Golden Lake TMDL Critique Mayank Gupta & Karla Bussen.
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Transcript of Golden Lake TMDL Critique Mayank Gupta & Karla Bussen.
Golden Lake TMDL Critique
Mayank Gupta & Karla Bussen
Golden Lake Description
• Shallow Lakeo 57.2 acres; max depth=24 ft; mean
depth= 8fto 90% littoral (<15ft)
• Lakeshore is well developed• Class 2B: supports aquatic and recreation uses
o warm & cool fisheries, swimming, non-motorized boating
• Naturally brown tinted water due to tannin
Watershed Description
• West-central Portion of the Rice Creek Watershed District (RCWD)o Sub-watershed of Upper Mississippi
Watershed• Main tributary is Anoka County Ditch 53-62.• 6,426 acres drain to lake through the ditch
and 139 acres directly drain into the lake
303d: Impaired Water
• 1st listed in 2002 as an impaired water o Aquatic recreation standards not met due to
excess nutrients/eutrophication • Targeted start/completion years: 2004/2008
(September 30,2009)• 5C – Impaired by one pollutant and no TMDL study
plan is approved by EPA
Water Quality Standards
Parameter Golden Lake Standard for Similar (Shallow) Lakes
Total Phosphorous 89 μg/L 60 μg/L or less
Chlorophyll-a 47 μg/L 20 μg/L or less
Water Clarity 1.1 meters [3.69 feet] 1 meter [3.28 feet] or greater
Water Quality Standards
Water Quality Standards
Water Quality Standards
Curlyleaf Pondweed
Sources of Phosphorous
• 40% Watershedo MS4so 14% failing septic systems
• 57% Internal Loadingo anoxic conditionso physical disturbance (bottom-
feeding fish and wind)o curlyleaf pondweed
• 3% atmosphere
Models and Methods
• Model used: BATHTUB
Margin of Safety
Pollution Reduction Plans
Reductions designed to meet W.Q. standards from June-Sept. (growing season)
Implementation Plan Reduce total Phosphorous load in the watershed
and improve in-lake water clarity.
How will this be achieved?
• Regulationo management rules
• Education o storm water article in city paper each montho full-time environmental education coordinatoro Public Advisory Commitee
• Incentiveso BMPs, shoreline restoration, native landscaping,
lakeshore buffers