Gilfillan Lake: Sustainable Lake Management Plan

Meeting 1

April 22, 2009

Overview for Tonight

Data presented to assist you in developing your vision for the lake

Water balance for Gilfillan Lake Water Balance: Sources and sinks for water in Gilfillan

Lake Ideas to control lake levels with group input

Intro to Shallow Lakes Management Definition of A Shallow Lake Shallow Lake States: Clear vs. Turbid Shallow Lake Management and Goals Tools at our disposal with group input

Sample Visions:

Lake level may vary seasonally or by precipitation received but generally remains at or around the established Normal Water Level.

Gilfillan Lake has a healthy fish community, and anglers can catch and eat a variety of fish year round.

Gilfillan Lake supports waterfowl and other upland and aquatic wildlife.

Only non-motorized boats may be used on Gilfillan Lake. Gilfillan Lake is impaired by nuisance algae blooms no more than

10% of the season (April 1 – October 31). Submerged and emergent aquatic vegetation is limited to the near-

shore areas. Gilfillan Lake is safe for swimming. The community is involved in planning for and monitoring Gilfillan

Lake.

Water Balance

LAKE OUTFLOW

Sinks of Water Evaporation off lake

surface/ Evapotranspiration

Outlet Groundwater

Extraction by private wells in the area & leakage through lake bottom

Sources of Water Precipitation Stormwater runoff from

the tributary watershed Groundwater

Septic inputs

Precipitation: 33 inches average (22.8 to 45.7 inches)

White Bear Lake

05

101520253035404550

1975 1980 1985 1990 1995 2000 2005 2010

An

nu

al P

rec

ipit

ati

on

(in

ch

es

)

Annual Precipitation

1978-2008 Average7 of past 10 years at or below average

Watershed Runoff: 17-35 inches average

Gilfillan Lake:

Parameter Value

Lake ID 62-0022700 Lake area 102 acres

Lake Volume 357 acre-feet Maximum depth ~ 5 ft.

Mean depth 3.5 ft. Littoral area % 100%

Watershed area 630.6 acres Watershed area : Lake Area ratio 6.2 : 1

Watershed impervious cover ~ 17%

Precipitation and Lake Level; loosing ~12 inches

Gilfillan Lake Elevation & Precipitation

0

2

4

6

8

10

12

Jan-93 Jan-94 Jan-95 Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Jan-08 Jan-09

Date

Pre

cip

itat

ion

906

907

908

909

910

911

912

Jan-93 Jan-94 Jan-95 Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Jan-08 Jan-09

Lak

e E

leva

tio

n

Precipitation Lake Elevation

Increase Lake Levels

Get more water to the lake Increase drainage area (more stormwater) Augmentation from another source

1,000,000 gal/yr w/o permit= <0.5 inches over lake surface

DNR doesn’t believe lake level augmentation is not a legit use of groundwater

Tie it to an impairment?

Keep water from leaving Prevent groundwater leaving Modify outlet Use less groundwater in the area

Shallow Lakes

DefinitionShallow Lake States: Clear vs. TurbidManagement ToolsGroup input (later)

Shallow Lakes: Definition

Definition >80% littoral or max depth <15 feet

Shallow Lake States: Clear

Shallow Lake States: Turbid

Shallow Lakes: Biology

Shallow Lakes: Management

Biology & Hydrology Control sources (nutrients) Rough fish management Plant management Water level management

Sample Visions:

Lake level may vary seasonally or by precipitation received but generally remains at or around the established Normal Water Level.

Gilfillan Lake has a healthy fish community, and anglers can catch and eat a variety of fish year round.

Gilfillan Lake supports waterfowl and other upland and aquatic wildlife.

Only non-motorized boats may be used on Gilfillan Lake. Gilfillan Lake is impaired by nuisance algae blooms no more than

10% of the season (April 1 – October 31). Submerged and emergent aquatic vegetation is limited to the near-

shore areas. Gilfillan Lake is safe for swimming. The community is involved in planning for and monitoring Gilfillan

Lake.