watershed hydrology & sediment dynamics...• assess river character. stage 2 data analysis •...

Watershed Hydrology & Sediment DynamicsSediment Transport in Stream Assessment and DesignMonday, August 1, 2016Patrick Belmont

“It is hard to imagine that a transport estimate made in the absence of a sound understanding of watershed history and dynamics would be of much use at all.”

A. Alabyan and A. Sidorchuk. Siberia G. Parker. Browns Gulch, Montana

G. Parker. Fly River, Papua New Guinea.

J. I

mra

n. B

rahm

aput

ra R

iver

, Ban

glad

esh.

Great diversity in channels and watersheds...

...emerging from complex interactions

Wheaton et al., 2011

How much and what type of sediment is being delivered to this channel?

What information do you need to answer those questions?

Is sediment supply a BIG number or SMALL number?

Interception Storage

Surface Storage

Unsaturated Zone Storage

Saturated Zone Groundwater Storage

Channel StoragePlan

t Sto

rage

trans

pira

tion rain, snow, condensation

stemflow, canopy drip

infiltration

percolation

outlet

plant uptake

Atmospheric Moisture

Hydrology matters...

Land use matters...

Soils and surficial geology matter...

Trimble, 1999

Sediment transport throughwatersheds is complicated

Natural and human-caused‘legacy effects’

Storage matters...

Grain size matters

Sediment type and grain size fractionation matter...

Bed and lower point bars made of bed material load

Banks and levees made of suspended load

Floodplains preserve old channel deposits + overbank

Floodplain

Coarse and fine load often have different sources/transport paths

Sediment type and grain size fractionation matter...Coarse and fine load often have different sources/transport paths

All else held constant, aggradation on the bed causes… aggradation on the floodplains

Sediment type and grain size fractionation matter...Coarse and fine load often have different sources/transport paths

All else held constant, aggradation on the floodplain… increases shear stress on the bed

So while the sources may be independent, effects on channel morphology and hydraulics are linked

A few key messages up front…Predicting sediment supply at any given location is difficult, but tractable

Ideally we want to know locations, mechanisms, and rates of erosion and deposition

Size matters…boulders, cobbles, gravel, sand, mud play distinct roles

Spatial and temporal variability over wide range of scales

Interactions of multiple non-linear processes

Many biological influences: veg-hydro-geomorph, beavers, human alterations

Simplified models can be useful or misleading

Many new tools available, none are comprehensive or bullet-proof

In many cases, all that is needed/feasible is to know if supply is a big # or small #

Roadmap

Push-button GeomorphologyThe geek approach. What computer models can and can’t tell you.

Basin-average erosion rates: The cosmo methodMillennial-scale landscape rates of erosion.

Reservoir and pond sedimentation ratesTime- and space-integrated measurements that may be useful.TOM

OR

RO

W

Watershed Sediment BudgetTools and techniques for robust constraints on sources and sinks.

Basic ReconnaissanceWith a tight budget, what do you really need to know?

Forget rates. What can we learn from basic form-process relationships?Continuity and discontinuity. Geomorphic Assessments.

TOD

AY’S

TO

PIC

S

A bit of hydrologyTargeted modeling and metrics. Stationarity Assumption?

Interception Storage

Surface Storage

Unsaturated Zone Storage

Saturated Zone Groundwater Storage

Channel StoragePlan

t Sto

rage

trans

pira

tion rain, snow, condensation

stemflow, canopy drip

infiltration

percolation

outlet

plant uptake

Atmospheric Moisture

Hydrology matters...

Clark et al. (2015) A unified approach for process‐based hydrologic modeling: 1. Modeling concept. Water Resources Research 51(4): 2498-2514.

Excellent perspective on the frontier of hydrologic modeling

Hrachowitz, et al. (2013). A decade of Predictions in Ungauged Basins (PUB)—a review. Hydrological sciences journal, 58(6), 1198-1255.

Farmer, W. H., & Vogel, R. M. (2016). On the deterministic and stochastic use of hydrologic models. Water Resources Research.

Hydrologic modeling

Have flows changed?

Lytle and Poff, 2004

A basic lexicon of flow regime characteristics

Lytle and Poff, 2004

Changes (or not) in Flow Duration Curves

1940 - 1975

1976 - 2009

Slide modified from

Schottler, 2011 WR

C C

o

10

100

1000

10000

0 20 40 60 80 100

Flow

exceedance probability

Elk

1

10

100

1000

0 20 40 60 80 100

Flow

exceedance probability

Whetstone

10

100

1000

10000

0 20 40 60 80 100

exceedance probability

10

100

1000

10000

0 20 40 60 80 100

Blue Earth

10

100

1000

10000

0 20 40 60 80 100

exceedance probability

Le Sueur

1. Sort big to small2. Rank (m) from 1 to n

3. Compute EP = m/(n+1)

FDCs: Choose your axes carefully

Illustrating shifts in FDCs

Laue

r et a

l., in

revi

ew

1948 1952 1956 1960 1964 1968 1972 1976 1980 1984 1988 1992 1996 2000 2004 2008 20110

10

20

30

40

50

60

70

Date

Pre

cipi

tatio

n-m

m p y

Making sense of highly variable hydrologic dataHourly Data for Precipitation: 1948-2011

1948-1977: Early Period

1977-2011: Late Period

An increase in highand extreme totalstorm amounts.

1. Sort big to small2. Rank (m) from 1 to n

3. Compute EP = m/(n+1)

http://cran.r-project.org/web/packages/waterData/waterData.pdfhttp://cran.r-project.org/web/packages/waterData/vignettes/vignette.pdfhttp://cran.r-project.org/web/packages/waterData/index.html

R package forautomated download of USGS flow databasic streamflow metric analysis & plots

See flood frequency document distributed with electronic course materials for a detailed explanation of probability and statistics that go into flood frequency analysis

TP 1=

QTQT KQ logloglog σµ +=

𝑄𝑄𝑇𝑇 = 10𝑙𝑙𝑙𝑙𝑙𝑙𝑄𝑄𝑇𝑇

T = Return Period or Recurrence Interval

P = Probability of Exceedance

QT = Discharge you are computing

σlogQ = Standard deviation of the log transformed annual peak flow series

KT = Frequency factor (from table, = f (skew and return period)

µlogQ = Mean of the log transformed annual peak flow series

Flood frequency analysis

FDC and FF spreadsheet

USGS Peak FQ Programhttp://water.usgs.gov/software/PeakFQ/

USDA Flood Frequency Calculationhttp://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/national/water/?&cid=stelprdb1042910

Alternative flood frequency tools

Stout, 2012

Site not gaged? Develop a regional curve

StreamStats

Frequencies of hydrologic phenomena (e.g., precipitation, streamflow) can be represented by a time-invariant PDF that can be estimated from historic record.

These PDFs provide the basis for evaluation of risks to water supplies, floodplain development, infrastructure.

Hornberger, 1998

The stationarity assumption in hydrology

30 35 40 45 50 55 60 65 70 75 80 85 90 95

Hornberger, 1998

In some places, these PDFs are systematically changing

The stationarity assumption in hydrology

Non-stationary conditions

Interception Storage

Surface Storage

Unsaturated Zone Storage

Saturated Zone Groundwater Storage

Channel StoragePlan

t Sto

rage

trans

pira

tion rain, snow, condensation

stemflow, canopy drip

infiltration

percolation

outlet

plant uptake

Atmospheric Moisture climate non-stationarity

land use non-stationarity

Standard practice for predicting flood frequency/magnitude assumes stationarity(Interagency, 1982)

Review of techniques to adjust for non-stationarity provided by Gilroy & McCuen (2012)

Streamstats assumes stationarity

National Flood Insurance Program assumes stationary flood flows

Stuck on stationarity?

Finding Hydrologic DataPrecipitation:PRISMhttp://www.prism.oregonstate.edu/

NOAA: Frequency Duration Datahttp://hdsc.nws.noaa.gov/hdsc/pfds/

NOAA: NNDC datahttp://www7.ncdc.noaa.gov/CDO/dataproduct

NRCS: Snotelhttp://www.wcc.nrcs.usda.gov/snow/

NRCS: SCANhttp://www.wcc.nrcs.usda.gov/scan/

Streamflow:USGS: Water Watchhttp://waterwatch.usgs.gov/

USGS: NWIShttp://waterdata.usgs.gov/nwis

Many state agencies, consortiums

Groundwater:USGS: NWIShttp://waterdata.usgs.gov/nwis/gw

Soil Moisture:NWS: CPChttp://www.cpc.ncep.noaa.gov/soilmst/w.shtml

Effective Discharge

Discharge

Flood flows, bankfull, and effective discharge

So what is bankfull?The elevation at which water spills out of the channel and onto the floodplain

(so it only occurs where you have well defined banks and a floodplain)

Elevation of the top of bank If banks are at different elevations, it is the top of the lower bank

It is typically identified at a visible break in slope between the channel and floodplainOften it is the transition from unvegetated to (woody) vegetated surface

Roadmap

Push-button GeomorphologyThe geek approach. What computer models can and can’t tell you.

Basin-average erosion rates: The cosmo methodMillennial-scale landscape rates of erosion.

Reservoir and pond sedimentation ratesTime- and space-integrated measurements that may be useful.TOM

OR

RO

W

Watershed Sediment BudgetTools and techniques for robust constraints on sources and sinks.

Basic ReconnaissanceWith a tight budget, what do you really need to know?

Forget rates. What can we learn from basic form-process relationships?Continuity and discontinuity. Geomorphic Assessments.

TOD

AY’S

TO

PIC

S

A bit of hydrologyTargeted modeling and metrics. Stationarity Assumption?

How would you describe these channels?

Insightful books for watershed analysisand stream restoration

Stage 1 Data Compilation (description and mapping)• Derive watershed boundary conditions• Determine landscape units• Assess river character

Stage 2 Data Analysis• Define and interpret River Styles• Explain contemporary character/behavior• Assess river history

Stage 3 Predict future river structure

Stage 4 Prioritize watershed management issues

Stage 5 Identify target conditions for river

Stages of a River Styles Assessment

River Styles HierarchyWatershed Watershed area determined by drainage divide. Determines

the boundary conditions within which rivers operate.

Geomorphic Unit Instream and floodplain landforms (pools, bars, levees, backwaters, etc.) that reflect distinct form-process associations.

River Style Length of channel with a characteristic assemblage of geomorphic units.

Landscape Unit Topographic unit determined on the basis of local relief, valley slope and morphology. Defines the valley-setting.

Hydraulic Unit Uniform patches of flow and substrate material within a geomorphic unit.

Microhabitat Individual elements (e.g., logs, rocks, gravel patches) within a stream.

Grabowski et al. 2014

Many other classification schemes out there

Montgomery and Buffington, 1997

Many other classification schemes out there

Modified from Montgomery, 2004

Time & Space scales of change are linked

Tools for geomorphic assessments

USU Fluvial Habitats CenterJoe Wheaton, Nick Bouwes, Wally MacFarlane, Gary O’Brien etc.http://etal.joewheaton.org/

Topotoolbox (requires Matlab)https://topotoolbox.wordpress.com/

Stream Profiler (requires ArcGIS and Matlab)http://geomorphtools.org/tools.htm

UMass-Amherst: Collection of Frameworks and Protocolshttp://extension.umass.edu/riversmart/fluvial-geomorphology-assessment-methods

River Styles tree developed for NSW, Australia

Brierley et al., 2002

YOU decide how to divide up the river network!

Visual representation of River Styles tree for NSW, Australia

These are each different‘process domains’

Different ecological functionshydro-geomorphic processessensitivities to changepotential for recovery

At the watershed scale, what are the primary gradients?

River longitudinal profile

Flow accumulation

Valley confinement

Valley confinement

Confined

Partially Confined

Unconfined

Downstream gradients in a textbook river

Downstream gradients in an escarpment river

QuiescentRills and gullies

Debris flows

Landslides

Other landscape scale considerations:How active are the hillslopes?

Which hillslopes are/aren’t connected?

Indicators of channel behavior

Channel planform

Bed material texture

Assemblage of geomorphic units that make up a reach

RiverStyles Form-Process Relationships

Metrics ofchannelplanform

Interpretations fromchannel planform

Kleinhans, 2010

Channel adjustment in different valley settings

Channel adjustment in different valley settings

Roadmap

Push-button GeomorphologyThe geek approach. What computer models can and can’t tell you.

Basin-average erosion rates: The cosmo methodMillennial-scale landscape rates of erosion.

Reservoir and pond sedimentation ratesTime- and space-integrated measurements that may be useful.TOM

OR

RO

W

Watershed Sediment BudgetTools and techniques for robust constraints on sources and sinks.

Basic ReconnaissanceWith a tight budget, what do you really need to know?

Forget rates. What can we learn from basic form-process relationships?Continuity and discontinuity. Geomorphic Assessments.

TOD

AY’S

TO

PIC

S

A bit of hydrologyTargeted modeling and metrics. Stationarity Assumption?

Rea

ch 1

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Rea

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Some history on the landscape we’ll beexamining this afternoon

Little Bear River Watershed

Seven high resolution, real-time flow/turbidity monitoring stations:http://littlebearriver.usu.edu/

Long profiles of EF, SF Little Bear and other drainages of the Bear River Range

Longitudinal profiles extracted with Stream Profiler Tool: geomorphtools.org

Little Bear East ForkLittle Bear – South Fork

Littl

e B

ear E

ast F

ork

Littl

e B

ear S

outh

For

k

Little Bear Flood Flows

Your assignment for this afternoon:

Work in groups of 3-4

Utah DNR has requested a map illustrating thedifferent reach types that occur along the river. This info will be used to determine which sites to prioritize for furthermonitoring and restoration.

The Little Bear Watershed is being targeted for a majorwatershed restoration project with the goal of restoringcutthroat and brown trout habitat.

Your assignment for this afternoon:1. Obtain GIS and/or Google Earth data

2. Peruse GIS data for 30 min. Identify points/areas of interest along the channel and throughout the watershed.

3. Spend ~30 min delineating distinct reaches of the mainstem Little Bear. Split lb_mainstem_to_edit at reach breaks and describe each reach wrt:1. valley confinement2. number of channels, sinuosity and lateral stability3. slope and/or discontinuities in the long profile4. notable sediment sources and sinks5. other relevant attributes

Turn in by tonight:Shapefile or screen-shot illustrating reach breaks<1 page document describing each reach, other key points/areas of interest, and any other observations made in the field