Surface Water Management Division
Lake Armstrong
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Lake Armstrong is a 30 acre lake located 2.5 miles north of Arlington. It has an average depth of 4.6 meters and a maximum depth of 7.3 meters. The watershed covers 369 acres and is mostly undeveloped. It has one of the least developed shorelines in the county. There is a public boat launch on the south end of the lake. Gas-powered boats are not permitted. |
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Water Quality Information
Summary
Lake Armstrong shows signs of increasing eutrophication with high nutrient levels, moderate to heavy algae, and low water clarity. The lake appears to be at risk of future declines in water quality, especially if widespread land clearing and land development occur near the lake.
Reports
A comprehensive Snohomish County State of the Lakes Report was produced in 2003 and includes a specific section on Lake Armstrong. Individual lake updates to this report are provided each year as new data are collected.
Data
Snohomish County Surface Water Management (SWM) together with volunteer lake-monitors have been collecting water quality data for Lake Armstrong since 1994. Current and historical lake water quality data are available online in SWM's interactive Water Quality Database.
Lake Armstrong Maps
- Bathymetric Map - this map shows contour lines of equal depth similar to a topographic map. Public access sites are also indicated on each map when applicable.
- Aerial Photo - 2007 aerial photos of the lake with relevant features such as public access sites and nearby roads.
- Watershed Map - this map shows the boundary of the Lake Armstrong watershed. A watershed is the land area that drains into the lake.
Lake Armstrong Resources
Contact
Gene Williams, Senior Planner, 425-388-3464 extension 4563
Marisa Burghdoff, Water Quality Analyst, 425-388-3464 extension 4639
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