Big Trout Lake Stormwater Management Design Project

By Hannah Rollin

Problem

Valuable Trout Lake for the state of Minnesota

Excess sediment and stormwater flows directly into the lake due to the current curb and gutter system and the culvert

Increasing temperature of the lake and decreasing the clarity

Constraints

Limited land area availableSnowmobile routeSteep slopes (instability)

Field Assessment

Surface and groundwater measurementsTemperature

Salinity

Soil type assessment

General land type observations

Proposed Solution

Use a vortex separator to remove sediment from the stormwater

Downstream Defender® The vortex system forces particles to settle into the sump

Efficient and easy to maintain

Small footprint

System of Perforated Pipes

Infiltration of stormwater will aid in temperature reduction

Watershed and Drainage Assessment

Delineate the watershed in GIS

Calculate drainage area: Grass/Vegetated area: 167,277ft2

Paved area: 156,722 ft2

Calculate runoff from precipitation data 37,040 ft3

Final Design

Two 4ft Downstream Defenders (each can handle 8cfs)

12 perforated pipes, 2ft in diameter

Next Steps

Research possibility of installing larger pipes for larger storage volume

Survey elevations to calculate gradients of pipes

Cost analysis

Questions?