Water Quality in Tryon Creek

Initial Results from Portland’s Revised Watershed Monitoring Approach

Portland Area Watershed Monitoring and Assessment Program (PAWMAP)

• Based on EPA’s Environmental Monitoring and Assessment Program– Designed by national monitoring experts– Uses probabilistic sampling designs, core indicators,

and consistent monitoring methods to provide statistically–defensible assessments of resource condition

• A few revisions to better support watershed plan– Monitoring bird communities– Eventually, terrestrial habitat

Monitoring Design

• Collect all measures at same locations

• Sample the entire stream system

• Sample WQ in streams during stormflows

• Probability-based sampling

• Rotate stations on a 4-year repeating cycle– Years 1, 2, 3, 4 → different stations each year– Years 5-8 repeat 1-4

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0592

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04980476

0464

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04260380

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Willamette River

Columbia Slough

Johnson Creek

Fanno Creek

Tryon Creek

PAWMAP Year 1 and 2 Sampling Stations

Year

1

2

0754

0720

0592

0544

0524

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0464

0426

0208

0144

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0006

Tryon Creek

Fanno Creek

Willamette RiverJohnson Creek

Year

1

2

PAWMAP Year 1 and 2 Sampling Stations

Copper

Lead

Zinc

E. coli

Dissolved Oxygen

Total Suspended Solids

Preliminary Conclusions• Water quality typically worse during storms than

during seasonal sampling• Considerable variability in spatial pattern of

pollutants:– Tryon in upper range for E. coli & zinc; lower for TSS,

copper and lead– Middle Tryon and Falling generally had higher

concentrations than other stations in Tryon– Resolution of spatial patterns greatly increased after 2

more panels

• Exceedences of WQ criteria common for E. coli (& temp.); infrequent for other parameters