HomeMy WebLinkAbout2015-01-14 PACKET 05.3.
Metropolitan Council Releases Final Report on
Northeast Metro Water Supply
Analysis evaluates options for using surface water to supplement/replace
groundwater use
Saint Paul—Dec. 29, 2014--The Metropolitan Council has released a report that evaluates approaches to preserve and protect
water supply in the northeast metro. The report assesses the feasibility and costs of several alternatives designed to help
restore the aquifer that supplies groundwater to northeast metro communities.
The report studies three approaches that focus on water supply. Two identify alternatives for using surface water from the
Mississippi River as a way to decrease reliance on groundwater and relieve pressure on the Prairie du Chien-Jordan aquifer,
which provides much of the metro area with drinking water. The approaches are:
1. Connect northeast metro communities with Saint Paul Regional Water Services to supply them with drinking water.
2. Convey surface water from the Mississippi to the northeast metro for local treatment and distribution.
3. Continue to develop groundwater sources.
In addition, the Council evaluated the feasibility of augmenting White Bear Lake with water from the Mississippi River. This
option was dealt with separately because it does not involve drinking water and would likely have a different ownership and
operations structure.
Best outcome may be a combination of approaches and strategies
“We know that any of the options studied is feasible,” said Keith Buttleman, an assistant general manager in the Environmental
Services Division. “We have a better idea of associated costs. And, we know pros and cons of each. That information and
analysis will lend significant value as legislators and local officials work to identify a course of action.”
Since release of the draft report in July, Council staff and consultants added more cost information and evaluated the option of
continuing to rely exclusively on groundwater. The final report also adds a variation on the second approach, which would move
northeast metro communities to surface water, but use supplemental groundwater from existing wells to meet peak demand.
Council staff are quick to say the options are not mutually exclusive, and the best outcome may be a combination of various
approaches and strategies. The alternatives evaluated should be viewed as examples.
“The best option for moving forward may be a hybrid of the examples considered in this study, and could involve approaches
that were not considered in this study,” said Buttleman.
For example, communities in the northeast metro could pursue less expensive approaches, which could include conservation or
stormwater reuse to reduce groundwater pumping, before making large-scale investments in alternative infrastructure solutions.
Such a plan could combine these less expensive options with aggressive monitoring of groundwater and surface water, and
establish triggers for further action in the event these less expensive approaches are not effective.
“The goal is to identify solutions that balance effectiveness against reasonable costs,” said Buttleman.
Laying the foundation for a plan of action
“We have a lot more information for legislators and local officials today on which to base decision making than when we started
this study,” said Buttleman.
“What will take further work is the analysis that the U.S. Geological Survey (USGS) is conducting on the impact of the various
options on the lake and aquifer,” said Buttleman. The USGS study is expected in 2016.
The approaches in the study were developed in collaboration with various partners, including the USGS, White Bear Lake
Conservation District, White Bear Lake Level Resolution Committee, Saint Paul Regional Water Services, communities, and
other stakeholders in the northeast metro.
The study is funded by a 2013 Minnesota Legislature appropriation of $2 million from the Clean Water Legacy Fund. It is one of
several studies that are under way to address water supply needs in the seven-county metro area.
Approaches:
#1. Saint Paul System Expansion: Connect northeast communities with Saint Paul Regional Water Services to
supply treated drinking water.
Water would be conveyed through a chain of lakes--Charley, Pleasant, Vadnais--to McCarrons
Water Treatment Plant.
The study identifies three alternatives under this option. Each option assumes water mains from the water treatment plant to a
centralized location in each community served.
1A. Serve North Saint Paul. Capital cost: $5 million. Annual operating cost: $1.4 million.
1B. Serve the five study-area communities closest to Saint Paul (Mahtomedi, Shoreview, Vadnais Heights, White Bear Lake,
White Bear Township), as well as North Saint Paul. Capital cost: $155 million. Annual operating cost: $11 million.
1C. Serve the five study-area communities nearest Saint Paul, and Centerville, Circle Pines, Columbus, Forest Lake, Hugo,
Lexington, and Lino Lakes. North Saint Paul would also be served. Capital cost: $623 million. Annual operating cost: $20 million.
Considerations:
Serving North Saint Paul only would have a very modest benefit.
The McCarrons Water Treatment Plant currently has excess capacity of 30 million gallons per day, which could serve
the communities nearest to Saint Paul’s system without a major expansion of supply and treatment infrastructure.
Expanding service beyond the six closest communities would help to achieve regional water supply goals of reliability
and sustainability, but require additional large-scale infrastructure and significantly increase capital costs.
#2: New Surface Water Treatment Plant: Convey water from the Mississippi River to the northeast metro for local
treatment and distribution.
Using this approach, the study evaluates scenarios that involve construction of a new surface water treatment plant, preferably
at Vadnais Lake, to serve northeast communities.
2B. Serve the study-area communities nearest Saint Paul (Mahtomedi, Shoreview, Vadnais Heights, White Bear Lake,
White Bear Township) with a new surface water treatment plant with a capacity of 40 million gallons per day. Capital cost: $227
million. Annual operating cost: $9 million.
2C. Serve the study-area communities nearest Saint Paul, as well as Centerville, Circle Pines, Columbus, Forest Lake,
Hugo, Lexington, and Lino Lakes, with a new, larger surface water treatment plant with a capacity of up to 60 million gallons per
day. Capital cost: $609 million. Annual operating cost: $16 million.
2D. Serve the study-area communities closest to St. Paul, and North St. Paul, with a combination of a smaller surface water
treatment plant, with capacity of up to 15 million gallons a day to meet average daily demand, combined with using existing
groundwater wells to meet peak demand. Capital cost: $164 million. Annual operating cost: $7.5 million.
Considerations:
Continues local participation in supply and treatment of drinking water.
Saint Paul Regional Water Services owns land on Vadnais Lake. The water quality and location of Vadnais Lake make
it the preferred site for a new water treatment plant.
Expanding service beyond the six closest communities would help to achieve regional water supply goals of reliability
and sustainability, but require additional large-scale infrastructure and significantly increase capital costs.
Combining a surface water approach for daily water usage, while relying on groundwater in peak situations, would
significantly reduce costs, though it would present engineering challenges.
#3: Continued Development of Groundwater Sources
Under this approach, existing community water supply systems would continue to be maintained. New wells would be drilled as
additional supply is needed. Groundwater treatment facilities that are currently planned would be built. Capital cost: $91 million.
Considerations:
Lowest capital costs of all options.
Study area communities retain control over operations of water supply and treatment systems.
Potential for continued decline in aquifer and lake levels.
Lake Augmentation: Pump filtered water from the Mississippi River into White Bear Lake via the chain of lakes that
includes Charley, Pleasant, and Vadnais lakes.
This approach would draw and convey two billion gallons of water a year from the Mississippi River through the chain of lakes to
augment White Bear Lake.
A pumping station would be built near Vadnais Lake to convey water to White Bear Lake. Capital cost: $50 million.
Annual operating cost: $300,000.
Considerations:
The Mississippi River is impaired with zebra mussels, as is Vadnais Lake. Augmentation would require filtration.
With filtration, augmentation should not degrade water quality in White Bear Lake.
Saint Paul Regional Water Services has sufficient capacity to draw and convey two billion gallons a year for
augmentation.
It is not certain that augmentation of two billion gallons a year will maintain the water level of White Bear Lake at the
ordinary high water level, though the water level would likely improve.
It is unlikely that augmenting White Bear Lake will benefit other area lakes.
A balanced approach
"A more balanced use of groundwater and surface water could go a long way toward addressing the region’s long-term water
supply," said Buttleman.
"As a region, we have room for improvement in managing our water resources wisely. We need to develop a better
understanding of how to recharge our aquifers through water conservation efforts such as the reuse of stormwater and
wastewater to offset groundwater use for non-potable purposes. Ultimately, a combination of strategies including groundwater,
surface water, stormwater, reclaiming wastewater, enhanced aquifer recharge, and conservation efforts will likely get us to the
most sustainable solution at the least cost. The feasibility of utilizing these strategies depends on where you are in the
metropolitan area."
"In the northeast metro, understanding impacts to lakes from groundwater use particularly is important. This report gives us an
understanding of the potential to use surface water from the Mississippi River to reduce groundwater use. Other ongoing work
in the northeast metro is evaluating the potential to use some of the other tools in our toolbox, and seeks to better understand
the underlying causes of lake level declines."
Ongoing study
Four ongoing activities will provide additional key information to decision makers in the coming years about northeast metro
water supply:
1. The USGS is conducting a study that will provide critical information on the interaction between groundwater and surface
water in the area. It is expected to be complete in 2016.
2. A Metropolitan Council feasibility assessment of the potential for enhancing aquifer recharge and reusing stormwater in the
North and East Metro Groundwater Management Area. The results of this study, expected in 2015, will evaluate the potential of
using alternative approaches to reduce impacts to lakes and to address other identified water sustainability issues within the
Groundwater Management Area.
3. The University of Minnesota Technical Assistance Program will identify opportunities for industrial water users in the North
and East Metro Groundwater Management Area to reduce their water consumption. This work is expected to be completed in
mid-2015.
4. The Minnesota Department of Natural Resources is completing a management plan for the North and East Metro
Groundwater Management Area. The plan is in development and could impact future groundwater appropriations and
monitoring.
The Metropolitan Council is the regional planning organization for the seven-county Twin Cities metro area. It runs the regional
bus and light rail system and Northstar Commuter rail. The Council collects and treats wastewater, manages regional water
resources, plans regional parks, and administers funds that provide housing opportunities for low- and moderate-income
individuals and families. The Council is appointed by and serves at the pleasure of the governor.
The report summary is available here. The complete report is available here.
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Paul, MN 55101-1805 · 651-602-1000
FEASIBILITY ASSESSMENT OF
APPROACHES TO WATER
SUSTAINABILITY IN THE
NORTHEAST METRO
SUMMARY
DECEMBER 2014
The Council’s mission is to foster
efficient and economic growth for
a prosperous metropolitan region.
Metropolitan Council Members
Susan Haigh ChairEdward Reynoso District 9
Katie Rodriguez District 1Marie McCarthy District 10
Lona Schreiber District 2Sandy Rummel District 11
Jennifer Munt District 3Harry Melander District 12
Gary Van Eyll District 4Richard Kramer District 13
Steve Elkins District 5Jon Commers District 14
James Brimeyer District 6Steven T. Chávez District 15
Gary L. Cunningham District 7Wendy Wulff District 16
Adam Duininck District 8
The Metropolitan Council is the regional planning organization
for the seven-county Twin Cities area. The Council operates the
regional bus and rail system, collects and treats wastewater,
coordinates regional water resources, plans and helps fund
regional parks, and administers federal funds that provide housing
opportunities for low- and moderate-income individuals and
families. The 17-member Council board is appointed by and
serves at the pleasure of the governor.
This publication printed on recycled paper.
On request, this publication will be made available in alternative formats to people with
disabilities. Call Metropolitan Council information at 651-602-1140 or TTY 651-291-0904.
About this Report
The 2005 Minnesota Legislature directed the Metropolitan Council to “carry out planning activities
addressing the water supply needs of the metropolitan area,” including the development of a Twin Cities
Metropolitan Area Master Water Supply Plan (Minn. Stat., Sec. 473.1565). After completing that plan, the
Council took on many technical and outreach projects that strengthen local and regional water supply
planning efforts. These projects have also elevated the importance of water supply in local comprehensive
planning, which is carried out by local communities.
This study is one of several the Council is leading to support an update to the Master Plan and other
activities identified by the 2005 Minnesota Legislature to address the water supply needs of the seven-
county metropolitan area. This study is funded from the Clean Water Legacy Fund (Minn. Laws 2013 Ch.
137, Art. 2, Sec. 9).
The Council retained Short Elliott Hendrickson Inc. (SEH) to complete this technicalassessment of the
capital and operational costs, as well as the potential benefits, of four approaches to the regional
sustainability of water resources in the northeast metro area. This study has been carried out with input
from and engagement with local stakeholders, including community public water utilities, through a
water supply work group. This group continues to meet regularly to discuss the study along with other
water supply topics of importance to group members.
This summary was prepared to communicate the key findings of this study.
Recommended Citation
Metropolitan Council. 2014. Feasibility Assessment of Approaches to Water Sustainability in the
Northeast Metro –Summary. Prepared by Short Elliott Hendrickson Inc. Metropolitan Council: Saint
Paul
.
Study Objectives
The primary objective of this study is to understand the relative costsandimplementation
considerationsof different approaches to water sustainability.The northeast metro provides a study
area for this evaluation. The Minnesota Legislature requested this part of the metro area to be studied
specifically, given the continued concern over lake levels and the interaction of groundwater and lakes
in the area, especially White Bear Lake. The study area includes 13 communities.
The results will be incorporatedin the Twin Cities Metropolitan Area Master Water Supply Plan. The
studywill bereferenced to support future planning of metro area water supplies and water sustainability
practices.
This feasibility assessment evaluates only three approachesto water supply:
Approach 1: Connect northeast metro communities to Saint Paul Regional Water Services to supply
drinking water (Saint Paul Expansion)
Approach 2: Developa surface water connection to a new sub-regional surface water treatment plant
(New Surface Water Treatment Plant)
Approach 3: Continued development of groundwater sources
In addition to the water supply approaches evaluated, the Council evaluated the feasibility ofdirect
augmentation of White Bear Lake using water from the St. Croix and Mississippi Rivers.This projectis
evaluatedseparately in this study, as it does not directly involve drinking water supplies. In addition, a
direct lake augmentation system wouldlikely have different ownership with responsibility for
constructing, operating, and maintaining the system.
Theapproacheswere selected in consultation with stakeholders in the northeast metro,based on their
potential to reduce impacts on surface waterbodies, including White Bear Lake, from groundwater
pumping activities. The Council chose the communities in the study area based on proximity to new
surface water supplies, proximity to sensitive surface water bodies, as well as their inclusion in the
1
USGS study of White Bear Lake that was published in 2013.
These are not the only viable approaches to achieve water sustainability in the northeast metro. The
U.S.Geological Survey (USGS) has acknowledged that thecommunities included in the study area are
not the only water users influencing White Bear Lake. There could be many other configurations of
solutions that include other municipal water systems, private water users, and other solutions in
addition to the infrastructure solutions considered in this study.
The alternatives evaluated should be viewed as examples.The best option for moving forward may be
a hybrid of the examples considered in this study, and could involve approaches that were not
considered in this study. For example,communities in thenortheast metro could utilize less expensive
approaches. Thesemightincludeconservation or stormwaterreuse to reduce groundwater pumping
before making large-scale investments in alternative infrastructure solutions. Such a plan could couple
these less expensive options with aggressive monitoring of groundwater and surface water, and set
triggers for further action in the event these less expensive approaches are not effective.
Fourongoing activitieswill better inform decision-making related to water use in the northeast metroas
they are completed.
1
Jones, P.M. Trost, J.J., Rosenberry, D.O., Jackson, P.R., Bode, J.A., and O’Grady, R.M., 2013, Groundwater
and Surface-Water Interactions near White Bear Lake, Minnesota, through 2011: U.S. Geological Survey
Scientific Investigations Report 2013-5044.
Feasibility Assessment of Approaches to Water Sustainability in the Northeast Metro –Summary
1
1.The USGSis conducting a study, Characterizing Groundwater and Surface Water Interaction
in Northeast Metro Area Lakes, MN,withfunding fromthe Council through a Clean Water Fund
grant.This study will provide critical information on the surface water/groundwater interaction
in the area. This will allow for better understanding of how proposed approaches will mitigate
low lake levels.The study is expected to be complete in 2016.
2.The Council is completing afeasibility assessment of the potential for aquifer recharge and
reusing stormwaterin the North and East Metro Groundwater Management Area.The study
area for this feasibility assessment includes the communities in the current study area, and
additional communities in Anoka, Ramsey, and Washington counties.The results of this study,
expected in 2015, will evaluate the potential of using alternative approaches to reduce impacts
to lakes and to address other identified water sustainability issues within the Groundwater
Management Area.
3.University of Minnesota Technical Assistance Program (MnTAP) will identify opportunities for
industrial water users in the North and East Metro Groundwater Management Area to reduce
their water consumption as part of the Minnesota Department of Natural Resources (DNR)
strategies under the Groundwater Management Area plan. The source of water in this
delineated region is almost exclusively groundwater. Several approaches will be used for this
effort in order to reach, inform, and interact with a broad range of industrial users.This work is
expected to be completed in the summerof 2015.
4.The DNRis completing a management plan for the North and East Metro Groundwater
Management Area.This plan is currently in development, and could impact future groundwater
appropriations, groundwater monitoring activities, and the assessment of water use
sustainability in the area.
The results of these activities willprovide useful information to determine the best course to move the
northeast metro in the direction of greater sustainability of water resources.In addition, communities
participating in this study have noted that groundwater use could be further reduced by more active
conservation programs. Further investigation is needed of the potential for conservation to both reduce
future groundwater useand recharge the aquifer and connectedsurface water bodies.
Below are key findings for the approaches evaluated for thisstudy. Following the findings is a series of
fact sheets that summarize the advantages and disadvantages of each alternative evaluated.
Approach 1: Saint Paul Expansion
Saint Paul Regional Water Services (SPRWS) operates a regional water system that borders the
southern-most communities in the study area. Saint Paul obtains its water primarily from the Mississippi
River via an intake and pumping station in Fridley. This water is pumped east to Charley Lake in North
Oaks, from which it flows by gravity through a chain of lakes to Vadnais Lake in Vadnais Heights. Water
is pumped from Vadnais Lake to the McCarrons Water Treatment Plant (WTP) in Maplewood. Figure 1
shows a schematic of Saint Paul’s water supply system.
Figure 1. Saint PaulSupply System Schematic
Feasibility Assessment of Approaches to Water Sustainability in the Northeast Metro –Summary
2
The Council evaluated three alternatives for serving water to communities in the study area from
Saint Paul Regional Water Services.Each alternative assumes wholesale delivery of water via
dedicated transmission mains from the water treatment plant to a centralized location in the water
distribution system of each of the communities served:
Alternative 1A:
Service to North Saint Paul via the Hazel Park boostedpressure zone.
Alternative 1B:
Service to Shoreview, Vadnais Heights, White Bear Lake, White Bear
Township, and Mahtomedi directly from McCarrons Water Treatment Plant. North Saint
Paul would still be served via the Hazel Park boosted pressure zone as in Alternative 1A.
Alternative 1C:
Service to all 13 communities in the study area, which includes
Shoreview, Vadnais Heights, White Bear Lake, White Bear Township, Mahtomedi, North
Saint Paul, Hugo, Centerville, Lino Lakes, Circle Pines, Lexington, Columbus,and Forest
Lake.
Key findings of the analysis of Approach 1 are as follows:
The Saint Paulraw water main and pumping are essentially at capacity with existing Saint Paul
maximumdailydemands (approximately 80 million gallons per day). However, significant storage
exists in the chain of lakes usedby Saint Paul (3.5 billion gallons)that could be used to provide
additional water to the northeast metro.
The Saint PaulMcCarrons Water Treatment Plant currently has approximately 30 million gallons per day
of excess capacity.
The six communities nearest to the Saint Paul watersystem (Shoreview, Vadnais Heights, White
Bear Lake, White Bear Township, Mahtomedi, and North Saint Paul) could be served by Saint Paul
without expanding its major water treatment facility or improving its raw water delivery system to the
plant. To expand service beyond these six communities, additional large-scale infrastructure
improvements would be needed. This would significantly increase the capital costs of the system.
The SaintPaulHazel Park pressure zone, which is adjacent to North Saint Paul and White Bear
Lake, has limited capacity to provide water to the northeast metro.Only North Saint Paul can be
served from the Hazel Park pressure zone without large-scale infrastructure improvements.
A new trunk water main that connects to the Saint PaulMcCarrons Water Treatment Plant is
necessary to bring water to the majority of the northeast metro.
Approach 2: New Surface Water Treatment Plant
The Council considered two alternative sites for a new water treatment plant with a surface water
source from the Mississippi River.The preferred site after initial screening is on Vadnais Lake, and
would usethe raw water source of Saint Paul Regional WaterServices. Threealternatives were
evaluated for serving water to communities in the study area from a new water treatment plant:
Alternative 2B:
Service to Shoreview, Vadnais Heights, White Bear Lake, White Bear
Township, Mahtomedi, and North Saint Paul (similar to Alternative 1B, replacing service from
Saint Paul with service from a new water treatment plantwith a capacity of 40 million gallons
per day).
Alternative 2C:
Service to all communities in the study area (similar to Alternative 1C, replacing
service from Saint Paul with service from a new water treatment plantwith a capacity of 60
million gallons per day).
Alternative 2D:
Service to Shoreview, Vadnais Heights, White Bear Lake, White Bear
Township, Mahtomedi, and North Saint Paul with service from a new water treatment plant
sized to meet average day demands. Peak demands will be met by each community’s existing
Feasibility Assessment of Approaches to Water Sustainability in the Northeast Metro –Summary
3
groundwater supply system(conjunctive use of surface water and groundwater). The new
infrastructure in this alternative is similar to Alternative 2B, but smaller in size since it does not
need capacity to meet peak demands. The water treatment plant capacity in this case is15
million gallons per day.
Key findings of the analysis of Approach 2 are as follows:
Saint Paul Regional Water Services owns land on Vadnais Lake, which could serve as a
location for a new water treatment plant.
The water quality in Vadnais Lake is better than the Mississippi River due to chemical treatment,
oxygen being added, and settling of solids.Preliminary screening of plant sites basedon water
quality and location resulted in the identification of Vadnais Lake as the preferred site for a new
water treatment plantat this concept level.
Conjunctive use of surface water and groundwater is feasible. However, it presents an
engineering challenge with regard to mixing, and must be carefully designed and operated to
avoid uncontrolled byproducts in the distribution system.
A conjunctive use system could be significantly less expensive than a system that would provide
exclusively surface waterto meet all demands, while providing nearly the same benefits in
terms of aquifer recovery.
Approach 3: Continued Development of Groundwater Sources
The current course of utilizing groundwater exclusively to meet the water supply needs of northeast
metro communitieswill not be without capital costs.At least two communities are planning for future
water treatment facilities to improve the quality of water in their distribution systems, and two
communities are planning for the construction of additional well facilities between now and 2040. This
study identified approximately $90 million is anticipated capital investments for water supply and
treatment facilities for study area communities through 2040, if they were to continue to use
groundwater supplies.
Some of these costs might be necessary even with a switch to a surface water source. For example, it
would likely be recommended that cities continue to maintain their existing well supply infrastructure
over time. If conjunctive use of groundwater and surface water were implemented, communities would
likely also maintain existing groundwater treatment plants, and may decide to also continue with plans
for future groundwater treatment plants.
Despite the estimated costs, the continued use of groundwater issignificantly less costly than surface
water, both from a capital and operational cost perspective. The cost of water for northeast metro
communities currently ranges from $1.34 / 1,000 gallons to $3.69 / 1,000 gallons. Saint Paul Regional
Water Services customers, by comparison, pay an average of $3.70 / 1000 gallons for surface water.
In addition to an analysis of the cost of this approach, the potential impacts to aquifer levels and lake
levels need to be considered. Groundwater modeling conducted as part of this study indicates some
continued decline in water levels in the Prairie du Chien – Jordan aquifer under this scenario.
Lake Augmentation
The Council evaluated the feasibility of augmenting White Bear Lake water levels with water from the
Mississippi River and St. Croix River. Key findings are as follows:
The St. Croix River is significantly further away and has significantly higher pumping pressure
required than water from the Mississippi River for augmentation.In addition, the St. Croix
River is a National Scenic Riverway, making construction in or near the river difficult from a
regulatory standpoint.
Feasibility Assessment of Approaches to Water Sustainability in the Northeast Metro –Summary
4
The Mississippi River is impaired with zebra mussels, as is Vadnais Lake. Augmentation from
this source will require filtration.
With filtration, augmentation with water from Vadnais Lake is not anticipated to degrade White
Bear Lake water quality.
Saint Paul Regional Water Serviceshas sufficient capacity to draw and convey 2 billion gallons of
water annually (2 BG/yr) for augmentation.
Based on historic data, it is not certain if augmentation of 2 BG/yr will maintain the water
level of White Bear Lake atthe ordinary high water level, though it is likely that the water
level will be improved in the lake through the augmentation system.
It is unlikely that augmenting White Bear Lake will provide benefit to other lakes. It is currently
uncertain to what degree augmentation will provide benefit to the underlying bedrockaquifer that
serves a water supply for northeast metro communities.
Evaluation of Alternatives
The Council analyzed thealternativesandestimated the capital, operational, and maintenance costs of
each.In addition, a qualitative evaluation of other advantages and disadvantages was completed for
each alternative, including water source reliability, potential to impact lake levels, implementation
obstacles, and water rate impacts. The evaluations are presented at the end of this summary.
Conclusions
The analyses conducted for this feasibility assessment yieldedpreviously unknown information about
potential approaches to improve the sustainability and reliability of groundwater in the northeast metro
area and the Twin Cities region.Importantly, this includes information about the necessary
infrastructure components and costs of some of the infrastructure solutions that have been proposed.
Groundwater flow modeling was also used to estimate the potential benefit tothe Prairie du Chien –
Jordan aquifer due to reducedgroundwater pumping that would result from the alternativesevaluated
in this study. Given the relationshipbetween water levels in White Bear Lake and water levels in the
aquifer, it is reasonable to extrapolate that an increase in aquifer level would over time cause the lake
level to increase.Where aquifer levels are estimated to increase over a broader area, it is likely that
other lakes that have similar connectivity to the aquifer would also receive somebenefit.The magnitude
of benefit is difficult to assess with our current understanding of the hydrogeologic system.This
understanding is expected to increase with the current investigation of the USGS, which is scheduled to
be completed in 2016.
The useof surface water to replace groundwater use for municipal supplies was evaluated at multiple
scales to estimate how the costs and benefits of such approaches change as a greater number of
communities are included. It is clear from the analysis at multiplesystem scales that there is less
benefit obtained at greater marginal cost as the system is expanded outward toward less densely
developed communities. This is in part due to the proximity of the source of water. Therefore, if a
surface water supply is implemented in the future, it would be sensible to target it to a geographic area
that has greater density, is as closeto the source of water as possible, and reduces pumping in
proximity to sensitive surface water features.
Direct augmentation of White Bear Lake with Mississippi River water via Vadnais Lake was found to be
feasible, though the system required would need to be very large in scale in order to overcome the
2
historically documented seepage rates from the lake to the aquifer below.In addition, if future
2
Minnesota Department of Natural Resources, 1998, Lake-Ground Water Interaction: Report to the Legislative
Committee on Minnesota Resources.
Feasibility Assessment of Approaches to Water Sustainability in the Northeast Metro –Summary
5
groundwater pumping or climate conditions causefurther reductions in the underlying aquifer system,
the rate of seepage from the lake could increase over time.The benefits of a lake augmentation system
would be exclusiveto the lake water levels, not likely providing any broader benefit to other lakes or to
water source reliability.
None of the proposed approaches would be easy to implement.All have significant capital and
operational costs, andadditional discussion is needed to determinewho should be responsible for
those costs if anyof these approaches wereimplemented.There are, however, models for cost sharing
that have been implemented in other locations in the United States that could be used as a starting
point for discussion. Two of these models have been applied to the northeast metro in the fullreport to
illustrate the potential impacts to rate payers with implementation.
Communities in the study area have expressed a desire to explore the potential to use conservation,
stormwatercapture for irrigation, aquifer recharge, or other less expensive methods to reduce
groundwater use before switching their supply source to surface water at significant expense.However,
such approaches could take longer and would result in less aquifer recovery than elimination of
groundwater use through a switch to surface water.Decision makers and the DNRwill need to decide
whether this approach is acceptable given the risk of additional declines in lake level or of slower
recovery of lake level.
Additional Work is in Progress
Several pieces of information not found in this investigation could be important considerations in water
supply planning decisions for the northeast metro area. This evaluation of alternatives stops short of
identifying the best way forward.Local government units, state lawmakers, the DNR, and other
stakeholders should all be part of the discussion in developing a plan for water supply for the region
that protects our natural resources in the most cost-effective manner.This future plan could include one
or more of the options investigated in this study, and could also include other approaches not evaluated
here.
Currently unanswered questions include:
What is the potential to use conservation, aquifer recharge, or stormwaterreuse to
reduce aquifer impacts from pumping activities?
TheCouncil is leadingan ongoing study to
look at aquifer recharge and stormwaterreusefor the North and East Metro Groundwater
Management Area, which is expected to be completed in 2015.Additional evaluation of
conservation potential is recommended.
How much will changes in pumping impact the water levels in White Bear Lake, and how
long will those changes take?
The current USGS study in the northeast metro, to be
completed in 2016, will develop a localized groundwater model that will consider groundwater-
surface water interactions, and will incorporate a significant amount of new data currently being
collected from lakes in the northeast metro.
What is the sustainable limit for groundwater withdrawals in the northeast metro?
The
Council, in coordination with the DNR, is trying to make an initial assessment of sustainable
levels of groundwater use in sub-regional areas across the metro area that would preventfuture
problems with water use. This is a complex problem, due to the complexity of the physical
systems involved. There is not currently a timeline for completion of this activity, though it is
acknowledged that identifying sustainable limits on water use is essential for future planning.
Feasibility Assessment of Approaches to Water Sustainability in the Northeast Metro –Summary
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Feasibility Assessment of Approaches to Water Sustainability in the Northeast Metro –Summary
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Feasibility Assessment of Approaches to Water Sustainability in the Northeast Metro –Summary
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Feasibility Assessment of Approaches to Water Sustainability in the Northeast Metro – Summary
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Feasibility Assessment of Approaches to Water Sustainability in the Northeast Metro – Summary
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Feasibility Assessment of Approaches to Water Sustainability in the Northeast Metro – Summary
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Feasibility Assessment of Approaches to Water Sustainability in the Northeast Metro – Summary
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FeasibilityAssessment of Approaches to Water Sustainability in the Northeast Metro – Summary
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Feasibility Assessment of Approaches to Water Sustainability in the Northeast Metro – Summary
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