Cooperator: Minocqua/Kawaguesaga
Lake Protection Assoc., Town of Minocqua
Project Chief: Herbert S. Garn
Location: Oneida County
Project Number: 9KB41
Period of Project: October 2005–September
2009
new 10/18/07
Problem
The Lake Association is concerned about the lakes’ water quality,
occasional algal blooms, excessive weed growth and the effects of additional
development. The lakes are heavily used over the summer and are a popular recreation/tourist
area. Like many northern lakes undergoing urbanization, Minocqua is having a
building boom with a population that has grown by 39 percent since 1990. The
sensitivity of the lake’s water quality to changes in nutrient loading
associated with additional development within the lake’s watershed is unknown.
The trophic state of Minocqua and Kawaguesaga Lakes is mesotrophic- eutrophic,
and quantified information on actual phosphorus loading sources and rates are
not available to accurately evaluate the potential changes in lake condition
under increased or decreased loading. The effects of increasing development in
the watershed and possible resulting increased stormwater runoff and nutrient
loading are a concern to residents, the Town, and other entities. In order to
establish realistic water-quality goals for the Lakes, accurate nutrient loading
estimates are needed to enable water-quality models to be calibrated and used
to simulate future response of the lake. With a calibrated model, the lake’s
response to incremental increases or decreases in phosphorus loading can be evaluated
and used to refine the lake-management plan.
Objective
This study will quantify the actual phosphorus and sediment loads entering and
leaving Minocqua/Kawaguesaga Lake from the watershed, and will determine how
incoming loads affect lake water quality. The objectives of the project are to:
- quantify
the flows, phosphorus and sediment loads entering and leaving the Lakes;
- determine measured water and phosphorus budgets for Minocqua and Kawaguesaga Lakes, thereby
providing a better understanding of the problems and sources of nutrients for
developing future lake management actions;
- evaluate and relate the measured water and contaminant loads to observed and modeled water-quality responses within
the Lakes using lake models such as BATHTUB or WiLMS; and
- model the response of the Lakes to future phosphorus-loading scenarios and to specific management
actions aimed at reducing phosphorus loads to the Lake.
A better understanding
of the hydrologic and phosphorus inputs and potential response of the lake to
various management scenarios will enhance the management of Minocqua and Kawaguesaga
Lakes.
Approach
The study will consist of gage installation and two years of data collection
followed by data analysis and report preparation. Water quality will be sampled
six times per year in both Lakes and water levels will be recorded. To estimate
the nutrient loading at the Tomahawk and Link Creek inlets and the outlet, daily
streamflow will be measured continuously and water samples will be collected
manually. Phosphorus load data at the stream sites will be used to estimate unit-area
loads for unmonitored portions of the basin. Piezometers will be installed around
the shore of the lakes to measure ground-water levels and phosphorus concentration
to develop a ground-water model and evaluate inputs. These measured data, along
with other estimates, will be used to develop complete hydrologic and phosphorus
budgets for the lake. Concurrent water and phosphorus budgets for the lake and
in-lake water-quality data will be used to calibrate a lake water-quality model
used to estimate the response of the lake to various phosphorus-loading scenarios.
tThe calibrated model will be used to simulate the likely response of Minocqua
and Kawaguesaga Lakes to phosphorus loading changes from the watershed.
Progress (October 2005 to September 2006)
Project in data collection phase. Operated streamflow AVM stations on the two
inflow sites and a standard station on Tomahawk River outflow from Kawaguesaga
Lake. Collected water-quality samples for TP loads at these 3 sites and other
miscellaneous stormwater sites. Sampled both lakes 5 times during the summer
2006. Installed 15 piezometers that were sampled 3 times during the spring and
summer 2006. A GPS level survey of adjacent lakes and discharge measurements
of selected streams for calibration of the GW model was completed in October
2006. Finalized and published data collected during WY2006 in the annual data
report.
Plans (October 2006 to September 2007)
Continue on-going streamflow and water-quality data collection at 3 sites. Conduct
lake sampling from the two lakes monthly during the summer and sample 15 piezometers
three times during the 2007 field season.
Report
Published all streamflow, load, and concentration data in the WY 2006 Wisconsin
annual data report, which is now available as Site Data Sheets on the web and
also on CD. Lake water-quality data were published in the data report “Water-quality
and lake-stage data for Wisconsin lakes, Water Year 2006.”
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