A Infiltration-Inflow Improvements
CITY OF
CHANHASSEN
7700 Market Boulevard
PO Box 147
Chanhassen, MN 55317
Administration
Phone: 952.227,1100
Fax: 952,227,1110
Building Inspections
Phone: 952,227,1180
Fax: 952,227,1190
Engineering
Phone: 952,227,1160
Fax: 952,227,1170
Finance
Phone: 952,227,1140
Fax: 952,227.1110
Park & Recreation
Phone: 952,227,1120
Fax: 952,227.1110
Recreation Center
2310 Coulter Boulevard
Phone: 952.227,1400
Fax: 952,227.1404
Planning &
Natural Resources
Phone: 952.227,1130
Fax: 952,227.1110
Public Works
1591 Park Road
Phone: 952,227.1300
Fax: 952,227.1310
Senior Center
Phone: 952,227.1125
Fax: 952,227,1110
Web Site
www.ci.chanhassen.mn.us
A
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MEMORANDUM
TO:
Paul Oehme, City Engineer/Dir. of Public Works
?c9.
FROM:
Alyson Fauske, Assistant City Engineer
DATE:
June 12, 2006
SUBJ:
Infiltration/Inflow Improvements, PW254: Discuss Draft
Feasibility Report
REQUESTED ACTION
Discussion on draft report - no action required.
BACKGROUND
The Metropolitan Council Environmental Services {MCES}has implemented an
Inflow/Infiltration (III) Surcharge Program which will fine municipalities for III to
the MCES facilities. The MCES surcharge for the City ofChanhassen is
approximately $1,559,600.00, to be paid $311 ,920.00/yearforfiveyear.s.
Each year, monies paid by the City to reduce III problems can be credited towards
the MCES surcharge. WSB & Associates has been hired by the City to provide a
Feasibility Report outlining the III issues, recommended remedial measures and
proposed budgets.
Staff will present the content and findings of the Draft Feasibility Rep()rta.tthe
June 12,2006 Work Session.
Also included in the background is a preliminary sewer rate study if the proposed
1&1 improvements were to be implemented and another rate study if no 1&1
improvements are implemented and the City accepts the MCES surcharge.
Attachment: 1. Draft Executive Summary Report
2. 6- Year CIP
3.. Sewer Rate study
Cc: Todd Hubmer- WSB & Associates, Inc.
The City ot Chanhassen . A growing community with clean lakes, quality schools, a charming downtown, thriving businesses, winding trails, and beautiful parks, A great place to live, work, and play,
G:\ENGIPUBLICIPW254 I&Ilbkgd ws 061206 draft report,doc
1. EXECUTIVE SUMMARY
Infiltration and inflow (III) is an increasing problem for the entire Metropolitan Council
Environmental Service (MCES) sanitary service area. Infiltration is clear water (either
storm water or groundwater) which enters the sanitary sewer through cracked sanitary
sewer pipes or damaged manholes, and inflow is clear water from direct connections to
the sanitary sewer such as sump pumps and foundation drains. In response to this
problem, MCES has adopted an III Surcharge program in which municipalities will be
charged for excess clear water flow to the Metropolitan Disposal System. The MCES
Surcharge program will also provide rebates and credits of the surcharges as incentives
for cities to initiate municipal programs to reduce local clear water flow.
The City of Chanhassen has initiated programs to reduce III to the sanitary sewer system.
These programs include sanitary sewer televising, sewer rehabilitation, home inspection
projects, and beginning in 2007, a Street Reconstruction Program incorporating sanitary
sewer repair and replacement. The City completed home inspections in 1999 to identify
direct sump pump and foundation drain connections to the sanitary sewer.
Despite the programs in place to reduce III, the City of Chanhassen is currently exceeding
MCES limits during peak flow events. The major contributing sources of III into the
sanitary sewer system in Chanhassen appears to be infiltration into manholes and
separated joints in the City's trunk system and MCES interceptor. Other contributing
sources of III are reconnecting sump pumps to the sanitary system and possible leaking
joints in service laterals. Therefore, to achieve MCES wastewater flow goals, the City
must continue efforts to reduce the clear water flow into the sanitary sewer system.
These efforts include manhole inspections, sanitary sewer televising, rehabilitation and
replacement projects to repair known points of infiltration and inflow, and home
inspections at point-of-sale and issuance of building permits to verify continued private
residence compliance with the City's ordinances.
Currently, the MCES surcharge amount for the City of Chanhassen is approximately
$1,559,600, to be paid at $311,920 per year for a period of five years. The recommended
minimum City budget for the 6-year III Reduction Program is approximately $2,304,000
and consists of $1,100,000 from the existing street reconstruction CIP; $1,010,000 from
new III Reduction CIP; a general operating budget of $134,000; and MCES Interceptor
televising of $60,000 (plus improvement costs to be determined). The costs accrued by
the City through the III Reduction Program will be eligible for a MCES surcharge rebate
upon approval by the MCES. In addition, costs spent on rehabilitation or reconstruction
of the MCES interceptor may be directly reimbursed by the MCES.
The MCES is currently proposing to impose a demand charge for communities not
meeting III limits by the year 2013. These demand charges are anticipated to be up to 5
times the surcharge fees, and these charges may not be available to the City to correct III,
but will be used by MCES to improve system capacity.
Sanitary Sewer Infiltration and Inflow Redm:tion Plan
City of Chanhassen, MN
WSB Project No. 1694-00
Page 2
City of Chanhassen Table 2
Infiltration and Inflow Reduction Plan
WSB Project No. 1694-00 Cost Opinion
6.Year Capital Improvement Program (CIP) Funding Sources
General Totat
Year Task Existing CtP New CtP Operating MCES
Budget Expenditures
Sanitary Sewer 1&1 Rehabilitation and Reconstruction Program
1. Construct sewer rehabilitation and reconstruction $120,000.00
2. Televise Sanitary Sewer $30,000,00
3. Inspect manholes in low areas and adjacent to lakes and wetlands $30,000.00
2006 4. Develop Sewer Rehabilitation Plan for 2007 $17,000.00
5. Inspection of sump pump connections $2,500.00
5. Public education $2,000.00
Televise MCES Interceptor Through Chanhassen $60,000.00
Subtotat $150,000.00 $0.00 $51,500.00 $60,000.00 $261,500.00
Street Reconstruciton Program (sanitary rehab portion) $200,000.00
Sanitary Sewer 1&1 Rehabilitation and Reconstruction Program
1. Construct sewer rehabilitation and reconstruction $130,000.00
2. Televise Sanitary Sewer $50,000.00
3. Develop Sewer Rehabilitation Pian for 2008 $12,000.00
2007 4. Inspection of sump pump connections $2,500.00
5. Public education $2,000.00
Review and adjust City sewer and water utility charges $25,000.00
Construct Phase I of MCES Sewer Rehabilitation To Be Determined
Evaluate improvements and prepare annual report to MCES $5,000,00
Subtotat $200,000.00 $210,000.00 $16,500.00 $0.00 $426500.00
Street Reconstruciton Program (sanitary rehab portion) $250,000,00
Sanitary Sewer 1&1 Rehabilitation and Reconstruction Program
1. Construct sewer rehabilitation and reconstruction $130,000.00
2. Televise Sanitary Sewer $50,000.00
3. Deveiop Sewer Rehabilitation Plan for 2009 $12.000.00
2008 4. Inspection of sump pump connections $2,500.00
5. Public education ' $2,000.00
Implement adjustments to City sewer and water utility charges $15,000.00
Construct Phase II of MCES Sewer Rehabilitation To Be Determined
Evaluate improvements and prepare annual report to MCES $5,000.00
Subtotal $250,000.00 $200,000.00 $16,500.00 $0.00 $466500.00
Street Reconstruciton Program (sanitary rehab portion) $0.00
Sanitary Sewer 1&1 Rehabilitation and Reconstruction Program
1. Construct sewer rehabilitation and reconstruction $155,000.00
2. Televise Sanitary Sewer $30,000.00
2009 3, Develop Sewer Rehabilitation Plan for 2010 $12,000,00
4. Inspection of sump pump connections $2,500.00
5. Public education $2,000.00
Construct Phase III of MCES Sewer Rehabilitation To Be Determined
Evaluate improvements and prepare annual report to MCES $5,000.00
Subtotal $0.00 $200,000.00 $16,500.00 $0.00 $216,500.00
Street Reconstruciton Program (sanitary rehab portion) $250,000.00
Sanitary Sewer 1&1 Rehabilitation and Reconstruction Program
1. Construct sewer rehabilitation and reconstruction $165,000.00
2. Televise Sanitary Sewer $30,000.00
2010 3, Develop Sewer Rehabilitation Pian for 2011 $12,000.00
4. Inspection of sump pump connections $2,500,00
5. Public education $2,000.00
Evaluate improvements and prepare annual report to MCES $5,000.00
Subtotal $250,000.00 $200,000.00 $16,500.00 $0.00 $466,500.00
Street Reconstruciton Program (sanitary rehab portion) $250,000.00
Sanitary Sewer 1&1 Rehabilitation and Reconstruction Program
1. Construct sewer rehabilitation and reconstruction $165,000.00
2. Televise Sanitary Sewer $30,000.00
2011 3. Develop Sewer Rehabilitation Plan for 2012 $12,000.00
4. Inspection of sump pump connections $2,500.00
5. Public education $2,000.00
Evaluate Improvements and prepare annual report to MCES $5,000.00
Subtotal $250,000.00 $200,000.00 .. $16,500.00 $0.00 $466,500.00
Total CtP Expenditures 2006-2011 $1,100,000.00 $1,010,000.00 $134,000.00 To be Determined $2,304,000.00
Note: Table is based' on available information to date and should be revised annually as new information becomes availabie. Additionai years of Improvements shouid be determined
in future revisions
City ofChanhassen, MN
Infiltration and Inflow Reduction Plan
WSB Project No. 1694.00
K:\OI694-00\Admin\Docs\Table 2 . 6yrCIP.x1s
.
EHLERS
& ASSOCIATES INC
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To: Greg Sticha
From: Jessica Cook and Mark Ruff
Subject: Effects of Infilatration and Inflow on Sewer Rates
Date: June 7,2006
The City has requested that Ehlers & Associates evaluate the impact on sewer rates of
two different scenarios for working with the Metropolitan Council on Infiltration and
Inflow ("I & I") concerns.
To address this problem, the City has already budgeted $75,000 per year from the hook-
up fund to pay for I & I improvements. In addition to being a concern for the met
Council, I & I has increased costs for City residents and businesses. Last year we
estimated that the City pays the Met Council to dispose of 40% more flow than the usage
measured at residents' meters. The difference was attributed to I & I, and the cost gets
passed along to users in the form of higher rates.
Scenario 1: The first scenario is a negotiated improvement plan whereby the City agrees
to make improvements to its system to reduce the amount of! & 1. The costs of the
improvements that exceed the budgeted $75,000 per year have been assigned to the
operating fund, to be paid by users. The improvements should result in a reduction of the
amount of metered flow for which the Met Council charges the City. However,for
purposes of this evaluation, no reduction in the Met Council disposal fees has been
assumed. In theory, the improvements should reduce the outflow, reducing the need to
increase rates.
Scenario 2: The second scenario is that the City pays a $311,000 penalty to the Met
Council each year for five years. The penalty is paid by existing and future users through
fee increases. The connection fund will continue to make budgeted 1&1 improvements,
but not reduction in the Met Council disposal fees has been assumed.
The chart on the next page shows the fee impact for these two scenarios.
3060 Centre Pointe Drive
Rosevi11e, MN 55113-1105
(651) 697-8546 Fax: (651) 697-8555
jcook@ehlers-inc.com
http://www.ehlers-inc.com
Scenario One: Scenario Two:
N e20tiated Improvements Penalty
New 1&1 Costs Year New Improvement Cost $311,000 penalty each year from
(in operating 2006 $75,000 2006-2010.
fund) 2007 $135,000
2008-2011 $ 125,000/year
2005 Study 1&1 Impvts. 2005 Study 1&1 Penalty
Year % Increase % Increase* Year % Increase % Increase
Projected 2005 5.0% 5.0% 2005 5.0% 5.0%
User Rates 2006 8.0% 8.0% 2006 8.0% 8.0%
2007 5.5% 12.5% 2007 5.5% 19.0%
(for an average 2008 5.0% 5.0% 2008 5.0% 5.0%
family that uses 2009 5.0% 4.0% 2009 5.0% 5.0%
9,000 gallons per
month) 2010 5.0% 4.0% 2010 5.0% 5.0%
2011 5.0% 4.0% 2011 5.0% 3.0%
2012 5.0% 4.0% 2012 5.0% 3.0%
2013 5.0% 4.0% 2013 5.0% 3.0%
*Reduced 1&1 may result in lower
rates.
Please note that the purpose of this study was to compare the impact of the two scenarios,
while keeping the cash balance in the fund at the same level as the previous rate study.
Whichever option the Council chooses, rate increases can be "flattened" to minimize the
impact in 2007 and realize some of the benefit of reducing 1&1.
3060 Centre Pointe Drive
Roseville, MN 55113-1105
(651) 697-8546 Fax: (651) 697-8555
jcook@ehlers-inc.com
http://www.ehlers-inc.com