• Pipe Lake continues to have very clear water, with low nutrient concentrations and low algal growth. • Pipe Lake had some of the deepest Secchi depths in the Lake Stewardship Program. Secchi depths have been getting even deeper over time. • Long-term trends suggest that water quality in Pipe Lake has been improving over time, with decreasing nitrogen and chlorophyll concentrations in addition to the deeper Secchi depths. • Pipe Lake had an algal bloom in July resulting in a Toxic Algae Warning issued on the lake. Toxin testing found elevated microcystin concentrations at 280 µg/L, above the Washington State Recreational Guideline of 8.0 µg/L.
This bathymetric map shows contour lines of equal depth, similar to a topographic map would for mountains and valleys. The red 'X' marks the location where water quality samples are taken.
This map shows the area of the watershed relative to the area of the lake. Generally speaking, the larger a watershed is relative to a lake, the greater the influence land use practices on lake water quality.
The average of these three TSI indicators during the growing season can be used
to place lakes in one of three broad categories:
<40 = oligotrophic (low productivity),
40 to 50 = mesotrophic (moderate productivity)
>50 = eutrophic (highly productive).
