Memo- Sump Pump Inspection Program Update and Change Order
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Public Works Department
Memorandum
From:
Honorable Mayor and Members of the City Council
(~ r-C)
Steven J. Stadler, Public Works Director \)'~
To:
Date:
July 6, 2000
Subject:
Sump Pump Inspection Program Update and Change Order
CONTRACT CHANGE ORDER
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In July, 1998 City Council authorized a contract with Howard R. Green Company to
complete city-wide sump pump inspections. The City's consultant completed the
inspection program late last year. The original project budget of $104,151.00 was
based on inspections of 2,976 properties. In order to complete the program 3,760
inspections were actually required.
This equates to a fee increase of $30.912.24 - see attached original fee and final
billing invoice.
The increase occurred because the Hennepin County data which the City provided to
Howard R. Green Company did not break down property identification numbers (PIDs)
into individual units in multi-family situations, i.e., Westbrook Patio Homes,
Meadowcreek Condominiums, etc.
The additional fees are based on the contract per unit cost for residential unit
inspections.
There are funds available in the sanitary sewer utility account to cover this increase.
The maximum MCES loan/grant amount for this project was $40,000. The City has
been approved for this amount.
PROGRAM UPDATE
Program results can be summarized as follows:
. 3,099 residential inspections completed
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661 non-residential inspections completed
44 properties with cross-connected sump pumps at initial inspection
34 properties still in violation, 16 of these are in Westbrooke Patio Homes
21 properties with water on the basement floor
106 properties not yet inspected
Note: The above numbers don't match those shown in the attached final report - the
HRG database doesn't include all properties inspected. This is because the County
property records, used as the basis of our inspection locations, don't include individual
units within Westbrooke or similar units.
CITY COST SAVINGS THROUGH PROGRAM:
Estimated potential cost savings if all properties in violation can have sump pump
discharges redirected: $10,OOO/yr. These savings will no doubt go up if we can
complete the inspections as the "hold-outs" no doubt include a higher percentage of
violations.
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Howard R. Green Company
CONSULTlNG ENGINEERS
Proposed Fee
Anticipated 1997-1998 Budget for Entire Program
1. Initial Residential Inspections
(Single family to 4-plex)
2. Initial Non-Residential Inspections
29 Commercial
26 Multiple Residential
3. Reinspections
4. Video
5. Handouts
6. Training
2,781 x $27.50 ;; $76,477.50
140 x $3'7.50
55 x $37.50
278 x $49.50 ;;
7,312.50
13,701
4,200
1,600
800
TOTAL BUDGET
5104,151
Anticipated 1997-1998 Budget for Phase I Program
L Authorized Contract Amount
$22,297
Net Additional Fee to Complete Entire Program
S81,854
NOTE: If the City considers completing remaining inspections with City
personnel, Howard R. Green estimates that approximately 2,000 person
hours will be required. That could be a full-time person for one year or a
part-time person over an extended period of time. Also, our fees for the
program are based on estimated numbers of inspections, Actual final !I
program costs will be based on a number of units actually inspected and "
reinspected. '
O:\PROJ\000400\400-1604.dec.Hopkim.doc
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Howard R, Green Company
CONSULTING ENGINEERS
Hopkins, City of
Invoice Date:
Invoice No;
Project Code:
5/16/00
26239
801570J
1010 1'1 Street South
Hopkins, MN 55343
Attention: Steve Stadler
Re: Hopkins -Sump Pump Inspection
Sump Pum Inspection/Evaluation Program for Hopkins Phase I and Phase II
FINAL BILLING
For Services Rendered Through May 12, 2000.
Hopkins -Sump Pump Inspection
Sump Pump Services
3,099 Residential Inspections
@ 27.50
85,222.50
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:!:7S Re-Inspections
@ 49.50
13,761.00
661 Non-Residential Inspections @ 37.50
24,787.50
Total Sump Pump Services
123,771.00
Video
4,200.00
Handouts
] ,600.00
Training
800.00
Additional Work: Printing
Preparation for Distribution
Postage
1,960.65
2,182.00
549.59
Fee Earned to Date *
135,063.24
Less Previous Billings *
100,895.58
Total This Invoice **
34,167.66
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ACCOUNTS ARE PAYABLE WITHIN 30 DAYS UNLESS SPECIAL ARRANGEMENTS ARE MADE.
A SERVICE CHARGE OF 1.5"" PER MONTH WILL BE LEVIED ON OVERDUE UNPAID BALANCES.
PLEASE REMIT PAYMENTTO: HOWARD R. GREEN COMPANY. NW 7148 . PO BOX 1450 . MINNEAPOLIS, MN 55485-7148 . 1-8001728-7805
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Howard R. Green Company
Project No. 801570J
Sump Pump Inspection and III Reduction Program - Phase II
City of Hopkins, Minnesota
TABLE OF CONTENTS
Certification Page.............................................................................,......................................... ii
Table of Contents ..... ..................................................................,.............................................. .lii
I. INTRODUCTION AND HISTORy......................................... ...... .................................... 1
II. SUMMARY OF CITYWIDE RESULTS .................................... .......................... .............. 3
III. CONCLUSION AND RECOMMENDATIONS.................................................................. 8
APPENDIX
A.
B.
C.
D.
Map of the Sump Pump Inspection Area
Sample Inspection Form and Other Handouts for Educational Package
Sample Letters for Property Owners Not in Compliance
Non-Compliant Locations
Properties which are Currently Not Inspected
Properties which are Currently Failing
Properties with Water in the Basement
Compliant Locations
Number of Sump Baskets
Number of Sump Pumps
Locations with Water Present in Basket
Pump Discharge Locations
Pump and Basket Combinations
Properties with Cisterns
Properties with Year-round Pump Usage
E.
F.
G.
H.
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J.
K.
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O:\PROJ\801570J\Phase II\Final Report
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Howard R. Green Company
Project No. 801570J
Sump Pump Inspection and III Reduction Program - Phase II
City of Hopkins, Minnesota
Maps Provided:
1. Map of Properties in Non-Compliance to Date
2. Map of a(l Sump Pump Locations
3. Map of Properties with Water in the Basket During Inspection
4, Map of Locations with Roof Leader Discharges Near the Building
5. Map of Properties with Cisterns
O:\PROJ\801570J\Phase II\Final Report
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Howard R. Green Company
Project No. 801570J
Sump Pump Inspection and 1/1 Reduction Program - Phase II
City of Hopkins, Minnesota
L INTRODUCTION AND HISTORY
The City of Hopkins, Minnesota authorized Howard R Green Company (HRG) to initiate
the second phase of the City's Sump Pump Inspection and Inflowllnfiltration (1/1) Reduction
Program in September 1998. DurIng the winter of 1998-1999, HRG focused on the
remaining Hopkins properties, consisting of approximately 2,781 residential and 195 non-
residential, to be inspected for possible cross connection of their sump pumps. Phase I of
the project was planned in a target area designated by the City of Hopkins, with Phase II
making up the remainder of the City. The Phase I area was selected based on the
frequency of sanitary sewer backups in the area. Pumping of clear water from sump pumps
into the sanitary sewer system can significantly contribute to system inflow and cause
sewage backups.
The City chose to initiate a sump pump Inspection program due to frequent sewer backups
high levels of rainfall induced inflow/infiltration (1/1) clear water into the sanitary sewer
system. Infiltration, within the system includes all extraneous surface runoff and
groundwater that leaks into the sanitary sewer system through cracks or defects in existing
manholes and pipelines. Inflow, on the other hand includes deliberate connections (cross-
connections) to the system. The City reviewed sewer flows of previous years as well as all
possible sources of the 1/1. While they realized that sump pump discharges to the sanitary
sewer were not the sole source of the problem, these discharges were one of the major
contributors of inflow.
This study on sump pump discharges and the effects of the inflow was prompted by specific
events related to high levels of rainfall in July 1997. During this time period, sewer backups
occurred in several locations, including the Hazel Lane vicinity, which serves as a collector
sewer and discharges flows to the MCES interceptor, as well as in the vicinity of 13th
Avenue.
The locations and the related sanitary sewer service areas were used to establish the
geographic boundaries of the first phase of the Sump Pump Inspection Program with Phase
II making up the remaining properties within the City limits. A map showing Phase I, Areas
1 and 2, and Phase II boundaries are included in the Appendix of this report.
This study outlines the effects of sump pump discharges and other clear water inflow to the
sanitary sewer system, and will project the estimated effects of inflow within the study
areas.
Cities throughout Minnesota have become more aware of these inflow sources and their
significance through education efforts of the League of Minnesota Cities, Minnesota
Pollution Control Agency, and Metropolitan Council Environmental Services. These
agencies are encouraging communities to implement sump pump inspection programs in
order to reduce the amount of clear water inflow burdening the conveyance and treatment
infrastructure.
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Howard R. Green Company
Project No. 801570J
Sump Pump Inspection and III Reduction Program - Phase II
City of Hopkins, Minnesota
The City of Hopkins has recognized the success of these programs in reducing inflow in
other communities throughout Minnesota, and is proactive in providing the benefits of inflow
reduction to its property owners.
Through other studies, cities have found that 5% to 7% of properties have sump pump
systems cross-connected to the sanitary sewer. Therefore, the purpose of the Sump Pump
Inspection and 1/1 Reduction Program for the City of Hopkins is as follows:
1. To reduce the occurrences of sewer backups into basements related to inflow
sources.
2. To educate the public on the effects of cross connections to the sanitary sewer.
3. To reduce rainfall induced inflow by an estimated 25.9 million gallons per year.
4. To eliminate an estimated 208 single sump pump and 45 multiple sump pump cross
connections.
5. To avoid wastewater conveyance and treatment costs of up to $33,626 per year for
treatment of clear water inflow in the target area.
The City of Hopkins initiated Phase" of the Sump Pump Inspection Program as a result of
the success of the Phase I program. They have applied for and received grant and loan
funds from Metropolitan Council-Environmental Services (MCES) to complete a citywide
program. Phase II of the program completed the citywide program.
The Scope and Approach of the Phase II project program includes:
1. A major communication/education component with new ordinances and public
meetings, local video access, mailings to property owners, and press releases.
2. Physical inspection of approximately 2,976 locations throughout the City of Hopkins.
These inspections were documented on inspection forms that were developed for
the City (see the Appendix of this report for a sample).
The inspection forms were utilized to develop the various lists that are included in the
Appendix of this report. Subsequently, the completed inspection forms were utilized to
prepare a computerized database of this information, which was then formatted onto
computer discs that are compatible to the City's computer network. City staff can utilize the
information, which illustrate the following items:
1. Existing sump pumps.
2. Existing sump baskets.
3. Non-compliant locations.
The maps will be useful resources for the City. For example, the maps can be cross-
referenced to other capital improvement projects being planned by the City to implement
1/1 reduction programs into future improvement projects such as new storm sewer draintile
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Howard R Green Company
Project No. 801570J
Sump Pump Inspection and l/I Reduction Program - Phase II
City of Hopkins, Minnesota
improvements, facilitating sump pump connections to existing storm sewers/draintiles, and
roof leader rerouting. The maps will also help the City focus its re-inspection programs
more efficiently and effectively.
We recommend that the City focus its next 1/1 reduction steps on the property owners in
non-compliance with the Code, or those not inspected to date. Howard R Green has made
extensive efforts to contact the properties in both Phase I and Phase 1/ that have not been
inspected to date. These properties appear to be either vacant, difficult to reach, or
unwilling to comply with the City Code to have their sump pump system inspected.
There are eighteen properties within the city limits that are not in compliance and 105
properties that have not been inspected. Based on our experience, these categories result
from the properties with the highest rate of clear water discharge from sump pumps.
II. SUMMARY OF CITYWIDE RESULTS
The Sump Pump Inspection Program has resulted in the collection of a great deal of data.
The use of this data will provide the City with a focused strategy for inflow reduction.
Table I provides a summary of the data that was collected in both phases of the program.
Maps and lists of the data are included in the Appendix of this report.
To date, 99.47% of the 3,398 properties inspected have complied with the City's Code that
relates to sump pump discharges. This code prohibits cross-connections between the City
sewer system and sump pump discharge. The code also prohibits all clear water
discharges to the Municipal Sanitary Sewer.
The City should establish a plan of action to work with the 0.53% that have not complied
to date. We recommend that the City establish various deadlines for the remaining
properties in non-compliance. A letter should be sent to the property owners outlining the
City's deadlines and potential consequences of non-compliance (i.e., implementation of the
$1 DO/month penalty, etc.).
Three sample letters that the City can utilize as guidelines in enforcing Code compliance
are included in the Appendix of this report.
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Howard R. Green Company
Project No. B01570J
Sump Pump fnspection and lff Reduction Program - Phase II
City of Hopkins, Minnesota
Analvsis of Data from Phase I and Phase II of the Sump Pump Inspection Program
The following outlines basic conclusions drawn from the data that was collected.
· There are at least 284 existing sump pumps in the City. This represents 8.36% of
the properties inspected to date. This statistic is high, but within the typical 7% to
11 % found in other communities. The City of Hopkins has the potential to reduce
inflow from sump pumps significantly through this program. For example, jf all 284
existing sump pumps had discharge into the system, it can be predicted that
397,600 GPO of inflow would have entered into the system. The inspections have
confirmed that at least 28 sump pumps were discharging into the sanitary sewers
at the time of the first inspection.
The key benefits of eliminating sump pump discharges are the reduction of flow and
the avoidance of additional costs of conveyance and treatment. Significant
reductions in base sanitary sewer flow most likely will not occur during dry weather.
Elimination of cross-connected sump pump discharges will reduce the large
increases in flow that occur during extreme wet weather such as the 11 + inch
rainfalls during July 1997. This flow reduction thereby reduces conveyance and
treatment costs.
We note that many of the sump pumps had been diverting their flow away from the
sewer system prior to this inspection program. The results of the program indicate
that several of the cross-connected sump pump discharges were redirected
because of this program. It can be assumed that these sump pumps were
adversely affecting the sewer flows prior to the program.
In addition, it was observed that 21 properties noted standing water over the
basement floors during these inspections. We were unable to observe what the
source of the standing water was or if it was flowing through a floor drain into the
sanitary sewer system. If the standing water was due to seepage through defects
in the home foundation or other clearwater source, then this would constitute
excessive inflow to the sanitary sewer system. The City will need to establish its
policies to address this situation at these locations. It is possible that other locations
in the City may have had water flowing over the basement floors during July 1997
or other wet periods, which could also have contributed to the excessive flows.
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Howard R. Green Company
Project No. 801570J
Sump Pump Inspection and III Reduction Program - Phase II
City of Hopkins, Minnesota
The data indicates that 28 properties with sump pumps failed the first inspection and
had been contributing to the system inflow. Based upon experience, there is a
distinct possibility that some of the properties that have not been inspected to date
are also contributing inflow to the system. Likely, half of the non-inspected
properties may fall into this category. The following table summarizes these III
contributors:
Properties discharging into the sanitary sewer at first inspection
Properties with standing water over basement floors
Estimate half of locations not inspected
Total
28
21
53
102
Benefits from the Citywide Proqram
The findings in Phase I and Phase II indicate that the City of Hopkins has exceeded
the III reduction outlined in the "Benefits" section of the Howard R. Green Company
Phase I proposal dated September 1997, and again in the Phase I( proposal dated
December 22, 1997. The proposals estimated that 7% of properties would have a
single sump pump and 1.5% of properties would have multiple sump pumps.
The findings in Phase I and Phase" indicate that the City of Hopkins possesses the
following conditions:
7.65% of properties have single sump pumps
0.71 % of properties have multiple sump pumps
0.62% of properties have water standing over the basement floor
1.38% of properties have baskets without sump pumps
It appears that Phase I and Phase II of the Sump Pump Inspection Program were
cost-effective for the City of Hopkins.
With the above-mentioned results, the City should see a 3- to 4-year payback in the
program, which is exceptional. The City of Hopkins has an agreement with MCES
(Metropolitan Council- Environmental Services) that can provide up to $40,000 in
loan and grant funding to help reduce the City's costs.
· Following first inspections, several properties redirected their sump discharges. It
is assumed that 102 illicit discharge locations can be redirected as a result of this
program if the City establishes a polley to require corrective action in the 21
locations with water over the floor and sends notices to complete all inspections.
I ISPNWFSI VOLl IDA T A IPROJ\801570j1Phase II\Final Report.doc
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Howard R Green Company
Project No. 801570J
Sump Pump Inspection and lI[ Reduction Program - Phase II
City of Hopkins, Minnesota
. A review of the existing sump baskets data in Phase I and Phase II indicates that
a total of 331 properties with sump baskets exist. There are 284 existing properties
with pumps in these sump baskets. The 47 existing sump baskets without a pump
represent a possibility for future sump pump discharges to the sanitary sewer
system. See the Pump and Basket Combinations list in the Appendix.
These baskets have had stickers placed in them to inform the public of the City
Code requirements. It is very important for the City Building Officials to monitor
these empty sump baskets to ensure future compliance. We recommend that the
City of Hopkins develop specific policies and procedures to address this potential
for clear water discharge to the sanitary sewer system.
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Property locations identified with multiple sump pumps and/or baskets (25 locations)
can be major sources of sump pump inflow. Typically, these locations, shown in the
Number of Sump Baskets and Number of Sump Pumps lists and maps in the
Appendix, will have the most significant flows. The City should conduct detailed
engineering reviews on these specific locations.
Other studies have identified year-round flows up to 160 gpm from these types of
installations. The number of locations is significant, and the inflow impact can be
great. These should be given a high priority for connection to storm sewers by the
City. There may be additional multiple sump pump locations in the list of non-
inspected properties.
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The City should consider a comprehensive review of the properties with sump
pumps to determine potential sources of the clear water (i.e., high groundwater
levels, watermain leaks, improper drainage and lot grading, lack of storm sewers
and draintile, etc.). The fact that 168 of 331 properties with existing sumps had
water present (see the Map of Properties with Water in the Basket During
Inspections in the Appendix) in the sump at the time of inspection indicates that
50.76% of the properties in Hopkins with sumps may have serious impacts due to
groundwater. This corresponds with 1) the large number of locations with existing
baskets and no pumps, and 2) the large number of locations with water over the
floors. If property owners decided to install these sump pumps quickly due to
extreme wet conditions, the 1/1 impacts would be significant. The City may want to
consider regulations that require pump installation with all sump baskets. This
would ensure proper discharge locations. A sump pump permitting system with
inspections at the time of installation should also be considered. The City will need
to establish a policy on the properties that experience water flowing over the floor
and into the floor drains.
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Howard R. Green Company
Project No. 801570J
Sump Pump Inspection and III Reduction Program - Phase II
City of Hopkins, Minnesota
. It may be prudent for the City to develop new ordinances and codes to manage new
development. Ensuring that basements are constructed one to two feet above
known water levels and/or mottled soils may prevent the ground water problems in
the future. This could be similar to flood plain management regulations. The
inspections in Phase I and Phase II have definitely identified that this type of
problem appears to occur in specific areas.
. Inspections determined that 2,801 (82.43%) properties in the City have roof leaders.
Most appear to discharge rainwater far enough away from the foundation to reduce
the incidents of water seeping into the basement. The City should consider
notifying the 392 locations that have their roof leaders near the foundation, which
can be a major source of water seepage into basements. These property owners
more than likely would appreciate assistance from the City via advice on extending
their roof leaders away from the foundation. See the Map of Locations with Roof
Leader Discharges Near the Building in the Appendix.
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Roof leaders can pose a problem in buildings with flat roofs. The City may want to
consider a review of all flat roofed buildings to determine where this water drains.
This is typically in commercial and industrial buildings. If drainage is to the outside
of the building, the water rarely gets into the sanitary sewer. However, buildings
with interior drainage can easily be cross connected. If none exist, the Building
Department should develop policies to prevent these types of cross-connection.
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Howard R. Green Company
Project No. 801570J
Sump Pump Inspection and III Reduction Program - Phase II
City of Hopkins, Minnesota
III. CONCLUSIONS AND RECOMMENDATIONS
A. Results from the inspection proaram are as follows:
Twenty-eight of the properties Inspected had their sumps cross-connected to the
sanitary sewer during the first inspection, and several have been redirected.
Twenty-one locations had water in the basement at the time of the inspection. We
were unable to determine if this water was flowing into the sanitary sewer via the
floor drain. The City will need to establish policy and codes to work wIth these
property owners to redirect these inflow sources.
Eleven locations were identifIed with cisterns for collectIng rainfall. These locations
should be inspected to determine if there are any cross connections to the sanitary
sewer.
The mappIng included in the Appendix to this report is based on the database
provided by the City. For the City of Hopkins, we were able to complete 3,398
inspections of the 3,503 existing properties within City limits, but were only able to
map 3,211 due to Incomplete property identification numbers. Our intent was to
identify areas in need of public works improvements, which can only be
approximately shown on the maps in the Appendix. It was not the focus of this
report to resolve inconsistencies in the database. As of November 12, 1999, no
updates to the database have been supplied, and the report reflects as such.
B.
Estimated Effects of Sump Discharaes and III in Julv 1997
Since this program was initiated in response to the wet weather conditions in July
1997 and the related sewer backups, a review has been done in an attempt to
quantify the effects of the 1997 wet weather flows. The analysis IS based upon
assumptions outlined in this section and is intended to outline the estimated
impacts. Actual effects from the wet weather in July 1997 could vary from the
estimates reported in this section. The most accurate way to pinpoint the effects
of the sump pumps and other III sources would be to perform a detailed metering
and observation immediately following a significant rainfall event.
The Phase I area was comprised of two specific areas, as shown in the map in the
Appendix. They will be described as follows:
1. Phase I - Area 1 - Northwest portion of Hopkins
2. Phase I - Area 2 - Northeast portion of Hopkins
Phase II made up the remainder of the City.
I IS PNWFS\V OLl IDA T A IPROJI80 1570jlPhase II\Fiillll Report. doc
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Howard R. Green Company
Project No. S01570J
Sump Pump Inspection and III Reduction Program - Phase II
City of Hopkins, Minnesota
A review of the City of Hopkins' sanitary sewer map indicates that both areas in
Phase I are serviced by 8" diameter sanitary sewer lines. Detailed information on
the slope of the pipes was not available; therefore, it was conservatively assumed
that the slope was 0.40%. This represents the minimum allowable grade on an 8"
sewer.
Based on above, the maximum capacity of the 8" sewers serving both Phase I
areas is 345 gpm. This is the maximum flow rate that could be handled by these
sewers before a surcharge condition would occur. A surcharge condition could
eventually lead to sewer backups similar to the reports received by the City of
Hopkins in July 1997.
This table identifies the estimated peak sanitary sewer flows that would be
generated with each service area during wet weather flows similar to July 1997.
This type of analysis is used to design sanitary sewer trunk lines and wastewater
treatment facilities. The analysis indicates the following:
Maximum capacity of 8" sanitary sewer
Estimated Phase I peak wet weather flows
Phase I - Area 1
Phase I - Area 2
345 gpm
379 gpm
258 gpm
The estimated sanitary sewer flows from the Phase I study areas identified in the
above table are based on the following assumptions:
y Count of actual lots in study area
y 3.5 residents per household (MPCA guidelines)
);,- Peaking factor of 4 (MPCA guidelines)
The following two sections, C and D deliniate additional analysis based on the
above estimated sanitary sewer flows, and sump pump inspections.
C. Estimated III Contributions to the Sanitary Sewer in Phase I - Area 1
This analysis indicates that the 8" sewer serving Area 1 will approach its maximum
wet weather capacity. It is very likely that this may have occurred during July 1997.
Further review of the sump pump inspection results indicates that the following
estimated 1/1 contributions may have added to the surcharge conditions and
resulting sewer backups:
Properties discharging into the sanitary sewer during the first inspection 4
Properties with flow over floors 6
Estimate half of locations not inspected -1
Total number of locations contributing to 1/1 in Area 1 13
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Howard R. Green Company
Project No. 801570J
Sump Pump Inspection and J/I Reduction Program - Phase II
City of Hopkins, Minnesota
The 13 locations have a potential to contri bute an average of 130 gpm to the
sanitary sewer system. If this 130 gpm of III flow is added to the 379 gpm peak flow
shown in the above table, the resulting 509 gpm flow would represent a surcharge
condition that could have contributed to the sewer backups in July 1997.
The previous are only estimates, and the following factors could also affect the
surcharge conditions:
1. What is the actual sump pump capacity?
Many sumps can have 10 gpm capacity or more. It would be
beneficial to have the actual pump capacity to determine if flows
exceeded 130 gpm. There is a strong probability that flow from
sumps and over floors exceeded 10 9 pm in July 1997.
2.
What was the actual flow rate of water across the floors?
This rate is difficult to estimate without observing the actual
conditions in July 1997. An estimated flow of 10 gpm is
conservative.
3.
Were there any other locations that experienced standing water or water
flowing over the floor in July 1997?
This could only be confirmed by actual observation in 1997 or during
a similar future wet weather condition. The antidotal information
suggest that any additional sources of this nature would add
significant III flow to the surcharge condition.
1. Were any of the other 18 sump pumps identified in Area 1 discharging into
the sewer in July 1997?
This is obviously difficult to confirm. It should be noted that if all 20
eXIsting sump pumps in Area 1 were discharged into the sanitary
sewer, the peak flow from sumps could be estimated at 200 gpm,
which could surcharge the system dramatically during peak domestic
flows.
We recommend that the City confirm connections between the
known sump pump discharges and the existing storm sewers.
These drain pipes can typically be installed in the street boulevard.
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Howard R. Green Company
Project No. 801570J
Sump Pump Inspection and 1/1 Reduction Program - Phase II
City of Hopkins, Minnesota
D. Estimated III Contributions to the Sanitary Sewer in Phase I - Area 2
Review of the sump pump inspection results indicate the following estimated III
contributions may have contributed to the surcharge conditions and resulting sewer
backups in July of 1997:
Properties discharging into the sanitary sewer during the first inspection 2
Properties with flow over floors 5
Estimate half of locations not inspected .-2
Total number of locations contributing III in Area 2 13
It is estimated that these 13 locations contributed an average of 130 gpm, based on
the rate of 10 gpm/sump pump.
Our analysis indicates that Area 2 has an estimated peak flow of 258 gpm. The
existing 8" sanitary sewer has an estimated capacity of 345 gpm. The addition of
130 gpm of ]/1 from sumps and other known III sources would amount to a
combined peak flow of 388 gpm. This is near the maximum capacity of the 8"
sewer. Based on this, it does appear that a surcharge could have occurred.
The most likely scenario in Area 2 relates to higher discharge capacities (10 gpm+)
or more clear water sources over the floors that were not detected in this Sump
Pump Inspection Program. The mapping done in Area 2 appears to support this
scenario because of the high concentration of known sump pumps and water
flowing over basement floors. It may be necessary for more observations to be
conducted in Area 2 following a significant storm event to determine if there are
other III sources.
There are 52 known sump locations in Area 2, 5 properties with known water in the
basements, and 12 locations that have not been inspected. If these 69 locations
contributed 10 gpm each to the sanitary sewer systems in July 1997, a peak flow
of 690 gpm (397,440 GPD) could have occurred, surcharging the 8" sewer. In
addition, there is a strong possibility that some unidentified locations also had water
over the floor during July 1997 that could not be detected during this inspection
program.
If 690 gpm of III was contributed on top of the peak domestic use of 258 gpm, the
resulting 948 gpm flow would have resulted in surcharge conditions.
Due to the strong concentration of sump pumps and other potential I/! sources in
Area 2, it is recommended that the City consider a Capital Improvement Plan to add
storm sewers and area drains to help convey the runoff and sump pump
discharges.
\\SPNWFS\vOLl \DA T A \PROJ\801570j\Phase II\FinaJ Rcport.doc
11
I
.
.
I
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Howard R. Green Company
Project No. 801570J
Sump Pump Inspection and III Reduction Program - Phase II
City of Hopkins, Minnesota
It is recommended that a study be done on the proposed installation of a storm
sewer and/or trench drain along the back lot lines south of Orillane Avenue.
It is also recommended that a study be conducted along Cottage Downs, Valley
Way] Park Terrace, Bridle Lane, Wilshire Walk, and Edgemoor Drive, to determine
the relationships between basement floor elevations and the high water levels in the
pond. A review of the hydraulics of the existing storm drainage system would be
useful in providing recommendations for storm sewer and sump pump discharge
systems.
It is also recommended that a review of the existing storm sewer system south of
State Highway 7, west of County Road 18, and north of County Road 18 be done
to determine if storm sewers should be extended to provide outlets to the sump
pumps identified in this vicinity.
E. Citywide
Review of the citywide sump pump inspection results indicate the following
estimated III contributions may have contributed to the surcharge conditions and
resulting sewer backups in July of 1997:
Properties discharging into the sanitary sewer during the first inspection 28
Properties with flow over floors 21
Estimate half of locations not inspected 53
Total 102
It is estimated that these 102 locations contributed an average of 1,020 gpm, based
on the rate of 10 gpm/sump pump. The additional 1 ,020 gpm is divided accordingly
amongst the 7 different lift stations located throughout the City and ultimately flows
east in the 33" trunk sewer along Lake Street NE.
An analysis of the contribution to each lift station should to be done to pinpoint
which sections of the sanitary sewer system are overburdened by the addition of
clear water.
I ISPNWFS\ VOL 1 lOA T A IPROJIR01570jlPhase Il\Final Report.doc
12
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.
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TABLE I
Results for the City of Hopkins, Minnesota
Sump Pump Inspections and III Reduction Program (801570J)
By Howard R. Green Company
From Project beginning to November 12, 1999
BASE DATA
Number of Properties in the Provided Database:
3,503
2,784 79.47%
614 17.53%
3,398 97.00%
105 3.00%
2,851 83.90%
353 10.39%
194 5.71%
3,398 100.00%
Inspections Completed to Date: % of properties in Database
Residential
Non-Residential
Subtotal:
Number of Non-lnspected Properties:
Property Ownership: % of properties Inspected
Own
Rent
Not Available
Subtotal:
EXISTING CONDITIONS
Basement: % of properties Inspected
2,805 82.55%
25 0.74%
306 9.01%
3,067 90.26%
3,398 100.00%
24 0.71%
260 7.65%
3,114 91.64%
3,398 100.00%
Sump Pump Baskets: % of properties Ins~
Multiple
Single
None
Subtotal:
Sump Pumps: % of properties Inspected
Multiple
Single
None
Subtotal:
Beason System Installed (if known): % of properties that know r~ason
Home came with system 128
Response to Inspection program 20
Water in basement 69
Previous system failed 4
Subtotal: 221
57.92%
9.05%
31.22%
1.81%
100.00%
o :\Proj\80 1570J\CorrespondenceIReports\PrelimRpt. Hopkins.nov99 .xls
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TABLEl
Results for the City of Hopkins, Minnesota
Sump Pump Inspections and III Reduction Program (801570J)
% of properties with inspected
Observed at
First Inspection
241 7.09%
1 0.03%
3,128 92.05%
2 0.06%
8 0.24%
3 0.09%
15 0.44%
3,398 100.00%
(Continued)
EXISTING CONDITIONS (continued)
Inspected Discharge Point:
cross-connections
Outside (pass)
Storm Sewer (pass)
Other (pass)
Floor Drain (fail)
Sanitary Sewer (fail)
Laundry Tub (fail)
Other (fall)
Subtotal:
Observed at
Final Inspection
250 7.36%
3 0.09%
3,127 92.02%
o 0.00%
8 0.24%
o 0.00%
10 0.29%
3,398 100.00%
0.29%
Beaver Systems/Drain tile: % of properties Inspected
Water in Basement: % of properties with Basements
Water in Basket: % of properties with Baskets
Cistern Locations: % of properties Inspected
Roof Leaders; % of properties Inspected
Yes
Roof Leader Discharge: % of properties with Roof Leaders
Near
Away
Subtotal:
Properties Reporting when Pump Runs (if known)'
Spring
Summer
Fall
Winter
Year-round
Number of properties reporting:
10
21
168
11
2,801
392
2,409
2,801
0.75%
50.76%
0.32%
82.43%
14.00%
86.00%
100.00%
% of properties reporting
191
203
29
13
10
213
Properties not in compliance (failures): % of properties Inspected
O:\Proj\80 1570J\Co rrespon dencelReports\Prel i mRpt. Hopkins. nov9g .xls
18
89.67%
95.31%
13.62%
6.10%
4.69%
0.53%
2of3
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TABLE I
Results for the City of Hopkins, Minnesota
Sump Pump Inspections and 1/1 Reduction Program (801570J)
(Continued)
STUDY PROJECTIONS*
Sump Baskets:
Multiple
Single
None
26
315
3,162
3,503
Subtotal:
Sump Pumps:
Multiple
Single
None
25
268
3,210
3,503
Subtotal:
* Projections based on actual inspections vs. total number of properties
0: IP roj\80 15 70J\Correspond ence\Re ports\Prel 1m Rpt. Ho pki ns. n ov99.xls
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TABLE II
Sanitarv Sewer flows for the City of Hopkins in the Sump Pump Study Area
8" Sanitary Sewer Line capacity = 345 GPM
Northwest portion of Hopkins -- Area 1
16th Avenue
15th Avenue
14th Avenue
13th Avenue
12th Avenue
11th Avenue
Robinwood Lane
Elmo Park Add
RLS No 1053
Lot/acre
24
32
42
49
51
50
22
10.8
5.2
Unit per
Acre 3.5 PEl/at
84
112
147
171.5
178.5
175
77
9.7 366.66
10 52
Peaking
Factor
4
4
4
4
4
4
4
4
4
GPD
100 galJPE day
33600
44800
58800
68600
71400
70000
30800
146664
20800
Total Flow
GPM
day/1440 min
23.33
31.11
40.83
47.64
49.58
48.61
21.39
101.85
14.44
378.79 GPM
Northeast portion of Hopkins -- Area 2
. Peaking GPD GPM
Lot 3.5 PEllot Factor 100 galJPE day day/1440 min
Drillane Road 29 101.5 4 40600 28.19
Oakridge Rd 9 31.5 4 12600 8.75
Cottage Downs 18 63 4 25200 17.50
Valley Way 8 28 4 11200 7.78
Park Terrace 3 10.5 4 4200 2.92
Bridle Lane 4 14 4 5600 3.89
Edgemore Drive 4 14 4 5600 3.89
Wilshire Walk 8 28 4 11200 7.78
5th Avenue 13 45.5 4 18200 12.64
Wayside Road 28 98 4 39200 27.22
Sweet Briar Lane 22 77 4 30800 .21.39
Farmdale Road 21 73.5 4 29400 20.42
Burnes Drive 12 42 4 16800 11.67
Campbell Drive 22 77 4 30800 21.39
Althea Lane 35 122.5 4 49000 34.03
Herman Terrace 21 73.5 4 29400 20.42
Hollyhock Lane 4 14 4 5600 3.89
Hazel lane 3 10.5 4 4200 2.92
County Road 18 1 3.5 4 1400 0.97
.; Total 257.64 GPM
O:\Proj\80 1570J\sanitary sewer cales.xls
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'City of Hopkins, Minnesota
Properties which are Currently not Inspected
.
Pin number Owner_name number Street_Description
2411722240013 NICOLE R RUNNING 201 10TH AVE N
2411722240015 KJl.THLEEN A MAIER 209 10TH AVE N
2411722240043 LINDA LORRAINE SOUKUP 237 11TH AVE N
2411722310087 JOAN F MORAN 137 12TH AVE N
2411722240094 ROBERT D BASKERVILLE 310 12TH AVE N
2411722340114 LISA WATSON 1 01 12TH AVE 5
2411722340110 John D. Ross' 119 12TH AVE S
2411722340106 DALE PHILLIP WOJCIK 133 12TH AVE S
2411722340087 RAYMOND E MELCHIOR 46 12TH AVE S
2411722210022 J M & B W JOHNSTON 410 13TH AVE N
2411722320008 MARY FLAWLESS 118 15TH AVE N
2411722320071 o & L NELSON 18 15TH AVE N
2411722230063 MARY ROBINSON 206 15TH AVE N
2411722230099 V & E MILLER 23315THAVEN
2511722230052 ADV~EnHOPKINS BUS CTR ASSC 525 15TH AVE S
2411722320078 CARL TON BISHOP MOORE 11 16TH AVE N
2411722320081 G & D L1NDBERY 25 16TH AVE N
2411722230028 P R & E 5 EMPANGER 302 16TH AVE N
2411722230021 ROBERT W ELMQUIST ETAL 344 16TH AVE N
2311722140139 GEORGE R CAVINESS 244 17TH AVE N
2311722140144 Michael J. Wolbrink 230 18TH AVE N
2311722140019 L & J ROGNESS 314 18TH AVE N
2311722140013 M D & M R NENADICH 341 18TH AVE N
2311722410050 R 5 BELL & D BELL 125 19TH AVE N
2411722340101 Rafford & Darvine Gill' 121 0 1 ST 5T S
2311722140061 SANDRA J BREITENSTEIN 204 20TH AVE N
2311722140064 T M & M E WHEELER 205 21ST AVE N
2411722130040 J W GALLEY & K S GALLEY 607 2ND ST N
2411722130145 D & K TREANOR 300 5TH AVE N
2411722430157 Resident 44 5TH AVE S
2511722120009 CETOM ASSOCIATES 715 5TH 5T S
2411722420131 P & C KLOSSNER 130 6TH AVE N
2411722420017 NEVA I FEILER 15 6TH AVE N
2411722420022 WilLIAM C BYRNES 34 6TH AVE N
2411722430027 L A THOMAS & G M THOMAS 15 6TH AVE S
2411722430021 JAMES D MELIUS 43 6TH AVE S
2511722130036 SAMUEL B DANDO 506 6TH AVE S
2411722130048 Nancy Knudson 229 7TH AVE N
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City of Hopkins, Minnesota
Properties which are Currently not Inspected
.
Pin number Owner_name number StreeCDescription
2411722430050 HAMIL TON HOLDING COMPANY 21 7TH AVE S
2411722430046 FEDERAL NATL MTGE ASSOC 45 7TH AVE S
2511722130160 ALBERT & MAUREEN CARRIVEAU 602 7TH AVE S
2411722420081 BRADLEY A GRABHAM 144 8TH AVE N
2411722130077 DALE BRAKEMEIER 238 8TH AVE N
2411722130074 DAVID B LENTZ 245 8TH AVE N
2411722420063 STEVEN SWANSON 26 8TH AVE N
2411722420059 James R. Koss' 27 8TH AVE N
2411722420062 BRIAN 0 WOODRUFF 30 8TH AVE N
2511722130073 JENNIFER J BECKEY 641 8TH AVE S
2411722220002 HOPKINS MIDWEST HOTEL L TO PT 30 ADDRESS UNASSIGNED
2411722220003 HOPKINS HSG L TO PTNRSHP 30 ADDRESS UNASSIGNED
2411722220004 HOPKINS MIDWEST HOTEL L TO PT 30 ADDRESS UNASSIGNED
2411722220015 HOPKINS HSG L TO PTNRSHP 30 ADDRESS UNASSIGNED
1911721440007 DAVID C RICE 152 ASHLEY RD
1911721420041 WESTERN PROPERTIES 150 BLAKE RD N
1911721110078 DAVID GIMBERLlNE 431 BLAKE RD N
1911721120021 WHITE CASTLE SYSTEM lNC 540 BLAKE RD N
1911721440091 YVONNE M MUELLER 201 BLAKE RD S
1311722440043 THE KNOLLWOOD ASSOC 30 COTTAGE DOWNS
1300000000004 Vacant Lot 709 COTTAGE DOWNS
1311722420048 K N & S A KEPHART 30 DRILLANE RD
1311722420315 M D & J B STEWART 30 DRILLANE RD
1911721220036 CHEYENNE LAND COMPANY 601 EDGEMOOR DR
1911721220035 LAUNCE A AIRHART ET AL 603 EDGEMOOR DR
1911721140006 GATEWAY HOPKINS WAREHOUSE 8098 EXCELSIOR BLVD
1911721420045 HOPKINS COMMERCE CENTER 8594 EXCELSIOR BLVD
1911721310063 WASH ME CORP 8940 EXCELSIOR BLVD
1911721320032 SUPER VALU STORES INC 9300 EXCELSIOR BLVD
1911721220025 H E GROUP INC 105 FARMDALE RD E
2411722110035 JOHN R HENDRICKSON 1 FARM DALE RD W
2511722330005 CENTURY NORTH CONSTR CO INC 1020 FEL TL CT
2511722330006 ALAN FORREST 920 FEL TL CT
1911721340109 ELLA F DICKHOFF 142 HARRISON AVE S
1911721340010 WILTON HARRY ANDERSON ETAL 33 HARRISON AVE S
1911721340023 DANIEL A BLOCK 38 HARRISON AVE S
1911721440066 DAVID P WEBB 217 HOLLY RD
2011721330068 MICHAEL G LESCARBEAU 227 HOMEDALE RD
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o :\P roj \80 1 57 OJ\co rrespo ndence\Repo rts \Nov 16. RptN R.x 15
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City of Hopkins, Minnesota
Properties which are Currently not Inspected
.
Pin_number Owner name number Street_Description
1911721330027 SUPER VALU (RON) 101 JEFFERSON AVE S
1911721110105 GAIL A MAPES 1312 LAKE 5T N E
1911721110117 DAVID L KANNENBERG 1403 LAKE 5T N E
1311722230010 G A HETLAND & SHETLAND 2 LORING RD
1311722240024 TIMOTHY J & CAROL A GRAUPMAN 7 LORING RD
1911721230084 C W & B L HIVELY ET AL 224 MADISON CIR S
2411722310031 Rodney Miller - Realtor 1001 MAINSTREET
2411722320056 PERFECT IMAGE SALON 1617 MAINSTREET
2011721330015 BARBARA B PILLlNGER 117 MAPLE HILL RD
1911721340085 MARY F MOORE 25 MONROE AVE S
19117002 CAPEWELL 610 OAK PARK LA
1911721240135 AUBURN LIMITED PARTNERSHIP 701#10 OAK PARK LA
1911721240133 AUBURN LIMITED PARTNERSHIP 701 #11 OAK PARK LA
1911721240127 AUBURN LIMITED PARTNERSHIP 701#70 OAK PARK LA
1911721240121 AUBURN LIMITED PARTNERSHIP 701#80 OAK PARK LA
1911721240116 AUBURN LIMITED PARTNERSHIP 701#92 OAK PARK LA
1911721240115 AUBURN LIMITED PARTNERSHIP 701#93 OAK PARK LA
1311722440046 R J & D L HANSON 30 OAKRIDGE RD
1911721440053 DAVID P WEBB 221 OAKWOOD RD
1911721110064 ERIK J LUNDGREN 1203 OXFORD 5T
1911721110067 BRUCE A NEMER 1312 OXFORD ST
1 91172111 0065 TINA M CAINE ET AL 1320 OXFORD ST
1311722440016 Jon and Jane Gordon 825 PARK TER
2511722140060 MICHAEL HUNT 542 PARK VALLEY DR E
2511722140090 D D ROESNER ETAL 618 PARK VALLEY DR W
1311722210019 ALAN R ANDERSON 5 ST ALBANS RD E
2411722140074 D & C CONKEY 344 SWEET BRIAR LA
1911721220003 GERALD A & DIANE E HANSON 11 WAYSIDE RD E
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.
"City of Hopkins, Minnesota
.
Pin number Owner name
2311722140004 BECKY WILLIAMS
2311722140008 R W & G M MARTINSON
2311722130043 R 0 BARNES JR & D D BARNES
2411722130031 NGUYEN VAN DINH & WIFE
2411722420074 SNYDER DRUG
1911721440010 BRIAN R BURLEY ET AL
1 911721430002 THE BLAKE SCHOOL
1311722420033 F T PALLANCH & J V PALLANCH
2011721330001 J W FONS III & K L FONS
2411722320054 ROMENS INTERIORS INC
2011721330098 SUSAN K GROSSMAN
2411722120010 IND SCHOOL DIST NO 274
1911721440038 VALLAFSKY
1911721440076 o E CARUSON ET AL TRUSTEES
2311722130020 J E KUMPULA JR ET AL
2511722140034 T R & J K M BALFANY
2511722140029 JOHN J VESOV1CH ETAL
2411722220069-2 HOPKINS MIDWEST HOTEL L TO PT
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O:\P roj\801570J\correspondence\Reports\Nov 16. RptF.xls
Properties which are Currently Failing
number Street_Description
308 17TH AVE N
313 18TH AVE N
300 21ST AVE N
246 6TH AVE N
15 9TH AVE N
130 ASHLEY RD
110 BLAKE RD S
606 DRILLANE RD
101 INTERLACHEN RD
1605 MAINSTREET
200 MAPLE HILL RD
801 MINNETONKA MILLS RD
100 OAKWOOD RD
202 OAKWOOD RD
202 PARK RD W
509 PARK VALLEY DR E
526 PARK VALLEY DR W
1501 STATE HWY NO 7
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City of Hopkins, Minnesota
.
Pm number Owner name
2411722310089 JOHN R KLATT ETAL
2411722240086 EVA M ROSE
2411722230141 J J KUEHMICHEL & L J LOFTUS
2411722220050 R T KENDALL ETAL
2411722230002 D A MOLDENHAUER ET AL TRSTE
2411722220026 JOHN & PAT MEYER
2411722220024 A & N BRINKHAUS
2411722340129 CITY OF HOPKINS
2411722420011 R GOGIA & J L GOGIA
2411722430044 ALEC JUDE ALBRECHT
2411722140097 ARTHUR E JOHNSON ET AL
1311722440015 HAROLD W COTTLE
1311722420035 EDWARD I STERN - Jim Mackinnin
3011721110002 A M KESSENICH
2411722330012 IND SCHOOL DIST NO 274
2411722120010 IND SCHOOL DIST NO 274
2511722140029 JOHN J VESOVICH ETAL
2411750 Eisenhower Elem School
2411722220069 HOPKINS MIDWEST HOTEL L TD PT
2411722110018 R K MANGOLD & T I MANGOLD
2411722110038 DC WATERS ET AL TRUSTEES
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O:\Proj\801570J\correspondence\Reports\Nov 16, RptWtrBsmnt.xls
Properties with Water in the Basement
number Street_Description
146 10TH AVE N
346 12TH AVE N
337 14TH AVE N
421 14TH AVE N
346 15TH AVE N
422 15TH AVE N
402 16TH AVE N
1010 1ST ST S
102 5TH AVE N
53 7TH AVE S
307 BURNES DR
302 COTTAGE DOWNS
506 DRILLANE RD
250 INTERLACHEN RD
1600 MAINSTREET
801 MINNETONKA MILLS RD
526 PARK VALLEY DR W
1001 STATE HWY NO 7
1501 STATE HWY NO 7
310 WAYSIDE RDW
401 WAYSIDE RDW
1 of 1