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.
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?
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.
- 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 (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.
We'll provide a site map once we finalize the quality assurance project plan for this study (early 2021). We're working with permittees to finalize the detailed monitoring design and will add more details when they are available.