HomeMy WebLinkAbout11/20/07~
MINUTES OF THE LAKE ADVISORY COMMITTEE
November 20, 2007
CALL TO ORDER
The Lake Advisory Committee (LAC) Meeting was called to order at 4:35 P.M.
Members present: Dan O'Keefe (Chair) Harry Alcorn (Vice Chair), Char Jasan,
Donna Mankowski, Jim Marchessault.
Others present: Ross Bintner, Water Resources Engineer; Ken Hedberg, Council
Liz Winiger, Spring Lake Association; Joe Bischoff, Wenck Associates; Jim Eggen;
PLSLWD; 2 WD Board members.
APPROVAL OF MINUTES
Motion to approve prior meeting minutes, Marchesault, Alcorn - Pass (5:0)
OLD BUSINESS
OTHER BUSINESS
STAFF UPDATE
A. Docks Task Force:
i. Alcorn summarized the purpose of the dock task force meeting and
explained that the first of four meetings was generally for information
gathering. O'Keefe explained that the DNR would be attending the
next meeting.
B. Shoreline Parking Signs
i. Bintner explained that information signs were on order and would be
placed at the 5 winter accesses in the coming weeks.
C. Further information on Watershed/ Impervious Surface / and NEMO
presentation.
i. Bintner presented example maps were included in LAC packet that
show Prior Lake impervious surface maps and said explained an
interactive feature of the land.umn.edu website.
ii. Bintner presented a visual watershed map that delineated land
elevation on a color scale explaining that higher land was shown in
read, lower land in blue. Hedberg asked the direction howard lake
drains. Bintner said it drained to Louisville swamp.
NEW BUSINESS
Lake Biology and TMDL Presentation by Joe Bischoff with Wenck Engineers, presenting
for the WD.
Bischoff explained that the Prior Lake Spring Lake Watershed District (WD) is 42 square
miles and contains 9 lakes and 5 municipalities.
Bischoff said that lakes accumulate the physical and biological processes of the
watershed. Warm water is less dense than cold water, so if lakes are greater than about
12' deep they can stratify and will spend the whole summer with cold wrater trapped
under warm water. The biology of shallow and deep lakes will vary widely based on this
stratification. A shallow lake continually mixes, and with the mixing comes nutrients
from lake sediment. Deep lakes will stratify and nutrients from bottom sediments will
remain trapped in the lower stratified zone. Many lakes do not fit neatly into the
deep/shallow categories, so the littoral percent is taken into context.
Lower Prior is the most like a deep lake, Upper Prior is most like a shallow lake, spring
functions like a mix of the two.
Trophic cascades & top down controls. In the clear water state a lake will have a lot of
top predator fish that keep panfish population down. The panfish, which eat
invertebrates have a small population. High invertebrate populations will keep algae
down through grazing pressure which allows light penetration and submerged plant
growth and sediment stabilization.
A turbid water state reverses the balance, few predator fish means high panfish
populations. Those panfish eat the zooplankton, which normally eats algae. This
causes algae blooms and low light penetration - low plant growth and sediment
resuspension.
Turbid/Clear water state stability: we know how to switch lakes into the turbid water
state easily; it is much harder to go the other way.
What are some of the factors that drive our lakes into a turbid water state? Some
examples include: boating impacts, development in the watershed, shoreline
development, carp and other rough fish, increased impervious and stream bank erosion,
invasive species, and others. Much is still not known but the science is advancing every
year.
Bischoff showed a picture of a carp exclusion barrier experiment that showed clear water
behind the barrier and soupy water outside.
Bischoff showed a graph of prop disturbance and sediment transport saying waterskiing
can have a big effect on water quality.
What is a TMDL? A TMDL or total maximum daily load is a study that determines the
maximum pollutant a waterbody can take and still meet state standards for water quality.
Load allocations are unpermitted sources such as farm fields. Waste load allocations
are from cities, industries, and other permitted sources.
2
With increased nutrients, water clarity decreases. More algae growth caused by
increased nutrient availability reduces water clarity. Shallow and deep lakes act
differently in nutrient availability.
The TMDL study will look at the water budget of the lake, and the nutrient budget of the
lake. This method is called the "uniUarea-load" method. Another part of the budget will
be understanding the internal loading of P from bottom sediments.
So what happens when a TMDL is done? - answer: Implementation Plan. Both the
Watershed and City are regulated entities and will need to tackle implementation of the
TMDL. Mn-dot and the County will also play minor roles, taking care of discharges
from their systems. Farmers and other uses do not have any regulation, rather they are
incentive based.
Bischoff detailed some of the current activities undertaken by the WD to improve water
quality.
Alcorn asked what timelines will need to be met by the City. Bischoff said that during the
5 year permit cycle an adaptive management strategy would likely be pursued.
Hedberg asked how long the lake has been impaired. Bischoff said the watershed
district does. Marchessault asked what sort of City regulations address water quality,
citing a stormwater pond that would be needed for the expansion of his Burnsville
Buisness. Bintner answered that all new development and some redevelopment is set in
the Public Works Design Manual.
Marchessualt asked if we are retrofitting any old developments. Hedberg stated that the
upcoming 2008 reconstruction project served as an example, saying the City would
retrofit an exiting neighborhood to treat stormwater.
O'Keefe asked what came first, the fish change, or the water changes. Bischoff said it
wasn't easy to parse out which was the leading factor. Carp are one exception, they are
known to drive water quality.
Bintner asked how we monitor effectiveness once the TMDL is in place. Bischoff said
water quality monitoring as well as biological monitoring would be needed. For City
specific things, BMPs can be individually assess each.
Alcorn asked if one could assume that pollutants in Spring are effecting Upper and
Lower Prior, or if we could say that farming is more prevalent than urbanization. Bischoff
said the unit area load method would be a good method to assess that.
Hedberg asked if any other of the Lakes in the City are required to be studied, and what
the District was doing for those lakes. Bischoff said only those in the impaired waters list
are required to be studied. The fakes draining to Spring will be included in this study, but
not directly. Bintner added that Pike is a listed water and could be studied, and that
Cleary Lake is a nearby lake that is also listed. Bintner explained that even Lower Prior
is under a TMDL, but not for nutrients, but for Mercury (Hg).
Jasan asked at what point do we check the TMDL load, and it seems like the program is
a reactive approach. Bischoff agreed that is was reactive, and ones that are impaired
3
are studied. Nondegradation is the discussion that was more proactive. Jasan asked
how long it takes to identify the problem. Bischoff said it depends on the pollutant, and
the process runs from 12-18 months.
Hedberg said both Crystal and Arctic lakes also contribute water to Upper Prior and
asked what was being done to assess those waters. Bintner stated that to his
knowledge those lakes were not currently being monitored and that individual residents
of those lakes, could if interested, join the Citizen Assisted Monitoring Program (CAMP)
to monitor the water on their lake.
Bintner said that someday a WLA would be in place and the City will be asked to do
something. Bintner asked what sort of fnancial impact would be expected of the City.
Bischoff explained the shingle creek Cloride TMDI and said they received a$600,000
grant to address part of the issue of old technology. As far as Lakes go, iYs a matter of
negotiating with the PCA to assess the stormwater utility.
Hedberg said that meeting the standard might not be good enough and that going above
the standards because the Lakes were too important a resources to only meet the
standard.
Bintner added that the current direction was to assess maintenance activities in terms of
'biggest bang for the buck' in terms of stormwater, but that the dollars were fixed right
now. The TMDL may ask that more resources be allocated. Bintner asked for a quick
wrap up of the `next steps' to the TMDL. Bischoff said the model would be done at the
end of the year, and a TMDL would be drafted by Spring.
Liz Winger asked if Spring Lake could get shore restriction signs and asked about weed
and swimmers itch treatment. Eggen answered off microphone. Mankowski said it
might be a good idea to put information on the website on what is allowed for treatment
in the lake, and to put the rules and regulation on the website and promote it in the
Wavelength.
ADJOURNMENT
THE MEETING WAS ADJOURNED AT 6:20 P.M.
Respectfully submitted,
Ross Bintner
Water Resources Engineer
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Page I of2
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Ross Bintner
From: Ross Bintner
Sent:
To:
Tuesday, November 06, 2007 1 :40 PM
Ken Hedberg; 'dano@netlake.com'; 'jimm@bsp-mail.com'; 'Charlene Jasan'; 'Mankowski, Donna';
'Harry Alcorn Jr. PharmD.'
Cc: Michael T. Peterson; Charlotte Green; Larry Pop pier; 'Mike Kinney'
Subject: November LAC Meeting
Attached you will find October meeting minutes and an agenda for the November LAC meeting.
LAKE ADVISORY COMMITTEE
November 20, 2007
4:30 P.M. - 6:30 P.M.
Prior Lake City Hall
I have scheduled a presentation from Wenck and Associates, the PLSLWD Engineer about the Total Maximum
Daily Load (TMDL) study. Below you will find a notice to other water organizations inviting them to attend the
meeting as well. Please forward this to any other interested parties that you think may want to attend!
Ross T Billtn~r. P.E.
Wat~r R~$()urces Engineer
p 9524479831
C: 952 2922000
F 952,440.4245
E' rhintn(jf,itbcltyofpnormk9 com
~V: httrll!wVi'iV cltvcfprtcdake.coml'NaterResources shIm!
Prior lake Email Updates. Sign up now.
From: Ross Bintner
Sent: Tuesday, November 06,2007 12:16 PM
To: 'pnelson@co.scott.mn.us'; 'Mike Kinney'; 'MHous89824@aol.com'; 'Mankowski, Donna'; 'lizw@mchsLcom';
'Ioren@priorcreative.com'
Cc: 'Lori Carlson'
Subject: Prior Lake Lake Advisory Committee Invite:
To: Scott WMO Watershed Planning Commission.
Prior Lake Spring Lake Watershed District Board of Managers
Prior Lake Association
Spring Lake Association
The Prior Lake Lake Advisory Committee (LAC) is extending invitations to guest speakers in the upcoming
months. Last month we learned about non point source pollutants from John Bilotta with the University of
Minnesota Extension. This month we will hear about the TMDL study underway on Spring and Upper Prior Lakes
and discuss specifics of lake biology and watershed protection. In the months to come we hope to cover
additional topics such as wetland biology, land use management, fisheries, shoreline restoration, rain gardens or
stormwater. These meetings will be a chance to get your questions answered and should be very informative!
Our next meeting is on November 20 at 4:30pm in the Prior Lake City Council Chambers.
The presentation will be about "TMDls and Water Quality in Spring and Upper Prior lakes" from Joe Bischoff
with Wenck Associates.
The LAC is extending invitations to water focused organizations to attend this public meeting, Please forward this
on to your membership. Hope to see you there!
11/19/2007
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Ross Bintner
From: Ross Bintner
Sent: Tuesday, November 06, 2007 3:40 PM
To: 'dano@netlake.com'; 'Charlene Jasan'; 'jimm@bsp-mail.com'; Ken Hedberg; 'Harry Alcorn Jr.
Pharm.D.'; 'Mankowski, Donna'
Cc: 'jbilotta@umn.edu'; Larry Poppler
As a follow up on one of the messages we learned about from John Bilotta at our last meeting, I found an
interactive tool that the University of Minnesota produced that allows citizens to explore the increasingly urban
nature of their watershed. Attached is the impervious map from Scott County for 2000.
If you would like to explore the data further the linked website lets you compare and view areas of the state
through a series of years.
bttp://lalld.umo.edu
To use the comparison tool, go to quickview data, or click the link below and follow these steps:
b1tp://land.J.JJnn.edu/quickview data/index. html
1. Under "Twin Cities Metro Area" Click on "Impervious Surface Classification and Change"
2. A popup will appear with a map of the 7 County area:
3. Use the toolbar to pan and zoom around the map, or left click in the map and drag to pan.
4. Click the purple "change from <date> to <date>" buttons to view the change in impervious.
Lake water quality is tracked through satellite photos as well. The data can be explored at a related University of
Minnesota Site.
bttg://water. umn .edu
Or in date form at the DNR "Lakefinder" site.
h1m) /WVjIN. qnr. statE:LJ" n. us/lakefind/index.html
Ross T Bluff)(t(, P.E.
Water Resources Engineer
P: 95.2,,:'41.9831
C: $152292 2080
F: 9S:U40.4.245
E: r~)lntnerta!cltYQfpnorI4'lke com
W: httn:!lvNiW dwomricrlake comJ'iNalerResources shlmJ
Prior lake Email Updates. Sign up now.
11 /19/2007
108,309
32,509
54,460
7,466
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Total Area:
Total Impervious area:
Percent Impervious Area:
235,508 Acres
11,617 Acres
5.1 %
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Note: This map is being viewed at a resolution higher then 1/4 acre per pixel and may appear jagged.
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Agriculture 1,787 16.78 0 5,775 54.24 0
. Forest 1,074 10.09 1-10 556 5.22 0.24
Grassland 51 0.48 11-25 1,029 9.66 1.76
, ExtmoUo' 0 0 26-40 1,114 10.46 3.46
Water 1,627 15.28 41-60 1,159 10.88 5.41
Wetland 302 2.84 61-80 604 5.67 3.94
. Urban 5,802 54.49 81-100 405 3.8 3.43
Total Area: 10,648 Acres
Total Impervious area: 1,941 Acres
Percent Impervious Area: 21.5 %
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Impervious Surface around the Twin Cities Metropolitan Area between...
http://land.umn.edu/zoomify/imperv Ide faul t. htm
Impervious Surface around the Twin Cities Metropolitan Area between 1986 and 2002
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1986 - Change - 1991 - Change - 1998 - Change - 2002
I Chanqe over the whole period of 1986 - 2002 I
How these maDS were made
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What the colors mean
c:::::::J Agriculture
_ Forest
[3 Grassland
11II Shrub land
_ Water
_ Wetland
Urban
c=J 1-10% I..rvious
c=J 11-25% In'f)el'llious
11III 26-40'% II1'f)eNious
_ 41-60'% In'f)eNious
_ 61-80% II1'f)eMous
_ 81-100% Impervious
Areas where ImpeNiousness
InCtNSed by:
c=J 20-40%
_ 41-60%
_ 61-80%
_ 81.100""'
during the selected time period
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11/19/2007 2:33 PM
Impervious Surface around the Twin Cities Metropolitan Area between...
http://Iand.umn.eclu/zoomify/imperv/de faul t. htm
Impervious Surface around the Twin Cities Metropolitan Area between 1986 and 2002
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1986 - Change - 1991 - Change - 1998 - Change 2002
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How these maps were made
Print Map
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What the colors mean
c=J Agriculture
_ Forest
c::=J Gl1Issland
IIIl Shrub land
_ Wal8r
III Wetland
Urban
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2840% l"1lttrvious
41-60% l"1lervious
61-80% I"1lttMoUS
81-100% Impervious
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Areas where Imperviousness
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_ 61-80%
_ 81-100".4
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Powered by Zoomifv
II I 1912007 2:34 PM
1231997 10/1/03 12,42 PM Page 1
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Using satellite images taken from Spllc". statewlele census of
water d.rlty - a key Indicator of hJk. wat., quality - has been
cruted for the first tim..
Employing state of the art image analysis technology, the Remote
Sensing Laboratory and Water Resources Center at the University of
Minnesota have used satellite remote sensing to determine clarity
transparency for about 10,500 Minnesota lakes. This satellite-based
method enabies resource managers to analyze how lake water darity
varies statewide over time. Resource managers are using this
information to better target monitoring and management efforts.
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The Minnesota Pollution Control Agency (MPCA) coordinates the
collection of Secchi disk readings by staff and citizen volunteers
on about 850 lakes annually. These measurements are essential
to the satellite data analysis, but they include only a small
percentage of the state's lakes. Satellite data enable monitoring
of nearly all the 10,000+ lakes in the state.
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Measuring Lake Clarity
The clarity of lakes usually is measured in terms of the depth to
which one can see an object below the water surface. The
standard device used to do this is a Secchi disk. a white disk.
eight inches (20 centimeters) in diameter attached to a rope that
is lowered through the water column until the disk disappears
from sight. That depth is called the Secchi disk transparency.
The clearer the lake is, the deeper the measurement
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Monitoring Lakes from Space
The landsat satellite orbits the Earth 438 miles above the surface. Its sensor, called a multispectral scanner,
records images of the same 11S-mile wide path every 16 days. Nineteen images from five orbits are needed to
cover Minnesota. The smallest area recorded is 30 x 30 meters (about 1/4 acre). The scanner records digital
images of the surface reflectance in visible and infrared wavelengths of the etectromagnetic spectrum. The
infrared spectral bands are especially useful for mapping vegetation, and the visible blue and red bands are
sensitive to physical properties of water, including its clarity or transparency.
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The first step In mapping lake clarity is to separate water from land features. Next the anaJyst determines the
retatk>nship between the Intensity of reftected blue and red wavelengths and the Secch6 disk transparency for a
set of 25-50 -calibration-lakes. The relationship then Is applied to all the lakes in the Image, providing a census
of lake clarity.
Citizen ~oIunlHfsand field Klentl$\$usl! Sl!Cchi Satellite remote sensing provides a cost.effective way to gather the information for water quality assessments
dish to detl!fmlnl! lake w.llfltdatity. in lake-rich areas like Minnesota. This has been done statewide for -1990 and -2000 time periods and is
available at hnp://water.umn.edu. New dates, as well as earlier dates (-1975, -1985 and -1995), will be added as
comp'eted and will enable analysis of changes in lake clarity over time. This map was created using -2000
satellite data and Secchi disk readings.
lake Clarity Depth
Feet Meters
- le5s than 1.5 le5s than 0.5
1.5 -3 0.5.1
... 3 -6 1 -2
6- 12 2 -4
- greater than J 2 greater than 4
Minnesota Lake Clarity by Ecoreglon
Factors that Affect Clarity
lake clarity is affected primarily by three
different constituents found In water:
(1) microscopic plants called algae
suspended in the water,
(2) suspended sediment - clay and sllt-
primarily from soil erosion, and
(3) dissolved natural organic matter, called
humic material, that is derived from the
partial decay of terrestrial plants.
Algae and decomposition products of algae
are the primary factors controlling light
penetraUon in most Minnesota lakes. For
such lakes. water clarity is closely related to
nutrient status.
Lakes with high clarity have low levels of
algae and nutrients. Most lakes with low
water clarity have high concentrations of
algae (measured in terms of chlorophyll) and
high concentrations of the primary nutrients,
phosphorus and nitrogen. Sediment tends to
be important in some lakes of southern
Minnesota where soil erosk>n is a problem.
Humic color affects some lakes in northern
Minnesota. especially in forested watersheds
with wetlands.
Satellite imagery provides an accurate
measure of water clarity across a broad
spectrum of lakes, but additional monitoring
may be required to Interpret which factor
(algae, sediment, or humic matter) is limiting
water clarity.
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/"- Ecoregion Boundaries
"TlJi5legefld pertains to all illustrations and maps.
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Water Clarity Affects Plants and Animals
The yegetation and aquatic life that will be sustained in a particular lake is
_led by the lake clarity. Some species thrl.. only within. nalTOw range of
water conditions or quality, and require very clear water. Other pfants and
animals can survive in a broad range of condltiOfl$. The illustration below
depicts the optimum clarity ranges for setected MIMeSOta fish species.
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