This study serves as an initial review of available hydrologic and stream benthos monitoring data collected by the City of Bainbridge Island. Since 2004, between three and ten years of continuous flow measurements have been made in three streams and one stormwater conveyance system. Stream benthos sampling has occurred between two and six times since 2008 at eight stream sites and three of these sites include continuous flow measurements. The study streams are located in watersheds that span a range of development and forest cover and have substantially varying contributing watershed areas. Given the limited number of years of data, the variability between years, and the inconsistent periods of records, this initial data analysis was conducted to glean any available information to date, to identify any obvious changes in environmental conditions, and to make recommendations for future efforts.

This report suggests some potential refinements for the City of Bainbridge Island to make in its long term monitoring program to assist in watershed management. Recommended future actions include discontinuing the collection of three separate stream benthos samples from each site for taxonomic analysis and instead combining the samples in the field and having the lab analyze a single sample from each site each year. If that change is made, then it is recommended that a stream benthos field replicate sample be collected from a randomly selected site each year to allow incorporation of within site variance in trend analyses. This would result in a cost savings to the program (cost of analyzing 9 rather than 24 samples each year).