2a Wellhead Protection PlanCITYOF
CHANI EN
690 Ci{y Center Ddve, PO Box 147
Chanhassen, Minnesota 55317
Phone 612.93Z 1900
General Fax 612.937.5739
Engineering Fax 612.937.9152
Public Safety F, tv 612.934.2524
Web www. ci. chanhassen, mn. us
MEMORANDUM
TO:
FROM:
Todd Gerhardt, Acting City Manager
Anita L. Benson, City Engineer
DATE: January 5, 1999
SUB J:
Authorize Preparation of Wellhead Protection Plan
File No. PW-379
Wellhead protection is a program intended to prevent contaminants from entering
wells used by public water supply systems. The emphasis is preventing problems
before they occur, supporting public health protection, and the protection of
resources the City has invested in the public water supply system. Pursuant to
Minnesota Rule 4720.5130, subpart 3, the City of Chanhassen is required to
prepare and submit to the Minnesota Department of Health a wellhead protection
plan for all wells in the public water supply system when another well is added. As
you are aware, the City is currently in the process of constructing Well No. 8
which is scheduled to be on line in the summer of 1999. A wellhead protection
plan must be completed and submitted to the Minnesota Department of Health
within two years from the date that Well No. 8 goes on line. However, rule
provisions exist which provide for .additional time periods to prepare a wellhead
protection plan. The Minnesota Department of Health has evaluated the City of
Chanhassen and determined that the City must complete a wellhead protection plan
within four years from the date the new well is connected and on line.
The 1996 Well Field Study and Water Management Plan prepared by BRA &
Associates identified the necessity to prepare a Wellhead Protection Plan. The
Engineering Department has received a proposal to prepare a Wellhead Protection
Plan from Northern Envkonmental. The proposal from Northern Environmental
breaks the work scope into two groups which can be completed over a two-year
time frame if desired. Group One consists of pumping tests, groundwater flow
model development and resource evaluations. The estimated cost for completion
of Group One activities is $19,430. Group Two consists of wellhead protection
area delineation and vulnerability assessment. Specific tasks identified under this
group include delineation of the wellhead protection area, delineation of the
drinking water supply management area (DWSMA) vulnerability, and a report of
findings. The estimated cost for completion of Group Two activities is $12,080.
However, the estimated cost for Group Two activities may vary depending on the
results of the vulnerability assessment.
The Minnesota Department of Health has determined that the City of Chanhassen
has four years to complete a wellhead protection program from the date Well No.
Todd Gerhardt
January 5, 1999
Page 2
- 8 is connected and on line pursuant to Minnesota Rule 4720.5130i Subpart 3. :
However, it is recommended the City take a Proactive aPproach intended tO
prevent con. taminants from entering wells used bythe public wateesupply system
by completing a wellhead protection plan in a phased approach asoutlined in the.
proposal submitted by Northern Environment~i. Fundih-g for the preparation Ora
wellhead protection plan has been providedfor in the 1999 budget.
Attachments: ' -
1. Minnesota Department of Health Letter dated Decemberll, 1998.
2. Proposal from Northern Environmental'dated October 15, 1998.
c: Charles Folch, Director of Public Works Operations _
Dave Hempel, Assistant~City Engineer~ -
Phil Gravel, Bonestroo _
Dan Barrett, Northern Environmental
g:Xeng~anitahn emos\wellhead.doc ·
. - _ · . . ~::
Minnesota Department of Health
South Central District Office
Nichols Office Center
410 Jackson Street, Suite 500
Mankato, Minnesota 56001
(507) 389-2501
December 1 i, 1998
The Honorable Nancy Mancino
City of Chanhassen
P.O. Box 147
Chanhassen, MN 55317-0147
Dear Mayor Mancino,
7998
Pursuant to Minnesota Rule 4720.5130 Subpart 3, the City of Chanhassen is required
to prepare and submit to MDH a wellhead protection plan for all wells in the public water
supply system when you connect another well to yOUr municipal public water supply. A
wellhead protection plan must be completed and submitted within two years from this
date unless your public water supply system qualifies for additional time as specified in
the wellhead protection rule.
Wellhead protection (WHP) is a program intended to prevent contaminants from
entering wells used by public water supply systems. The emphasis is on preventing
problems before they occur, supporting public health protection, and the protection of
the resources you have invested in your public water supply system.
As noted above rule provisions do provide for additional time periods to prepare a WHP
Plan. The rule grants additional six-month time periods for each of the following:
each two existing or new wells up to six,
· privately owned systems,
· lack of state or local funding,
· the wellhead protection area is within more than one governmental jurisdiction, and
· the wellhead protection area is influenced by another public water supply well that is
not in the public water system.
The City of Chanhassen is to complete a WHP plan four (4) years from the date the
new well is connected and online. This determination is based on the first three criteria
listed above. If it is determined during the delineation of the wellhead protection area,
that your wellhead protection area qualifies for the last two criteria listed above you will
be autOmatically granted 6 months for each the criteria you meet.
The Honorable Nancy Mancino
Page 2
The Minnesota Department of Health (MDH) is committed to providing you with a high
level of assistance and technical support in this endeavor. I am the planner that has
been assigned as a primary contact to work with you to develop your WHP Plan and will
be contacting you in the near future to discuss requirements and how to get started.
MDH will also sponsor a wellhead protection plan development workshop that will be
targeted for public water' suppliers just beginning the wellhead protection planning
effort. Additional workshops will target specific plan elements including delineation and
vulnerability assessments, contaminant source inventories, and other plan components.
There are several initial steps you must take to ensure development of an effective
WHP Plan. The first step is to identify a Wellhead Protection Plan Manager. This
individual will coordinate plan development and implementation and serve as the
principal contact for MDH. A public water supplier should also budget for plan
development and implementation over the time required to develop and implement the
plan.
Enclosed for your information is a fact sheet entitled "The Ten Most Asked Questions
About Wellhead Protection" which discusses wellhead protection planning in
Minnesota. We look forward to working with you to provide your customers with a safe
and healthy water supply. If you have questions, please contact me.
Sincerely.,
Terry LY Bovee
Planner
Source Water Protection Unit
cc: Don Ashworth, City Manager; Chanhassen, MN
Gerald Boucher Water Superintendent; Chanhassen, MN
Richard Foster, Boonestroo, Rosene, Anderlik & Assoc., Inc.
Bill Anderl, MDH Community Engineer, West Metro District Office
Eno.
Bonestroo
Rosene
Anderlik &
Associates
Engineers & Architects
Bonestroo, Rosene, Anderlik and Associates, Inc. is an Affirmative Action/Equal Opportunity Employer
Principals: Otto G, Elonestroo, RE. · Joseph C. Anderlik, RE. · Marvin L. Sorvata, RE. ·
Richard 15. Turner, RE. · Glenn R. Cook, P.£, · Robert G, Schunicht, RE. · Jerry A. Bourdon. P.E, ·
Robert W. Rosene, RE. and Susan M. Eberlin, C.RA., Senior Consultants
Associate Principals: Howard A. Sanford, RE. · Keith A. Gordon, RE. · Robert R. Pfefferle, RE. ·
Richard W. Foster, P.E. · David O. Loskota, RE. · Robert C. Russek, A.I.A. · Mark A. Hanson, PE. ·
Michael T. Rautmann, RE. · Ted K.Field, RE. · Kenneth R Anderson, RE. · Mark R. Rolls, RE. ·
Sidney P Williamson, RE., L.S. · Robert E Kotsmith · Agnes M. Ring · Michael R Rau, RE. ·
Allan Rick Schmidt, RE.
Offices: St. Paul, Rochester, Willmar and St. Cloud, MN · Milwaukee, WI
[~/ebsite: www. bonestroo.com
November 13, 1998
City of Chanhassen
Public Works Building
1591 Park Road
Chanhassen, MN 55317
Attn: Mr. Charles Folch
Re:
Well Field Study
BRA File No. 393-98-000
Dear Charles:
We had Northern Environmental prepare a Proposal for a well field study and Phase I of the
Wellhead Protection Plan that will be required due to the construction of Well No. 8. We can
discuss the Proposal along with the Well 8 construction status at our meeting next Wednesday.
If you have any questions, please contact me at (651) 604-4840 or e-mail at
froster .~.,bonestroo .com.
Yours very truly,
BONESTROO, ROSENE, ANDERLIK & ASSOCIATES, INC.
Richard W. Foster, P.E.
RWF:tlh ? r, ~ I
Attachments
Northern Environmental
Hydrologists · Engineers · Geologists
372 West County Road O
New Brighton, MN 55112
Fax 1-612.635-0643
1-612-635-9100
1.800-776-7169
TO:
CC:
FROM:
SUBJECT:
Dick Foster DATE:
Phil Gravel
Dan Barre ,t~Douglas Bergstrom, Mark Janovec
City of Chanhassen, Well Field Study
October 15, 1998
We have reviewed much of the available information regarding the City of Chanhassen's existing
well fields in order to determine the City's likely status with respect to the wellhead protection
program. The city is currently ranked 1045 on the phasing list, however, the City's plans to construct
and bring on-line a new well, will put them at the top of the list. Several work activities and their
general applicability to both wellhead protection and water resource management, are presented in
this memo. These items broadly include pumping tests, ground-water flow model development,
resource characterization, and wellhead protection program activities.
While wellhead protection needs to be addressed directly by the City, the Minnesota Department of
Health (MDH) will allow at least two years to complete the process. That window gives the City
some latitude in laying the groundwork for its wellhead program and, allows the costs to be spread
out over several years. For this reason, we have divided the following work items into two broad
groups. The first group involves a collection of tasks that will pdmadly be necessary for wellhead
protection ultimately, but serve other functions as well, and generally represent independent work
activities. The second group comprises activities specifically required by the wellhead protection
rules, and that are usually presented as a group to the MDH, for the firSt phase of wellhead
protection.
GROUP I
Pumping Tests
The first focus for the City, as required, will be delineation and vulnerability assessment activities.
The situation is somewhat complicated for Chanhassen because they pump water from two different
aquifers -- the Prairie du ChierJJordan Aquifer and a glacial drift aquifer. The wellhead protection
rules will require separate delineations for each aquifer. We suggest that a 24-hour pumping test
be conducted on Well 3, Well 7, or new Well 8 in the Galpin Well Field, for characterization purposes
of the Praide du Chien/Jordan Aquifer wells. A 72-hour pumping test will be required for one of the
wells completed in the glacial ddft aquifer. This work will be required for wellhead protection and will
prcvide an excellent basis for ground-water flow modeling. Ground-water flow modeling, in turn, is
a key part of the delineation activities. The cost estimate presented below, was developed with the
assumption that Cit'.v staff can assist with coordination of the test, including the logistics of managing
well down time, pump operation, and water disposal. In addition, the estimate assumes that
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automatic data collection equipment is available from the MDH. The cost estimate for the bedrock
aquifer test includes data collection for at least 12 hours pdor to pumping, for 24 hours dudng
pumping, and for 12 hours during recovery. The cost estimate for the glacial ddft aquifer test
includes data collection for at least 12 hours prior to pumping, for 72 hours during pumping, and for
24 hours during recovery. Also included are data analysis and preparation of a letter report.
Deliverable:
A letter report of pump test results
Estimated costs: $7,440.00
Time to complete: 2 to 4 weeks from authorization (depending on equipment availability)
~t'O, Undwater Flow Model I~evelopment
While no ground-water flow model has been developed for the City of Chanhassen, several existing
regional models may be adapted for wellhead protection purposes. These include the Minnesota
Pollution Control Agency's (MPCA) Metro Model and the Hennepin Conservation District's (HCD)
Prairie du Chien/Jordan Model. Neither of these models would be appropriate for use in
Chanhassen without modification; however, they could perhaps be modified with relatively little effort
to preclude the need to develop a model one from scratch for the bedrock. I would recommend that
the existing MPCA and HCD ground-water flow models be examined to determine the following:
The general integrity of the models (our willingness to use them for our work
product);
If HCD's bedrock model for Hennepin County could be modified or extended, to
include the City's Prairie du Chien/Jordan wells in suffident detail to satisfy MDH staff
for wellhead protection.
An initial assessment of the existing models will likely require about $1,590.00. Modifications, if
required, will be detailed in writing after the initial review, but will likely require approximately
$3,000.00 of additional effort for the bedrock aquifer model. One immediate use for the bedrock
model in the Galpin Well Field area, in addition to wellhead protection, is to examine effects of
current and proposed future pumping on water levels in the area, to determine if pdvate wells in the
area are affected.
The existing ground-water flow models could not easily be modified to simulate ground-water fiow
in the ddft. In order to predict the wellhead protection area or evaluate the resource characteristics
of the aquifer, a simple model of the drift aquifer would be necessary. Preparation of such a model,
including background data review and preparation of the model input, will likely require $6,200.00
of staff time, assuming we limit model scope to the Lotus Lake Well Field itself and approximate
regional boundary conditions. In addition to wellhead protection area delineation, such a model
could be used to assess the long-term sustainable yield of the aquifer.
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The software used in constructing either flow model will be based upon the Analytic Element Method
(a modeling approach developed at the University of Minnesota). The model that we build for
delineation purposes can also be used to answer other questions you may have about your
groundwater flow system in the vicinity of the existing wells. For example, the model can be used
to:
'cUrrently,
Method to
Determine optimal well spacing at existing wellfield;
Identify potential locations for new wells or well fields;
Predict drawdown effects at vadous pumping rates and various locations;
Simulate effects of future wells or other hydrologic boundaries on flow field; and
Track contaminant plumes
the MDH, and the MPCA are using computer codes based upon the Analytic Element
solve ground-water flow problems.
Resource Evaluations
If a drift model is developed for the Lotus Lake Well Field, a resource characterization could be done,
to evaluate the sustainable yield of the aquifer. Results would include an assessment of whether
the aquifer will support development of up to five additional wells and of interference effects from
one projected pumping scenario. Results would be presented in a written report. Cost for such an
analysis would be $1,200.00.
In addition, the bedrock model could be used to evaluate the effect of present and future pumping
on nearby private wells in the vicinity of the Galpin Well Field. Such an analysis would be
straightfonvard with a bedrock aquifer model appropriate for use around the Galpin Well Field. The
cost of performing such an analysis would depend on the number of proposed pumping scenarios
and the type of results needed by the City. Costs would likely be in the range of $1,000.00 to
$2,000.00, but this estimate should be viewed as approximate until an exact scope is determined.
GROUP il
Wellhead Protection Area Delineation and Vulnerability Assessment
According to the rule, a wellhead protection plan must include:
A delineation of the wellhead protection area (WHPA) for the City's wells;
A delineation of the drinking water supply management area (DWSMA);
An assessment of the vulnerability of the identified DWSMA to contamination;
An inventory of contaminant sources within the DWSMA;
Additional information on the physical setting of the aquifer based on results of the
delineations and vulnerability assessments;
A management plan that includes specific wellhead protection measures;
An implementation plan; and
A monitoring plan to evaluate efficacy of the management/implementation plan
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Typically, the first three items in the list above are completed together and reported to the MDH.
Preparation of these items is usually considered to be Phase I of the wellhead protection planning
process. The results from the Phase I activities are often used to establish the scope for future work
because the level of detail with which remaining activities need to be carded out depends on the
results of the vulnerability assessment.
To assist the City in understanding the steps in the planning process, we've put together this phased
approach. The first phase focuses on the wellhead protection area delineation tasks, while the
second phase focuses on the development of the wellhead protection plan itself. The following is
a brief explanation of the tasks, deliverables, and estimated costs for the first phase of the project.
Task 1.0 - Delineation of the Wellhead Prote(;tion Area
The MDH draft rule states that WHPAs must be delineated using five criteria: 1) a minimum ten-year
travel time; 2) aquifer flow boundaries; 3) daily pumpage; 4) ground-water flow field characterization;
and, 5) aquifer transmissivity. The rule does not specify a method for the delineation.
We will delineate the wellhead protection areas for the city's wells using a single layer steady-state
ground-water flow model. We assume that model development activities have already been
completed, as described eadier in this memo. The delineation will be based on a 10-year time of
travel, unless otherwise specified by the City. Pdor to preparing the WHPA delineation, we will
arrange a scoping meeting with MDH staff, as required by the wellhead protection rule. Should any
substantial scope changes result from the meeting (in particular, requiring us to modify the existing
ddft or bedrock models), City staff will be informed immediately.
Deliverables:
Scoping meeting with MDH
Map of WHPA delineations for all existing wells.
Estimated Cost:
WHPA Delineations - $2,000.00
Drafting $700.00
Total - $2,700.00
Time to Complete: 2-3 weeks after scoping meeting is conducted
Task 2.0 - Delineation of DWSMA
Because wellhead protection areas will not follow jurisdictional boundaries, the MDH has designated
a DWSMA as the area that must be managed for wellhead protection. The DWSMA must include
the entire delineated wellhead protection area, and be bounded by real geographic linear features.
These boundaries can include center lines of highways, streets, roads, railroad right-of-ways,
property lines, etc. Using parcel information from the county assessor and the City, Northern
Environmental will match the boundaries of the wellhead protection areas to existing geographic
boundades.
Deliverables:
Map of DWSMAs
Estimated Cost:
$1,500.00
Time to Complete: 2 weeks after wellhead protection area delineation completed
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Ta~k 3.0 - Drinking Water ,~upply Mana(~ement Area Vulnerability
The likelihood of contamination reaching the City's water supply depends on several factors~aquifer
depth, permeability, and recharge regime. Under this task, the vulnerability of the DWSMAs will be
assessed using the geologic sensitivity criteria and guidelines developed by the Minnesota
Department of Natural Resources (DNR). To perform this task for the City, Northern Environmental
will collect existing information needed to complete the vulnerability assessment.
Deliverable:
Estimated Cost:
Tin~. e to Complete:
Vulnerability assessment performed according to DNR evaluation cdteda.
$2,400.00
2 weeks after DWSMA-delineation completed
Task 4.0 - Report of Findings
Under this task, Northern Environmental will compile all the information and analyses done for Tasks
1.0 - 3.0 and generate a technical report. The report will include all maps and tables prepared under
the previous tasks, as well as a description of the methods used, relevant findings, and assumptions.
The report will include complete documentation of the computer models of ground-water fiow used
for conducting the delineation analyses. Recommendations regarding the problems and/or issues
that should be addressed in the wellhead protection plan, will be included in the report.
Deliverable:
Estimated Cost:
Time to Complete:
Five copies of report
$5,480.00
6 weeks after the completion of Tasks 1.0 - 3.0
Summary of Estimated Costs
The costs of the tasks identified in this letter are summarized below:
Group I
1. Pumping Tests $7,440.00
2. Bedrock Ground-water Model
A. Preliminary Assessment $1,590.00
B. Modifications $3,000.00
3. Drift Aquifer Ground-water Model $6,200.00
4. Resource Evaluation $1,200.00
Subtotal: $19,430,00
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Grcup II
Wellhead Protection (Phase I) A. WHPA Delineation
B. DWSMA Delineation
C. Vulnerability Assessment
D. Report
$2,700.00
$1,500.00
$2,400.00
$5.480.00
Subtotal: $12.080.00
TOTAL: $31,738.00
The Group I activities need not be conducted as a group. Each of the first three items can be
computed independent of the others, although item 4 requires the completion of item 3. Group !i
activities require that the first three items be conducted simultaneously.
If you have any further questions, please feel free to contact us at (612) 635-9100.
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