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 since the area is developed and stormwater management actions are implemented more broadly.

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?  

Study design

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

Read the Quality Assurance Project Plan (2020), Addendum 1 (2021), for detailed information about the study design, sampling schedules, and more.  

  • Data loggers measuring water level and conductivity are deployed in October (starting from 2020), the year before the summer sampling event at each site. Summer sampling includes benthic macroinvertebrates, sediment chemistry, water chemistry, and physical habitat condition analysis.
  • For data analysis, we will also gather landscape characteristics, contributing watersheds, and stream health-stressor identification across the region.

Sampling locations

The study includes hand-picked urban stream sites in the municipal stormwater permitted area in Clark and Cowlitz counties. Eight or nine sites are monitored each year. Five sites are monitored annually and the other sites form rotating panels (i.e., sampled once in five years). 

Map showing Lower Columbia Urban Streams Monitoring Locations

Lower Columbia Urban Streams study sampling locations.  You can view the full size ArcGIS online map here

On-going study details