Big Chetac Chetac Lake Lake Big Getting Rid of the Green Getting - PowerPoint PPT Presentation

Big Chetac Chetac Lake Lake Big Getting Rid of the Green Getting Rid of the Green Phase 3 Phase 3 Nutrient Budget and Management Nutrient Budget and Management Data Analysis Report Data Analysis Report

Prepared for: Prepared for: Big Chetac Chetac Chain Lake Chain Lake Big Association and Association and Wisconsin Department of Wisconsin Department of Natural Resources Natural Resources Prepared by: Prepared by: Short Elliot Hendrickson Inc. Short Elliot Hendrickson Inc.

Special Thanks to: Special Thanks to: � Bernie Lenz (formerly of SEH) Bernie Lenz (formerly of SEH) � � Craig Roesler, WDNR Craig Roesler, WDNR � *for assistance in writing this report *for assistance in writing this report Big Chetac Chetac Chain Lake Association Chain Lake Association Big *for patience and understanding *for patience and understanding

General Lake Information General Lake Information � Surface Area = 2,406 acres Surface Area = 2,406 acres � � this is about 25% larger than what is stated in this is about 25% larger than what is stated in � the DNR Lake Book the DNR Lake Book � Maximum Depth Maximum Depth – – 28 ft 28 ft � � Average Depth 14 ft Average Depth 14 ft � � Drainage Lake Drainage Lake � � Watershed = approx. 34,541 acres Watershed = approx. 34,541 acres � � A little more than 14 to 1 watershed to lake A little more than 14 to 1 watershed to lake � ratio ratio

Big Chetac Chetac Lake Watershed Lake Watershed Big Benson Creek Heron Creek Red Cedar Springs Direct Drainage Watershed = 34,541 acres 0 895 .90 874 2 Turtle Pond 0 855 .211 49 0 65 8.5 000 35 Knuteson Creek Not in the immediate Hwy 48 Tributary watershed for Big Chetac Lake

General Impressions General Impressions � Lake is highly eutrophic (nutrient rich) Lake is highly eutrophic (nutrient rich) � � Lake has lots of Curly Lake has lots of Curly- -leaf pondweed, an leaf pondweed, an � invasive species invasive species � Lake is well developed around the Lake is well developed around the � shoreline shoreline � Lake use and enjoyment are impaired due Lake use and enjoyment are impaired due � to poor water quality and excessive weeds to poor water quality and excessive weeds (at least with CLP) (at least with CLP)

Six Phase Lake Study to be Six Phase Lake Study to be completed: 2007- -2009 2009 completed: 2007 � Phase One (2007) Phase One (2007) � Water quality, lake stage, and tributary sampling Water quality, lake stage, and tributary sampling � � data collection for Phase Three analysis • • data collection for Phase Three analysis � Phase Two (2007) Phase Two (2007) � Groundwater, internal loading, and CLP Groundwater, internal loading, and CLP � � • data collection for Phase Three • data collection for Phase Three � Phase Three (2008 Phase Three (2008- -09) 09) � Nutrient and Water Budget Analysis Nutrient and Water Budget Analysis � � • today’ ’s discussion s discussion • today � Phase Four (2008 Phase Four (2008- -09 09 � Historical Sediment Core Sampling and Analysis Historical Sediment Core Sampling and Analysis � � � Phase Five (2008) Phase Five (2008) � Full point- Full point -intercept plant survey intercept plant survey � � � Phase Six (2009) Phase Six (2009) � Lake User Survey and Comprehensive Lake/Aquatic Plant Management Lake User Survey and Comprehensive Lake/Aquatic Plant Management � � Plan Plan

Water Budget Water Budget 3 (33,354 acre � Lake Volume Lake Volume – – 41,141,263 m 41,141,263 m 3 (33,354 acre- -feet) feet) � 37,188 m 3 3 /day � Tributary and Watershed In Tributary and Watershed In- -flow flow – – 37,188 m /day � � Outflow to Birch Lake and over the dam Outflow to Birch Lake and over the dam – – 26,671 26,671 � 3 /day m 3 /day m � Precipitation, Evaporation, and Lake Storage also taken Precipitation, Evaporation, and Lake Storage also taken � into account into account � Rainfall = 13.6 Rainfall = 13.6” ” � � Evaporation from Lake = 21.2 Evaporation from Lake = 21.2” ” � � Lake Storage = 1.1 Lake Storage = 1.1” ” � � Total Hydraulic Residence Time Total Hydraulic Residence Time – – approx. 3 years approx. 3 years � � Based on 2007 data from May through September Based on 2007 data from May through September � • • Dry year, except in late August and September Dry year, except in late August and September

In- -Lake Water Quality Lake Water Quality In � Three lake sites: North, Central, and South Three lake sites: North, Central, and South � Basins Basins � 15 dates between May and September 2007 15 dates between May and September 2007 � � Essentially every meter from surface to bottom Essentially every meter from surface to bottom � � Total Phosphorous, Total Nitrogen, Chlorophyll Total Phosphorous, Total Nitrogen, Chlorophyll � , and water clarity (Secchi disk) a , and water clarity (Secchi disk) a � Temperature, Dissolved Oxygen, and pH Temperature, Dissolved Oxygen, and pH � Profiles also collected Profiles also collected

Goals of Lake Sampling Goals of Lake Sampling � Determine seasonal changes in phosphorus Determine seasonal changes in phosphorus � mass, algal abundance and pH mass, algal abundance and pH � Determine the total in Determine the total in- -lake phosphorous mass lake phosphorous mass � for the year for the year � Determine if Big Determine if Big Chetac Chetac Lake was nitrogen or Lake was nitrogen or � phosphorous limited. phosphorous limited. � Determine the time period for which each basin Determine the time period for which each basin � became anoxic or oxygen depleted in the bottom became anoxic or oxygen depleted in the bottom waters waters

Big Chetac Chetac Lake trends Lake trends Big Total P & Chlorophyll Concentrations (0-2m) and Secchi Disk Averages for Big Chetac Lake 180 6 160 5 140 120 4 TP & Chl (ug/L) Secchi (ft) 100 3 80 60 2 40 1 20 0 0 7 7 7 7 7 7 7 7 7 7 7 7 7 7 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 2 2 2 2 2 2 2 2 2 2 2 2 / / / / / / / / / / / / / / 5 9 0 0 4 6 3 0 3 7 1 2 8 6 2 / 2 1 2 / / 1 2 / 2 / 1 / 5 7 7 8 9 0 / / / / / / / / 4 5 6 6 7 7 8 9 1 Sampling Dates Total Phosphorous Chlorophyll Secchi Depth Linear (Total Phosphorous) Linear (Chlorophyll) Linear (Secchi Depth)

Total In- -Lake Phosphorous Mass Lake Phosphorous Mass Total In � Phosphorous sampling at Phosphorous sampling at � three basins, top to bottom, three basins, top to bottom, multiple times multiple times � Calculate amount of Calculate amount of � phosphorous at each depth phosphorous at each depth in each basin, each time in each basin, each time � Record the increases Record the increases � � The difference between the The difference between the � minimum phosphorous minimum phosphorous mass and the maximum mass and the maximum phosphorous mass during phosphorous mass during the year shows the lake’ ’s s the year shows the lake response to inputs of response to inputs of phosphorus phosphorus � It doesn It doesn’ ’t matter how much t matter how much � phosphorous is coming into a phosphorous is coming into a lake, if – – if if the lake can handle the lake can handle lake, if it! it!

Big Chetac Chetac Can Can’ ’t Handle It!! t Handle It!! Big 2007 In-Lake Phosphorous Mass 14000 13113 13052 12000 10564 10146 10000 9952 Phosphorous (lbs) 8570 8248 8000 North Basin 7305 Central Basin 6914 South Basin 6294 6000 Whole Lake 5377 4966 4318 4000 3495 3489 2000 0 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 / / / / / / / / / / / / / / / / / / / / / / / / 5 2 9 6 3 0 6 3 0 7 4 1 8 5 1 8 5 2 9 5 2 9 6 3 2 / / 1 2 3 / 1 2 2 / 1 1 2 / / 1 2 2 / 1 1 2 / 5 5 6 7 8 8 9 0 / / / / / / / / / / / / / / / / 4 5 5 5 6 6 6 7 7 7 8 8 8 9 9 9 1 Sampling Dates

In- -lake Mass per Basin lake Mass per Basin In Percent In-lake Phosphorous Mass by Basin South Basin 24% North Basin 44% Central Basin 32%

Nitrogen or Phosphorous Nitrogen or Phosphorous Limited? Limited? 2007 Seasonal TN:TP Ratios (Whole Lake) 25 20 20 18 18 17 16 15 15 Ratio (TN:TP) 14 13 13 13 11 11 10 10 9 7 5 0 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 / / / / / / / / / / / / / / / / / / / / / / / / 5 2 9 6 3 0 6 3 0 7 4 1 8 5 1 8 5 2 9 5 2 9 6 3 2 / / 1 2 3 / 1 2 2 / 1 1 2 / / 1 2 2 / 1 1 2 / 5 5 6 7 8 8 9 0 / / / / / / / / / / / / / / / / 4 5 5 5 6 6 6 7 7 7 8 8 8 9 9 9 1 Sampling Dates