
SURFACE WATER
RIVERS, LAKES & COASTAL ENVIRONMENTS

Pine Lake
Sammamish, WA
Water Quality
Pine Lake | Clean
Beach | Aliso and San Diego Creeks
The Pine Lake Watershed is located along the western slopes
of the Cascades in Washington and has experienced a rapid increase
in urban development. Historically plagued with large blue-green
algal blooms composed of primarily Aphanizomenon, the City of Sammamish
contracted Tetra Tech, Inc. to develop a lake and watershed management
plan to protect against future degradation of the lake’s water
quality. In support of the management plan, water quality data was
sampled at bi-weekly intervals to monitor nutrient and physical changes
with the lake. Additionally, external loading from the surrounding
development was sampled. Results from the sampling effort were reviewed
for quality control and assurance and used to develop a phosphorus
prediction model. This model addressed the internal dynamics of phosphorus
flux between the surface and bottom waters of Pine Lake and also
defined the effect of external loading of phosphorus from different
land-uses within its watershed. To account for future conditions,
land-use scenarios were varied to model a spectrum of potential land-use
zoning regulations, build-out conditions, and best management plans
including LID scenarios to identify cost effective measures to maintain
the positive renewal of Pine Lake. Currently the management plan
is being prepared and reviewed by the City of Sammamish.