golden lake tmdl critique

Golden Lake TMDL CritiqueMayank 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