Des Moines Creek Water Quality Monitoring Program, King County - DNRP

The Des Moines Creek benthos sampling is part of a larger Des Moines Creek Water Quality Monitoring Program that began in 2012. This program is designed to monitor and assess water quality in Des Moines Creek and will follow three broad goals:
• Understand the status and trends of water quality and ecological health of Des Moines Creek.
• Determine the likely causes of key water quantity, water quality, and habitat problems.
• Evaluate changes in water quality and ecological health as a result of conservation/restoration actions, stormwater management, and land use changes.

The monitoring plan is being planned and implemented by the Des Moines Creek Basin Committee. The committee is made up of the City of SeaTac, the City of Des Moines, and the Port of Seattle. These agencies are the basin stakeholders overseeing a watershed based planning effort (Des Moines Creek Basin Committee, 1997).

Benthos sampling was conducted only in 2012 at two stream locations to evaluate whether improvements in the basin (habitat, water quality, flow) are improving Benthic Index for Biotic Integrity (B-IBI) scores.

Benthos samples are collected using a Surber sampler with a 1 sq ft frame and a 500 µm mesh net from 8 sq ft of sample area. Riffle or non-depositional substrate is sampled generally along the midline of the creek. Each 1-sq ft is agitated for 60 seconds to a depth of about 10 cm. Eight 1-sq foot samples are collected and composited into one sample and preserved in 90-95% ethanol before being sent to a qualified taxonomic consultant.

More information regarding BIBI sample collection procedures, habitat data collection procedures, taxonomic identification, quality assurance, and data management can be found in the Des Moines Creek Sampling and Analysis Plan.

For more information, contact Dean Wilson at 206-477-4851 or dean-wpcd.wilson@kingcounty.gov.