Lower Columbia urban streams

Stormwater Action Monitoring (SAM) manages status and trends monitoring of urban streams in Clark and Cowlitz counties in the Lower Columbia River region to track how stormwater runoff from urban areas affects the health of small, wadable streams.

Study goals

Stakeholders, including municipal stormwater permittees in Clark and Cowlitz counties, want to know how urban stream health changes over time in the Lower Columbia region as the area is developed and stormwater management actions are implemented more broadly.

The Lower Columbia urban stream study collects water chemistry, water flow, sediment chemistry, benthic macroinvertebrate samples, and in-stream and riparian habitat information as stream health indicators.

This monitoring is designed to assess the current stream conditions and eventually answer the question: are the quality and biota conditions of receiving waters in the region improving with broad implementation of required stormwater management practices?.  

Monitoring study design

The study includes hand-picked urban stream sites in the municipal stormwater permitted area. Five sites are monitored annually and the other sites form rotating panels (i.e., sampled once in five years), so that all sites are sampled within a 5-year sampling cycle.

Data loggers measuring water level and conductivity are deployed in October the year prior to the summer sampling event at each site. Summer sampling includes benthic macroinvertebrates, sediment chemistry, water chemistry, and physical habitat condition analysis.

For data anaysis, we will also gather landscape characteristics, contributing watersheds, and stream health-stressor identification across the region.

Lower Columbia urban streams site map

We will provide a site map after sampling starts (scheduled summer 2020). We are working with the permittees to finalize the detailed monitoring design and will add more details as they are available.