certain point, it takes only asmall bit of rain for the pH tochange. After that point, changeoccurs relatively quickly. Acidrain is not considered to be asignificant problem in the PugetSound lowlands.

14

partly offset by an increase inconcentration of sediments mixed intothe water column by wind.) In lakesthat thermally stratify, Secchi diskreadings may decrease again with fallturnover. As the surface water cools,the thermal stratification created insummer weakens and the lake mixes.The nutrients thus released from thebottom layer of water may cause a fallalgae bloom and the resultant decreasein Secchi disk reading.

Rainstorms also may affectreadings. Erosion from rainfall,runoff, and high stream velocities mayresult in higher concentrations ofsuspended particles in inflowingstreams and therefore decreases inSecchi disk readings. On the otherhand, temperature and volume of theincoming water may be sufficient todilute the lake with cooler, clearerwater and reduce algal growth rates.

Both clearer water and lower growthrates would result in increased Secchidisk readings.

The natural color of the wateralso affects the readings. In mostlakes, the impact of color may beinsignificant. But some lakes arehighly colored. Lakes stronglyinfluenced by bogs, for example, areoften a very dark brown and have lowSecchi readings even though they mayhave few algae.

Expected Impactof PollutionPollution tends to reduce waterclarity. Watershed development andpoor land use practices causeincreases in erosion, organic matter,and nutrients, all of which causeincreases in suspended particulatesand algae growth.

Secchi disk depth is usuallyreported in feet to the nearest tenth ofa foot, or meters to the nearest tenth ofa meter. Secchi disk depths for threeWestern Washington lakes are shownhere to provide examples of the rangeyou may expect to measure, There isno State water quality standard forSecchi depth.

Secchi disk readings can beused to determine a lake’s trophicstatus. Though trophic status is notrelated to any water quality standard,it is a mechanism for “rating” a lake’sproductive state. Information oncalculating trophic status is includedin the interpretation section at the endof this chapter.

NutrientConcentrationsWhy Are They Important?Nutrients in lakes serve the samebasic functions as nutrients in agarden. They are essential for growth.In a garden, growth and productivityare considered beneficial, but this isnot necessarily so in a lake. Theadditional algae and other plant

JuneSeptembe

Secchi Disk Readings (meters)Taken in Three Lakes

in June and September 1989.Summit

LakeBlackmans

LakeBlack Lake

7.0 2.9 2.3r 6.8 3.7 0.9

growth allowed by the nutrients maybe beneficial up to a point, but mayeasily become a nuisance.

15

The main nutrients of concernare phosphorus and nitrogen. Bothelements are measured in severalforms. Phosphorus can be measuredas total phosphorus (TP) or as solublereactive phosphate (SRP). SRP is alsosometimes called phosphate (PO4) ororthophosphate (ortho-P). SRPrepresents the fraction of TP that isavailable to organisms for growth.

Nitrogen can be measured astotal nitrogen (TN), total Kjeldahlnitrogen (TYN),,nitrate-nitrogen(NO), nitrite-nitrogen (NO2) [these areusually measured.as nitrate-nitrite-nitrogen (NO3- N02)], or ammonia-nitrogen (NH). TN is similar to TPand is used to represent the totalamount of nitrogen in a sample. TKNrepresents the fraction of TN that is-unavailable, for growth or bound up inorganic form; it also includes NH4.The remaining fractions, NO3-NO2and NH4 represent bioavailable formsof nitrogen. If they are summed, theycan be compared to the SRP fractionof phosphorus.

One chemical form of anelement can be converted intoanother. The conditions under whichthe conversion occurs are influencedby many factors, such as, pH,temperature, oxygen concentration,and biological activity.

The total concentration of anutrient (e.g., TP or TN) is notnecessarily the most usefulmeasurement. For example, if asample is analyzed for TP, all formsof the element are measured,including the phosphorus “locked up”in biological tissue and insolublemineral particles. It may be moreuseful to know the concentration ofphosphorus that is actually availablefor growth. SRP better reflectsbioavailability.

Although there are manydifferent forms of nutrients that can bemeasured, there are only threecommonly used combinations. Theyare (1) measure all forms of bothelements -- TP, SRP,.TN, NO3-NO2,NH4; (2) measure only total nutrients -TP and TN; or (3) measure onlyavailable nutrients -- SRP and NO3-NO2 and NH4. (In the first example,

TKN could be measured instead ofTN. Depending upon which form ismeasured, the other can be estimatedby difference.)

Reasons forNatural VariationThe concentration of nutrients and theforms they are found in changecontinually. How and why theychange is a very complex field ofstudy. The total input of nutrientsvaries through time, depending uponland use and other factors. During thesummer, nutrient input may increasedue to fertilization of cropland, lawns,and gardens. During the winter, highrainfall causes increased washoff oforganic matter such as leaves, twigs,grass, and other debris. Becausedecomposition of this organic matterreleases nutrients, it constitutes animportant source of nutrient loading.

Whether the increase in totalnutrient concentrations results inhigher available nutrientconcentrations, and therefore animmediate increase in growth orproductivity, depends upon theoriginal form of the nutrient andphysical conditions. If nutrients enter

as organic matter that first needs to bedecomposed before it can be utilizedfor growth, temperature becomesimportant because of its effect on therate of decomposition. (Duringwarmer months, nutrients entering thesystem as intact organic matter wouldbe decomposed relatively quickly ascompared with cold, wet-weathermonths when decomposition is slow.)

These dynamics are furthercomplicated by the fact that increasedgrowth leads to greater numbers oforganisms, which need even morenutrients. So, as nutrients becomeavailable they are immediatelyutilized. In this case, an increase intotal nutrients would not be reflectedby any measurable increase inavailable nutrient fractions. In short,clear or simple relationships betweenincreases in organic matter or othersources of nutrients and resultantincreases in either total or availablenutrient concentrations becomeobscure.

Nutrient concentrations alsomay vary with depth in a lake. Nearthe top of the lake, where lightstimulates algae growth, total nutrientconcentrations may be higher thanthose deeper in the lake. These high

16

total concentrations reflect theincreased concentration of organicmatter -- algae. But because theorganisms are utilizing most of thenutrients that are produced, availablenutrient concentrations may be low.Since decomposition of organicmatter -- formation of availablenutrients from total nutrients occurs toa larger extent near the bottom of alake, available nutrient concentrationsmay be higher at depth.

Expected Impactof PollutionMost sources of pollution to lakescontribute nutrients in one form oranother. These sources includestormwater runoff, which may carryfertilizers from lawns and cropland aswell as organic matter such as leaves,grass, and insects; waste productsfrom farm animals and domestic pets;failing lakeside septic systems; andeffluent from industrial and municipalwastewater treatment plants. As thenumber or size of pollutant sourcesincreases, average nutrientconcentrations also increase.

Nutrient Concentrations (µg/L) Measured in the Top Layer (Epilimnion)and Bottom Layer (Hypolimnion) of Three Lakes in September 1989.

SummitLake

BlackmanLake

BlackLake

Top Bot Top Bot Top BotTP 6 12 22 35 46 146SRP 5 5 9 4 11 75TN 150 170 440 420 750 490NO3-NO2 3 10 3 3 3 --NH4 5 5 18 9 5 168

Nutrient concentrations arereported in units of milligrams ofnutrient per liter of water -- mg/L, ormicrograms per liter of water - µg/L.Milligrams per liter is equivalent toparts per million (ppm); microgramsper liter is equivalent to parts perbillion (ppb). There is no State waterquality standard for nutrients.Nutrient concentrations for threeWestern Washington lakes are shownabove to provide examples of therange you may expect to measure.

Total phosphorusconcentrations can be used todetermine a lake’s trophic status.

Though trophic status is not related toany water quality standard, it is amechanism for “rating” a lake’sproductive state. Information oncalculating trophic status is includedin the interpretation section at the endof this chapter.

Total SuspendedSolids and TurbidityWhy Is It Important?Total suspended solids (TSS) concen-trations and turbidity both indicate theamount of solids suspended in thewater, whether mineral (e.g., soilparticles) or organic (e.g., algae).However, the TSS test measures anactual weight of material per volumeof water, while turbidity measures theamount of light scattered from a watersample (more suspended particlescause greater scattering). Thisdifference becomes important whentrying to calculate total quantities ofmaterial within or entering a lake.Such calculations are possible withTSS values, but not with turbidityreadings.

High concentrations ofparticulate matter affect lightpenetration and productivity,recreational values, and habitatquality, and cause lakes to fill infaster. Particles also provideattachment places for other pollutants,notably metals and bacteria.

Reasons forNatural VariationTSS and turbidity values vary for twomain reasons -- one physical, the otherbiological. Heavy rains and fast-moving water are erosive. They canpick up and carry enough dirt anddebris to make even an unpollutedinflowing stream look muddy. So,heavy rainfall may cause higher TSSconcentrations or turbidity, especiallywhere the stream flows into the lake.In lakes, the most important reason forvariation in these parameters is causedby seasonal changes in algae growth.Warm temperatures, prolongeddaylight, and release of nutrients fromdecomposition may cause algaeblooms that increase turbidity or TSSconcentrations.

Expected Impactof PollutionPollution or general human activitiesusually result in higher TSSconcentrations or turbidity. Forexample, loss of vegetation due todevelopment exposes more soil toerosion, allows more runoff to form,and simultaneously reduces thewatershed’s ability to filter thenutrients and organic matter fromrunoff before it reaches the inflowingstreams. Although much of theparticulate matter may settle to thelake bottom, the addition of nutrientswill eventually cause increased algaegrowth.

TS S concentrations are reported inunits of milligrams of suspendedsolids per liter of water -- mg/LTurbidity is reported as nephelometric(NTU), or Jackson turbidity units(JTU), depending on the instrumentused to perform the measurement.The State water quality standard isbased on turbidity as measured by anephelometer. The standard states,“turbidity shall not exceed 5 NTUover background coniditions.”Turbidity measurements for threeWestern Washington lakes are shownhere for comparison purposes. TSSmeasurements are not available.

Chlorophyll aWhy Is It Important?Chlorophyll is the green pigment inplants that allows them to createenergy from light -- to photo-synthesize. By measuringchlorophyll, you are indirectlymeasuring the amount ofphotosynthesizing plants found in asample. In a lake water sample, theseplants would be algae orphytoplankton. Chlorophyll is ameasure of all green pigmentswhether they are active (alive) orinactive (dead). Chlorophyll a is ameasure of the portion of the pigmentthat is still active; that is, the portionthat was still actively respiring andphotosynthesizing at the time ofsampling.

As described in the previousdiscussions on DO, pH, nutrients, and

T

JuneSeptembe

Turbidity (NTUs) Measured in theop Layer (Epilimnion) of Three Lakes

in June and September 1989.Summit

LakeBlackmans

LakeBlackLake

0.8 0.8 1.7r 0.7 1.6 12.5

17

Secchi disk depth, the amount of algaefound in a lake greatly affects thelake’s physical, chemical, andbiological makeup. Algae produceoxygen during daylight hours but useup oxygen during the night and againwhen they die and decay.

18

Decomposition of algae also causesthe release of nutrients to the lake,which may allow more algae to grow.Their processes of photosynthesis andrespiration cause changes in lake pH,and the presence of algae in the watercolumn is the main factor affectingSecchi disk readings. Algae, ofcourse, also can cause aestheticproblems in a lake; a green “scum,”swimmers itch, and rotting scent arecommon problems associated withhigh algae concentrations.

Reasons forNatural VariationSunlight, temperature, nutrients, andwind all affect algae numbers and,therefore chlorophyll a concentration.During the spring when water beginsto warm, the days are sunnier, andnutrients are still plentiful, the firstoutbreak or “bloom” of algae mayoccur. As the days becomeincreasingly warmer and sunnier,algae will continue to grow; however,they may soon outgrow the availablesupply of nutrients. Consequently, thetotal amount of algae growth may be -limited.

Wind also can impact algaepopulations. A good strong wind maymix the lake, causing an immediatedecrease in algae concentrations asthey become mixed throughout thewater column. On the other hand, thewind also may cause a release ofnutrients into the lake system bystirring up nutrient-laden bottomsediments. Then, after the wind diesdown, the number of algae and thechlorophyll concentration mayincrease.

Mof T

JuneSeptem

Algae ToxicitySome algae produce a poisonous toxin.Typically, the amount of toxin producedis too small to have a serious impact.However, if populations of these algaeget very dense, the concentration of thetoxin can become seriously high. Dogsand farm animals have been known todie from drinking water that containedtoo many of these algae and their toxin.The algae of concern in this case is agroup called the “blue-green” – namedafter their particular pigment color.Sometimes, you can identify a “bloom”of blue-greens in your lake or pond bythe oily, bluish-green sheen theyproduce in the water.

As summer turns to fall andtemperature and sunlight decrease,algae concentrations will decrease aswell. Often, in deeper lakes wheretemperature stratification has occurred(see discussion on temperature, page10), there will be a fall algae bloomwhen the lake mixes again andnutrients are released to the entirewater column.

Algae populations, andtherefore chlorophyll a concentra-tions, vary greatly with lake depth.Algae must stay within the top portionof the lake where there is sunlight tobe able to photosynthesize and stayalive. As they sink below the sunlitportion of the lake, they die.Therefore, few live algae (as mea-sured by chlorophyll a) are found atgreater depths. Some algae, notablyblue-greens, have internal “flotationdevices” that allow them to regulatetheir depth and so remain within thetop portion of the lake tophotosynthesize and reproduce.

Expected Impactof PollutionAs previously described, the mostcommon concern associated withpollution or development of a lake’swatershed is the increase in nutrientsto the lake. Since the lack o fnutrients is often what limits thenumber of algae that can grow in alake, the increase in nutrients causedby pollution usually results in morealgae. The populations will continueto increase, causing the aestheticproblems described above.

Chlorophyll a is reported inµg/L. There is no State water qualitystandard for chlorophyll a.Chlorophyll a concentrations for threeWestern Washington lakes are shownbelow to provide examples of therange you may expect to measure.

Chlorophyll a concentrationscan be used to determine a lake’strophic status. Though trophic statusis not related to any water qualitystandard, it is a mechanism for“rating” a lake’s productive state.Information on calculating trophicstatus is included in the interpretationsection at the end of this chapter.

Chlorophyll a Concentrations (µg/L)easured in the Top Layer (Epilimnion)hree Lakes in June and September 1989.

SummitLake

BlackmansLake

BlackLake

1.5 3.3 7.6ber 1.5 3.9 56.2

Fecal ColiformBacteriaConcentrationsWhy Is It Important?Fecal coliform bacteria aremicroscopic animals that live in theintestines of warm-blooded animals.They also live in the waste material orfeces excreted from the intestinaltract. When fecal coliform bacteriaare present in high numbers in a watersample, it means that the water mayhave received fecal matter from onesource or another. Although notnecessarily agents of disease, fecalcoliform bacteria indicate thepotential presence of disease-carryingorganisms, which live in the sameenvironment as the fecal coliformbacteria.

Reasons forNatural VariationUnlike the other conventional waterquality parameters, fecal coliformbacteria are living organisms. Theymultiply quickly when conditions arefavorable for growth and die in largenumbers when they are not. Becausebacterial concentrations are dependentupon specific conditions for growthand these conditions change quickly,fecal coliform bacteria counts are noteasy to predict. For example,although winter rains may wash morefecal matter from urban areas into alake, cool water temperatures maycause many of the organisms to die.Direct exposure to sunlight is alsolethal to bacteria, so dieoff may behigh even in the warmer water ofsummertime.

Expected Impactof PollutionA lake heavily polluted by nutrients-may have very low concentrations offecal coliform bacteria. It depends onthe source of pollution. Urbanizationof watersheds may generate newsources of fecal coliform bacteria,

even as “old” sources disappear -- forexample, when agricultural landfertilized by cow manure is convertedinto residential developments. In thiscase, pet wastes, failing septicsystems, and interconnections withleaking sanitary sewers may replacecow manure as a fecal coliformsource. Stormwater runoff inurbanized areas has been found to besurprisingly high in fecal coliformbacteria concentrations. The presenceof disintegrating storm and sanitarysewers, misplaced sewer pipes, andgood breeding conditions are commonexplanations for the high levelsmeasured.

Most states have strict standardsfor fecal coliform bacteria concen-trations, primarily for reasons ofpublic health. The abundance of fecalcoliform bacteria is measured as thenumber of “colonies” in 100 mL ofwater -- #/100 mL. The WashingtonState standard for lakes reads “fecalcoliform organisms shall not exceed a

geometric mean value of 50organisms/100 mL, with not morethan 10 percent of the samplesexceeding 100 brganisms/100 mL."

The equation below describeshow to calculate a geometric mean.

Geometric Mean =

If the lake is used for a drinkingwater supply, more stringent standardsapply. The standards differ dependingupon the method used and the numberof samples collected. Suffice to saythat for drinking water, coliformnumbers should be one or less.

Fecal coliform concentrationsfor three Western Washington lakesare shown here to provide examplesof the range you may expect tomeasure. This group of lakes displaysa fairly narrow range in measuredbacteria concentrations. Largevariations (tenfold or more) within alake are not unusual, given the rate atwhich bacteria multiply and die.

πnXXXX ...321

M

JuSe

Fecal Coliform Bacteria Concentrations (#/100 mL)easured in the Top Layer (Epilimnion) of Three Lakes

in June and September 1989.Summit

LakeBlackmans

LakeBlackLake

ne 1 36 0ptember 0 37 1

19

20

A TypicalLakeMonitoringProgram

Getting StartedThe first step in beginning anymonitoring program is to think aboutyour objectives or purpose formonitoring as discussed in ChapterOne. Your monitoring plan may notbe anything like someone else’s planif your goals and objectives aredifferent. Some typical objectives forcitizen monitoring include charac-terizing the entire lake, learning abouthow lakes function, or assessinggeneral lake water quality trends.

Once you have defined yourpurpose for sampling, you can figureout where to collect the samples, whatanalyses to perform, and when to dothe work. The complexity of yourprogram also will be affected by thenumber of volunteers and yourbudget.

It is often useful to begin a lakemonitoring program by obtaining ordrawing a rough map of the lake.Show the inflows and outflows; markthe shallow portions of lake andknown deep “holes;” and show anyaquatic plant beds, rocky shorelines,or other physical differences you mayhave noticed. Note the prevailingwind direction. You also may want tolocate or record such things as thepresence of stormwater runoff pipesor culverts, types of shorelinevegetation (lawns, native vegetation,or agricultural land), and adjacentland use.

Depending upon the locationand development pressure aroundyour lake, it may be interesting torevise this map periodically to provideongoing documentation of factors thatwill influence lake water quality.

21

SelectingSampling LocationsThe selection of sampling stations isdirectly dependent upon your moni-toring objectives. If your objective isto characterize the entire lake, and ithappens to be a large lake with anumber of shallow bays, inflowingstreams, or other distinguishingcharacteristics, then it is likely anumber of stations will be needed toprovide an adequate characterization.If your objective is to learn how lakesfunction, stations in physically diverselocations (bays and open water) and atdifferent depths should be selected.Conversely, if tracking water qualitytrends is your objective, it could beargued that one station could be usedto represent any lake.

Avoid sampling near shore,near inflows, or in the downwinddirection. Prevailing winds blowalgae, zooplankton, and debris downthe lake and toward the shoreline;samples collected in these areas areless representative of the lake’soverall water quality. If a boat is notavailable, choose a location aboutmidway down the shoreline andsample off a long pier, using a pole tocollect the sample as far from theshoreline as possible.

In deep lakes, sampling at twodepths (near surface and near bottom)is a good idea. In a large lake, if youhave sufficient volunteers and moneyfor more than one station, chooseadditional stations according to yourinterests or physical aspects of thelake. For example, you may want tocompare the mid-lake station to ashallow bay. If the lake is long, youcould establish stations in a transectalong the midsection. Addition of astation at the mouth of importantinflowing streams will help you figureout how much they contribute topollution in the lake.

You will always want to returnas near as possible to the samelocation in the lake. Obviously, if youare sampling from shore this location

22

is easy to document and remember.However, if you are sampling from aboat, it can be a little more difficult.Identify landmarks along the shoreand line the boat up with them anddocument the location. An examplefield note – “Line the boat up on avisual transect between the smallyellow house on the northern shoreand the-gray barn on the southernshore, and follow along this transectuntil the inflow at the eastern tip ofthe lake is directly across from theboat. Drop the anchor here.” (By theway, it is important to use an anchorso you don”t float away from thestation during the sampling.)

SelectingParametersWater quality parameters, too, shouldbe selected to meet project objectives,number of volunteers, and availablemoney. Field measurements such aspH, temperature, dissolved oxygen,and Secchi depth are inexpensive tomeasure once the initial equipment orchemical reagents have beenpurchased. This information alone isenough to do a general water qualityassessment, determine trophic state,provide plenty of educationalinformation, and even describe waterquality trends if data are collected fora long enough period. Includingadditional parameters such as nutrientanalyses and chlorophyll a justprovides more in-depth informationfor meeting these same objectives.Since these parameters can be moreexpensive to analyze -- dependingupon the measurement method used --a decision on whether to measurethem and at how many stations will bemoney-dependent. If only a few,nutrient or chlorophyll a samples canbe collected, pick the stations that bestmeet your monitoring objectives.Information on how to collect samplesfor each of these measurements anddifferent methods for analysis aredescribed in Chapter Four.

When to SampleAgain, the monitoring objectives willbe the primary factor influencingwhen to sample. The followingassumes your monitoring objectivesare fairly general.

The most critical time period in alake is typically during the growingseason. For general water qualityassessment purposes, it is sufficient tomonitor from April or May throughSeptember or October, either monthlyor preferably, every 2 weeks. Forgeneral purposes, there is little benefitin monitoring more than every 2 weeksand, in fact, for some, parameters thereare statistical reasons for not doing so.If you choose to sample a lakethroughout the year, even researchprofessionals typically sample onlymonthly during the winter.

Samples also should becollected at about the same time ofday each time you sample. Thisallows for some consistency indaylight hours and in all the indirecteffects daylight has on the differentlake processes.

ExampleLakeMonitoringStrategiesEducationalMonitoringIn this example, the purpose of themonitoring program is not to identifyor rate water quality problems, but tolearn about how lakes function. Themonitoring program is designed toemphasize the changes or differencesbetween stations or through the year.DO, temperature, pH, and Secchidepth are good parameters to startwith. If money were available tomeasure nutrients, TP and SRP wouldprobably be the best choices. Theseparameters should all changenoticeably with season, depth, and

probably station. If the lake is deepand more than one station can besampled, sampling at two depthslikely will be more informative thansampling at two stations. Additionalstations might be added to show theeffect of shallow bays, inflowingstreams, or other characteristics.Sampling could occur on a one-timebasis or a few times through thesummer and maybe once during thewinter depending of course, upon howmuch time you wish to spend.

General LakeCharacterizationHere the objective is to collectinformation from all portions of thelake as a kind of baseline study tobetter understand the lake. Manystations would be selected tocharacterize each of the different partsof the lake. The inflow, outflow,small bays, weed beds, a transect ofstations along the mid-section of thelake, and at two or more depths ateach station are a few ideas on whatstations you might select. All theparameters described would beneeded for a thorough characteri-zation. Sampling through one seasonwould probably provide enoughinformation to generally characterizehow the different portions of the lakefunction. Because of the generalnature of this objective, there wouldbe little merit in continuing asampling program such as this forvery long. Perhaps after the firstseason a few sampling sites would beexcluded and the parameters sampledwould be pared down to create a lesscostly, more focused long-termsampling program.

Water QualityAssessmentIn this case, the objective is todetermine or even rate the waterquality of the lake. DO, pH,temperature and Secchi depth wouldof course be sampled because they areeasy and inexpensive. TP, SRP, andperhaps chlorophyll a would be

23

sufficient to allow you to rate thewater quality in most cases. For manyscientific purposes, TN, NO3,-NO2,and NH4, data would be a greatadvantage. Sampling at one stationand two depths would likely allow anadequate general assessment. If theultimate objective was to use thisassessment data to monitor waterquality trends, the sampling programwould last for a number of years andthen be reinstated every few years tocontinue the trend monitoring.

Most monitoring programs thatare not purely educational actually fallsomewhere between the generalcharacterization approach and thewater quality assessment approach.Typically, at least two stations aremonitored (more in a bigger lake), andall the parameters listed aremonitored, at least at the two mostimportant stations or depths. At lessimportant stations, just the fieldmeasurements (DO, pH, temperature,and Secchi depth) are usually taken.

How to Reportand AnalyzeLake WaterQuality DataData analysis and interpretation canbe as simple as comparing measure-ments to State standards, or be verycomplex involving advanced statisticsand a thorough understanding of lakedynamics. The following sectiondescribes some simple, straight-forward approaches to looking at thedata you have collected and evenmaking some preliminary determi-nations on what it all might mean.The first step in assimilating andreporting data is to create a summarytable of your data, showing theaverage and range for each parametermeasured. This will make it easy tocompare the data to water qualitystandards or data from other lakes.

You can learn the most aboutyour lake by looking at how ameasurement changes over time (like

over a growing season) and how onemeasurement changes with respect toanother. It’s easiest to see thesechanges by plotting the numericalvalues on graph paper.

The horizontal axis (x-axis) isused for the independent variable. It iscalled independent because it is notaffected by the variable shown on thevertical axis (y-axis). Typical x-axisvariables include time, date, anddistance. The y-axis is used for thedependent variable, which changes overtime or date or distance. Typical y-axisvariables include the parametersmeasured in your sampling program,such as dissolved oxygen, totalphosphorus concentrations, Secchi ,depths, and temperature. Choose thescale of each axis to match the range ofnumbers -you have measured.

Any of the parameters measuredcan be plotted to compare changes overtime or between stations. The data forthe sample plots shown were collectedfrom Lake Sammamish during thesummer of 1989. The first plot is asimple depiction of the change in oneparameter -- chlorophyll a -- throughthe year. Although not discussed inthis guide, the high early spring peak inchlorophyll a is fairly typical. Theavailable nutrient supply is very high atthis time because of the low winterproductivity. Consequently, as soon assunlight increases in the spring, condi-tions are just right for a large bloomsuch as the one shown. In this lake,chlorophyll a levels remained low untillate summer, when another smallerpeak in concentrations was measured.

The second graph on thefollowing page compares TP and SRPconcentrations measured in the topmeter of the lake. Notice that the TPconcentration increased through mostof the summer (until August), whileSRP decreased. This corresponds tothe process described earlier whereincreased growth and productivityduring summer result in higher totalnutrient (TP) concentrations but loweramounts of available nutrients (SRP)because available nutrients are beingutilized, almost immediately forcontinued growth.

If you have sampled at morethan one station or depth, the next-level of comparison is to plot theresults on the same graph use differentsymbols for each station or depth --circles for one and a square for theother. When connecting the points,use different styles of line for eachstation or depth -- like a solid line forone and a dotted line for the other.Different colors serve the samepurpose as different shapes and linestyles. The third plot compares DOmeasured in the top meter of LakeSammamish to that measured at 20meters depth. This provides a goodexample of the effects of stratificationin a lake. As shown, sometime in lateMay the concentration of DO began todiffer at the two depths -- a sign thelake was stratifying. As the summerprogressed, the difference becamemore acute, as photosynthesis andaeration near the surface createdoxygen while chemical and biologicalprocesses near the bottom used it up.

By July and August,DO near the bottomof the lake was toolow to support manyfish and other aquaticlife.

24

You may even want to comparedifferent parameters to each other. Ifthe reporting units and expected rangeof values are the same, you can usethe regular y-axis for both parameters.If the units and expected range aredifferent, use a y-axis on the left forone of the parameters and drawanother y-axis on the right for theother parameter. The parameters thatare commonly compared for lake dataare total phosphorus and totalnitrogen, total phosphorus andavailable phosphorus, and totalphosphorus and Secchi depth. It alsois interesting to compare the change intemperature, DO, and pH with depthin a lake.

After you have made the plots,go back to the beginning of thischapter and review each of theparameters and their reasons forvariation. Try to explain thevariations in your plots by what younow know about how each of theparameters functions.

An additional and relativelyeasy data analysis technique is tocalculate your lake’s trophic stateindex (TSI). TSI provides a simplemeans of determining and comparinglake productivity.

Determining a Lake'sTropic StatusSince lake water quality has so muchnatural variation, it is not possible toset water quality standards for lakes.It can be much more valuable tocompare changes in one lake’s qualityover the years or to compare betweenlakes, than to have simple limits for“good” and “bad” lakes. A methodhas been devised for “rating” lakes.This method is called the trophic stateindex (TSI) or the Carlson index (afterthe scientist who devised it).

Calculating TSITSI can be calculated by using theSecchi disk depth, the totalphosphorus concentration at thesurface of the lake, or thechlorophyll a concentration at thesurface. Either one day’s values or,preferably, average values over thesummer can be used. The equationsused to calculate TSI are given on thefollowing page.

Using Secchi disk depth:

TSI = 60 - 14.41 (In SD)

Where SD is the Secchi depth inmeters, and ln stands for thenatural log of a number.

Using total phosphorus:

TSI = 14.42 (In TP) + 4.15

Where TP is the total phosphorusconcentration measured in thesurface water in µg/L, and lnstands for the natural log of -anumber.

Using chlorophyll a:

TSI = 9.81 (In Chla) + 30.6

Where-chla is the chlorophyll aconcentration, in µg/L, and lnstands for the natural log of anumber.

Once you have calculated theTSI, you can compare the results toother lakes or recalculate the valueeach year to see whether there appearsto be any upward or downward trendin your lake. Again, because of thelarge natural variation for theseparameters, it would take a number ofyears of data to determine whetherany trend existed.

You should be aware that youwill not calculate the same TSI valuewith each of the parameters. In otherwords, if TSI is calculated using Secchidisk depth, the same result may not beobtained when calculating it with TP.

Accdevthe fromthe couhav

comandTSIprodspeabetwoligare 60 a

TropEutro

Meso

Eutro

(NOTETrophi

Comparison of Trophic State Index to Water Quality Parametersand Lake Productivity

hic State TSISecchi Disk

(m)

TotalPhosphorus

(µg/L)Chlorophyll a

(µg/L)phic 0 64 0.75 0.04

10 32 1.50 0.1220 16 3 0.3430 8 6 0.94

trophic 40 4 2 2.6050 2 24 6.4060 1 48 20

phic 70 0.500 96 5680 0.250 192 15490 0.120 38 427

100 0.062 768 1,183: The original source of this table with the equations is Carlson, R.E., 1977. A

c State Index for Lakes, Limnology and Oceanography, 22:361-369.)

25

ording to the scientist whoeloped this index, chlorophyll a isbest indicator to use if using data the summer months, while TP is

best during the rest of the year. Ofrse, if Secchi disk data is all youe – that’s what you will use.

The table above provides aparison of each of the parameters

the resultant TSI. The higher the value, the “older” or moreuctive the lake is. Roughlyking, lakes with TSI valueseen 0 and 40 are considered to be

otrophic, those between 40 and 60mesotrophic, and those betweennd 100 are eutrophic.

A great deal of information wascovered in this chapter. If you’veread it from end to end you areprobably feeling a little overwhelmedby now. Take a break and let yourmind assimilate some of theinformation. Unless you are alsointerested in stream monitoring, youshould read Chapter Four next.Chapter Four explains how to goabout collecting the samples anddifferent analysis methods for thedifferent water quality parameters.You may want to return to this chapternow and again to refresh yourmemory -- with luck you’ll find thateach time you read it you willunderstand some concept a littlebetter.

26

27

CHAPTER THREE

The PhysicalCharacter ofStreamsNo two streams are exactly alike – noteven two segments of the same streamare exactly alike. Consider all thethings that make a stream reach whatit is: water velocity, depth, width,pools, riffles, vegetation, and theshape and nature of the shoreline. Allof these physical characteristicsinfluence water quality and the typeand variety of habitat that is availableto support aquatic life.

Stream VelocityStream velocity is a measure of thewater’s speed. A fast-moving streamis usually more turbulent than a slow-moving stream. The speed and extraturbulence give the water the force toscour the stream bottom and banksand pick up sediment and othermaterial. The faster the stream ismoving, the larger the materials it canpick up and carry with the current. Infact, algae and other organisms can’tlive in a stream or stream section thatis moving too fast because of thisstrong scouring force.

Stream velocity changes withseason; in the Puget Sound Regionthis generally means faster during thewinter and slower during the summer.Velocity also changes within streamsegments; where the streambankwidens or the channel deepens, thevelocity decreases. Velocity alsovaries across the width of a stream.This is especially true when thestream is following a curve; thevelocity is much greater on theoutside of the curve than on theinside. The difference is often sogreat that while the force on theoutside of the curve is strong enoughto be cutting away at the bank, theforce on the inside is so small thatmaterial is deposited along the bank.

Stream DepthStream depth determines the forma-tion of pools, riffle, and glide areas.A pool forms in deeper segmentswhile riffles form in shallow areas. Aglide is the smooth, fast-moving areathat often separates pools from riffles.Depth determines how much sunlightreaches the stream bottom, which inturn determines whether organismsthat require light, such as algae, cangrow there. The shallower a stream,the greater the proportion of waterthat is exposed to the air and sun.Exposure to the air where water canpick up more oxygen is good, but toomuch exposure to the sun can beharmful if water temperatures increasetoo much. Stream depth also varieswith season, so that a segment thatwas a pool or glide during the wintermay become a riffle during summer.

Stream WidthThe narrower a stream, the greater theinfluence of streamside vegetation. Anarrow stream may have a full canopyof trees or shrubs above it, ascompared to a wide stream where thetrees and other vegetation influenceonly the very edge. Banksidevegetation keeps temperatures coolerby creating shade, and provides placesfor fish and other organisms to hide.

Shoreline Shapeand CharacterSome streams have sharp curves,others are straight. Some have highsteep banks, others have gentlysloping banks. Bankside character-istics range from exposed dirt, to rock,to thick vegetation. The shape andcharacter of the shoreline affects howwater moves past it, what vegetationgrows there, and the type of habitatavailable. The change in the speed andforce of water as it cuts around acurve further forms the shoreline andinfluences the pattern of riffles, pools,and glides. A straight or channelizedstream is less stable and more prone toflooding than a curving, meanderingstream because of this distribution ofenergy.

StreamWater QualityParametersThis section discusses the waterquality parameters volunteersfrequently test: temperature, dissolvedoxygen, pH, nutrients, total suspendedsolids and turbidity, and fecalcoliform bacteria. For each parameteryou’ll learn why it’s important, whymeasured values differ from one timeto another, and how pollution couldaffect the measurement. Most of theparameters described are related toeach other and the relationship isdescribed in the section on each of theparameters. For example, there is arelationship between temperature anddissolved oxygen. This relationship isdescribed in both the discussion ontemperature and the discussion ondissolved oxygen. If you find itdifficult to understand the discussionunder one parameter, move on to thenext; with luck you will find the nextdiscussion helps to clarify the first.Chapter Four describes the differentmethods for analysis for each of these

Streatotal streamcross(widtvelocwill ha shaassumthe sastreamquite flow

Stream Dischargem discharge refers to thevolume of water in the

. It is a function of the-sectional area of the streamh and depth), and theity. A wide, deep streamave a greater discharge than

llow, narrow stream,ing their flow velocity isme. Conversely, twos of similar size may have

different discharges if thevelocity differs.

29

parameters.

TemperatureWhy Is It Important?Temperature is important because it -governs the kinds of aquatic life thatcan live in a stream. Fish, insects,zooplankton, phytoplankton, and otheraquatic species all have a preferredtemperature range. If temperatures gettoo far above or below this preferredrange, the number of individuals ofthe species decreases until finallythere are none.

Temperature also is importantbecause it influences water chemistry.The rate of chemical reactionsgenerally increases at higher tempera-ture, which in turn affects biologicalactivity. An important example of theeffects of temperature on waterchemistry is its impact on oxygen.Warm water holds less oxygen thancool water, so it may be “saturated”with oxygen but still not containenough for survival of aquatic life.Some compounds are also more toxicto aquatic life at higher temperatures.

Reasons for NaturalVariationIn addition to seasonal variations instream temperature caused bychanging air temperatures, many otherphysical aspects of a stream causenatural variation in temperature. Theorigin of the stream – whether it flowsfrom a glacier, a lowland lake, or a

spring or wetland – determines itsinitial temperature. Tributaries mayalter the stream temperature as theymix with the mainstem. Velocity alsoinfluences temperature. A particle ofwater in a fast-moving stream isexposed to sunlight for a shorter timethan that in a slow-moving stream.

The physical character of thestream and shoreline also areimportant. A well-shaded shorelinereduces the impact of warming by thesun. In a wide shallow stream, even aforested shoreline will permit lots ofsunlight to fall upon the stream. Anarrow, deep stream with a well-vegetated bank would remain cooler.

The character of the watershedalso affects temperature. If thewatershed is forested and steep-orhilly, runoff water will move quicklyand the sun won’t have much time towarm the runoff before it reaches thestream. Conversely, in a flat andsparsely vegetated watershed, thewater moves more slowly, with moretime to absorb heat from the groundsurface and the sunlight.

Expected Impactof PollutionWe usually think of thermal pollutionin terms of the discharge of heatedmunicipal and industrial discharges.However, the process of watersheddevelopment also can affecttemperatures in nearby streams.Streambank vegetation often is lostwhen land is cleared, therebyexposing the stream to increasedwarming by sunlight. A less obviousimpact is that runoff water may bewarmer, especially during the summer

months when it flows over hot asphaltor concrete. Although temperature-induced impacts from developmentare important, they are difficult tomeasure as part of a typical streammonitoring program. It usually ismore informative to note the loss ofthe shade trees and shorelinevegetation or the increase in pavedareas in the watershed as indicators oflikely temperature effects.

Temperature is reported indegrees on the Celsius temperaturescale (oC). The State water qualitystandard for temperature variesaccording to the stream classification.Temperature can not exceed 16oC inClass AA streams, 18oC in Class Astreams, 21oC in Class B streams, and22oC in Class C streams. In additionto the maximum allowedtemperatures, the total amount ofchange in temperature as caused byhuman activities also is regulated. Inother words, even if the temperaturein a Class AA stream remains below16oC, if human disturbance causes toomuch change (as determined by aseries of equations described in theregulation) then the standard will havebeen violated.

The following table summarizestemperature data for three PugetSound area streams. The streams wereselected to represent a range in landuse and water quality conditions. TheCedar River watershed is almost 90%forested and has 44 “very good” waterquality. The Newaukum Creekwatershed is primarily forest, andagricultural land – mostly dairyfarming – and is considered to have“fair” water quality. Land use in theSpringbrook Creek watershed is

State Water QualityStandards

Water quality standards havebeen established for all surfacewaters in Washington. Riversand streams are rated in one offour classes: Class AA –Extraordinary, Class A –Excellent, Class B – Good, andClass C – Fair. Different waterquality standards apply to thedifferent classes as set forth bythe Washington AdministrativeCode (WAC) 173-201-045. Foreach of the parameters discussed,the applicable standard isdescribed in this chapter.

Temperature (oC) Summary Data from 1988-89From Three Western Washington Streams

with Different Land Use and Water Quality.

YearlyAverage

Summer Range(May-Oct)

Winter Range(Nov-Apr)

Cedar River 9.5 10.0-16.0 4.9- 8.2Newaukum Creek 9.9 9.9-13.0 5.0-10.1Springbrook Creek 11.4 12.5-19.0 4.0-11.0

Revised From: Metro 1990. Quality of Local Lakes and Streams 1988-89 StatusReport. Municipality of Metropolitan Seattle, Water Resources Section.

31

commercial and industrial with someagriculture; the water quality isconsidered to be “poor.” These samestreams will be used throughout thissection on water quality parameters toprovide an example of the normalrange that can be expected in eachtype of data.

Dissolved OxygenWhy Is It Important?Like terrestrial animals, fish and otheraquatic organisms need oxygen tolive. As water moves past their gills(or other breathing apparatus),microscopic bubbles of oxygen gas inthe water, called dissolved oxygen(DO), are transferred from the waterto their blood. Like any other gasdiffusion process, the transfer isefficient only above certain concentra-tions. So, a certain minimum amountof oxygen must be present in water foraquatic life to survive. In other words,oxygen can be present in the water,but at too low a concentration tosustain aquatic life. In addition tobeing required by aquatic organismsfor respiration, oxygen also is used fordecomposition of organic matter andother biological and chemicalprocesses.

Reasons forNatural VariationOxygen is produced duringphotosynthesis and consumed duringrespiration and decomposition.Because it requires light,photosynthesis occurs only duringdaylight hours. Respiration anddecomposition, on the other hand,occur 24 hours a day. This differencealone can account for large dailyvariations in DO concentrations.During the night, when photo-synthesis cannot counterbalance theloss of oxygen through respiration anddecomposition, DO concentrationssteadily decline. They are lowest justbefore dawn, when photosynthesisresumes.

Dissolved oxygen concen-trations increase wherever the waterflow becomes turbulent, such as in A

riffle area, waterfall, or a dam.Oxygen concentrations are muchhigher in air, which is about 21percent oxygen, than in water, whichis a tiny fraction of 1 percent oxygen.Where the air and water meet, thistremendous difference in concentra-tion causes oxygen molecules in theair to dissolve into the water untilsaturation is reached. More oxygendissolves into water when turbulencecaused by rocky bottoms or steepgradients brings more water intocontact with the surface. A similarprocess happens when you add sugarto a cup of coffee. The sugardissolves, but it will dissolve morequickly if you stir the coffee.

Another, physical process thatimpacts DO concentrations has to dowith the temperature of the water andgas saturation. Cold water can hold,more gas – that is DO – than warmwater. So, during the summer monthswhen stream water is warmer, oxygencan be limited by the ability of thewater to “soak up” more oxygen gas.A table comparing oxygen saturationat different water temperatures can befound on page 11 in the Lakeschapter.

There are other reasons forseasonal variation. During latesummer, streamflows can get verylow in the Puget Sound area. Many ofthe tributaries that provide oxygenatedwater to the main stream dry up, andas water moves slowly over what maypreviously have been riffles or rapids,there is less opportunity for aerationand oxygenation. Warmer summertemperatures also cause increasedbiological activity (growth, producti-vity, respiration, and decomposition),and therefore greater daily variabilityin DO.

Expected Impactof PollutionPollution tends to cause a decrease instream oxygen concentrations. Thischange can be caused by addition ofeffluent or runoff water with a lowconcentration of DO or chemical orbiological constituents that have ahigh oxygen demand – that is theyrequire large amounts of oxygenbefore they can be thoroughlydecomposed. The latter is often themore typical and more serious case.

The demand for oxygen doesn’toccur directly where the effluent orrunoff water is discharged but instead

somewhere downdecomposition fican make it diffirelationship betwoxygen demandiand decrease in oconcentrations. Tdetermine the amrequired for decopollutant source called the biochedemand (BOD). measurement is nin citizen monitocovered in this teMethods for the and Wastewater reference manuastudies and proviBOD analysis. Tincluded in the reback of this book

Stormwateoxygen-demandistreams. When adeveloped, greatpollutants are relvolume of runoffconventional polnutrients, organioxygen for decomchemical reactioconcentrations ostreams located ideveloping wate

Dissolved tions are reportedmilligrams of ga(mg/L). (The unito parts per milliwater quality stastreams is based classification. DOmust exceed 9.5 streams, 8.0 mg/

aquatic life can use it. Heavy metalstend to be more toxic at lower pHbecause they are more soluble andmore bioavailable.

Reasons forNatural VariationGeology of the watershed and theoriginal source of the water determinethe initial pH of the water. Thegreatest natural cause for change in

Measured i

Cedar RiverNewaukum CSpringbrook C

Revised From: MReport. Municip

Dissolved Oxygen Concentrations (mg/L)n Three Western Washington Streams during 1988-89.

YearlyAverage

Summer Range(May-Oct)

Winter Range(Nov-Apr)

11.4 9.4-11.9 11.0 - 12.4reek 11.0 9.9-11.1 10.9 - 12.2reek 5.8 2.1- 6.2 4.3 - 8.8

etro 1990. Quality of Local Lakes and Streams 1988-89 Statusality of Metropolitan Seattle, Water Resources Section.

stream wherenally occurs. Thiscult to show a directeen addition of an

ng pollution sourcexygenhere is a way toount of oxygenmposition of aby measuring what ismical oxygenSince thisot typically includedring efforts it is notxt. Standard

Examination of Wateris a commonly usedl for water qualitydes information onhe full reference isference section at the.r runoff also deliversng substances to watershed becomeser quantities ofeased and the total increases. Mostlutants (sediments,c matter) require

position or forns. Consequently, DOften decrease inn a developed orrshed.oxygen concentra- in units of

s per liter of watert mg/L is equivalenton [ppm].) The statendard for oxygen inon the stream concentrations

mg/L for Class AAL for Class A

streams, 6.5 for Class B, and 4.0 forClass C. The table above containssummary data for DO concentrationsmeasured in three WesternWashington area streams.

pHWhy Is It Important?The pH of a sample of water is ameasure of the concentration ofhydrogen ions. The term pH wasderived from the manner in which thehydrogen ion concentration iscalculated – it is the negativelogarithm of the hydrogen ion (H+)concentration. What this means tothose of us who are not mathema-ticians, is that at higher pH there arefewer free hydrogen ions, and that achange of one pH unit means there isa tenfold change in the concentrationof the hydrogen ion. For example,there are ten times more hydrogenions available at a pH of 7 than at apH of 8. The pH scale ranges from 0to 14. A pH of 7 is considered to beneutral. Substances with pH less than7 are acidic, while substances with pHgreater than 1 are basic. The pH ofmost natural waters ranges between6.5 and 8.5.

The pH of water determines thesolubility (amount that can bedissolved in the water) and biologicalavailability (amount that can beutilized by aquatic life) of chemicalconstituents such as nutrients (e.g.,phosphorus, nitrogen, and carbon) andheavy metals (e.g., lead, cadmium,copper). For example, in addition todetermining how much and what formof phosphorus is most abundant in thewater, pH also determines whether

pH in a stream is the seasonal anddaily variation in photosynthesis,Photosynthesis uses up hydrogenmolecules, which causes theconcentration of hydrogen ions todecrease and therefore the pH toincrease. Respiration and decomposi-tion processes lower pH. For thisreason, pH is higher during daylighthours and during the growing season,when photosynthesis is at its peak.

Although pH may be constantlychanging, the amount of changeremains fairly small. Natural watersare complex, containing manychemical “shock absorbers” thatprevent major changes in pH. Small orlocalized changes in pH are quicklymodified by various chemicalreactions so little or no change may bemeasured. This ability to resist changein pH is called buffering capacity. Notonly does the buffering capacitycontrol would-be localized changes inpH, it controls the overall range of pHchange under natural conditions. ThepH scale may go from 0 to 14, but thepH of natural waters hovers between6.5 and 8.5.

Expected Impactof PollutionBecause polluted conditions typicallycorrespond with increased photo-synthesis in a stream, pollution maycause a long-term increase in pH. Themore common concern is changes inpH caused by discharge of municipalor industrial effluents. However, mosteffluent pH is fairly easy to control,and all discharges in WashingtonState are required to have a pHbetween 6.0 and 9.0 standard pHunits, a range that protects mostaquatic life. So, although thesedischarges-may have a measurable

impact on pH, it would be unusual(except in the case of treatment plantmalfunction) for pH to extend beyondthe range for safety of aquatic life.However, since pH greatly influ-ences the availability and solubility ofall chemical forms in the stream,small changes in pH can have manyindirect impacts on a stream.

pH is expressed in terms of pHunits. The State water quality standardfor pH in Class AA, A, and B streamsstates that pH must fall within a rangeof 6.5 to 8.5. For Class C streams, pHmust fall within a range of 6.5 to 9.0.Because pH represents the antilog of anumber it is not mathematicallycorrect to calculate simple averages orother summary statistics. pH shouldbe reported as a median or range ofvalues. The table at the rightsummarizes pH data to provide acomparison for three WesternWashington streams.

NutrientsWhy Are They Important?Nutrients in streams serve the samebasic function as nutrients in a garden.They are essential for growth. In agarden growth and productivity areconsidered beneficial, but this is notnecessarily so in a stream. Theadditional algae and other plantgrowth allowed by the nutrients maybe beneficial up to a point, but mayeasily become a nuisance.

The main nutrients of concernare phosphorus and nitrogen. Bothelements are measured in severalforms. Phosphorus can be measuredas total phosphorus (TP), or solublereactive phosphate (SRP) (alsosometimes called phosphate (PO4) ororthophosphate (ortho-P). The lastthree represent different terms used todescribe the fraction of TP that issoluble or available to organisms forgrowth. Nitrogen can be measured astotal nitrogen (TN), total Kjeldahlnitrogen (TKN), nitrate-nitrogen(NO3), nitrite-nitrogen (NO2) [theseare usually measured as nitrate-nitrite-nitrogen (NO3-NO2)], or ammonia-nitrogen (NH4). TN is similar to TP

and is used toamount of nitrepresents theunavailable foorganic form;The remainingand NH4) reprof nitrogen. Ifcan be compaof phosphorus

One cheelement can banother. The cthe conversionby many factotemperature, oand biologica

The totanutrient (e.g.,necessarily thmeasurement.sample is anaof the elemenincluding the in biological tmineral particuseful to knowphosphorus thfor growth. SRbioavailability

Althougdifferent formmeasured thercommonly usare: (1) measuelements – TPNH4; (2) meas– TP and TN;available nutrNO2 and NH4TKN could beeither case, thbe estimated b

T

Cedar RiverNewaukum Springbrook

Revised From:Report. Munic

Summary of pH Data (pH units) Collected fromhree Western Washington Streams During 1988-89.

YearlyMedian

Summer Range(May-Oct)

Winter Range(Nov-Apr)

7.6 7.4 – 7.9 7.2 - 7.5Creek 7.7 7.9 – 8.0 7.4 - 7.6 Creek 7.0 6.9 – 7.2 6.7 - 7.0

Metro 1990. Quality of Local Lakes and Streams 1988-89 Statusipality of Metropolitan Seattle, Water Resources Section.

33

represent the totalrogen in a sample. TKN fraction of TN that isr growth or bound up in it also includes NH4. fractions (NO3-NO2,esent bioavailable forms they are summed theyred to the SRP fraction.mical form of ane converted intoonditions under which occurs are influencedrs, such as pH,xygen concentration,

l activity.l concentration of a

TP or TN) is note most useful For example, if alyzed for TP, all formst are measured,phosphorus “locked up”issue and insolubleles. It may be more the concentration of

at is actually availableP better reflects.h there are manys of nutrients that can bee are only threeed combinations. Thesere all forms of both, SRP, TN, NO3-NO2,ure only total nutrients

or (3) measure onlyients – SRP and NO3-. (In the first example exchanged for TN. Ine remaining fraction cany difference.)

Reasons forNatural VariationThe concentration of nutrients and theform they are found in changescontinually. How and why theychange is a very complex field ofstudy. First, the total input of nutrientsvaries depending upon land use andother factors. During the summer,nutrient input may increase due tofertilization of cropland or lawns andgardens. During the winter, highrainfall causes increased wash-off oforganic matter such as leaves, twigs,grass, and other debris. Becausedecomposition of this organic matterreleases nutrients, it constitutes animportant source of nutrient loading.

If the stream is fed by a lake orother water source with naturally highvariations in nutrient concentrations,the stream will reflect the samevariations. In the Puget Sound region,salmon carcasses from annualspawning migration represent a largeseasonal source of organic matter andnutrients.

34

Whether the increase in totalnutrient concentrations results inhigher available nutrient concen-trations, and therefore an immediateincrease in growth or productivity,depends upon the original form of thenutrient and physical conditions. Ifnutrients enter as organic matter thatfirst needs to be decomposed before itcan be utilized for growth, tempera-ture becomes important due to itseffect on the rate of decomposition.(During warmer months, nutrientsentering the system as intact organicmatter would be decomposedrelatively quickly as compared tocold, wet-weather months whendecomposition is slow.)

These dynamics are furthercomplicated by the fact that increasedgrowth leads to greater numbers oforganisms that need even morenutrients. So, as nutrients becomeavailable they are immediatelyutilized. In this case, an increase intotal nutrients would not be reflectedby any measurable increase inavailable nutrient fractions. In short,clear, simple relationships between in-creases in organic matter or othersources of nutrients, and resultantincreases in either total nutrientconcentrations or available nutrientconcentrations, become obscure.

Expected Impactof PollutionIncreased nutrient concentrations arealmost always an impact of pollution.Municipal and industrial dischargesusually contain nutrients, and over-land flow from developed watershedscontains nutrients from lawn andgarden fertilizers as well as theadditional organic debris so easilywashed from urban surfaces. Agricul-tural areas also contribute to nutrientincreases through poor manure andfertilizing practices and increasederosion from plowed surfaces.

Nutrient loading can result inincreased algae growth. In streamsegments where conditions are right,algae take the form of an attachedgrowth – called periphyton – on rocks,logs, and other substrate. You may

have noticed lomasses of algaestepped on rockthese growths. attached algae cunsightly condihabitat conditioorganisms.

Nutrient reported in unitmilligrams of nwater (µg/L or State water quanutrient concenabove summarithree Western W

Total SusSolids anWhy Is It ImTotal suspendeconcentrations indicate the amsuspended in thmineral (e.g., so(e.g., algae). Homeasures an acper volume of wmeasures the amfrom a sample (particles cause This differencewhen trying to

Thr

Cedar River

Newaukum

Springbrook

A = yearly averaRevised From: Report. Munici

Nutrient Concentration (µµµµg/L) Measured inee Western Washington Streams during 1988-89

(No TN data are available.)

TP SRP NH4 NO3-NO2A 14 9 18 290S 7-30 5-16 1-111 126-195W 10-25 3-11 1-29 315-585

A 100 83 100 1987S 43-65 37-59 1-28 1440-2350W 74-213 55-180 72-380 1560-3020

A 194 147 451 608S 180-254 52-230 175-725 320-740W 105-293 80-234 74-1240 405-963

ge; S = summer range (May-Oct); W = winter range (Nov-Apr)Metro 1990. Quality of Local Lakes and Streams, 1988-89 Statuspality of Metropolitan Seattle, Water Resources Section.

ng green filaments or in streams or evens made slippery by

Excessive growths ofan cause low DO,tions, odors, and poorns for aquatic

concentrations ares of micrograms orutrient per liter ofmg/L). There are nolity standards fortrations. The tablezes nutrient data from

ashington streams.

pendedd Turbidity

portant?d solids (TSS)and turbidity bothount of solidse water, whetheril particles) or organicwever, the TSS test

tual weight of materialater, while turbidityount of light scattered

more suspendedgreater scattering). becomes importantcalculate total

quantities of material within orentering a stream. Such calculationsare possible with TSS values but notwith turbidity readings.

High concentrations of parti-culate matter can cause increasedsedimentation and siltation in astream, which in turn can ruinimportant habitat areas for fish andother aquatic life. Suspended particlesalso provide attachment places forother pollutants, such as metals andbacteria. High suspended solids orturbidity readings thus can be used as“indicators” of other potentialpollutants.

Reasons forNatural VariationTSS and turbidity values varynaturally for two main reasons – onephysical, the other biological. Heavyrains and fast-moving water areerosive. They can pick up and carryenough dirt and debris to make anystream look dirty. So, heavy rainfallmay cause higher TSS concentra-tions or turbidity, unless theadditional, particles are dispersedthroughout large volumes of floodwater. The native soils and geology ofthe watershed of course determinehow easily erosion occurs.

A small part of the naturalincrease may be explained by seasonalchanges in algae populations. It is thesuspended forms of algae (i.e., thosefloating in the water column) that aremeasured by TSS and turbidity. If theoriginal water source is a lake, orwetland where algae populations canvary drastically with season, this mayshow up as changes in stream TSS orturbidity. However, in streams them-selves, attached forms of algae (i.e.,those attached to rocks, logs, or othersubstrate) are far more common. Thechange in these populations aren’tmeasured by TSS or turbidity untilthey wash off the substrate. Wash-offmay not occur until the algal massdies, is scoured off by large flows, orthe mass becomes too large to remainon the substrate.

Expected Impactof PollutionLand use is probably the greatestfactor influencing changes in TSS orturbidity in streams. As watershedsdevelop, there is an increase indisturbed areas (e.g., cropland orconstruction sites), a decrease in

vegetation, and increases in the rate ofrunoff. These all cause increases inerosion, particulate matter, andnutrients, which in turn promoteincreased algal growth. For example,loss of vegetation due to urbanizationexposes more soil to erosion, allowsmore runoff to form, and simul-taneously reduces the watershed’sability to filter runoff before inreaches the stream.

TSS concentrations are reportedin units of milligrams of suspendedsolids per liter of water (mg/L).Turbidity is reported as nephelometricor Jackson turbidity units (NTU orJTUs), depending on the instrumentused to perform the measurement.

CNS

ReRe

There are no State water qualitystandards for TSS. The waterquality standard for turbidity isbased on the amount of increaseover background conditions. ForClass AA and A streams, ifbackground turbidity is 50 NTUor less, then the total amount ofincrease can not be more than5 NTU. If the background isgreater than 50 NTU, then theincrease can not be above 10percent of the back- ground level.For Class B and C streams, ifbackground turbidity is 50 NTUor less, then the total amount ofincrease can not be more than 10NTU. If the background is greaterthan 50 NTU, then the increasecan not be above 20 percent of theback- ground level. The followingtables provide summary infor-mation for both TSS and turbidityfor three Western Washingtonstreams.

Turbidity (NTUs) Measured in Three Western Washington StreamsDuring 1988-89.

YearlyAverage

Summer Range(May-Oct)

Winter Range(Nov-Apr)

edar River 1.1 0.4- 1.2 1.0 - 2.0ewaukum Creek 2.4 0.7- 1.5 3.1 - 4.0pringbrook Creek 22.0 13.0- 44.0 13.0 - 35.0

vised From: Metro 1990. Quality of Local Lakes and Streams 1988-89 Statusport. Municipality of Metropolitan Seattle, Water Resources Section.

35

36

Fecal ColiformBacteria

Why Is It Important?Fecal coliform bacteria are micro-scopic animals that live in theintestines of warm-blooded animals.They also live in the waste material,or feces, excreted from the intestinaltract. When fecal coliform bacteria arepresent in high numbers in a watersample, it means that the water hasreceived fecal matter from one sourceor another. Although not necessarilyagents of disease, fecal coliformbacteria indicate the presence ofdisease-carrying organisms, whichlive in the same environment as thefecal coliform bacteria.

Reasons forNatural VariationUnlike the other conventional waterquality parameters, fecal coliformbacteria are living organisms. They donot simply mix with the water andfloat straight downstream. Insteadthey multiply quickly when conditionsare favorable for growth, or die inlarge numbers when conditions arenot. Because bacterial concentrationsare dependent on specific conditionsfor growth, and these conditionschange quickly, fecal coliformbacteria counts are not easy to predict.For example, although winter rainsmay wash more fecal matter fromurban areas into a stream, cool watertemperatures may cause a major

dieoff. Exposure to sunlight (with itsultraviolet disinfection properties)may have the same effect, even in thewarmer water of summertime.

Expected Impactof PollutionThe primary sources of fecal coliformbacteria to fresh water are wastewatertreatment plant discharges, failingseptic systems, and animal waste.Bacteria levels do not necessarilydecrease as a watershed developsfrom rural to urban. Instead,urbanization usually generates newsources of bacteria. Farm animalmanure and septic systems arereplaced by domestic pets and leakingsanitary sewers. In fact, stormwaterrunoff in urbanized areas has beenfound to be surprisingly high in fecalcoliform, bacteria concentrations.

The presence of old, disintegratingstorm and sanitary sewers, misplacedsewer pipes, and good breedingconditions are common explanationsfor the high levels measured.

Fecal coliform concentrationsare reported in units of the number ofbacteria colonies per 100 mL ofsample water (#/100 mL). TheWashington State standards for fecalcoliform bacteria vary according tostream classification. For Class AAstreams, the geometric mean can notexceed a value of 50 organisms per100 mL, and fewer than 10 percent ofthe samples can be greater than100/100 mL. For Class A streams, thegeometric mean can not exceed avalue of 100/100 mL, and fewer than-10 percent can be greater than200/100 mL. For Class B and Cstreams the geometric mean can notexceed 200/100 mL, and fewer than10 percent of the samples can begreater than 400/100 mL. Theequation used to calculate a geometricmean is described below.

Geometric Mean =

The table below providescomparison values from threeWestern Washington streams.

TSS (mg/L) Measured in Three Western Washington StreamsDuring 1988-89.

YearlyAverage

Summer Range(May-Oct)

Winter Range(Nov-Apr)

Cedar River 3.6 0.6- 5.0 3.5 - 6.2Newaukum Creek 5.7 1.6- 5.1 7.5 - 8.8Springbrook Creek 19.8 8.0- 26.0 6.7 - 44.0

Revised From: Metro 1990. Quality of Local Lakes and Streams 1988-89 Status Report.Municipality of Metropolitan Seattle, Water Resources Section.

Fecal Coliform Bacteria Concentrations (A#/100mL)Measured in Three Western Washington Streams

YearlyGeometricAverage

SummerRange

(May-Oct)

WinterRange

(Nov-Apr)Cedar River 19 20-60 1-60Newaukum Creek 439 47-1000 340-1800Springbrook Creek 399 170-5800 57-900

Revised From: Metro 1990. Quality of Local Lakes and Streams 1988-89 StatusReport. Municipality of Metropolitan Seattle, Water Resources Section.

n XXXX π....321

37

PollutantConcentrationsVersusPollutant LoadingBefore discussing data interpretationit may help to understand thedifference between measuring theconcentration of a pollutant andknowing what the load of thepollutant is. Imagine you have a literof water and put five tablespoons ofsalt in it, the resulting concentrationwould be five tablespoons per liter(5 Tbsp/L). Now imagine you have atwo-liter jug of water and add tentablespoons of salt, the resultingconcentrations would still be fivetablespoons per liter (5 Tbsp/L).Although in the second case, theconcentration of the pollutant, in thiscase salt, is the same as it was in the

first case, the total amount of thepollutant – the load – is twice as high.Sometimes this pollutant load is moreimportant information than thepollutant concentration.

Consider now a stream in thePuget Sound area where flow is lowduring summer and high duringwinter. For example, let’s say winterflows are ten times higher thansummer flows and the phosphorusconcentration is the same in thestream during both winter andsummer sampling periods. If you onlyconsidered the pollutant concentrationyou might be tempted to conclude thatthere was no difference in pollutantlevels through the year. BUT, there isten times more water in the streamduring the winter, so there is ten timesmore phosphorus being transported bythe stream in the winter. During thewinter the stream contributes tentimes the phosphorus load itcontributes in the summer, even

though pollutant concentrations arethe same.

Likewise, think about a lakethat has two inflowing streams.Stream A has ten times the flow ofstream B, but both have similarconcentrations of nutrients. Stream Ais contributing ten times morenutrients to the lake than Stream B – itconstitutes ten times greater load.

Although State standards andpollution indices are by necessitybased on pollutant concentrations, inthe case of streams, pollutant loadsprovide much more comparativeinformation for assessing the level ofimpact. Pollutant loads are a functionof pollutant concentrations andstreamflow. Pollutant loads can becalculated for nutrients, TSS, andfecal coliform bacteria. Chapter Fiveprovides a detailed example of how tocalculate a pollutant load.

38

Developing a StreamMonitoring ProgramConsider this – streams are movingtargets. When you collect a sample ofstream water, it reflects a mixture ofunknown upstream conditions andcharacteristics. Say you sampled ashady, fast-moving portion of stream,where you’d expect coolertemperatures. If the segment justupstream (beyond your vision) hadbeen a long stretch of shallow, sunlit,sluggish water, the temperature ofyour sample might be relatively high– not what you had expected. Thewater sample reflects upstreamcharacteristics and not just those ofthe sampling site.

This problem becomes morecomplex when you consider theaddition of nutrients or organicmatter. When nutrients are added to astream, they may not result in ameasurable increase in algae growthuntil a few miles downstream, wheretemperature, sunlight, or othergrowing conditions are just right. Theresultant mass of algae will eventuallyrequire oxygen for decomposition.However, even as the algae die, theyare carried farther downstream so thatthe decrease in oxygen does not occurat the same point as the increase inorganic matter. This is an importantconcept to understand when you aredeveloping your monitoring plan.Data you collect may not reflectconditions at the site in the way youmight expect.

Getting StartedBefore beginning a stream waterquality sampling program, it is helpfulto do some map work. Begin with aU.S. Geological Survey (USGS)topographic map. These maps can befound in any map store and manylocal sporting goods stores.Depending on the length of thestream, you might need more than onemap.

First, trace the boundary of thewatershed. Start at the mouth of thestream, and moving laterally away

39

from the stream, follow the risingtopography lines until you reach aspot where the land elevation beginsto decrease. This is the edge of thewatershed – mark the point on themap. Make a number of these pointson both sides of the stream and nearthe headwaters. Then try connectingthe dots by following between thetopography lines. This is the boundaryof the watershed. If you have troubledrawing in the line, imagine droppinga ball in the area and think againabout which direction it would roll. Ifit would roll toward the stream, thenthe area should be included in thestream’s watershed.

Use your knowledge of the areato add detail to the map, which islikely to be at least several years old.Many changes can occur in awatershed over several years,especially if it is in a developing area.Start by roughly outlining areas of themajor land uses in the watershed.Show agricultural, rural, residential,urban, industrial, and any othercategory you find appropriate for yourstream. If you know of a new mall orhousing development, mark itslocation, too.

Next, think about the streamcorridor itself. -Do you know ofplaces where the bank is very steep,eroding, or trodden down by farmanimals? Do you know wherestormwater pipes or culverts enter thestream? Have people discardedwashing machines, tires, cars, andother junk along the bank? Markthese features on the map. Look atwhere toads cross over the stream andtry to remember what the area near theroad looks like. This might helprefresh your memory about otherfeatures to note on the map.

Keep this stream map current.Place it in your glove compartmentand make additional notes wheneveryou see something worth noting, bigor small. You may be able to betterunderstand the reasons for waterquality changes by continuallyupdating your map.

A more advanced form ofsurveying stream features is to take a“stream walk” or “stream survey.”

40

This entails selecting a streamsegment and walking its length tomake detailed notes on your observa-tions. (Be sure to get landownerspermission before starting out!)These notes should include the typeand amount of streamside vegetation,the presence of logs or other largedebris in the stream, the compositionof the stream bottom, the presence of -oil/film or algae scums, and other,easy-to-recognize details. Standardchecklists and field note forms areavailable to help you make goodrecords. The U.S. EnvironmentalProtection Agency (EPA) has astandardized streamwalk form and hasdeveloped a computerized databasefor inclusion of citizens’ streamwalkresults. The reference section at theend of this guide provides informationon EPA’s program.

Selecting StationLocationsThe number of sampling stations andtheir locations will depend on yourobjectives, the number of volunteersinvolved, your budget, and safety andaccess considerations. If only one stationcan be sampled, a logical place for itwould be at or near the mouth of thestream. (If you are monitoring strictlyfor fun or for a class project, conven-ience may be the overriding factor insampling location.) If more than onestation can be monitored, the headwatersof the stream or a location well abovethe area of human impact would be agood choice if you want “background”water quality data for comparison.

If you are interested in the effect ofa tributary, locate one station above thetributary and one just below the mouth ofthat tributary. Pick a spot far enoughbelow to ensure it has completely mixedwith the main stream. To compare landuse impacts, position stations upstreamand downstream of the land use ofinterest, say a city or farmland. The ideais to isolate the source of interest.

NOTE: Because all stations inthe watershed should be sampled onthe same day, don’t establish morestations than you can comfortablysample on a short winter’s day.

41

Selecting ParametersIt often is possible to save money andtime by not sampling for everyparameter at every station. Like loca-tions, parameters should be selected tomeet project objectives, number ofvolunteers, and available money. Fieldmeasurements such as pH, temperature,dissolved oxygen, and stream gageheight (see Chapter Five: Hydrology)are quick and inexpensive to measureonce the initial equipment or chemicalreagents are purchased.

TSS measurements can be madewith equipment available at local highschools and so can sometimes be madewith little or no lab cost. Turbiditymeasurements require specialequipment and therefore have anassociated, though low, lab cost.Usually people choose to measureeither turbidity or TSS, not both sincein some respects they measure the samething. Available equipment and moneymay be determining factors in selectingbetween them.) These measurements(pH, temperature, DO, and TSS orturbidity) alone can comprise anadequate monitoring program again,depending upon your objectives.Consequently, these measurementsoften are made at all stations selected.

Including additional parameterssuch as nutrient or bacteria analysesprovides more in-depth information.Since these parameters can be moreexpensive to analyze – depending uponthe measurement method used – adecision on whether to measure them andat how many stations may be moneydependent. If only a few of these samplescan be collected, pick the stations thatbest meet your monitoring objectives. Ifflow measurements are being made,nutrient concentrations should bemeasured at the same stations to allowcalculation of loadings.

Stream flow, although an impor-tant parameter, can be time consumingand difficult. Typically, flow is onlymeasured at the most important stations,such as the mouth of the stream and justbelow tributaries where major changesin flow are expected. Instructions ontaking stream flow measurements areincluded in Chapter Five.

When to SampleA maximum sampling program wouldentail sampling every two weeksthroughout the year. However,depending upon your objectives, aseasonal approach may be just aseffective and will save time and money.This approach would entail biweekly ormonthly sampling from May throughSeptember and then another spurt ofsampling from December or Januarythrough March. In this way samplingwill be concentrated on the most criticaltime periods in a stream – the low flowperiod when temperature and DO levelsmay be at their extreme, and the highflow period when pollutant loading maybe at its peak. You may, of course,choose to sample during just one ofthese seasons; again, it will depend uponyour monitoring objectives. For exam-ple, if salmon migration is a concernyou might choose to sample only duringlate summer when high temperaturescoupled with low DO could determigration. Likewise, you might chooseto sample only during storm events toestimate peak pollutant loads.

Example StreamMonitoring StrategiesEducational MonitoringIf the purpose of your monitoring pro-gram is to learn how streams work,then the sampling strategy shouldinclude locations, parameters, andtime that would best depict thedifferences that have been describedthroughout this chapter. Diversestations, such as a pool and a riffle, orshaded and unshaded segments,should be selected. Temperature, DO,and pH should change some throughthe day and should provide interestingcomparison data if monitored throughthe summer season. They will likelynot change much through the winterseason, but will provide interestinginformation if compared to summerdata. TSS or turbidity is interesting tocompare between seasons, or beforeand after storms. In this case,comparison of TSS concentrations toloadings would be even better. If one

or two nutrients could be sampled,SRP and TP would likely provide thebest comparison data.

Baseline StudyThe purpose of a baseline study wouldbe to provide fairly general informationon the stream. The information might beused to develop a more intensivemonitoring plan or to provide informa-tion against which some future samplingresults might be compared. Generally, abaseline study will include selecting anumber of stations throughout thestream that represent stream segments ofdifferent character or land use. The sameparameters might be analyzed at eachstation; DO, temperature, pH, TSS, andnutrients – either TP and TN only – orTP, TN, SRP, NO3-NO2, and NH4.Bacteria also might be included if it wasthought to be an existing or potentialproblem in the watershed. A baselinestudy would last over one or two years,but probably no longer.

Water Quality Assessmentor Trend Monitoring

In this case the objective is to deter-mine whether the water quality is good,bad, or otherwise, and to monitorwhether the quality appears to bechanging over time. One station locatedat the mouth of the stream can be usedto assess the water quality and monitortrends. However, typically stations arealso located at other points in thestream, similar to stations selected forbaseline monitoring. Since the mainidea is to monitor over a long period, itbecomes even more important to selectfewer stations and cut back on theparameters monitored at each. Again,the field measurements – pH, temper-ature, and DO – can be inexpensive andeasy, and therefore measured in manyplaces. TSS or turbidity also are fairlyinexpensive and quite informative forassessment purposes. Nutrients (again,either TP and TN; or TP, TN, SRP,NO3-NO2, and NH4) and bacteriawould be measured at the mostimportant stations (e.g., those belowimportant tributaries or streamsegments).

42

How to Reportand Analyze StreamWater Quality DataThere is a great deal of variation injust how you may want to go aboutinterpreting the information youcollect. The level of interpretationwill be partially dependent upon thetype and quality of the data collected.The following are examples ofdifferent approaches to looking atyour stream water quality data.

The most straightforwardapproach is to create a summary tableof your data showing the average andrange for each of the parametersmeasured. This will make it easier tocompare them to applicable waterquality standards. That would be asfar as your interpretation would go.Does the stream meet water qualitystandards? Does it meet them at allstations at all times? You may wantto calculate and compare seasonalaverages as well. For example, the

year-round average may indicate thereis no DO problem, but perhaps bycalculating the summertime averageyou will find there is a seasonalproblem with meeting this waterquality standard.

In streams it is often moreinteresting to consider how the qualityof the water changes as it movesdownstream and either picks upadditional pollutants or picks upcleaner water that acts to dilutepollutants already present. Theeasiest way to make this comparisonis to plot the parameter of interestagainst the river mile to provide a nicevisual comparison. You can create aplot for any one sampling date or youcan create it using the averageconcentrations for many dates andshowing the range in the data byadding range bars.

To plot data the horizontal axis(x-axis) is used for the independentvariable. It is called independentbecause it is not affected by thevariable shown on the vertical axis

(y-axis). Typical x-axis variablesinclude time, date, and distance. They-axis is used for the dependentvariable; this variable changes overtime or date or distance. Typicaly-axis variables include the para-meters measured in your samplingprogram such as dissolved oxygen,total phosphorus, and temperature.Choose the scale of each axis to matchthe range of numbers measured.

The graphs below were createdfrom data collected in Portage Creek,a tributary to the Stillaguamish River,during 1988 and 1989. The graphscompare the change in totalphosphorus concentration with rivermile. The first plot contains data fromone sampling date (August 8, 1989),while the second summarizes theaverage total phosphorus concentra-tion for the year at each of thesampling points and also depicts therange in concentrations measured.

The first graph shows TPconcentration rising substantiallybetween river miles three and one.

43

However, this situation does notappear to be a common trend in thestream when compared to the secondgraph. The second graph depicts themajor increase in concentrationoccurring between stations seven andfive. The variation in the data (range)also becomes most pronounced belowstation seven. Concentrationsdecrease at the station nearest themouth, but it is unclear from thiscomparison of concentrations whetherthe decrease represents less phospho-rus or whether additional stream flowis masking an increase in the pollu-tant. In this case, land use activitiesbetween stations five and one appearto be those most affecting streamwater quality.

Because the discharge ofpollutants to streams may change withweather and flow conditions, it also isinformative to consider how thequality of the water changes over thecourse of the year. Again, a graphprovides the best means of visualcomparison. This time the horizontalaxis is used to show the date. Twostations, for example the mouth andthe headwater station, can be plotted

on the same graph to provideadditional comparisons.

The graph above depicts thechange in TP concentrations through

the year at the station nearest the

mouth and one near the headwaters.At both stations the concentrations arehighest during the December throughJanuary period, which corresponds tothe time of year when the most runoffenters the stream. Except for the oneJanuary date, the TP concentrationsnear the headwaters are consistentlybelow those measured near the mouth.At both stations TP concentrationsincrease during the summer and thenagain during the winter.

The next level of complexitytakes into account the change in thevolume of the river water to assesschanges in pollutant loading. This isgetting into pretty detailed analysisand is limited to those stations whereflow has been measured. Again thex-axis is used to represent the rivermile and the y-axis is used torepresent calculated pollutant loads.The graph below illustrates the changein the load of phosphorus withdistance downstream. Here it isclearly shown that the major increasein pollutant loading occurs betweenstations seven and five. The loaddecreases slightly below river milethree.

44

You may even want to comparedifferent parameters to each other byincluding them on the same plot. Ifthe reporting units and expected rangeof values are the same, you can usethe regular y-axis for both parameters.If the reporting units and expectedrange of values are different, use ay-axis on the left for one of theparameters and draw another y-axison the right for the other parameter.For streams, common comparisons ofthis type are: comparing differentnutrients or nutrient fractions to eachother (e.g., total phosphorus to totalnitrogen, or total phosphorus toavailable phosphorus), or comparingnutrients to dissolved oxygen or pH orTSS. After you have made the graphsreturn to the beginning of this chapterand review each and the parametersand their reasons for variation. Try toexplain the variations in your graphsby what you now know about howeach of the parameters functions.

Additional Analysis andInterpretation Hints❑ As stated previously, DO can

reach critical levels during latesummer when streamflows arelow and temperatures are high.Plotting the DO concentration inlate August against river mile willprovide information on wherelevels become critical and allowyou to guess what may havecaused it. NOTE: If DO appearsto be a problem in a reach of theriver, try a pre-dawn monitoringevent in late summer to assesswhat is termed the worst casecondition.

❑ For fecal coliform bacteria the useof seasonal averages is probablythe best way to compare betweenstations. Calculating and compar-ing the “load” of bacteria is mostinformative and may be the bestway to assess the data.

❑ There are a number of additionalparameters not described in thisguide that can provide interesting,informative data. Two that wouldbe worthwhile to investigateinclude BOD, and conductivity.Standard Methods for theExamination of Water andWastewater would be a goodstarting point for further research.A complete reference is includedat the end of this guide.

45

CHAPTER FOUR

From the Fieldto the LabNow that you’ve read about thedifferent parameters and why wemonitor them, it's time for the “hands-on” information needed to collect andanalyze the samples. Proper samplecollection and analysis are absolutelyvital to the success of your monitoringprogram, whether it’s simple orsophisticated. You just can’t getreliable data with-poor technique.This chapter begins by describingwhat makes good data and explainsthe language of quality assurance andquality control (QA/QC). Next, itpresents basic ground rules forsampling and step-by-step instructionsfor collection and measurement foreach parameter.

What MakesGood Data?Good data are data you can feelconfident about - confident that themeasurements made really do reflectthe true conditions in the lake orstream, and confident that you havecollected enough data over a longenough period to adequatelycharacterize your environment.

Period of RecordThe period of record is the length oftime over which you collect data. Ifthe data had been collected every2 weeks for 10 years, you would havea good period of record. Sudden orgradual increases in pollutant levelscould be reasonably attributed to someevent or change within the system.Conversely, if data had been collectedsporadically for 1 year, it would bedifficult to say whether changes inpollutant levels signified an unusualoccurrence or just normal seasonalchange. In fact, an unusually largechange measured on one samplingdate would likely cause as much in the

way of suspicions about equipment orlaboratory problems as concerns aboutwater quality. (Of course, if you had agood QA/QC plan those suspicionswould be hard to justify.)

A long period of record cansometimes compensate for lower levelsampling and analysis techniques.Even if there is a lot of “noise” inyour data, water quality trends may beidentifiable when you have a longperiod of record.

Quality ofEach Piece of DataIt is not enough to know you usedstate-of-the-art equipment andanalysis techniques. Equipmentbreaks down and people makemistakes. Checks are needed withinyour monitoring program to catchpotential problems. These checks arereferred to as a quality assurance andquality control (QA/QC) plan.

QA/QC is the practice ofmaking sure that collection andanalysis techniques provide precise(i.e., repeatable) and accurate (i.e..correct) information. Some QA/QCprocedures apply to field operationsand many apply to laboratoryprocedures.

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Before you read on, it isimportant that you understand whatQA/QC is all about. Imagine you haveused the best possible field collectiontechniques and then sent your samplesto a lab for phosphorus testing. Whatyou don’t know is whether themachine the lab uses to measurephosphorus will be working properlyat the time your samples aremeasured. You also don’t know howwell the sample you collectedrepresents average conditions in thelake or stream at the time ofcollection. By collecting a few extrasamples, namely lab replicates andfield replicates, you can answer thesequestions.

A field replicate is used tomeasure natural or field variability.The water you collect in one spot in alake may be slightly different from thewater a few feet away. If you collecttwo samples of stream water from theexact same spot by dipping the firstbottle and capping it, and then dippingthe second bottle, a good deal of waterwill have flowed past in the short timebetween dipping the samples. Thesecond sample actually represents anentirely different “slug” of water. Thetwo samples, called field replicates,will often be similar, but not always.Field replicates help you estimate themagnitude of this natural variation.

A lab replicate is used to assessanalytical precision – the ability of theequipment, technique, and technicianto come up with the exact same valuein subsequent measurements on thesame sample. For this reason, it isessential that the lab replicates aretrue replicates of the same sample. Forexample, if you fill a bucket withstream water, collect two phosphorussamples from the water in the bucket,and have them both analyzed at thesame time, the samples are labreplicates. If instead you fill twobuckets with water, collect onephosphorus sample out of eachbucket, and have them analyzed at thesame time, the samples are fieldreplicates. Laboratory replicates areusually submitted in such a way thatthe lab technician running the analysisdoes not know that the sample is a

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replicate. “Blind” replicates eliminatethe possibility for bias from thelaboratory in reporting their results.

The lab and field replicates areways of determining how precise yourresults are. It also is important toknow how accurate the measurementsare. Accuracy is measured in the labthrough the calibration standards.These are samples prepared fromdistilled-deionized “pure” water thatcontain a known concentration of aspecific substance or will, produce aknown instrument response.

Other QA/QC terms you mayhear are field blanks, lab blanks, andspiked samples, all of which areadditional checks on the accuracy andprecision of results. Unless youbecome involved in data analysis, themain QA elements in which you willbe interested concern field samplingprocedures and field equipmentchecks and calibrations.

The complexity of the QA/QCplan determines how much confidenceyou and others will have in yourresults. Certain objectives requiregreater accuracy and precision thanothers. If you were cutting down adead snag in the middle of the forest,you would decide approximatelywhere the snag should fall and thencut away. If the same snag were inyour front lawn, with the house, high-voltage electric lines, and the familycar nearby, you would make sure thatthe tree fell exactly where you wantedit to. You might even hire aprofessional to cut it down. The sameholds for water quality monitoring –there are times when a rough estimatewill do and times when you need to beexact.

QA/QC guidelines need to beset for each project regardless of theintended use of the data. If you do notinclude any QA/QC checks, make astatement to that effect in themonitoring plan. This will ensure thatpeople reviewing the data will knowhow to categorize the informationwhen comparing it with other data.

Perhaps one of the most notabledifferences between a “seasoned”water quality specialist and a beginneris the willingness of the former to

throw out questionable samples anddata. If there is a reason to suspect asample wasn’t collected or analyzedproperly, it is best to discard the dataand not let it “pollute” the high-quality data you may already havecollected.

Ground RulesThe following ground rules refer togeneral sampling guidelines that areapplicable to all water quality samplescollected. (For each of the parametersdescribed, special precautions may beneeded to ensure collection of a goodquality sample. These are describedlater for each parameter under thesection titled “Field SamplingConsiderations.”)

❑ The single most important groundrule for the monitoring program isthis: Document everything you do.A permanent record lets otherswho may want to use your resultsknow how the data were obtainedso they can use the sameprocedures or at least know howto compare them. Documentationbecomes even more important in avolunteer monitoring programsince it provides a ready-madetraining aid for new volunteers.

❑ Safety first! Never enter a streamor lake if the current is too strongor conditions too rough – use asafety line in swift waters. Alwayshave a buddy along who can helpif you get in trouble. Wear a lifevest whenever you are in a boat.

❑ All sample containers need to bewashed with a dilute acid (sulfuricor hydrochloric) and thoroughlyrinsed with deionized-distilledwater. It is very important to keepthese bottles clean betweencollecting the samples. Keep theircaps on tight, and don’t removethem until the sample water iscollected. The Puget SoundEstuary Program protocols andstandard methods referenced atthe back of this guide givedetailed washing guidelines.

❑ Rinse each container with samplewater three times before placingthe sample in the containerpermanently. (Some samplesrequire addition of a preservativethat may be added ahead of time.If this is the case, then the bottlesshould not be rinsed first.)

❑ When sampling in a stream, extraprecautions are needed to ensure asample is not collected from adisturbed area. Always beginsampling at the station nearest themouth of the stream and workyour way upstream.

❑ When it is necessary to enter astream to collect a sample, alwaystake a few steps upstream fromwhere you entered the water, faceinto the current, lean forward, andreach upstream to collect thesample.

❑ Always collect samples from afew inches below the surface of astream, or from the depth of aboutan arm’s length in a lake.

❑ When sampling in a lake or over abridge where equipment can besunk and lost, tie off theequipment to a solid, stable objectfirst.

❑ Label all sample bottles withstation name, date, time, andparameters to be analyzed. Useindelible ink!

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❑ Take lots of field notes. Includeweather observations, visualappearance of the samplingstation or water quality,equipment problems, anddescriptions of techniques used.

❑ Be consistent. Don’t changesampling method, equipment use,or station locations betweensampling stations or samplingdays without noting why thechange was made andpermanently identifying whichdata belongs to which set ofsampling techniques or equipmentused.

Collecting theSampleThere are quite a number oftechniques for getting water from thelake or stream into a sample bottle.The one selected depends upon thesampling site.

The most common method is tohand dip the sample. It also is theeasiest. Hand dipping is ideal if you’resampling from a boat and only need asurface sample, or if you can wade farenough from shore to collect yoursamples. To avoid capturing the tinyorganisms and debris that float on thesurface film of water, the sampleshould be collected from below thewater surface. Hand dipping lets youcollect water from the right locationand depth.

To collect samples as far fromthe shoreline as possible (lakes) orwell out into the main moving channel(stream), use a long or extendablepole. Rig the pole so that it can hold asample bottle, either temporarily orpermanently. Such a device is easy tomake and works well. It also allowsyou to control the depth at which thesample is collected.

Samples also have beencollected by using a weighted bucketattached to a rope. This method ishandy when sampling from a tallbridge where a long pole won’t work.If the water is shallow, make sure thebucket doesn’t disturb the streambottom.

More sophisticated equipmentis usually needed to collect samplesfrom more than one depth in a lake.Several samplers have been designedfor this purpose. The most commonare tube-shaped samplers withopenings on both ends. The ends arepropped open – like a mouse trap –while the sampler is lowered to thedesired depth. The line used to lower

the sampler is marked in 1-foot or1-meter sections and is equipped witha weight called a messenger. Whenthe sampler reaches the desired depth,the messenger is released. When themessenger hits the sampler, the trap issprung, the ends close, and thesampler then can, be lifted to thesurface.

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Sampling andMeasurementMethodsFor each parameter described inChapters Two and Three, fieldsampling considerations, commonmeasurement methods, and QA/QCconsiderations are discussed here.

Dissolved OxygenField SamplingConsiderationsDissolved oxygen concentrations maychange drastically in lakes dependingupon depth and distance from shore.Sampling stations and depths shouldbe selected according to whether ornot you are trying to measure thesedifferences or not. If just one surfacestation is being measured, pick astation near the middle of the lakeand collect the sample at arm’s lengthbelow the water surface.

When collecting stream DOsamples at several stations forcomparison, it is important to selectstations with similar flow conditions.Do not select one station in a slow-moving pool and another in a rifflearea (unless of course one of yourobjectives is to measure thesedifferences). The best sites aresmooth-flowing – like the “glide”area between riffles and pools.

DO samples should representaverage conditions in the streamreach being measured. A samplecollected in the middle of the streamat least a few inches below the watersurface is a safe bet. If the samplemust be collected from the shore, besure to pick a site where there isenough current to ensure adequatemixing – don’t sample from stagnant,slow-moving water if it is notrepresentative of the stream segment.

Assuming your objective is tocompare measurements betweenstations or between seasons, DOsamples should be collected at nearlythe same time of day each time yousample. Otherwise, the daily variations

in DO concentration that weredescribed in Chapters Two and Threemay mask changes due to other factors.The time of sampling and watertemperature should be recorded. Thisproblem with daily variations in DO(and other parameters) also comes intoplay if you sample more than onestation. For example, if it takes a fullday to accomplish the entire monitoringeffort, then by default some stationswill be sampled in mid-morning, whileothers will be sampled in mid-afternoon. To retain as muchconsistency as possible in the datacollected, always sample your stationsin the same order.

Measurement MethodsThere are three common methods formeasuring DO. The first and mostreliable is the Azide-Winkler titrationmethod, against which the others arecompared to test for accuracy. How-ever, this method also requires themost training and the use of somestrong chemicals. For these reasons, itis not often used in citizen monitoringprograms. The second and probablymost common method is the use of aDO probe, and meter. DO also can bemeasured with field kits.

For all three methods, the mostimportant step may be the collectionof the sample. Precautions must betaken to ensure the sample isn’taerated during collection and that nobubbles are trapped in the container.Both the Winkler method and kitsrequire that samples be collected intoa special type of bottle called a BODbottle.

If you are hand dipping theBOD bottle, lower the bottle abouthalfway into the water and let it fillslowly. If you are, sampling in astream, allow the water to overflowfor at least 2 minutes or until thewater in the bottle has replaced itselftwo or three times. Check to be sureno air bubbles are present before youlift the bottle – look closely justbelow the neck of the bottle, wherebubbles often get caught. If you seebubbles, gently tip the bottle to eitherside to allow bubbles to escape.Carefully stopper the bottle so no airpockets form below the cap. Do thisby tilting the BOD bottle slightly andslowly lowering the cap. You maywant to turn the bottle upside downand watch for bubble movement. Ifyou see bubbles, dump the sampleand start over.

If the sample was obtained by asampling device of some kind, thewater can not be simply poured into aBOD bottle since this would causeaeration of the sample. Instead, thesample must be drawn off from a tubelocated near the bottom of thesampling device. Place the rubbertube into the bottom of the BODbottle and fill the bottle, again

The Use of Field Kits forWater Quality Monitoring

Many of the measurementsdescribed in this guide can be madewith the use of water qualitymonitoring “field kits.” Forget abouttest tubes, glass beakers, expensiveelectronic equipment, or a technicianin a white lab coat. These kits areconvenient, easy to use, and come withclear, simple directions. The measure-ments can be quickly made while youare still in the field. This certainlybeats the alternative of taking samplesinto a lab and spending hours doingcomplex analyses.

However, the differencebetween a kit and traditional labtechniques is like the differencebetween opening a can of soup andmaking your own from scratch. Theinstant version just does not meet thestandards of the traditional method.Likewise, kit measurements do notmeet the requirements for precisionand accuracy needed for professionalquality data. At the same time, kitscan play an important role in moni-toring programs. Their usefulness ishighly dependent upon the moni-toring objectives. They are a greateducational tool and can providegood broad-based data for generaluse.

Specific instructions on how touse kits have not been included inthis guide because they are providedwith the kits and will vary accordingto the kit manufacturer.

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allowing the bottle to overflow untilthe water has been replaced two orthree times. While still letting samplewater flow down the tube, slowly pullthe tube from the bottom of the bottleand fill the bottle to its brim. Checkfor bubbles. Carefully stopper theBOD bottle as described above.

Azide-Winkler Method1. Fill a 300-mL glass

stoppered BOD bottle with samplewater. Remember – no bubbles!

2. Immediately add 2 ml ofmanganese sulfate to the collectionbottle by inserting the calibratedpipette just below the surface of theliquid. (If the reagent is added abovethe sample surface, you willintroduce oxygen into the sample.)Squeeze the pipette slowly so nobubbles are introduced via the pipette.

3. Add 2 mL of alkali-iodide-azide reagent in the same manner.

4. Stopper the bottle with careto be sure no air is introduced. Mixthe sample by inverting several times.Check for air bubbles; discard thesample and start over if any are seen.If oxygen is present, a brownish-orange cloud of precipitate or flocwill appear. When this floc has

settled to the bottom, mix the sampleby turning it upside down severaltimes and let it settle again.

5. Add 2 mL of concentratedsulfuric acid via a pipette held justabove the surface of the sample.Carefully stopper and invert severaltimes to dissolve the floc. At thispoint, the sample is “fixed” and canbe stored for up to 8 hours if kept in acool, dark place. As an addedprecaution, squirt distilled wateralong the- stopper, and cap the bottlewith aluminum foil and a rubber bandduring the storage period.

6. In a glass flask, titrate201 mL of the sample with sodiumthiosulfate to a pale straw color.Titrate by slowly dropping titrantsolution from a calibrated pipette intothe flask and continually stirring orswirling the sample water.

7. Add 2 mL of starch solutionso a blue -color forms.

8. Continue slowly titratinguntil the sample turns clear. As thisexperiment reaches the endpoint, itwill take only one drop of the titrantto eliminate the blue color. Beespecially careful that each drop isfully mixed into the sample beforeadding the next. It is sometimeshelpful to hold the flask up to a white

sheet of paper to check for absence ofthe blue color.

9. The concentration ofdissolved oxygen in the sample isequivalent to the number of millilitersof titrant used. Each milliliter ofsodium thiosulfate added in steps 6and 8 equals 1 mg/L dissolvedoxygen.

NOTE: Be very careful whendoing DO analyses. The reagents arecorrosive, so keep them away fromyour skin and clothes. Wear safetygoggles and wash your hands whenyou are done.

Probe and Meter Method1. Calibrate the probe

according to the manufacturer’ssuggestions.

2. Collect the water sampleinto any appropriate samplecontainer, being careful to avoidaerating the sample as describedabove.

3. Place the probe in thesample, allow the meter toequilibrate, and read the DOconcentration directly off the scale.NOTE: The probe may need to begently stirred to aid water movementacross the membrane.

Field DO probes are easilyruined through deterioration of themembrane, trapping of air bubblesunder the membrane, and contami-nation of the sensing element. It oftenis difficult to assess whether or not aprobe is functioning properly.Because of this, the meter must becalibrated before and after each seriesof measurements. When you calibratethe instrument, you compare DOconcentrations measured by the probeto those measured using the Azide-Winkler method described above andthen correct all samples for anymeasurement error. The metermanufacturer’s calibration procedureshould be followed exactly. If theerror is high or erratic, all sampleresults should be discarded.

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QA/QCConsiderationsEven though the Winkler DOs are themethod against which the others arecalibrated, there are still tests that canbe made to ensure the Winklersthemselves are accurate. To test themethod, you need to have sampleswith a known oxygen concentrationso you can compare your results towhat you know is the real answer.These are called calibration samplesor standards. A 100 percentsaturation solution can be prepared bybubbling air into distilled water. Iflow DOs are expected, a zero DOsolution can be made by addingexcess sodium sulfite and a trace ofcobalt chloride to a sample. In aprofessional lab, a calibrationstandard would be analyzed with eachbatch of samples run.

Randomly select 5 to 10percent of the samples for duplicatelaboratory analysis. If you areinterested in field variability, select5 to 10 percent of the samples forfield duplication (e.g., collect twosamples from the same station).

If you are using a probe andmeter or field kit for measurement,5 to 10 percent of your samplesshould be checked against theWinkler DO method.

pHField SamplingConsiderationsBecause pH values can changerapidly, this parameter must bemeasured in the field immediatelyafter collecting the sample.

Measurement MethodsThere are three methods formeasuring pH; a probe and meter,litmus paper, and a field kit. The mostaccurate and reliable method is theprobe and meter. This method is noless convenient than the othermethods, but requires a moreexpensive piece of equipment.

Probe and Meter1. Calibrate the probe and

meter according to the manufacturer’sdirections. Use of two buffers (pH 7and 10) for calibration isrecommended.

2. Sample water can becollected in any glass or plasticcontainer. Collect enough samplewater so that you can submerge thetip of the probe. Rinse the probe withsample water before placing it in thesample.

3. Place the probe in thesample and wait for the meter toequilibrate. If the meter needs to bemanually adjusted to correct for

temperature – you’ll know it does if ithas an extra temperature knob –adjust it to the temperature of thesample before allowing it toequilibrate. The meter will have cometo equilibrium when the signalbecomes steady. If it is taking a longtime to equilibrate, you may trygently stirring the probe. However donot agitate the sample since this maycause changes in the pH.

4. Read the pH directly fromthe meter according to themanufacturer’s directions.

Litmus PaperLitmus paper is simply a strip ofcolored paper that is soaked insample water. The paper turns adifferent color depending upon thepH of the solution. It provides a verycoarse measurement of pH – it is finefor making simple determinations,but it is too coarse a measurement forallowing comparisons betweensampling, dates or stations.

QA/QCConsiderationsFollow the manufacturer’sinstructions for storage andpreparation of the probe. Most probesneed to be kept moist during storage– this is important! Rinse the probewith distilled water and blot dry

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between all samples.The probe must be standardized

with known buffer solutions every3 hours and whenever a major changein the pH of the sample water isexpected. (In natural waters wherethere is no large influence from aneffluent discharge or other potentialsource for pH change, major pHchange is not likely to be a problem.)Follow the manufacturer’sinstructions for calibrating. Use twostandards for calibration, a neutralstandard and either an acidic or basic(alkaline) standard, depending uponthe expected pH range of the samples.In natural fresh waters, standardswith pH 7.0 (neutral). and pH 10.0(base) usually are appropriate.

To assess field variation,collect duplicates at 5 to 10 percent ofthe stations and measure pH.

The accuracy of field kits orlitmus paper can be checked bycollecting a few samples to be readback at the lab with a pH probe.However, due to the time lapse andpossibly rapid changes in pH, this labcheck would be used only as a roughverification of results.

TemperatureField SamplingConsiderationsWhenever possible, measuretemperature by placing thethermometer directly into the lake orstream. For stations where this is notpossible, allow the samplingcontainer to cool in the sample waterbefore the sample is collected.Measure temperature immediatelyupon sample collection. Remember toselect sampling sites and locationsthat are representative of the streamreach or lake.

Measurement MethodsWater temperatures are measuredwith a common thermometer, or byheat-sensing elements located at thetips of DO probes, pH probes, andthe like.

1. Measure temperature bylowering the thermometer so the tip isa few inches below the water surface,or place the thermometer in thesampling container. Allow thethermometer time to come toequilibrium and read immediately.

2. Record the time of day.

QA/QCConsiderationsAll thermometers should be checkedagainst a thermometer certified by theAmerican Society for Testing andMaterials or the National Bureau ofStandards. If this has not been done,be sure to use the same thermometerfor the entire study so thatthermometer error is at leastconsistent throughout the study. Ifmore than one thermometer is used,calibrate them against each other.

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Secchi Disk DepthField SamplingConsiderationsExcessive waves, wind, or sunlightmay jeopardize Secchi disk readings.To minimize these effects, takereadings during calm days that arepartly cloudy to sunny. Anchor theboat at the sampling station to avoidboat drift, and lower the Secchi diskoff the shady side of the boat. If theSecchi disk drifts too fast for anaccurate reading – that is, the line isnot vertical in the water – tryweighting the bottom of the disk tomake it sink faster or taking themeasurement on the downwind side ofthe boat. If none of these techniqueswork, and you do not think you canobtain an accurate reading, DO NOTmake the measurement because it willnot be a good representation of lakeconditions on that day.

Be sure to note weather condiionsalong with the Secchi disk reading.

NOTE: Secchi depth readingsare rarely taken in streams because ofthe inaccuracies associated withflowing water, disk movement, andshallow depths.

Measurement Methods1. Slowly lower the disk into

the water to the point where it justdisappears.

2. Place a clothespin on the linewhere it meets the water surface, ormark the point on the line in someother way.

3. Continue lowering the disk afew more inches, and then slowlyraise it until it just becomes visibleagain. Mark this spot with anotherclothespin or hold the rope herebetween your fingers.

4. The spot halfway betweenthe two marks represents the averageSecchi disk reading. Mark the spot bymoving the clothespin or other markerto the spot.

5. Carefully measure or countthe distance from the disk to themarked spot. Record the distance tothe nearest tenth of a foot or meter.

QA/QCConsiderationsThe Secchi disk reading is subjectivebecause of differences in people’svision and weather conditions. Thereis no QA/QC check that can be usedto “calibrate” the different readings.The slight differences in visiongenerally are considered insignificant.Some of the error caused by thesubjectivity of this measurement canbe reduced by having the same personmake the measurement each time.

NutrientsField SamplingConsiderationsThere are no special field samplingconcerns associated with nutrientsamples other than those described inthe section on basic sample collectiontechniques. It is especially importantthat sample containers be clean whencollecting nutrient samples.Containers used for nutrient analysesshould be acid-washed (soaked indilute hydrochloric acid) and rinsedthoroughly with distilled water. If youare collecting samples for laterlaboratory analysis, you must properlypreserve and store them. Professionallabs usually provide properly cleanedbottles, often with preservativealready in them. Clarify theseprocedures with the lab beforesampling.

Measurement MethodsAlthough there may be numerouslaboratory techniques for analyzingany one nutrient, this should not be aconcern for a volunteer monitoringprogram. For the purpose of thisguide, there are only two methods:analysis by a certified lab, or analysisby the use of field kits. In the firstcase, volunteers only need beconcerned with proper collection andpreservation techniques. In the secondcase, detailed directions will beprovided with the kits.

If nutrient samples are collectedfor later analysis, proper handling andpreservation are important. Thefollowing table details handling,preservation, and holding times foreach of the nutrients. All require thesame initial treatment – preservationwith sulfuric acid (except for SRP)and storing in the dark at 4oC. (Thismeans storing them on ice in a cooleruntil you can get them to arefrigerator.) The amount of time theycan be held in this condition beforeanalysis varies. It is the lab’sresponsibility to analyze the samplesbefore the time limit expires. Theyneed to report the time and day ofanalysis. One of the QA/QC checksyou should make when data arereturned is that samples were runwithin an acceptable time limit.

Preserve nutrient samples byinserting a few drops of sulfuric acidinto the sample bottle. Enoughsulfuric acid needs to be added toreach a pH<2. The amount needed

will vary depending upon the volumeof water being preserved; however, itdoesn’t need to be an exact amount.Typically about a half a milliliter orhalf an eye dropper full is enough topreserve a 250-mL sample. Test thenumber of drops needed on onesample and use that amount for therest of the study. Do not test pH on asample you intend to have analyzedunless you ensure that the sample isn’tinadvertently contaminated.

Because the preservation andhandling methods are the same for allbut the SPR, one sample bottle can beused for most of the nutrient analysesfrom one station. This will save time,energy, and space because fewerbottles will need to be washed, fewersamples will need to be collected, andless space will be needed in the icechest, refrigerator, and whatever otherstorage containers are used. Usuallyone 500-mL container plus anadditional 125 mL container, if SRP is.being analyzed, will suffice for all thenutrients. Have this OK’d with the labahead of time.

The Special Case of SRPSRP (aka orthophosphorus orphosphate) samples must be filteredwithin 8 hours of collection and thenanalyzed within 2 days. Because ofthe delay between collecting samplesand getting them to a lab for analysis,the filtering usually must be done bythe persons doing the monitoring.Filtering requires the use of a smallpump, filtering apparatus, and0.45 µm membrane filters that havebeen soaked in distilled water beforeuse. A minimum of 50 mL of watermust be filtered for each sample, andthen poured into a fresh, properlycleaned sample bottle (acid washedand distilled water rinsed). The entirefiltering apparatus needs to be acidrinsed and thoroughly rinsed withdistilled water between each sample.

P

Am

Nitr

Tot

SRP

TotPho

*SRP

Proper Storage and Handling Procedures for Nutrient Samplesarameter Preservation

with SulfuricAcid

Holding inthe dark at

4oC

PreferredTime Limitfor Analysis

MaximumTime Limitfor Analysis

monia Yes Yes 7 days 28 days

ate-Nitrite Yes Yes 24 hours 28 days

al Nitrogen Yes Yes -- 28 days

No* Yes 48 hours 48 hours

alsphorus

Yes Yes 48 hours 28 days

samples must be filtered within 8 hours and then preserved.

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QA/QCConsiderationsIn addition to standard lab QA/QC,lab replicates should be collected for5 to 10 percent of the samples, basedon a random selection process. If kitsare used for analysis, you may want tocheck your results against laboratorymethods. In this case, 5 to 10 percentof the samples should be replicated bythe laboratory method to check kitprecision against more sophisticatedlab methods.

TSS and TurbidityField SamplingConsiderationsThere are no special field samplingconcerns associated with theseparameters other than those describedin the section on basic samplecollection techniques. It is especiallyimportant for these parameters that thesample is collected from undisturbedwater. Once you step into a stream,you stir up the stream bottom – that’swhy you step upstream, lean, andreach into the current for the sample.In lakes, boat propeller action alsomay disrupt sediments in shallowareas. Again, do not sample fromdisrupted water.

Measurement Methods

TSS1. Before sampling, prepare

glass fiber filters by first soaking themin distilled water, drying them at103oC, and weighing and recordingtheir weights.

2. Place the dried, weighedglass fiber filter onto a filtering flask –wrinkled side up. Shake the samplebottle first, then pour in the water andturn on the pump. (The amount ofwater you need to filter may changeaccording to water conditions. Startwith 100 mL. Use less volume if thefilter gets clogged too quickly andmore if the water filters through veryfast.) Record the volume of waterfiltered.

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3. Dry the filter at 103 to105oC, let it cool to room temperature,and weigh it. Dry it, cool it, and weighit again. Continue until the fiberreaches a constant weight. Record theend weight.

4. The increase in weightrepresents TSS. Calculate TSS byusing the equation below.TSS (mg/L) = ([A-B]*1000)/CWhere A = End weight of the filter B = Initial weight of the filter C = Volume of water filtered

TurbidityTurbidity is a measurement of theoptical property of water – a measureof the amount of light that is scatteredand absorbed by particles in thesample. It is a simple measurementthat requires the use of either anephelometer or Jackson turbidimeterto compare a reference solution to thesample. Turbidity measurement doesnot require any sample preparation,other than shaking the sample bottlewell before analysis. The sample issimply poured into a glass tube,placed inside the instrument with areference solution and the result isread directly from the instrument.(The nephelometer has recentlybecome recognized as the moreaccurate and recommended piece ofequipment for this analysis. However,if a Jackson turbidimeter is what youhave available, it will work fine.)

TSS and turbidity samplesshould be held in the dark on ice or at40oC. In this condition, TSS samplescan be held for up to 7 days andturbidity samples for up to 2 days.

QA/QCConsiderationsRandomly select 5 to 10 percent of thesamples and collect lab replicates forthem. Lab QA/QC will involveselecting 5 to 10 percent of thesamples for duplicate analysis, andcalibration of all equipment used.

Fecal ColiformBacteria

Field SamplingConsiderationsBacteria samples, more than any ofthe other water quality parameters, arethe easiest to contaminate. The samplebottles and their caps must bethoroughly cleaned and sterilized inan autoclave before each use. Thecaps must remain tightly on thebottles until just before the sample iscollected. Care must be taken whenunscrewing the cap and collecting thesample to ensure nothing touches theinside of the cap or bottle - includingyour hands or fingers.

Because bacteria attachthemselves to small particulate matter,there are two sampling precautionsthat bear emphasis. First, alwayscollect the sample upstream of anyarea that may have been disrupted byentering the stream – take a few stepsforward, lean into the current, andcollect the sample at arm’s reach.Second, the top film of water will

have an excess accumulation ofbacteria, so it is not representative ofstream or lake conditions. For thesample to be a good representation ofwater conditions, only a small portionof this surface film should besampled.

A standard technique has beendeveloped for collecting bacteriasamples to account for thesedifferences. To avoid the surfacelayer, the bottle is “plunged” throughthe surface film by holding the bottledirectly upside down and quicklysubmerging it. An inch or two belowthe surface, tilt the bottle toward thecurrent and slide it in an arc towardthe surface, removing the bottle in avertical position. Leave about one-halfinch, of air space at the top.Immediately cap the bottle and put thesample on ice in a dark place (an icechest).

The official procedure foranalyzing bacteria requires analysiswithin 6 hours of collection. This israrely possible. However, they mustbe run within 30 hours or the resultsshould be discarded.

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Measurement MethodsThere are two common laboratoryprocedures for analyzing fecalcoliform bacteria: membrane filtration(MF) and most probable number(MPN). The two are not directlycomparable, so pick one method andstay with it. MF is the recommendedprocedure for freshwater monitoringand is more commonly used at thistime. However, it is not as reliable amethod as MPN in very turbidsamples.

Field kits also are available formeasuring bacteria. They still requireaccess to some special equipment –such as petri dishes and a small ovenor incubator – but if your group hasaccess to a small lab and someequipment, field kits can be usedsuccessfully for educational purposes.

QA/QCConsiderationsBacteria often exhibit a large amountof field variability, so collection offield replicates (5 to 10 percent of thesamples) can be important for thisparameter. Lab replicates for 5 tol0 percent of the samples can becollected, but some error is introducedwhen pouring from one samplecontainer to the other. Lab replicatesalso should be analyzed as part of thelab’s standard QA/QC policy.

Chlofophyll aField SamplingConsiderationsDue to the fact that algae liveprimarily near the surface of a lake,chlorophyll a samples are typicallycollected just below the surface.Collecting a sample at one stationnear the midpoint of the lake is oftenadequate for a simple characteriza-tion of seasonal changes or possibletrends in chlorophyll. If themonitoring objective is to compareportions of the lake, their chlorophyllsamples should be collectedaccordingly. Because algae can be

blown by the wind, samples collectednear shore or at the downwind end ofthe lake may not be representative ofaverage lake conditions.

Since algae can quicklyreproduce or die, which will changethe relationship between live cells anddead cells in your sample, samplesneed to be preserved in the field. Afew drops of magnesium carbonatesolution will adequately preserve a200-mL sample. (NOTE: Be sure thelab doing the analysis is aware thatyou are interested in the chlorophyll aconcentration, not just chlorophyll)

The density of the algaepopulation will determine how muchsample is needed for the analysis.During the winter when populationsare low, 1,000 mL (1 liter) may needto be filtered to get an accuratereading. On the other hand, in summermonths during an algae bloom, thefilter may clog before 50 mL havebeen filtered through it. To ensure thelab has ample water, a 1,000-mLsample should be collected.

Measurement MethodsChlorophyll a is measured by filteringa known amount of sample waterthrough a glass fiber filter. The filterpaper itself is used for the analysis.The filter is ground up in an acetonesolution and either a fluorometer orspectrophotometer is used to read thelight transmission at a givenwavelength, which in turn is used tocalculate the concentration ofchlorophyll a. Because of theequipment requirements for this test,it is assumed that the filtering andanalysis will be done by aprofessional lab.

QA/QCConsiderationsRandomly select 10 percent of thesamples for lab replicates. Fieldvariability can be assessed bycollecting field replicates for 5 to 10percent of the samples.

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CHAPTER FIVE

Getting aHandle onHydrologyAs described in Chapter Three, streamflow greatly influences the characterof a stream. By its own merits, it is animportant parameter for understandingstream water quality. Stream flow alsois necessary for calculating pollutantloadings – an important tool forinterpreting stream water quality data.The following chapter describes howto measure flow and how to set up astaff gage for measuring streamheight. It also explains how to usestaff gage measurements to predictstream flows and how to calculatepollutant loads using stream flowdata.

MeasuringStream FlowStream flow measurements canprovide important information forboth streams and lakes. In addition toallowing a comparison betweenpollutant loading and concentration,the changing relationship betweenprecipitation and stream flow can bean important indicator of impactsfrom developing watersheds.

As watersheds develop, an ever-increasing portion of the land iscovered by buildings, concrete, andasphalt. These impermeable surfacesprevent rainwater from seeping intothe ground, and instead tend tochannel and speed water on its way tothe nearest stream. In a developedwatershed, a small amount of rainmay cause a rapid rise in flow innearby streams, whereas the sameamount of rain may have caused animperceptible change in stream flowprevious to development.

Taking streamflow measure-ments can be a fairly involved processif done right, but there also are simplemethods that can be used to provide

rough estimates for comparison. Twomethods are described here. The firstis a slightly modified version of theofficial U.S. Geological Survey(USGS) method. It is the method thatmost professionals use. The second isa simple method for obtaining a roughestimate that doesn’t require anyexpensive equipment. For bothmethods, the first step is to choose agood spot for making themeasurements.

Selecting a Station forStreamflow MeasurementSelecting the proper location formeasuring stream flow can be asimportant to collecting accurateinformation as the method used to

take the measurements. Ideally, all ofthe following criteria should be met.In reality, they rarely are. However, itis important to understand thelimitations of the site you select andthe potential effects on streamflow.measurements.

❑ The site should be readily andsafely accessible. Never, enter astream if the water is too high ormoving too fast for you to feelcomfortable. Remember that asegment that was safely crossed insummer may be inaccessible inwinter. Expect a difference andmake a conscious decision eachtime you enter a stream.

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❑ The site should lie in a section ofstream that is freeflowing:

− The stream should be straightfor enough distance to haverelatively uniform flow. (TheUSGS recommends 300 feet.In most smaller streams, youwill be lucky to find a 100-foot straight section.)

− The station should be locateda sufficient distance upstreamof tributaries and tidal actionto ensure flow is not affectedby either.

− The stream should be con-fined to one channel. (Checkto be sure there are no sidechannels or evidence thatthese may form during highflow conditions.)

− Streambanks should be highand stable enough to containmaximum flows.

− The streambank and channelshould be relatively free ofthick brush or vegetation thatmay slow the water and makemeasurements difficult.

− Flow should be uniform andfree of eddies, slack water,and excessive turbulence.

− The streambed should beuniform. (Check for largeboulders or logs, andconsistency in depth andvelocity.)

Measuring StreamFlow with a MeterThe EquipmentThe three most common types of flowmeters in use are cup, propeller, andmagnetic meters. Cup and propellermeters determine flow velocityaccording to the number of revolu-tions of the cups or propeller over agiven time interval. Magnetic metersmeasure the difference in waterpressure as water flows around asensor.

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Whichever meter you use, itneeds to be mounted on a rod orstrung at the end of a cable to allowthe propeller or other mechanism tobe held in one place while themeasurement is taken. Usually themeters are mounted on what is calleda top-setting rod. A top-setting rodactually consists of two rods: asupport rod and a smaller rod that canslide up and down the support rod.This second rod holds the businessend of the meter (let’s call it thepropeller) and allows it to be raised orlowered to the desired depth.

You may be surprised to learnthat the velocity of water changeswith depth. Hydrologists havedetermined that average velocity in astream occurs just below mid-depth –at 0.6 times the total depth to be exact.That is where you want to place yourpropeller. Top-setting rods aredesigned so that you can slide thepropeller up or down the support rod –which rests on the stream bottom –and measure velocity at the desireddepth.

Making the Measurement:The USGS Method

1. String a measuring tapeacross the stream at right angles to theflow. Tie the tape off at both sides ofthe stream. Make it taut enough sothat it doesn’t sag near the middle.easure the stream width. Leave thetape in place.

2. First determine the widthintervals you will measure. Theofficial method requires that at least20 points of measurement be madeacross the width of the stream. To dothis, divide the total stream width by20 to calculate the distance betweenpoints. If you have been lucky enoughto find a station that has a relativelyuniform depth and velocity, or if it is anarrow stream, 20 points may be morethan you need. In many cases,especially in very small streams (anddepending upon the accuracy youdesire), it is adequate to measurevelocity at 1-foot, or one-half-footintervals even if that means you mayonly have five or ten measurements.

Measuring points should be closertogether or more frequent whereverthere is a lot of variation in the depthor velocity of the cross section.

3. Start at the very edge of onebank and work your way across thestream, measuring velocity with themeter at each of the 20 points andnoting your distance from the bankedge where you started. For example,if your stream was 20 feet wide, youwould make measurements at one-foot intervals. The first measurementwould be taken at zero feet from theedge (the velocity will likely be zero),the second at 1 foot and so on to 20.

NOTE: Stand at least 1 footaway on the downstream side of thetape and hold the meter and rod nextto the tape. Be sure you are standingfar enough from the meter to ensurethat the eddies around your boots arenot interfering with the flowmeasurement.

4. At each measuring point,read and record the total depth,multiply the total depth by 0.6 todetermine the depth of averagevelocity, set the propeller at the newdepth, read and record the velocity.Also, remember to record your

distance from the bank for eachmeasurement.

5. The total amount of watermoving through your section is afunction of the size of the stream(cross-sectional area) and the velocity.Use the velocity measurements andthe depth and distance measurementsyou recorded to calculate the totalvolume of water flowing through thesection (total discharge).

Finding the Average VelocityStream velocity varies vertically(from surface to the bottom) ateach point in a stream. Streamhydrologists have developed astandard technique to ensureconsistency in determining the“average” velocity at a given point.The USGS method assumes that atpoints where the depth is less than2.5 feet, the aver- age velocityoccurs at six-tenths of the totaldepth. Where the stream is deeperthan 2.5 feet, the velocity is mea-sured at two-tenths and eight-tenthsof the total depth, and the averageof the two readings is used as theaverage velocity -at that point.

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6. Total discharge is calculatedas the summation of the dischargefrom each of the intervals measured,as described and illustrated above andon page 61.

Measuring Stream Flowwith a Simple FloatIf a flow meter is not available or arough estimate is adequate, you canmeasure flow by using a float. Thefloat can be any buoyant object, suchas an orange or a partially filledplastic water bottle. It needs to beheavy enough so that about an inch ofit is below the water line. (Don’t use

glass or any material that may causeproblems if you are can’t retrieve thefloat after the measurement.)

1. Measure off at least 50 feetalong the bank of a straight section ofstream. If possible, string a ropeacross each end of the 50-foot length.

2. Estimate the cross-sectionalarea of the stream at one of these endsby using the total stream width andthe, average depth. (Calculate theaverage depth from depths measuredat 1- to 2-foot intervals.)

Total width (ft) x Average depth (ft)area

3. Release the float at theupstream site. Using a stopwatch,record the time it takes to reach thedownstream tape. (If the float movestoo fast for an accurate measurement,measure off 75 or 100 feet instead of50.) Repeat the measurement twomore times for a total of threemeasurements.

4. Calculate the velocity asdistance traveled divided by theaverage amount of time it took thefloat to travel the distance. If thedistance roped off is 50 feet and theorange took an average of 100seconds to get there, the velocity is0.5 ft/sec.

50 ft = 0.5 ft/sec100 sec

5. Correct for the surfaceversus mid-depth velocity by multi-plying the surface, velocity by 0.85.

0.5 x 0.85 = 0.43 ft/sec

6. Calculate the discharge incubic feet per second (cfs) bymultiplying velocity (ft/sec) by thecross-sectional area (ft2) of the stream.

0.43 ft/sec x 10.73 ft2 = 4.62 cfs

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Using a Staff GageA staff gage is nothing more than along ruler placed semi-permanently ina stream or lake and used to readwater depth. Stream gages are themost common and useful measure andare therefore emphasized here.However, you also can put a staffgage in a lake to monitor changes inlake water level.

Why Use a Staff Gage?Staff gage information can be used inan indirect way to estimate streamflow. If you place a staff gage near asection of stream for which you arecollecting flow data, you can identifythe relationship between stream depthand stream flow. Once you know thisrelationship, you can estimate flowfrom the stream depth without havingto take the time and trouble to make adetailed flow measurement. Periodi-cally, the staff gage will need to berecalibrated against measured flowssince the streambed, and thus therelationship between stream heightand flow, can be expected to changeover time.

Setting Up a Staff GageAs was the case with stream flow, siteselection is very important. Thecriteria used to select a flowmeasuring site are also important tothe selection of a gage site. In fact,most of the time you will want toplace a staff gage wherever youmonitor flow.

Once you have selected a goodflow monitoring site, it still may behard to find a proper place for thestaff. If placed too near the side of thestream, the staff may be dry duringsummer months. If placed near mid-stream, it may be washed away byhigh winter flows. The staff shouldnot be placed in very slow-movingwater or in a pool because sedimentswill accumulate around its base. Theresulting localized changes in waterflow patterns could affect yourreadings. On the other hand, turbulentwater can make it difficult to read thegage. If your station is located near a

bridge that has pilings in mid-stream,the downstream side of the pilingoften provides a good location for agage.

The simplest way to install astaff gage is to attach it to apermanent structure, such as thebridge piling mentioned above. Life israrely so convenient. You may have toprovide your own “permanent”structure, for example, by pounding astrong metal pipe into the stream bed.Be sure the pipe is strong and tallenough to last through high waterconditions. A PVC pipe also works.However, since these pipes are lightand hollow, numerous holes should bedrilled through them to allow thewater to flow freely through the pipe.This will alleviate much of the extrastrain on the pipe caused by high, fast-moving water. (NOTE: Lakes areeasy. Just attach the gage to the end ofa dock or pier where you can easilylean over and read it. Be sure the dock

is permanently anchored to the lakebottom. A floating dock or one that isremoved every year won’t work.)

You can also “gage” a streamwithout using a staff gage bymeasuring the distance between thewater surface and a known fixedheight. If a bridge crosses your streamnear where you want to establish astaff gage, you’re in luck. Thedistance between the bridge and thesurface of the water changes inresponse to changes in the streamdepth. Measuring the distance fromthe bridge to the water surface letsyou determine stream height.

To use this method, make apermanent mark on the side of thebridge to be sure your measurement isalways taken at the exact same spot.Drop a weighted tape measure untilthe weight touches the water andrecord the distance from the bridge tothe water. This is a wonderfullysimple method of obtaining stream

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height data, but it may not be highlyprecise. Even very small changes instream depth or height may reflectlarge changes in stream discharge,particularly in a wide stream. Whenmeasuring the distance to the watersurface from a bridge, you may havedifficulty telling just exactly when theweight has reached the water’ssurface. On a windy day, the tape maynot hang straight down to the watersurface, or waves may make the tapebounce. Furthermore, different peoplewho take the reading will likelyinterpret the point of contact withwater a bit differently. The fartherabove the water the bridge is, themore these factors are likely to affectaccuracy.

To reduce the error from thismethod, be sure your mark on thebridge is clear and has a line showingexactly where the tape should be read.Write down exactly how you aredefining the surface of the stream. Forexample, is it when the weighttouches the water, or when the weightis fully submerged? Taking care ofthese small details will improveconsistency in the measurement.

Forming a

Stage-DischargeRelationshipEach time you take a flow measure-ment, you should take a gage reading,On a sheet of paper or in a computerfile, keep a record of each flowmeasurement. You take and thecorresponding staff gage reading.Once you have enough data, yousimply plot these two variables on agraph and draw or compute theresulting curve.

Draw a graph with an x-axisand y-axis. The x-axis, the horizontalline, will be the streamflowmeasurement. The y-axis, the verticalline, will be the staff gage reading.Place a dot on the graph where eachstreamflow and corresponding staffgage measurement intersect. Draw asmooth, curved line between thepoints. Now you have a stage-discharge relationship. From now on,you can simply take the gage readingand estimate the stream flow fromyour prediction curve.

As convenient as a stage-discharge relationship is, it still needsto be supported by real data. The moredata points you use to develop yourgraph, the better, The graph isaccurate only for the stream flows that

fall within the data range you used tocreate the graph. For example, if allyour measurements were taken duringJune through September when streamflows were low, the graph could notbe used to predict high flows inDecember. Be sure to collect dataduring a wide range of flowconditions. In general, if you haveabout four data sets from the low-flowperiod and four from the high-flowperiod, you can comfortably preparethe graph. Make periodic checks ofthe discharge curve, especially afterperiods of flooding. Recalibrate thecurve if the periodic checks indicatethe relationship has changed.Eventually, natural changes in thestream bottom will result in a changein the relationship between flow andgage height.

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CalculatingPollutant LoadsThe importance of pollutant loadingcalculations was described in ChapterThree. Loading is a simple function ofconcentration and flow. Loading canbe reported in a number of differentunits and can be calculated as shownin the table.

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Resources andReferences

Volunteer MonitoringInformationThe Volunteer Monitor –The National Newsletter ofVolunteer Water Quality Monitoringc/o Adopt a Beach710 Second Ave., Suite 730Seattle, WA 98104(206-296-6591)

National Directory of CitizenVolunteer Environmental MonitoringProgramsRhode Island Sea GrantInformation OfficeUniversity of Rhode Island BayCampusNarragansett, RI 02882-1197(401-792-6842)

Save Our Streams ProgramIzaak Walton League of America1401 Wilson Blvd., Level BArlington, VA 22209(703-528-1818)

Volunteer Resource Guide:A Citizen’s Directory to VolunteerOpportunities in Caring forWashington’s Outer Coast, PugetSound, and Associated WatershedsVolunteers for Outdoor WashingtonAdopt a Beach607 Third Ave., Room 210Seattle, WA 98104(206-467-0278)

Available Soon:Field Guide to Watershed Inventoryand Stream Monitoring MethodsAdopt-A-Stream FoundationP.O. Box 55558Everett, WA 98201(206-388-3313; 1-800-424-4EPA)

Lake and StreamAssociationsThese groups promote the exchangeof information and public awarenessabout lakes and streams, and offertechnical support to private citizensand citizen groups.

Washington State Lake ProtectionAssociation (WALPA)P.O. Box 1206Seattle, WA 98111-1206

North American Lake ManagementSociety (NALMS)P.O. Box 217Merrifield, VA 22116

Adopt-A-Stream FoundationP.O. Box 55558Everett, WA 98201

Information ManualsField Manual forWater Quality Monitoringby Mark Mitchell and William StappWilliam B. Stapp2050 DelawareAnn Arbor, MI 48130

Adopt-A-Stream Teacher’s HandbookDelta Laboratories, Inc.34 Elton St.Rochester, NY 14607

Water Quality Indicators Guide:Surface Waters(Ask for: Pub # SCS-TP-161)P.O. Box 2890Washington, DC 20013

Standard Methods for theExamination of Water andWastewater, 17th ed.American Public Health Association(APHA)Washington, DC

Recommended Protocols forMeasuring Selected EnvironmentalVariables in Puget SoundUSEPA - Office of Puget Sound1200 Sixth Ave.Seattle, WA 98101

Water Quality Sampling KitsHACH CompanyP.O. Box 389Loveland, CO 80539(1-800-227-4224)

LaMotte Chemical ProductsP.O. Box 329Chesterton, MA 21620(1-800-344-3100)