Water Quality Monitoring

The City of Sammamish monitors water quality in streams, rivers and other water bodies. Monitoring is used to determine whether water bodies are meeting state water quality standards.

The City conducts a variety of water quality and flow monitoring activities of its natural resources and receiving waters for the purposes of (1) establishing baseline conditions to measure improvements, (2) ensuring safe swimming beaches, and (3) monitoring ecological changes.

Ebright Creek Water Quality Monitoring

The City just finished its first year of water quality, ecological, and flow monitoring on Ebright Creek to better understand the relationship between ecological health in Ebright Creek and upstream development activities (48North Solutions 2015). Monitoring included the following parameters:

  • B-IBI (Benthic Index of Biologic Integrity)
  • Water levels
  • Flow
  • Temperature
  • Turbidity

Ebright Creek - Annual Report, 12-20-2017
Ebright Creek - Annual Report, 12-14-2016
Ebright Creek - Annual Report, 12-15-2015

Pine and Beaver Lakes

King County, through its Lakes and Streams Monitoring Group, works with volunteers to collect water quality data at Beaver and Pine Lakes. Physical parameters such as water level, precipitation, temperature, and water clarity have been collected at frequencies ranging from daily to biweekly since about 1995. Water samples are also collected between May and October (the growing season) for analysis of phosphorus, nitrogen, chlorophyll, and other parameters to evaluate productivity and indicators of trophic state or potential for algal blooms. Sammamish provides monetary support to King County for this program.

Swimming Beaches

The City through an interlocal agreement with King County also monitors water quality at local swimming beaches during the summer months for fecal coliform bacteria. Beaver Lake, Pine Lake, and Sammamish Landing beaches are all monitored approximately every other week during the summer months. If results exceed certain criteria, beaches are posted for closure until water quality improves.

Stormwater Action Monitoring

The City also contributes to Ecology’s Stormwater Action Monitoring (SAM), previously known as Regional Stormwater Monitoring Program (RSMP), through its NPDES Phase II Permit and participates in a municipal caucus related to the program. The amount Sammamish contributes is based on population, so with the increase in population due to annexation, this contribution is expected to increase in the future. The water quality monitoring fund is used for status and trends monitoring to evaluate water quality in small streams and nearshore marine areas, stormwater program effectiveness monitoring, and implementation of the Source Identification Information Repository (SIDIR) program. The City does not have any streams or stormwater facilities included in the regional water quality monitoring program.

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