HomeMy WebLinkAbout6D - SW Metro Groundwater
CITY COUNCIL AGENDA REPORT
June 17,2002 /\~
:~ank Boyles, City Manage~
AGENDA ITEM: SOUTHWEST METRO GROUNDWATER GROUP MANAGEMENT PLAN
PRESENTATION: Since April 1997, representatives of the DNR, cities of Burnsville, Lakeville, Prior
Lake, Savage, Shakopee, Shakopee Utilities, the Shakopee Mdewakanton Sioux
Community, and the Metropolitan Council, have been meeting to discuss
groundwater management issues. As a result of this work, a Southwest Metro
Groundwater Work Group Management Plan was prepared.
A copy of the Plan is attached. Chris Elvrum of the Metropolitan Council, and Pat
Lynch from the DNR, will provide a presentation regarding the Plan. The purpose
of the presentation is to provide the Council with a basic orientation regarding the
key groundwater issues.
16200 Eagle Creek Ave. S.L, Prior Lake, Minnesota 55372-1714 / Ph. (952) 447-4230 / Fax (952) 447-4245
I :\COUNCI L \AGNRPTS\2002\GROUNDW A TE~g:AG:~;~&fIIQt)M)EMPLOYER
Southwest Metro Ground Water Work
Group - Management Plan
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Table of Contents
INTR 0 D U CTI 0 N ...... ....................... .... .............. ............... ............. ..... .................. ....... ...... .... ..................... 1
RISTO R Y AND FO RMA TI 0 N .................................................................................................................. 1
GOALS AND 0 BJE CTIVE S ... ............. .................. ......... ........ ........... ................. ................. ...................... 2
DEMOGRAPHIC OUTLOOK AND WATER DEMAND ....................................................................... 3
ISS DES . ...................... ........ .................... ...... .... ........ ................. ......... .................. ................ ....... .......... ........ 3
GEOLOGY !HYDROGEOLOGY ....................................................................................... ........ ....... ................. 3
GROUNDW A TER QUALITY ................................................................... ........................................................ 7
Nitrates..... .................................................................................................................. ........................... 7
Radium........ ............................. ................................................................................ ........ .......... ............ 7
INSTITUTIONAI..iREGULA TORy....... ..............:.. ........... .......... ........... .......... ......... ........ .......... ............ .... ....... 7
D A T A AND MOD ELS ................ ........ ........................ ...................... .................. ......................................... 8
DATA.. ...... ............... .... ................ .............. ........... ................... .......... ................. .............. ................... ....... 8
Modeling..................... ............................................................................................................... .......... 13
Additional Studies ............................... ....... ........... ............... .......... ........ ..... ......................................... J 4
FINDIN GS (POINTS 0 F AGREEMENT) ............................................................................................... 16
PHYSICAL ATTRIBUTES ...................................................................... ....................................................... 16
INSTITUTIONAI..iREGULA TORY STATEMENTS .................................... ........................................................ 21
NEEDS IDENTIFIED BY THE SMGWG ............................................................................................... 22
GEOLOGY!HYDROGEOLOGY!HYDROLOGY DATA COLLECTION ................................................................ 23
WATER QUALITY ............................................................................... ....................................................... 23
INSTITUTIONAL .... ..... ............ ...... ... ....... .... ......... ....... .............. ...... ......... ........ .... ........ ........ ....... ................ 24
REGULATORy............. ........................ .................... .......... ................. ............................ ............... ............. 24
CON CL U SI 0 N S .... ........ ..................... .............. ................... ...... ........ ............... .............. ............................ 24
RE C 0 l\1l\1END A TI 0 N S ........ ............ ........ ............... ... .;..... .......... ............. ...... ......................................... 25
INSTITUTIONAI..iREGULA TORy........... ..................................................................... ........ .......... .......... ...... 25
INTER-COMMUNITY COOPERATION.................... .................... .................................... ...... ........ .......... ...... 26
DATA COLLECTION.. ..................... .... ..... ......... ...... ....... .................................. .... ...... .................... ............. 27
CONSERVATION ... ..... ............... ............. .... ..................... ............................................ ......... ........ ..... ......... 27
COSTS ............. ......... ............ ............... .................................................................... ... ............... ............ .... 27
ORGANIZA TIONALRoLE. ..................................... ..................................................... .......... ......... ............. 27
BASIS FOR AGREEMENTS BETWEEN CITIES AND DNR.............................................................................. 27
Savage............... ...... .......................................................................................................... .......... ......... 27
Burnsvi/le ........ ........... ............................,................................................................ ........ ..... ........... ..... 28
Prior Lake.. ................... ............. ................. ............................................... ................ ......................... 28
Shakopee Public Utilities Commission (SPUC) and the City of Shako pee.......................................... 28
Lakeville... .................................................................... ................... ........................... ................... 29
Shakopee Mdewakanton Sioux Community (SMSC) ....................................................................... 29
DNR ......................... ................................................................................................. ........ ................... 29
Metropolitan Council..................................................................................................... ....... ............... 30
l\1EM 0 RAND UM 0 F At; REEMENT ............................ ......................................................................... 30
A CR 0 NYMS ....... ................ ................................................................. .................. ..................................... 31
Tables
Table 1. Community WeIIs and 2000 Water Appropriation............. ....... .............. ..4-5
Table 2. Community Population and Water Demand (current through 2020)........ ........6
Table 3. Status of Data Collection and Assessment Plan Tasks.. ........ .......... ............9-10
Table 4. Summary Table of Low Flow Data (1997 - 2001)............................... ..... 17-19
Figures
Figure 1. Generalized Stratigraphic Column for Scott and Dakota Counties................ 11
Figure 2. Bedrock Geology of Southwest Metro Area.......................................... 12
Figure 3. Area Discharging to Deans Lake - Savage Fen..................................... ..15
II
INTRODUCTION
The purpose of this management plan is to detail efforts that have been conducted in the Southwest
Metropolitan Area to protect natural resources while supplying water for the growth of the communities in the
area. In addition, the plan outlines several recommendations for future data collection and assessment as well
as actions for the involved communities and agencies to take. Each of the six communities and the agencies
involved will sign a Memorandum of Agreement to work with each other to implement the recommendations
contained in this plan.
This Management Plan was prepared by the Metropolitan Council (MC) in cooperation with the Minnesota
Department of Natural Resources (DNR) and the communities, agencies and organizations mentioned in the
following section. This report follows several years of effort by participants with the goal of protecting the
State's natural resources while planning for growth in the Southwest Metro Area. Although the process is
ongoing and should not be considered concluded with completion of this Plan, all the participants should be
commended for the countless hours contributed to date and be proud of the progress that has been made. As
areas continue to grow throughout the State, the Southwest Metro Ground Water Work Group can be looked to
as a model for involved parties to work together to provide adequate water supply for growth while protecting
the State's natural resources.
HISTORY AND FORMATION
In early 1997, it became apparent that several cities in the southwest portion of the metropolitan area, south of
the Minnesota River were heading for regulatory difficulties in obtaining sufficient water to supply projected
growth. The regulatory problems related to the withdrawal of ground water and the impact this was having on
some unique surface water features in the area. The key factor that caught the attention of the DNR was the
lowering of water levels in the Savage Fen, a rare calcareous wetland containing rare plant species. Continued
viability of the Fen relies upon upwelling of calcareous ground water from the Prairie du Chien (PduC)
aquifer. The PduC, in turn, is fed to some degree by water from the Jordan sandstone aquifer. The complex
connection of these two bedrock units and the impact of pumping them for water supply became the primary
focus of a group put together in 1997.
The Southwest Metro Ground Water Work Group (SMGWG) was formed in April 1997 to serve as a forum to
discuss the issues facing the communities and the regulators. After preliminary discussions with many of the
affected parties, the MC agreed to facilitate this group. The first meeting was held on April 28, 1997.
TIrrough December 2001, the group has met 27 times as a full group and many more times as a technical sub-
group evaluating data and putting together a work plan (December 9, 1997),
Participation in the SMGWG has remained very stable over the years with many of the following participants
consistently at the table:
Cities: Burnsville, Lakeville, Prior Lake, Savage and Shakopee
Tribal Interests: Shakopee Mdewakanton Sioux Community (SMSC)
StatelRegional/Federal Agencies: DNR, MC, Minnesota Department of Health (MDH), Minnesota
Pollution Control Agency (MPCA) and the U.S. Geological Survey (USGS)
Counties: Dakota and Scott
Other Participants: Minnesota Geological Survey (MGS), community consulting engineers (Barr,
SEH, BRAA, H,R. Green, CH2MHill, PCE), Minnesota Center for Environmental Advocacy
--r-------.
(MCEA), Lower Minnesota River Watershed District, Aggregate Industries (formerly CA1vlAS),
Technical & Regulatory Evaluations Group (TREG), and occasionally members of the public
GOALS AND OBJECTIVES
One of the first items that was undertaken by the full SMGWG was the detinition of goals for the group. At its
meetmg of July 22, 1997, the group adopted the following goals:
· Develop consensus on a strategy that will accommodate projected growth and assure ground water
availability in the south metro area, while protecting sensitive environmental features.
· Collect the best data possible upon which to make water use decisions.
· Create a long-term water supply management strategy that recognizes the importance of local control
issues, the charges of regulatory agencies, and builds on the cooperation that exists between the
communities and other government sectors.
These three goals have formed the basis for group actions since the time they were adopted. The statement
reinforces the group's desire to be flexible in its approach, yet representative of all of the participating
interests. Since the adoption of these goals, several objectives have been discussed that address how these goal
statements will be achieved. Specific objectives include:
· Definition by the DNR of "acceptable" impact and aquifer "safe yield" so that communities have a
framework for judging impact.
· Implementation of effective water conservation programs in each of the communities.
· Definition of how much water each community will need and the location and water source that they will
use to obtain that water.
· Exploration of alternative water supplies if adequate water cannot be obtained to meet the above objective.
Alternatives include using surface water such as the Minnesota River, using intercepted water at quarries,
using deeper aquifers such as the Franconia-Ironton-Galesville (FIG) or the Mt. Simon-Hinckley (MTSIH),
locating well fields away from areas that influence unique surface water features, and interconnecting
and/or jointly developing water supplies.
· Plan for and implement additions to the monitoring network that allow monitoring ofwater level changes
as the region develops and furthers understanding of the complex hydrogeology of the southwest metro
area.
· Coordination of changes to urban land uses and the regulatory approval to obtain water to supply the
population occupying the newly urbanized land, All land use approvals such as comprehensive plans,
MUSA extension and plat developments, should consider whether there is sufficient water to support the
development without negative impact to natural resources including ground water.
· Continuation of the forum that has met under the SMGWG umbrella.
2
DEMOGRAPHIC OUTLOOK AND WATER DEMAND
Two of the most important variables to define in managmg the water related problems in this region are the
growth that is expected to occur and the demand for water that that growth spawns. These numbers change
very quickly as development proposals come and go, but the community local comprehensive plan sets the
. long-term framework for how the community expects to evolve. Each of the five municipalities participating
in the SMGWG has prepared a comprehensive plan that has been reviewed by the Metropolitan Council for
consistency with its overall projections for metropolitan area growth. The SMSC has voluntarily submitted its
comprehensive plan to the Council as well, although state law does not apply to the autonomous Native
American community.
In 2000 the five communities and the SMSC appropriated approximately 7 billion gallons of water from 42
wells drilled in various aquifers. Table I shows the wells active in 2000 and the water appropriated from each.
The growth projections for each of the six communities were used in conjunction with water demand
projections made by the Council using the Windows version of the Institute for Water Resources, Municipal
and Industrial Needs (IWR-MAlN) water demand model. Table 2 shows the projections for each community.
Demand will likely increase by over 50% by 2020. To meet this demand, there are currently 25 additional
utility wells planned in the study area. The surface location and aquifer unit used for these wells is critical in
the prevention of impact to the unique surface water features in the area. Determining this mix will be the
greatest challenge that the Work Group faces in formalizing a management strategy.
ISSUES
After four years of meeting, there are several issues that have emerged. This section of the plan merely
identifies the issues, many of which will be addressed in this plan, while others will need further attention.
The issues can be generally divided into technical (geologylbydrogeology and ground water quality) and
insti tu ti onal/regulatory /po liti cal.
Geology/Hydrogeology
The biggest issue that faces the communities and the DNR in the study area is whether the ground water
system can supply the water needed for growth while maintaining surface water levels needed by the Savage
Fen, Boiling Springs, Eagle Creek and associated surface water bodies like Dean's Lake, the Minnesota River
Valley lakes, and the wetland corridor of the MN Valley National Wildlife Refuge. Addressing this issue is
difficult due to uncertainty inherent in characterization of natural systems. Groundwater models can be used to
predict the impact of withdrawals on the surface water features. However, these tools can not be relied on to
be a precise prediction of the effects. Groundwater monitoring can be used to improve model accuracy and
provide information of aquifer response at a specific location.
Several questions related to the above overlying issue have been raised and discussed, to some extent, by the
SWMGW. Among these are: the possibility of defining a boundary within which the Jordan aquifer should not
be pumped (see later discussion in Data and Models section); the ability of the FIG to provide an adequate
volume of water without significant drawdown; use of the MTS/H within regulatory limitations; the
interconnectedness between the PduC and Jordan; and the DNR-defined "safe yield" or acceptable drawdown
relative to the surface water features.
One area of discussion that will not likely be fully addressed in the near-term is the role of reduced recharge
due to increasing impervious surface in the overall availability of ground water. Obviously there is a need to
maintain recharge to the ground water system as the area continues to develop, so a development or
3
T
Table 1. Community Wells and 2000 Water Appropriation
COrmI11:rn.ity WelL-Aquifer .' , ..... Year Installed 2000Pumpage Mi11iouGa1l6ns
..
Burnsville 1 - Jordan 1964 229.3
, 2 - Jordan 1966 232.7
3 - Jordan 1969 39.7
4 - Jordan 1969 113.4
5 - Jordan 1970 156.8
6 - Jordan 1970 74.7
7 - Jordan 1972 237.4
8 - Jordan 1972 76.7
9 - St. Lawrence through Hinckley 1975 186.2
10 - Jordan 1975 245.6
11 - MTS/H 1981 159.4
12 - Jordan 1988 275.1
1 J - Jordan 1978 136.4
14 - MTS/H 1990 118,0
15 - Jordan 1990 303.4
16 - Jordan 1994 35.5
".\.,.'. ..' ,."'.'... r,.......,c.,. ,...'.... ,. ~ ~
....)'........'.'...
Lakeville 2 - Jordan 1964 0
3 - Jordan 1968 7.41
4 - Jordan 1969 47.8
6 - Jordan 1980 560.3 7
7 - Jordan 1984 43.04
8 - Jordan 1989 127.97
9 - Jordan 1995 129.47
10 - Jordan 1995 318.24
11 - Jordan 1996 121.70
12 - Jordan 1997 267.24
13 - Jordan 1998 266,16
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Prior Lake 3 - Jordan 1973 262.5
4 - Jordan 1975 139,3
5 - Jordan 1988 212.8
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Savage 1 - Jordan 1961 Abandoned - 2000
2 - MTS/H 1969 Abandoned - 2000
3 - Jordan 1985 311.0
5 - Drift 1989
6 - PDC 1989 311.4
7 - MTS/H 1995 182.6
8 - MTS/H 1998
9 - FIG 2000
10 - MTS/H 2001
11 - FIG 2000
ZOOO.Totar.... ...'........; "."" '.... ......=:-.....,... aUJ ,.,.
4
Table I. Community Wells and 2000 Water Appropriation (cant.)
Shakopee 2 - FIG* 1945 106,3
3 - St. Lawrence through MTS 1956 185.1
4 - Jordan 1971 106.9
5 - Jordan 1971 142.2
6 - Jordan 1981 241.8
. 7 - Jordan 1986 26.7
8 - Jordan 1989 266.4
9 - Jordan 1995 250.1
10 - MTSIH 2001
11 - Jordan 2001
.', "'('>.'" ..2000 [ptiiVn .",.... "i......"'..... ',,". ., r~?"" -'"
.. .. .,.
* converted from multi-aquifer to FIG well in 2002
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redevelopment approach that maximizes infiltration is warranted, Additional study could also
clarify whether "draining" ground water by putting in outflow structures below the water table
has a significant impact.
Finally, the injection of calcium-rich ground water up-gradient of the Fen in order to supply it
with the water that is no longer available has been considered. This technique was employed near
Nichols Meadow Fen in a pilot study and is not considered to be feasible in this setting,
Groundwater Quality
Water quality issues, which have some bearing on use of the ground water system for water
supply, also emerged during SMGWG meetings.
Nitrates
The nitrate level in a Scott County sample from bedrock (PduC) below the CAMAS quarry
reached lOO mg/l, which substantially exceeds the federal drinking water standard of lO mg/l.
SPUC has seen levels approaching lO mg/l at some of its Jordan wells, with levels increasing in
winter and decreasing in summer. Scott County officials believe the sources of nitrates are
agricultural practices, individual sewage treatment systems (ISTS or septic tanks) and possibly
storm water ponds.
Radium
Water from the aquifers in the area has 10cal1y high levels of radium inherent to the bedrock.
Although radium content does not prohibit the use of these aquifers, it does warrant advanced
levels of treatment for removal. Lakeville and Savage are both managing the problem with
blending and/or increased treatment with hydrous manganese oxide or manganese greensand.
Institutio nallRe~ula to ry
In additional to technical issues, there are many "other" issues that need to be addressed. The
basic question that brought the Group together in the beginning was how can the growing
communities in the southwest metro area provide water for existing and future development
without harming sensitive environmental features and ensuring that there is an adequate water
supply for future generations? Can consensus ever be reached on a management approach and
will all parties agree to implement the management plan strategy if consensus is reached?
Key among issues raised in this discussion is the role of the regulatory agency (the DNR) and the
effective links between community needs and regulatory decisions on water appropriations. Part
of this look to the future involves community comprehensive planning and work with the MC to
better incorporate water supply assessment into its Metropolitan Urban Service Area (MUSA)
expanSIOns.
The supply needs of the communities, and the role of conservation and water demand
management in keeping increases manageable must be addressed through community
conservation efforts and the DNR permitting process. Restrictions on the MTS/H will also playa
role in this strategy, as will the FIG's potential to be a good resource.
Acceptance of this management plan and adoption of a Memorandum of Agreement, discussed
later, will help to maintain regulatory equity while protecting the regional natural resources and
will result in a satisfactory end to the issue ofregulatory inequity. Sharing of resources and
coordination of water supply decisions and planning by all communities will be necessary to
7
achieve success. The final strategy should, however, be viewed as a flexible document that lays
out a means for changing future plans as more facts about the ground water system become
avaIlable.
DATA AND MODELS
Data
Very early in the SMGWG meeting process, it was ~ealized that data was going to be the key to
determining the impact of ground water use on surface water features. The SMGWG established
a Data Collection and Assessment Subgroup and charged it with finding the best data available
and identifying those data that were needed, but not in existence. The Subgroup prepared a Data
Collection and Assessment Plan in December 1997. ThIS plan identified 26 tasks that involved
the collection ofboth existing and new data, its evaluation and its use in modeling (Table 3).
Additional data sources not reflected in Table 3 include: CAMASIMC Blue Lake area water level
monitoring and modeling; historic Dean's Lake data; MPCA and county water quality data; and a
USGSIDNR study of water movement through fractures near Savage well #8,
The data assembled for this portion of the metro area can be mterpreted to iIIustrate the geology
of the region of interest. Figure 1 is a generalized geologic column for those units occurring in
the study area. Figure 2 shows the geologic plan view of the area. Features to note in Figure 2
are the buried bedrock valley cut into the Franconia Formation transecting the study area and the
Minnesota River Valley.
Data on the geologic units in the study area vary by unit. Data on deeper ground water aquifers
(FIG and MTSIH) are less available than on units closer to the surface. The cost of obtaining data
is very expensive, but understanding the relationship of geology to the flow patterns and
hydrologic behavior of the study area is essential to proper management of the system. For this
reason, the DNR is working with the communities to obtain data on the various units as the
communities seek state authorization to appropriate ground water. Prior Lake has installed two
monitoring wells in conjunction with a DNR approved Jordan appropriation well. In addition, the
DNR has required Savage and Shakopee to stop drilling while in the FIG and test the formation
prior to drilling into the MTSIH.
It is generally agreed that the discharge that sustains the Minnesota Valley's wetland system,
including Savage Fen, Eagle Creek and the Boiling Springs, is fed upward through glacial
material by water discharging from the PduC Group. This calcium rich water is important to the
existence of the fen's unique vegetation, Depending upon local geologic conditions, the Jordan
might feed water into this system from deeper within the bedrock section,
As part of its geologicfhydrogeologic study of the PduC/J in the spring of 1999, the MGS found
that the lower unit of the PduC Group, the Oneota Dolomite has less fractures than the upper
Shakopee Formation and may act as a leaky confining layer separating the PduC from the Jordan
(Runkel et.a1, 1999). This may be especially true where the Oneota is greater than 100 feet below
the bedrock surface. In this situation the Oneota appears to be relatively unfractured and has few
dissolution features. This suggests that m shallow situations where the Oneota is less than 100
feet from the bedrock surface such as near buried bedrock valleys, the PduC and Jordan may be
more hydraulically connected. The study states that the PduC and Jordan have not been shown to
be connected regionally nor regionally separated.
8
Table 3. Status of Data Collection and Assessment Plan Tasks
Study Task Description Status '.'
(Number) i' i,i..' .:....,. ..........'.,
IA1 Low flowlbaseflow surveys 1997,1998,1999,2000
IA2 MC watershed outlet monitoring Sites established at Credit R., Eagle Cr.
IA3 Study of Prior Lake outlet LMR WD and PLSL WD joint effort to route
flows around Dean's Lake and clean channel
from Prior Lake to Minnesota River
IE1 Surface water level measurement Continuous on Prior Lake (PLSL WD)
and Savage Fen (DNR)
ICl Evaluation of impacts of SW management Unfunded
plans of cities and WMOs
IIAl MGS evaluation of existing geologic data Complete
lIB 1 MGS study ofPduC/J Complete
geoiogylbydrogeology
lIC1 Incorporate results of Brick (MPCA) Complete as part ofMPCA Metro
seepage study Ground Water Model
IlIA 1 Enhance DNR ground water level Several wells added in study area by
monitoring network DNR, Prior Lake & Savage
IIIA2 Collect available ground water level MDH as part of ground water model
readings development; MPCA Metro Model
calibration data set; DNR ground water
level monitoring network; cities as part
of regulatory process
IIIA3 Synoptic ground water survey Conducted through Feb, 1999 (Aug.'99
missed)
HIBl Aquifer and well testing Completed by DNR, MDH and several of
the communities
IIIB2 SMSC pumping tests on community wells Completed by SMSC as part ofPduC/J
. tests; USGS cooperative study of Jordan
wells
III C 1 Collection of data associated with MDH On-going by MDH and communities
wellhead program
IIIDI CAMAS quarry expansion and Blue Lake Expansion abandoned; Barr assessment
WWTP impact of ground water impact on WWTP
complete (MC); all pumping at CAMAS
stopped and pumps removed
IIIE 1 Stable isotope/chemical character Unfunded
evaluation
IIIE2 Water budget and regional ground water Undern'ay as part of USGS study on
recharge regional recharge (Sept. 2001
completion)
IVAI Construction of Metro ground water Model Completed by MPCA. No further
framework funding anticipated.
IVA2 Development of conceptual Scott-Dakota Completed by MDH
9
*"-_.~-,,,~~,"--'-'.~--~'~~-"-'~--""--"'''''-'-'----"'.''-'---_._.~-"-_._--~~_.,",--
ground water model
IVA3 Construction of Scott-Dakota ground water Completed by MDH
model
VAl Study use and role of deep aquifers Study unfunded, but evaluation by DNR
continues
VBl Identify need for alternative sources On-going by DNR and communities
VB2 Evaluate alternative sources of water Large study unfunded, but partial
evaluation done by Savage and
Shakopee
VIAl Assemble available data, and contribute On-going as needed
data in return
VIBl Conduct assessment of demand On-going by DNR and communities;
- MC demand projections
management
VII Prepare management plan 2002
DNR = MN Dept. of Natural Resources
LMR WD = Lower Minnesota River Watershed District
MC = Metropolitan Council Enviromnental Services
MDH = MN Dept. ofHeaIth
MGS = MN Geological Survey
.MPCA = MN Pollution Control Agency
PduC/J = Prairie du Chien-Jordan Aquifer
PLSL WD = Prior Lake-Spring Lake Watershed District
SMSC = Shakopee Mdewakanton Sioux Community
USGS = U.S. Geological Survey
WMO = watershed management organization
WWTP = wastewater treatment plant
10
Figure 1 Generalized Stratigraphic Column for Scott and
Dakota Counties
Q
~ 0 FORMA nON LITHOLOGY HYDROSTRATIGRAPHIC UNITS
2 OR GROUP
w w
~ NAME
Sd >- Terrace Silt, Sand & Gravel Upper Glacial Drift Aquifer
0 0::: Deposits
N ~
0 ;Z Des Moines Lobe Unconsolidated Confining Unit
;Z 0:::
W w Till Clav and Silt
U f-
W ~ Superior Lobe
f- :J Unconso I idated
~ a Outwash and Till Sand & Gravel
....J
~YFm Lower Glacial Drift Aquifer
;Z
~
U Limestone and
;> Platteville Shale
~ Formation
0 \
Ul St. Peter Sandstone with
....J
Q Sandstone Shale layers near
Q
~ base St. Peter-Basal Confining Unit
Z Limestone &
0:::::; Prairie du \ Prairie du Chien Aquifer
U ~~ Dolomite with
0 Chien Group
N 0- Shale Layers
0 ....J~
W 0
....J
~ Jordan Sandstone Jordan Aquifer
Q..
>- Sandstone . with Shale
;:2 Dolomitic Shale
~ St. Lawrence St. Lawrence Confining Unit
w & Siltstone
Formation
Glauconitic
;Z Franconia Sandstone
~
i:2 Formation with Shale & Franconia-lronton-Galesville Aquifer
o:l \. Dolomite
~
U Ironton & Glauconitic
- 0:::
W Galesville Sandstone &
~
~ Sandstones Shale
:J
Eau Claire Siltstone, Shale & Eau Claire Confining Unit
Formation Silty Sandstone
Mt. Simon Sandstone & Shale Mt. Simon-Hinckley Aquifer
Sandstone
MIDDLE PROTEROZOIC, UNDIVIDED Volcanic and
Crystalline Rocks
tIl
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The MGS findings, MC geologic data on the Blue Lake Wastewater Plant de-watering project,
and the pumping tests by DNR and Savage in the fall of 1998, suggest that the PduC and Jordan
have a higher degree of connectivity between formations nearer the Minnesota River. The area
around the Savage Fen probably falls in the "shallow" category descnbed by MGS. It is still
unclear whether an area where pumping the Jordan will have no effect on the Fen can be defined.
Modeling
The complex geology and hydrogeology of the study area can be approximated and understood
with the help of mathematical models. The hydrogeologic setting of the SW Metro area is
difficult to model due to the changes in elevation, multiple conversions from confined to
unconfined conditions, and the importance of the bluff edge seepage faces and springs as
resources which are the focus of the assessment. Over the past 20 years, there have been many
"improvements" over past models, however they can not provide numerically precise results.
General trends and net upward or downward movement can be fairly reliable model results,
especially when well calibrated models are used, However, modeling has not replaced the need
for field measurements to verify model predictions and improve future model runs.
There are several ground water models that have been applied for different purposes within the
southwest metro area. Most of the ground water models constructed for areas in Scott and
Dakota Counties have been locally focused and limited in scope. The detail and geological
foundations for these models are extremely variable, but have generally improved as more
information has been collected and more attempts made to model the area. The following
collection of models have been used by the SMGWG to varying degrees:
. Barr Engineering model for Lakeville (1993)
. DNR Fen model using 1980s version of Otto Strack MLAEM model (later switched to Barr's
1994 model)
. Barr Savage Fen model (1994)
. Barr/Dakota Co. MLAEM (cooperative effort for drift and PduC/J among the County, Apple
Valley, Burnsville, Eagan, Hastings, Rosemount and So, St. Paul for wellhead protection,
1995)
. Barr model for Shiely Corp. (1997)
. MC 1998 Barr MOD FLOW model of Blue Lake WWTP de-watering system
. Dakota/Scott MODFLOW \VHP model (PduC/J) for MDH (Barr, 1999)
. Barr MOD FLOW model of FIG for Savage (1999)
. MPCA Metro Model (1999)
. SEH models of Burnsville's Kraemer intercept (Metro Model base, 2000)
. MDH MODFLOW runs to evaluate impact of cessation of CAMAS Quarry pumping (2000)
(Dakota/Scott MODFLOW model base)
. MC current scenario effort (Metro Model base 2001)
Although most of these models were developed to address a localized situation, some common
findings have occurred. First, the MGS statement that the PduC and Jordan act more as a single
unit as the Minnesota River and buried bedrock valleys are approached appears to be generally
accurate. The SEH model for Burnsville (discussed below), however, characterized' the two units
as separated by a leaky confining layer in the vicinity of the Kraemer Quarry.
13
Modeling rndicates that the buned bedrock valley has some effect on ground water flow in the
area. The magnitude of the influence on ground water remainS uncertain. A brief review of water
well records by the MDH indicates that the material that tills the northern portIOn of the buried
valley is relatively sandy. In contrast, the southern portion contams large amounts of clay.
Modeling using the results of the DNR's Savage aquifer tests showed that pumping the PduC/J
west of the valley will have less of an effect on water levels at the Fen and at Boiling Springs than
pumping from east of the valley.
A model series run by the MDH using the Scott-Dakota County regional model was used to
evaluate the response of ground water levels when the CAMAS quarry ceased pumping, The
results showed a potential rebound of about 45 feet in the PduC near the quarry after pumping
ceased and about 33 feet in the Jordan. The MDH modeling also showed ground water levels at
the Boiling Springs and Fen reboundrng up to one foot when pumping stops. Barr modeling for
the MC Blue Lake Wastewater Treatment Plant verified this conclusion.
SEH conducted groundwater modeling to evaluate the potential for intercepting ground water
prior to its discharge to the Kramer Quarry. As mentioned above, the PduC and Jordan were
treated as separate aquifers divided by a leaky confining layer. The ground water modeling
showed up to a one-half foot increase in water levels at the Fen with Jordan pumping wells
capturing Kraemer quarry water and the cessation of pumping of Savage's Jordan well #1.
The MC adapted the MPCA Metro Model for the study area, This mode!' helped to estimate the
areas that provide ground water to the Boiling Springs, Eagle Creek and Savage Fen, and Dean's
Lake areas (Figure 3). This area can change in response to pumping and changes in infiltration
inside or outside of the area, This figure is provided to show the general direction of flow and
time of travel for water discharging to the surface water features of interest. Specific attention
should also be placed on activities that could adversely impact water quality within this zone.
This model was also used to evaluate potential impact of additional wells in the area. The model
predicted some impact at the Savage Fen of virtually any high capacity well in the study area in
the PduC/Jordan aquifer. This is however, a modeling artifact. The concept of defining an area
where the Jordan could be pumped with no adverse effect on the Savage Fen was also explored,
It generally agreed that there are too many variables (other wells pumping schedules, geologic
variability, climatic change etc.) that make it very difficult to define that area. Evaluation of each
individual wells impact on the total system through monitoring and modeling may be a better
approach.
Mathematical ground water modeling is a rapidly developing field. Data developed in
conjunction with the many models available in the study area can be used in other model
applications. Various ground water models have shown that the further away wells are from the
F en, the less impact occurs from a single well's appropriation on the Fen's water level. However,
the cumulative effects of pumping have already adversely affected the Fen and other surface
water features. Increased distance could be the basis for future well siting in the area, provided
there is sufficient flexibility to change the concept if new information becomes available.
Additional Studies
Additional studies have contributed valuable information to the understanding of the geology and
hydrogeology of the study area. The MDH is active in both Scott and Dakota Counties with
assistance to communities in developmg wellhead protection programs. The MDH has provided
each of the five cities in the study area with draft assessments and is working with the SMSC to
14
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prepare a comparable assessment. The Scott-Dakota County ground water model referenced
above was also prepared as advlsory matenal for the communities.
The USGS has provided two inputs to the study effort. Currently, the USGS IS under contract to
the Metropolitan Area Ground Water Alliance (MAGW A) to prepare a recharge map for the
entire metropolitan area, This effort will provide information on recharge character within the
study area that can in turn be used to run model scenarios, The USGS also performed a study of
flow through fractured rock in the same area as the Savage/DNR pump test.
A series of surface water flow measurements were collected dunng fall low flow for four years on
tributaries to the Minnesota River and the river itself. Table 4 contains the summary information
that was used as calibration input to both the MPCA Metro Model and the MC ground water
model.
Ongoing monitoring of water levels m the calcareous fens in the MN River Valley began in 1987.
Savage Fen, Black Dog Fen, Fort Snelling Fen and Nichols Meadow Fen have been instrumented
for varying periods of time, Long-term (over the period of record) changes observed at Savage
Fen include subsidence of up to three feet and summer drawdowns that lead to regular dewatering
of the peat.
Budget priority changes have resulted in reduced staff involvement in calcareous fen monitoring,
thus measurements have been less frequent in recent years. Assistance from volunteers such as
hydrogeology students from UW River Falls has been helpful.
Continuous monitoring of Eagle Creek and miscellaneous out flow measurements of Boiling
Springs has been conducted by the DNR from 1998-2000. Additionally, Eagle Creek was
monitored on 2 separate occasions by the DNR to assess the potential impacts of nearby
dewatering for construction.
FINDINGS (pOINTS OF AGREEMENT)
With the issues raised, and the data availability and gaps identified, the SMGWG was able to
agree on several things in both the technical and non-technical arenas. The following sections
contain statements that reflect consensus items arrived at by the group.
Physical Attributes
The Savage Fen Wetland Complex is fed in large part by ground water from the PduC/J aquifer,
which is recharged south of the complex. The Savage Fen receives DNR protection under the
Minnesota Wetland Conservation Act. Increased ground water pumping by southwest metro
communities and reduced recharge from increased development over many years has adversely
affected the Fen, as well as Eagle Creek (trout stream), the Boiling Spnngs, valley bottom lakes,
and wetlands in the surrounding area.
The effect the buried bedrock valley traversing the study area has on ground water is not
completely understood. The sand and clay content of the sediments m the valley through the
study area varies. In areas where the hydraulic conductivity 10 the valley differs significantly
from the surrounding bedrock, it may act as a barrier to or diversion of ground water flow.
16
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Findings on the connection between the PduC and Jordan suggest that thIs connection is a function of
proximity to valleys and of the extent of tractunng and dIssolutIOn In the PduC. In the 1998 Savage
aquifer tests, hydrograph analysis between two city wells showed that the PduC and Jordan were acting as
single unit, with pumping m the Jordan drawing down the level of the PduC. This study also found
transmissivities increasing with proximity to the river, which the MGS also found true as a function of
Increased fractures in the PduC. The DNR also found that some of the observation wells did not respond
to aquifer test pumping possibly due to local geologic variability.
Although definitive statements about aquifer connectivity are difficult to make. it appears that well
locations more distant from the river valleys and buried bedrock valleys could provide better hydraulic
separatIOn between the PduC and Jordan aquifer. Continued data collection as part of already established
water level monitoring and by permitted pumping operations should help define this variability.
MDH data suggest that PduCIJ recharge in the study area has generally occurred within the past 35 years.
USGS data indicates that water in MTSIH is "thousands of years" old.
MDH modeling scenarios for cessation of CAMAS quarry pumping and its impact on the PduC and
Jordan show that ground water levels should generally increase in the area when pumping is ceased. This
suggests that water could be appropriated while maintaining the hydrogeologic conditions present prior to
cessation of quarry operations,
Burnsville's evaluation of the feasibility of Kraemer Quarry water mterception has shown some promise,
The city has studied its needs against the potential location and timing of wells to intercept water that
otherwise is discharged from the quarry de-watering pumps. The city would like to add to its current 16
wells to increase average capacity from 7.3 MGD to 10.2 MGD, with peak use going from 21.3 MGD to
29.7 MGD. The city is considering adding 4-5 new wells south of the quarry by 2016, depending upon
which final configuration is pursued. Some capacity (250 gpm) is factored in to supply a portion ofthe
City of Savage's demand. Kraemer currently de-waters about 7900 gpm from the PduC. Burnsville's
modeling shows that its withdrawal of 2750 gpm would reduce the de-watering by 1700 gpm if water is
pumped from the PduC and by 900 gpm if water is pumped from the Jordan. Some inflow oflandfill
water from the west is possible if the PduC is used; this would be less likely if the Jordan is used because
of the potential retardation of flow by the Oneota Formation of the lower PduC. Primarily for this reason,
the Jordan seems to have greater potential as a water supply for the City, As part of this evaluation,
Burnsville also considered potential impacts to the Blackdog Fen. They found that impacts could be
minimized through operational changes during the grOWing season, Seasonal movement of pumping to a
new well field (3 wells) along Bumsville Parkway could help accomplish this. This proposal would cause
significant funding issues for Burnsville. The city is preparing a quarry well feasibility study and will
determine if state financial help is available to off-set the extra expense ($2-3 million) of this project
which has a regional benefit.
Depending on their final plan, Burnsville could potentially supply several hundred gallons per minute to
Savage. Although a 16" interconnection along Highway 13 and an 8" interconnection along Highway 42
will exist, the difficulties of sharing water this way without a joint system are difficult, especially in
meeting peak demand. The City of Lakeville also noted that it has water available to supply Savage, if
needed, via Burnsville. However, the DNR notes there are issues of regional drawdown around Lakeville
that must be resolved before the Lakeville supply is considered as a long-term option.
It is generally agreed that the water supplying the surface water features comes primarily from the
PduC/Jordan aquifer and pumping from the lower aquifers (FIG and MTS/H) will have little or no effect
on those features. The pumping rate from FIG wells in the southwest metro varies from about 400 - 1,000
gprn. Cities have economic concerns about the use of low yielding wells to meet their non-essential uses
20
as required by the DNR rather than the MTS/H. The DNR considers the FIG aquifer to be a viable source
and has required testing and continued water level monitoring before agreeing to approve use of the
MTS/H aquifer. Higher yielding FIG wells present a productive alternative to the PduC/J and MTS/H.
Savage conducted several pumping tests on the FIG at its well #8 site and water level monitoring
continues while Savage pumps their well #8 using different pumping scenarios. Use ofthe FIG has
become part of the agreement between Savage and the DNR for current and future appropriations. This
agreement is discussed later in this plan as a model for others to consider.
The water quality characteristics of ground water in the region could present some volume and/or
financial limitations to its use. As mentioned above, nitrate and radium are problems in some areas.
There are also concerns about the nearness of the Burnsville and Freeway Landfills to the potential
Burnsville well field that is designed to capture quarry ground water. Monitoring would be needed to
assure that any new wells do not capture any substance that may leach from them.
InstitutionallRegulatory Statements
The Southwest Metro Area has numerous unique surface water features that need to be protected, while
communities in the area need a continued reliable source of water to support existing demand and future
growth. Communities in the study area are seeking additional water to meet increasing demand, but their
options to withdraw ground water are limited. The DNR has restricted further development of the PduC/J
in some areas, and Minnesota Statutes has strict guidelines for withdrawals from the MTSH (see below).
The MC is forecasting significant growth for Savage, Shakopee, Prior Lake, Burnsville and Lakeville.
Additionally, the Shakopee Mdewakanton Sioux Community will see an increase in demand to support its
growing commercial needs.
The use of the MTS/H aquifer is limited by legislation (M.S" Sl03G,27l, SubdAa) passed as part of the
1989 Ground Water Act. This law states:
"The commissioner may not issue water use permits that will appropriate water from the Mt,
Simon Hinkley aquifer in 'a metropolitan county..... unless the appropriation is for potable use,
there are no feasible or practical alternatives to this source,. and a water conservation plan is
incorporated with the permit. "
This law was passed to protect the MTS/H as the deepest aquifer in the region. The DNR has
documented 75 feet ofrecent drawdown in the MTS/H in the vicinity of Savage's abandoned well #2.
The DNR adopted guidelines in 1998 that are applied when communities are considering MTS/H use
requests, Consistent with Minnesota Statutes, these guidelines contain strict criteria for consideration of
the MTS/H, once agreed that it can be used, by applying a formula to determine how much water can be
withdrawn based upon historic use and the mix of water sources available to the community.
Several alternatives exist for source water development in the region. The possibility of multiple water
suppliers cooperating on development of a well site or sharing water from a single source looks promising
from a technical and practical standpoint, but difficult from a political standpoint. Joint development in
these areas could be a long-term outcome of the SMGWG effort.
DNR has stated that any further degradation of the Savage Fen Wetland Complex will not be allowed, but
that some degradation has occurred. The mean annual water level in 1991 of758 feet above mean sea
level was adopted as the base level from which all future changes will be judged, DNR will regulate
water appropriations to obtain zero additional negative impact on the complex. Additionally, resource
management methods such as voluntary water management will be used to help restore the hydrology of
the fen complex.
21
. 1
DNR considerations in granting increased appropnations are based upon statutory requirements including
the 1989 Ground Water Act, and the Wetland Conservation Act, as well as consistency with local water
supply plans, including effective implementation of a conservation program. Timelines for permit review
Include 60 days to take action on a permit (see MS l03G). Delays often occur because of difficulties in
obtaming complete information. DNR is committed to faster action for defining permit completion
requirements. DNR' s September 1997 short-term strategy for permitting includes the promotion of
conservation efforts, an examination of alternative sources, an increase in monitoring activities, a request
for communities to continue SMGWG participation, and continued pursuit of Legislative funding for
related activities. DNR is receptIve to and encourages joint water supply planning among the cities.
Peak demand for municipal water supplies is associated WIth seasonal pumping, such as lawn watering
and general increased summer demand. Attention to demand management via conservation practices
could reduce demand during this critical period. DNR requires effective conservation programs as part of
water appropriation permit action.
Quarry de-watering operations in southwest metro, generally located down-gradient from the surface
waters of concern, have historically pumped more water from the ground than the communities
participating in the SMGWG use for water supply. This water has historically been discharged into the
Minnesota River, and has not been used for any other purpose, With the cessation of operations at
CAMAS and removal of the pumps, de-watering w1l1 continue only at the Kraemer Quarry in Burnsville,
The total Kraemer use isjust slightly below the demand of the SMGWG communities. Burnsville's
proposed use of intercepted ground water before it is pumped from the quarry would allow for a "higher
and better" use of this discharge water.
A model for future cooperative agreements between the communities and the DNR has been in effect for
Savage for several years. This model agreement sets out in a flexible manner the number, location and
aquifer unit of wells, as well as the possibility for interconnection and well development with adjoining
cities. Changes in the agreement details have already been necessitated by information learned during
implementation. Creation of similar agreements with the other communities would seem desirable.
NEEDS IDENTIFIED BY THE SMGWG
Consensus has been reached on many of the needs that exist in the southwest metro area relative to
assuring water supply and protecting water resources. Many initial needs were addressed during the
period between the group's first meeting and preparation of this report. The following broad needs are
those that the involved parties consider priorities and should be addressed. Part of the Memorandum of
Agreement, described at the end of this plan, will be for the involved parties to address these needs or
identify others who can address them and sources for the necessary funding to address them, if needed.
· Collect and evaluate additional information including, pump test data, water level measurements,
surface water measurements, and groundwater withdrawals to better assess the effects of pumping on
surface water features (Savage Fen, Boiling Springs, Eagle Creek, Minnesota River Valley wetlands,
Blackdog Fen) and the potential for other water bodies to be impacted - ongoing, DNR, MC, and
Communities
· Continue to evaluate source water alternatives including intercepting quarry water, use of surface
waters, and alternative aquifer use - ongoing, Communities with aSSIstance from DNR, MC
· Evaluate and minimIze the impact of increased impervious surface on ground water recharge and
surface water flow - ongoing DNR, MC, Communities
22
. Continue to implement water conservation measures to improve water use efficiency and reduce
water demand - ongoing, Community implementation with oversight by DNR and MC
. Continue the SMGWG as a forum for discussion of sub-regional issues with meetings to be held as
necessary - ongoing, facilitated by MC, participation of all involved parties
Several more specific needs have been identified, Many of the data items will be collected as a necessary
part of adequately supplying the future water demand of the area, The SWMGWG will continue to be the
forum for determining what the future needs are and who will address them as well as a means for
dissemination of the additional information collected. The following IS a detailed list of needs identified
by the SWMGWG. They are not necessarily listed by priority.
Geology/Hydrogeology/Hydrology Data Collection
. Determine the vertical movement of water between the various surficial and bedrock units
. Document the degree of hydraulic connection between the PduC & Jordan aquifers
. Collect additional hydrogeological information including water levels and aquifer characteristic from
pump tests
. Identify generalized recharge areas and rates of recharge and the effects of increased impervious
surface on ground water recharge and surface water flow
. Further define the aquifer characteristics of the FIG in the study area and its ability to meet the
demands of communities as a replacement or alternative aquifer for the PduC/J and MTS/H
. Evaluate alternative pumping well and monitoring well locations
. Continue to explore the feasibility of intercepting water from a quarry for municipal supply
. Monitor water levels to evaluate the rebound around the CAMAS site now that all pumping has
ceased
. Establish a long-term monitoring program to document availability, water demand/use and water
levels, possibly implemented as part of city operations when new wells are added
. Document changes in Dean's Lake hydrology
. Monitor stream behavior during both high and low flows
. Document the effect of seasonal water demand fluctuations
. Study the isotope/chemical characteristics of the aquifers, and the water budget/recharge of the
ground water system
. Analyze the impact of an extended drought on the overall water situation in the area
. Analyze existing data to determine the local geologic variability within the buried valley and its
influence on the hydrogeologic system, identify and fill data gaps
. Document the current condition of Black Dog Fen
. Reinstate fen water level monitoring
. Incorporate additional data to improve local ground water models
Water Quality
. Collect details on the extent and treatability of radium and nitrate in ground water
. Determine the impacts of storm water management practices on surface and ground water quality
. Explore methods of locating wells so that nitrate and radium concerns can be avoided such as south in
areas with a thicker glacial till layer to avoid nitrates
. Implement'land and water management practices to limit, reduce and ultimately eliminate nitrate
introduction to the ground water system
23
Institutional
· Consider water supply in MUSA extensions and comprehensIve plan approvals
· Promote early DNR coordination of permit related issues through continued participation in the
SWMGWG forum as well as through other means
Regulatory
· Identify non-permitted, large volume users and quantify the extent of their water use
· Track the progress of implementing the community/DNR agreements, and any new agreements that
come out of the SMGWG process
CONCLUSIONS
I) The Southwest Metro Area has numerous unique surface water features that need to be protected, while
communities in the same area need a continued reliable source of water to support existing demand and
future growth. Groundwater withdrawals are limited due to potential impacts on the surface water
features and/or by regulatory requirements.
2) Demand will likely increase by over 50% by 2020 without increased conservation, To meet this
demand, there are approximately 25 additional utility wells planned in the study area.
3) Nitrate and radium levels in some municipal wells have raised questions on the source of the problem
and the possible options to solve them. Moving laterally away or deeper to another aquifer does not assure
that water of better quality will be found.
4) All parties need to be treated in a fair and equitable manner in the regulatory process while maintaining
flexibility to meet individual needs.
5) Strategies for supplying projected needs should be viewed as flexible plans that can change as more
facts about the ground water system become available.
6) The cost of obtaining data is high, but data are the key to understanding a very complex system in this
area and important in making good local decisions.
7) Findings on the connection between the PduC and Jordan aquifers suggest that this connection is a
function of proximity to valleys and of the extent of fracturing in the PduC. Although definitive
statements about aquifer connectivity are difficult to make, it appears that movement away from the river
valleys and buried bedrock valleys may provide better hydraulic separation between the PduC and Jordan
aquifer.
8) Alternative water sources available to communities that need to avoid impacting the
PduC/Jordanlsurface water system include the deeper FIG and MTS/H aquifers the Minnesota River and
the quarries. Data on deeper ground water aquifers are less available than units closer to the surface,
9) Pumping rates of FIG wells vary from about 400 -1,000 gpm. Cities have economic concerns about
the use of low yielding wells to meet their non-essential uses as required by the DNR rather than the
MTS/H. The higher volume FIG wells present a productive alternative for the PduC/J and MTS/H.
24
10) Properly calibrated ground water models can be used as a tool to explore ground water behavior and
cause-and-effect relationships, but the results should not be used without human judgement and
interpretation and coordinated monitoring efforts.
11) Modeling can identify the area where ground water flows to the surface water features. Within this
zone, special provisions such as pre-determined demand reduction (conservation) measures or seasonal
operation limits (volume, pumping rate, time) could be made to minimize impact,
12) Many additional needs exist in the areas of hydrology /hydrogeology, data collection, water quality,
and institutional/regulatory matters. The S\VMGWG should serve as the forum for communication of
agency and community efforts to address these needs.
13) Studies have shown a potential significant rebound of water levels in the PduC and Jordan near the
former CAMAS quarry after it stops pumping, thus indicating that water could be appropriated while
maintaining conditions that existed during quarry operations. Modeling scenarios have indicated that
water levels at the Boiling Springs and Fen should rebound when pumping stops, However, these
modeled results do not take into account climatic and human impacts. Monitoring should be employed to
verify the results,
14) Peak demand for municipal water supplies is associated with seasonal pumping, such as lawn
watering and general increased summer demand. Attention to demand management via conservation
practices could reduce demand during this critical period.
15) Development techniques and runoff management methods that maximize recharge are important to
maintaining ground water levels in the study area.
RECOMMENDATIONS
The six communities participating in the SMGWG, and the agencies involved in the following
recommendations will sign a Memorandum of Agreement to work with each other in implementing this
management plan, The signatories will look for long-term solutions and ways to cooperate in solving
water problems in this part of the region.
Instituti 0 nal/Regula to ry
- The agreement between the DNR and the City of Savage should serve as a model for the other
communities in setting forth a mutually agreeable scenario for ground water development to meet
anticipated community needs while protecting local water resources. Under this approach, DNR sets the
standard for water use, but the cities remain autonomous in securing water in a manner that works best for
the community. Each community would formalize its plan with the DNR, including criteria for flexibility
to amend the plan. These "Framework Agreements" must be flexible enough to allow agency or
community adjustment as the need arises, yet layout a program for future well locations, aquifer units,
pumping scheme, and total volume of use. This approach addresses the need for a long-term reliable
supply for a community and upholds DNR's Legislative mandate to protect the water supply and natural
resources of the state. This could be incorporated into a comprehensi ve broad scale water supply plan
that identifies each community's water supply source through 2020.
- DNR should continue to use its MTS/H guidance in the issuance of permits as part of the "Framework
Agreements". This clarifies the DNR's basis for future use of the MTS/H and maintains the Legislative
charge to the DNR to protect the MTS/H aquifer. In doing this, the DNR should work with the aquifer's
users to collect data and monitor application of the guidance to assure the mtegrity of the aquifer.
25
- The mean annual water level in 1991 m the Savage Fen of 758 feet above mean sea level, has been
adopted as the base level from which all future changes will be Judged. It is the goal of the SMGWG to
Increase water levels from this point. This long-tenn goal will be accomplished through some
combination of the following: water use reduction and eventual elimination of both quarries; well
orchestrated pumping schemes that locate pumping centers in areas that do not impact sensitive surface
water features dunng critical times of the year; recharge enhancement through low impact development
practices; implementation of effective community demand reduction and water conservation programs,
- The Metropolitan Council will provide technical support in evaluating availability of adequate water
supply to support projected growth. The MC wlll use the adapted MPCA Metro Model to evaluate the
potential impact of additional proposed wells. Due to the nature of the model, modeling will likely show
that most proposed PduC/J wells in the area will cause some change at the Fen. Because additional wells
can not cause a drawdown at Savage Fen, the communities should work with the DNR to implement a
monitoring plan which would include installation of monitoring wells to more accurately determine the
impact of the pumping and improve future model runs. A strategy of reducing withdrawals in wells in
closer proximity to the surface water features to compensate for Increased withdrawal further away could
also be evaluated with the model.
- Wells which could potentially impact the Fen will require special provisions in addition to monitoring.
The special provisions will include such things as pre-determined demand reduction (conservation)
measures or seasonal operation limits (volume, time) and will include use of alternate water sources.
- The DNR in cooperation with the southwest metro communities and other participating agencies will
also define the "Recharge Zone" for the surface waters of concern and promote enhanced infiltration
within these zones to off-set the loss of recharge from paved surfaces, A set of management practices that
can be used to achieve this objective should be agreed upon by the participants, and made part of the
Framework Agreement. Development practices that promote infiltration of water should be used in all
areas recharging ground water to any surface water feature that depends on ground water input. Because
of the nitrate threat, communities and other agencies involved with land use planning should discourage
the recharge of high concentrations of nitrate-laden water from agricultural area runoff or areas served by
on-site septic systems through the required use of best management practices and other safeguards,
- Use of discarded quarry water has been supported by the SMGWG since its inception. Efforts by
Burnsville to intercept and use part of the water discharged by the Kraemer quarry should be supported,
provided water influenced by a landfill is not induced and water levels in the nearby Black Dog Fen are
not adversely affected.
- All users of ground water in the study area, including industry, non-municipally supplied development
and those like MC that pump water to control ground water levels, must be considered in overall
management of ground water in the area.
Inter-Community Cooperation
- Joint development of water supply between communities or sales of water by one community to another
should be promoted as part of a long-tenn solution that would minimize the number of new wells.
Cooperative ventures could also include JOInt water treatment for nitrate and radium in ground water and
for surface water and ground water under the influence of surface water. Discussions should continue on
the possibility of development of a sub-regional supply system(s), under local control, for the
procurement and distribution of water among communities.
26
Data Collection
- The DNR, MDH, MGS, MC and the communities using the southwest area ground water resource
should continue to collect data to better define the ground water character of the area, addressing such
topics as the capability of the FIG to supply an adequate volume of water, changes in ground water
behavior due to decreased recharge and increase water use, and the location of new or alternative
cooperative pumping centers. The SMGWG should continue as a forum for discussion and dissemination
of additional information collected.
- A long-term cooperative monitoring program should be established to document ground water
parameters in the area, and to track availability and use of the resource. The program should be
established through the DNR in cooperation with the communities and other participating agencies as part
of the permitting of new and existing wells. This approach would allow for a preliminary informed
decision, with follow-up monitoring data to allow for adjustment. Funding for this program will come
from communities as part of the permit approval process, from a continuation of the DNR' s ground water
level monitoring program, and from any future regional program (recommended below) that provides
funds in cooperative ventures addressing regional water problems.
Conservation
- A good conservation plan that promotes wise use of the water resource is essential for every community
and non-community water user in the southwest metro area. It should be realized that there will be more
scrutiny of conservation plans in this part of the region if the MTS/H aquifer is the source of water or if
some adverse impact of unique surface water features is possible. The City of Savage has shown how
effective this approach can be with a reduction in per capita use.
Costs
- The costs of implementing this Management Plan should not present an unreasonable burden to the
water users, nor should the costs be used as a justification to prevent action that will preserve the water
resources of the area, DNR and MC should work with the communities to develop the means to cost-
share projects of regional interest in achieving the goals of this Management Plan.
Organizational Role
- The SMGWG fulfills a needed role in providing a forum for discussion among the agencies,
communities and public interested in water issues in this part of the region. The SMGWG should
continue to meet after adoption ofthe Management Plan, possibly on a semi-annual basis.
Basis for Agreements Between Cities and DNR
_ The following section contains summaries by community of the basis for agreement between that
community and the DNR. It is assumed that each community will have a DNR approved water
conservation plan, developed in accord with Minnesota Statutes, section 1 03G.29l, subd. 3 and section
473.859, subd. 3(4). Effective implementation of these plans will be included as an element in each
community/DNR agreement. It is also assumed that each community will work with the MDH on a
Wellhead Protection Plan when required.
Savage
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The City of Savage will continue to Implement its prior agreement with the DNR to develop the city's
supply system through 2008. Part of the city's effort may include negotiating with adjacent communities
to enter into a cooperative arrangement for the development of a supplemental water supply. The city
wIll work with DNR to develop additional water capacity from sources in the southern part of the city, in
Credit River Township or in cooperation with adjacent communities. The city will continue to size pipes
in the v1cinity of its neighboring communities such that interconnections can be made to exchange water
if ever desired to do so. The city will continue to implement its conservation plan, and strive to keep
water demand at a reasonable level, and will continue to treat/blend water with high radium levels when
necessary .
The DNR will use the framework provided 10 the prior agreement with the City of Savage to assure that a
long-tenn reliable source of water 1S available for the city.
BurnsviIle
The City of Burnsville proposes to install up to seven new wells through its ultimate development near
the year 2016. Part of this well development may include Jordan wells drilled south of the Kraemer
Quarry to intercept water before it discharges to the quarry. The SMGWG has supported this approach as
a beneficial use of water that is othenvise discarded via pumped discharge. The city will protect the
hydrologic integrity of the Black Dog Fen from further degradation. The city will continue its discussion
with Savage on the possibility of jointly developing capacity within the City of Bumsville. The city will
continue to implement its conservation plan, and strive to keep water demand at a reasonable level.
The DNR has reviewed the city's proposal for new wells by reviewing the ground water modeling results
and assessing the likely impact on ground water levels and on Black Dog and Savage Fens' water levels,
If the ci ty decides to pursue the wells up gradient of the Kraemer Quarry, the MDH and MPCA will assess
the results for water quality impact associated with landfill plume movement. MDH will also determine
if it would be considered a ground water source under the influence of surface water.
Prior Lake
The City of Prior Lake will supplement its ground water-based supply system with the addition of a FIG
well and another Jordan well. The location of these wells will be detennined in consultation with DNR.
SMGWG modeling of the likely impact of potential well locations on ground water levels in the northern
part of the study area will be useful 10 detennining the location of any new wells for Prior Lake.
Infonnation from the monitoring wells installed to monitor effects from well #6 will also be important in
evaluating future well locations. The city will continue to work with the DNR on monitoring the two
Jordan observation wells associated with city well #6. Additional wells beyond the FIG and additional
Jordan well are not antic1pated by the city at this time. This could change if land use plans change and
demand increases.
Shakopee Public Utilities Commission (SPUC) and the City of Shakopee
The City of Shakopee will work with its Utility Commission to assure that an adequate supply of water
exists prior to approval of new areas for development. In its land use decisions and its development
requirements, the city will encourage designs that maximize ground water recharge and maintain ground
water levels at predevelopment conditions.
SPUC will develop its well system in accord with a plan as agreed between the city and the DNR, with
mput from the MDH. Special attention will be placed on elimmating the possibility of high nitrate levels
in water delivered to customers. This will be achieved through mlxmg water sources, closing high nitrate
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yielding wells, and developing new wells from aquifers with low mtrate levels, SPUC will also work with
other LUGs to identify the source of the nitrates and implement methods to diminish nitrate levels in the
water supply. SPUC will continue to evaluate interconnection possibilities as its supply lines reach closer
to adjacent communities,
The DNR will work with SPUC to assure that the utility's well plans can be implemented in a timely
manner. The DNR will also work with the utility to determine an acceptable total volume for the MTSIH
and assist SPUC in defining options for obtaining that volume.
Lakeville
The City of Lakeville will work with the DNR to develop an acceptable water supply plan and then will
develop its well system in accordance with that plan. As part of the plan, the city will implement
conservation and demand reduction practices. The cause of well interference problems in the city will be
determined by the DNR. Lakeville will remain a possible source of water to supply Savage, or any other
neighboring community, as long as it can maintain sufficient volume to make this a viable option, The
city will continue to promote maximum infiltration from developments.
The DNR will work with Lakeville to assure that the utility's well plans can be implemented in a timely
manner.
Shako pee Mdewakanton Sioux Community (SMSC)
The SMSC is a sovereign nation and is not subject to the water-related laws or regulations of the State of
Minnesota. Nevertheless, it has participated in the SMGWG discussions and has pledged to cooperate in
arriving at solutions to water supply issues in the area. SMSC will continue to participate with SMGWG
communities in studying and developing the ground water resource, and in examining potential sharing
opportunities.
DNR
The DNR will act in a timely manner on all permit requests, while fulfilling its Legislative mandate to be
the State's agent in protecting its waters, The DNR will apply the same scrutiny to private water users as
it does to the public systems in the study area,
DNR decisions are based on the belief that the PduC and the Jordan are acting as one aquifer throughout
the region, The limited aerial extent included within these Cities' boundaries makes it unlikely that a zone
of hydraulic separation bet\veen these t\vo units can be identified that is of sufficient size that water
withdrawal from such an zone would not affect both ground water and surface water resource features
within a reasonable time,
The DNR will work with each community water utility and with the SMSC, if requested, to develop a
framework agreement on how each community water supply system will be developed. These
agreements will form the basis for permitting through the Water Appropriation process, The DNR will
support a flexible approach geared to achieving a goal of ground water protection and long-term
reasonable use.
DNR Waters will coordinate internal DNR interests in developing the above referenced agreement such
that a single DNR position is formulated.
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The DNR will consider the establishment of "allowable volumes" trom select aquIfers and will respond to
community proposals on how thIs volume can best be developed.
The DNR will contmue its basic data collection programs In the area as long as funding is available. Data
collection by commumties will be reqUlred in most cases where new wells must be drilled. DNR will
work with the communities to establish the data collection program for new wells.
The permittmg approach for issuing permits in the MTS/H aquifer will be in accord with the DNR
guidelines developed in 1998. ll1ese guidelines were developed in response to legislation requiring
protection of the MTS/H.
The DNR will take into consideration results that show both ground water and surface water impacts of
water use in the southwest metro area. They will work with communities to define an area within which
the impact would be adverse and special conditions would apply.
The DNR will work with parties interested in proposing legislation to support funding for cooperative
solutions to this area's problems. This effort would reflect items of regional interest.
The DNR will work with the MC and communities to define minimum conservation measures that all
communities need to adopt as part of their framework agreements. These minimum elements would be
adopted in the next iteration of the community's conservation and emergency plan and also be part of any
new or amended permits.
Metropolitan Council
The MC will continue to facilitate the SMGWG if it is agreed by the participants that the group will
continue to meet.
The MC will continue to improve the ground water model currently being used to evaluate alternative
ground water scenarios. Through use of the model, MC will assist communities to assess and avoid
potential impacts of the future appropriation of the water necessary to support their planned growth,
The MC will seek opportunities to incorporate a more thorough assessment of water availability prior to
extending the MUSA line and will not approve MUSA extensions until water supply and permit concerns
are addressed.
MEMORANDUM OF AGREEMENT
Following completion of this pt"'n, the six communities participating in the SMGWG, the DNR and the
Metropolitan Council will sign a Memorandum of Agreement to work with each other in implementing
this management plan. The primary focus will be working toward addressmg the priorities set forth in the
beginning of the Needs section of this plan. The SMGWG will continue to meet on a semi-annual basis
to share ideas and information on meeting the area water supply needs while protecting surface water
features.
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ACRONYMS
DNR = MN Dept. of Natural Resources
FIG = Franconia-Ironton-Galesville Aquifer
Jordan = Jordan Formation
LMR WD = Lower Minnesota River Watershed District
MC = Metropolitan Council
MDH = MN Dept. of Health
MGS = MN Geological Survey
MPCA = MN Pollution Control Agency
MTS/H = Mt. Simon-Hinckley Aquifer
MUSA = Metropolitan Urban Service Area
PduC = Prairie du Chien Group
PduC/J = Prairie du Chien-Jordan Aquifer
PLSL WD = Prior Lake-Spring Lake Watershed District
SMGWG = Southwest Metro Ground water Work Group
SMSC = Shakopee Mdewakanton Sioux Community
SPUC = Shakopee Public Utilities Commission
USGS = U.S. Geological Survey
WMO = watershed management organization
WWTP = wastewater treatment plant
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