Regulatory Effectiveness Project, King County - DNRP

Benthic macroinvertebrate sampling is conducted annually in August and September at 9 streams as part of a larger program studying the effectiveness of Critical Area Ordinance Regulations. Sampling began in 2008 and will conclude in 2012.

Sample collection methods are based on the recommended sampling protocols outlined by Karr and Chu (1999) with some minor modifications. At each location, a Surber sampler (500 micron mesh, 1 sq ft frame) is used to collect three samples along the midline of three separate riffles or non-depositional habitats starting downstream and working upstream. All large materials (e.g., large gravel and large wood) within the sampling area are scrubbed by hand and examined before being placed downstream. A “weed tool” is used to vigorously agitate the substrate within the perimeter of the frame to a depth of approximately 10 cm, for 60 seconds. Each sample is condensed separately and transferred into three sample containers and preserved in the field with 95-100% ethanol (EtOH). Samples are then sent to a private lab for taxonomic identification. Chironomids are identified to family level; other taxa are identified to the lowest practical level. Sampling is conducted annually between early August and mid September.

Contact Person: Jo Wilhelm, jo.wilhelm@kingcounty.gov, 206-263-6556 or Gino Lucchetti, gino.lucchetti@kingcounty.gov, 206-296-8366