water quality in stormwater retention ponds on uwb campus rick vos

Water Quality in Water Quality in Stormwater Retention Stormwater Retention Ponds on UWB CampusPonds on UWB Campus

Rick Vos

I would like to thank the I would like to thank the following people for their following people for their valuable assistance on this valuable assistance on this project:project:Dr. Dan JaffeJohn HawthorneJoel Pothoff of UWB Physical PlantHal Hoffman

Historical DataHistorical Data Impervious surface area in the North

Creek Basin while hard to measure, has increased from an estimated 26.4% in 1996 (May 1997) to roughly 49% today. (Kerwin 2001)

There has been a general increase in temperature and conductivity since 1979. (King County WLRD 2001)

Only 23% of land in North Creek Basin remains forested.(Kerwin 2001)

Objective:Objective:

To determine the water quality discharged from UWB campus into North Creek by measuring N03, PO4, pH and conductivity in retention ponds.

Compare values with historical data from North Creek.

GIS 2000

UWB Sampling LocationsUWB Sampling Locations

Experimental Method:Experimental Method: Phosphate and Nitrate were measured

using Hach DR/2010 Portable Data Logging Spectrometer with Hach PhosVer® 3 Phosphate Reagent and NitraVer ® 5 Nitrate Reagent AccuVac® ampoules.

Cole-Palmer Basic Conductivity Meter model # 19815-10.

pH measured using an Oakton Phtestr®

Quality AssuranceQuality Assurance Known standard solutions were prepared

for both nitrate (NO3-) and phosphate (PO4).

Prior to each test a sample blank was prepared and used for zeroing and a standard sample was used to check DR/2020.

A 147 µ S standard was prepared for calibration of the Cole-Palmer Conductivity meter. Meter was calibrated every 40 hours.

The Oakton pH tester was calibrated using a 7.0 buffer solution weekly.

Phosphate Comparison

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

13-May 15-May 17-May 19-May 21-May 23-May 25-May 27-May 29-May 31-May

Collection Date & Time (PDT)

Concentration (mg/L)

*Pond 1 Phosphate

*Pond 2 Phosphate

*North Creek Phosphate

Nitrate Comparison

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

13-May 15-May 17-May 19-May 21-May 23-May 25-May 27-May 29-May 31-May

Collection Date & Time (PDT)

Concentration (mg/L)

*Pond 1 Nitrate

*Pond 2 Nitrate

*North Creek Nitrate

pH Comparison

6

6.5

7

7.5

8

8.5

9

9.5

13-May 15-May 17-May 19-May 21-May 23-May 25-May 27-May 29-May 31-May

Collection Date & Time (PDT)

pH

Pond 1 phPond 2 phNorth Creek phph limits (WAC 173-01a)

What does this mean?What does this mean?

–Nitrate levels are lower in ponds

–Phosphate levels are generally lower in ponds than North Creek

–pH levels have exceeded required WAC 173-01a at all sampling sites.

Conductivity Comparison

0

50

100

150

200

250

13-May 15-May 17-May 19-May 21-May 23-May 25-May 27-May 29-May 31-May

Collection Date & Time (PDT)

Co

nd

uct

ivit

y (µ

S)

Pond 1 Conductivity

Pond 2 Conductivity

North Creek Conductivity

Input flow to Sampling Sites on UWB CampusInput flow to Sampling Sites on UWB Campus

In ConclusionIn Conclusion