HomeMy WebLinkAboutCity Council Packet 11-23-2010 Special 2.pdfCITY OF PLYMOUTH
AGENDA
SPECIAL COUNCIL MEETING
November 23, 2010
Immediately following Regular Council Meeting
COUNCIL CHAMBERS
1. CALL TO ORDER
2. TOPICS
A. Discuss proposed 2011-2015 Capital Improvement Program
3. ADJOURN
Special Council Meeting 1 of 1 November 23, 2010
rp)City of Agenda Q
Plymouth Number:
Adding Quatity to Life
STUDY SESSION
MEETING
November 23, 2010
To: Laurie Ahrens, City Manager
Prepared by: Doran Cote, P.E., Director of Public Works
Reviewed by:
2011-2015 CAPITAL IMPROVEMENT
Item: PROGRAM (CIP) DRAFT NO. 1
1. ACTION REQUESTED:
None.
2. BACKGROUND:
During discussion on the 2011-2015 CIP Draft No. 1 on November 9, 2009, Council
Member Willis asked for data concerning the cost effectiveness of the annual sanitary
sewer lining project (06 -SS -003).
Sanitary sewer lining is a new technology and preferred method of sewer lateral
rehabilitation that is most often used by professional contractors. The pipe liner
system for sewers was developed to address the issue of relining smaller sized
plumbing and sewer pipes in range of 2" to 8" in diameter. This pipe liner covers the
most popular piping sizes in American for the last 100 years. Fortunately any pipe
material used for plumbing can be relined and the lining technology is suitable for
nearly all plumbing applications.
Sewer Lining systems and plumbing contractors almost always use a PVC -coated
fiberglass pipe liner with a reinforced polyester needled felt tube which has been
filled with a liquid resin for adhesion to the existing plumbing pipe interior. The resin
impregnated tube lining is flipped inside out through a process of true inversion
utilizing compressed air. The resin impregnated tube liner will be inverted (turned
inside out) and pressed tightly against the host pipe until cured. The end result is
seamless pipe lined with PVC from end to end and a near new plumbing system.
Page 1
Sewer liners reduce the possibility of serious damage to underground pipes and
services due to digging and excavations and can repair damaged lateral pipelines and
increase the structural capacity of the pipe without excavation. Sewer lining
eliminates the costs of street paving, concrete repairs and traffic control. Liners can
also restore leaky sewer and pipes, eliminate sewer line root intrusion, close large
holes in sewer pipes, lower overall costs of sewer repair, seal open joints in plumbing
and sewer lines reducing and bridge missing pipes and connections, all of which help
with the reduction of inflow and infiltration (UI).
In June, 2004, the Metropolitan Council Environmental Services (MCES) identified
Plymouth as a community which exceeded our allowable flows due to excessive
inflow and infiltration (UI) and were thus subject to their Inflow/Infiltration
Surcharge Program (Attachment No. 1). Our exceedance, measured at 0.98 million
gallons per day (mgd) attributable to excessive wet weather I/I, resulted in Plymouth
being surcharged $343,000. In accordance with the program, the surcharge was
divided into 5 installments of $68,600 which is credited if efforts are made to reduce
I/I with activities such as sewer lining. This MCES based our surcharge on their
estimated cost of $350,000 per mgd for conveyance, treatment and infrastructure
improvements needed to address excessive 1/I.
Recognizing that UI occurs at points in the system other than the public laterals which
we maintain, studies' have proven that 40% of reduction in inflow can be attained
through an aggressive and comprehensive sewer rehabilitation effort. 30% of that
reduction can be realized through manhole sealing, 43% to mainline defects which
can be addressed with sewer lining and 27% in private service defects. Studies have
also shown that between 8,200 and 9,600 gallons of I/I per year per foot of sewer
renewal (pipe lining, manhole sealing and private service repairs) can be effectively
removed from the system with sewer rehabilitation.
Page 2
Given the proposed funding levels in the 2011-2015 CIP, in 2011 approximately
20,000 feet of sewer could be lined using the method described above. Using the data
from the studies cited, there is a potential reduction of UI of .18 mgd to 0.21 mgd
from sewer lining. Considering the current MCES treatment rate of $2,000 per mgd,
the sewer lining results in a potential savings of $131,000 to $153,300 per year in
treatment costs alone. In addition, the studies cited have shown that there is potential
reduction in operation and maintenance costs of $0.60 to $0.85 per thousand gallons
I/I removed resulting in an additional $40,000 to $65,000 savings.
The Sewer budget includes $4,700,000 for treatment cost paid to MCES. If the 0.98
mgd I/I measured by MCES is occurring daily, there is the potential we are realizing
700,000 annually for unnecessary treatment costs. The cost of doing nothing would
be an annual surcharge of $68,600 unless there is another exceedance, in which case
the surcharge would increase.
1 Evaluation of Sewer Rehabilitation Effectiveness and Materials Selection by James H. Forbes, Jr. P.E. and Craig
Watts, EIT
2 Sewer Renewal — A Strategic Plan as Part of EPA's CMOM Program by George E. Kurz, P.E., DEE, Paul
Stonecipher, P.E., Brent Freeman, P.E., and Greg Ballard, P.E.
3. BUDGET IMPACT:
Sanitary sewer lining has been performed annually since 2006 with funding levels
increasing from $200,000 in 2006 to $400,000 in 2010. The 2011-2015 CIP Draft
No. 1 proposes funding to continue to increase from $500,000 in 2011 to $710,000 in
2015. The 2030 Comprehensive Plan suggests that funding be targeted at $1,000,000
per year for sewer lining (Attachment No. 2).
The Sewer budget includes $4,700,000 for treatment cost and $30,000 for manhole
sealing.
4. ATTACHMENTS:
Attachment No. 1 — MCES Inflow/Infiltration Surcharge Program
Attachment No. 2 — 2030 Comprehensive Plan, Appendix Chapter 9E — Cost and
Funding Information
Page 3
Metropolitan Council Environmental Services
PREL 11VINA R Y
INFLOW/INFILTRATION
SURCHARGE PROGRAM
October 24, 2005
JJA Metropolitan Council
II Environmental Services
230 East Fifth Street St. Paul, Minnesota 55101-1626 (651) 602-1005 Fax 602-1138 TTY 291-0904
Page 4
Metropolitan Council Members
Chair:
Peter Bell
Council Members:
Roger Scherer District 1 Natalie Steffen District 9
Tony Pistilli District 2 Vacant District 10
Mary H. Smith District 3 Georgeanne Hilker District 11
Julius C. (Jules) Smith District 4 Chris Georgacas District 12
Russ Susag District 5 Richard Aguilar District 13
Peggy Leppik District 6 Song Lo Fawcett District 14
Annette Meeks District 7 Daniel Wolter District 15
Lynette Wittsack District 8 Brian McDaniel District 16
Council Regional Administrator
Thomas Weaver
General Manager, Environmental Services Division
William G. Moore
The mission of the Metropolitan Council is to develop, in cooperation with local communities, a
comprehensive regional planning framework, focusing on transportation, wastewater, parks and
aviation systems, that guides the efficient growth of the metropolitan area. The Council operates
transit and wastewater services and administers housing and other grant programs.
Cover Photo: Overflow out of a manhole as a result of excessive
Inflow/Infiltration overloading an interceptor.
Page 5
Table of Contents
Section One: Introduction............................................................................................1
Background Information.........................................................................................................2
1/1 Task Force Conclusions and Recommendations..............................................................3
NoticeLetters...................................................................................................................3
SectionTwo: 1/1 Policy...................................................................................................5
1/1 Policy and Corresponding Financial Implementation Strategies........................................5
Policy................................................................................................................................5
Fiscal Implementation Strategies.....................................................................................5
Section Three: 1/1 Costs to the MDS..........................................................................9
KeyAssumptions...................................................................................................................9
Procedure for Estimating 1/1 Storage Volumes.......................................................................9
Procedure to Estimate Treatment Plant Costs.....................................................................10
Procedure to Estimate Local Cost for 1/1 Reduction.............................................................11
Total Costs for Surcharge Program...............................................................................12
Section Four: The Surcharge Program...................................................................13
Costsand Implementation...................................................................................................13
TheSurcharge Program......................................................................................................13
2007 Surcharges............................................................................................................13
2008-2011 Surcharges..................................................................................................14
SurchargeExample........................................................................................................14
Surcharge Reserve/Contingency Fund..........................................................................15
Rebate or Avoidance of Surcharges..............................................................................15
Appeals..........................................................................................................................16
Community Exceedence Costs............................................................................................16
Appendix A: Definitions and Acronyms..................................................................19
Appendix B: Possible Control Strategies...............................................................21
Appendix C: Case Studies of 1/1 Related Costs....................................................23
Appendix D: Inflow/Infiltration Surcharge Program
Option B Agreement(Conceptual)..................................................25
Tables
Table 1: Preliminary I ITC and 2007 Surcharge...................................................................17
Page 6
f .: Section One
Introduction
The Metropolitan Council, through its Environmental Services Division (MCES), owns and
operates extensive interceptor systems, as shows
wastewater flow to the Metro Wastewater
Treatment Plant (WWTP) and serves 65
communities. Smaller systems convey flow to
the Council's plants in Shakopee (Blue Lake),
Eagan (Seneca), Empire, Cottage Grove
Eagles Point), Rosemount and Oak Park
Heights (St. Croix Valley). There is no
interceptor system for the Hastings plant.
More than 100 communities own and operate
local sewer systems that are connected to the
MCES regional interceptor system. Through
these local systems, wastewater service is
extended to residents, commercial
establishments, industry, and public agencies.
These end users are charged for this service
by the local community, which typically
charges for wastewater on the basis of metered water use. MCES, as a wholesaler of the
regional services, bills each community on the basis of its metered wastewater flow in the
interceptor system. Industries with high strength waste are billed individually by MCES for
the strength charge portion of their charges.
Each community bills its customers to recapture the cost charged by MCES and the costs to
maintain and operate the local sewers. Because MCES bases its charge for service on the
volume of wastewater received, these charges include any clear water entering the sewer
system as well as the wastewater generated by the customers. Clear water includes rain water
that enters the local sewer system through leaks in the publicly owned sewer and manholes
and from private property sources such as rain leaders, sump pumps, foundation drains, and
leaking house laterals. MCES flow records show a direct correlation between precipitation
and the volume of flow from many communities served by the regional wastewater system.
The addition of clear water into the local sewer systems creates two problems.
First, the additional flow uses system capacity that was originally designed for growth.
For this reason, MCES charges communities the same rate for a community's clear water
as it does for its wastewater.
Second, in some cases the additional flow may exceed the available sewer system
capacity. When the capacity of the sewer is exceeded, the wastewater may back up into
basements or spill out of manholes. These occurrences may result in problems for MCES
under federal and state regulations.
Page 7
Communities have legal, fiscal, and public health reasons for assuring that the total system
functions effectively and conforms to federal and state regulations.
Background Information
Sewers, pump stations, and treatment plants are designed to convey and treat wastewater.
The capacity or size of the facilities is dependent on the flow rate of the wastewater. For
conveyance facilities, the flow rate is usually the maximum rate expected for a one-hour
duration. For treatment plants, the facilities must handle not only the maximum hourly rate,
but the processes are designed to meet permit limits, usually specified as a peak month
condition. Consequently, the maximum 30 day average flow is important for sizing treatment
plants. The introduction of non -contaminated, clear water (I/I) into the collection system
increases the flow of the wastewater and consumes capacity of sewers, pump stations and
treatment plants. Although some allowance of I/I is included in the design for MCES'
interceptors and treatment works, whenever the rate of I/I exceeds the initial basis of the
design, all or a portion of the capacity allocated for growth is no longer available. In such
case, either larger facilities need to be constructed, excess I/I needs to be eliminated, or
growth needs to be curtailed.
A comprehensive master plan for the MCES interceptor systems was completed in December
2002. One of the more significant findings of the study was that groundwater and rainfall
runoff were entering the local collection systems at rates that sometimes will overload the
interceptor system. This uncontaminated clear water, called Infiltration/Inflow (I/I), is
consuming interceptor and treatment plant capacity originally designed to serve future
development. During significant rainfall events, portions of the interceptor system are at risk
of causing a backup of wastewater into basements or spilling wastewater into the
environment.
The master planning study for the interceptor system provided an opportunity to examine the
long-range implications of continuing to tolerate the current levels of I/I as development
continues in the region. During that examination, improvements to the MCES interceptor
system were looked at in two scenarios. Under the first scenario, it was assumed that the
level of I/I would be reduced to conform to the basis of the system's design. Under the
second scenario, it was assumed that the I/I would remain at current levels. The cost to
provide interceptor capacity that would serve regional growth under the latter scenario (based
on 2030 ultimate development) was estimated at approximately half billion dollars more than
the first because of the need to construct relief sewers and expand pump stations to handle
high peak flows resulting from excessive I/I.
However, the impact of I/I is also substantial at the treatment plants. Even if the interceptor
system capacity were expanded as assumed under the second scenario, the hydraulic capacity
of the Metro wastewater treatment plant could not be doubled to treat the resulting peak rate
from excessive I/I. Similarly, the hydraulic capacity of the Blue Lake plant may be
constrained by the current site. Therefore, simply expanding the interceptor system (the
second scenario) in conjunction with increasing treatment works capacity is not a feasible
option.
Since curtailment of growth was considered highly undesirable, Council staff assessed the
problem and concluded that the only viable engineering and regulatory options for the long -
Page 8
term service of the region are either 1) to eliminate excessive I/I flows at the source, or 2) to
store excessive I/I near its source in order to eliminate peaking and then treat the flow. The
practical limitations to expanding the system, the high cost of relief sewers, larger pump
stations and larger treatment facilities, and the impending federal requirements (Capacity,
Management Operations, and Maintenance or CMOM, etc.) on elimination of overflows
supported this conclusion. As discussed later in this program document, the former option
i.e., eliminating excessive I/I flows at the source) is the preferred option from an economic
standpoint.
With this background in mind, staff recommended the formation of an I/1 Task Force.
1/1 Task Force Conclusions and Recommendations
On April 8, 2003, the Metropolitan Council appointed the Infiltration and Inflow Task Force
headed by Council Member Russ Susag, District 5. The Task Force included representatives
from 15 communities from across the region as well as the Association of Metropolitan
Municipalities. Individuals on the Task Force from the different communities serve "at
large." The I/I Task Force membership, charter and full process and findings can be found in
the May 2004 Inflow/Infiltration Task Force Report at
http://www.metrocouncil. org/environment/Proj eetTeams/I-I-Home.htm
The Task Force concluded and recommended that the Metropolitan Council adopt an I/I
policy and corresponding implementation strategies to reduce excessive I/I from the
Metropolitan Disposal System (MDS).
Notice Letters
Since the beginning of June 2004, MCES has been sending letters to the public works
departments of municipalities for
1) actual excessive I/I events, or
2) potential peaking events that would have exceeded the allowable I/I limits had they
occurred at the normal high flow point in the daily (diurnal) cycle.
MCES will continue this practice throughout this program.
Page 9
Section Two
I/I Policy
1/1 Policy and Corresponding Financial Implementation Strategies
Based on direction from the I/I Task Force recommendations and statutory authority
Minnesota Statutes, Section 473.145), the Metropolitan Council—as part of the 2030
Development Framework and the Water Resources Management Policy Plan—adopted the
following policy and fiscal implementation strategy associated with the reduction of
excessive I/I in the metropolitan disposal system.
Policy
The Council will not provide additional capacity within its interceptor system to serve
excessive inflow and infiltration.
The Council will establish inflow and infiltration goals for all communities discharging
wastewater to the Metropolitan disposal System based on the designed peak -hour capacity of
the interceptor(s) serving the community. Communities that have excessive inflow and
infiltration in their sanitary sewer systems will be required to eliminate the excessive inflow
and infiltration within a reasonable time period.
Fiscal Implementation Strategies
In order to address this problem, the Council will take a twofold financial approach to the
excessive 1/I problem. In the first place, the Council will plan and prepare for a future where
sufficient I/1 has not been removed from the system, resulting in a need to build storage
facilities and provide treatment for excess I/1. In such a case, substantial capital
improvements would be necessary to ensure system integrity and the ability to meet growing
demand. This planning and preparation will include the establishment of a
reserve/contingency fund to make available funds, which may be necessary to carry out
capital improvements in the MDS. These funds would address the effects of excessive
community inflow and infiltration should community efforts be insufficient. Second, the
Council will establish financial incentives to encourage and assist those communities with
excessive 1/I in their systems to eliminate the sources of I/I.
Accordingly, the Council will initiate an inflow and infiltration removal program
commencing in 2007. This program will consist of four elements:
Element 1–Imposition of Inflow/Infiltration Surcharge. The first element will be the
immediate imposition of an inflow and infiltration surcharge for communities
experiencing high I/I commencing in 2007 and extending through 2012. The process by
which communities will be designated to have excessive I/I and the amount of the
surcharge is described in greater detail later in this program document. Funds raised by
the inflow and infiltration surcharge program will be placed in a reserve contingency
fund to be used for future capital improvements to address the capital improvements
necessary to address the impacts of excessive I/I on the system and for treatment works
costs associated with excessive I/I, should that become necessary.
Page 10
Element 2—Incentives for Communities to Remove Excessive Infiltration/Inflow.
MCES has determined that the cost to the region as a whole for I/I remediation is most
cost-effectively accomplished through the removal of excessive I/I at the local level. If
successful, this approach would obviate or greatly reduce the need for expensive capital
expenses for additional MCES facilities and the cost to treat I/I at the Council's treatment
facilities. Accordingly, MCES will work with communities with excessive I/I in order to
encourage the initiation and implementation of inflow and infiltration reduction programs
in those communities' local systems. As an incentive to initiate and implement such
programs, during the period in which the surcharge is imposed (2007 — 2011) the Council
will provide an opportunity for communities that are subject to the excessive I/I
surcharge to avoid the financial effects of the surcharge using either Option A or Option
B as listed below:
Option A. Beginning in 2008 and through 2014, a community will be eligible for a
rebate of the surcharges imposed by the Council on that community up to the amount
the community demonstrates has been spent for the removal of excessive I/I at the
local level.
Option B. Alternatively, the Council will allow a community with an inflow and
infiltration reduction program in place to continue with its program and receive a
credit against the surcharges to be imposed by the Council on the community in each
calendar year. This will allow a community to undertake activities for inflow and
infiltration reduction using local funds and not pay the surcharge amount, as long as
those funds are equal to or greater than the proposed surcharge amount. The
Council's I/I policy encourages I/I reduction programs to be a part of and consistent
with each community's 2008 comprehensive plan. Communities could choose this
alternative approach to avoid the Council's I/I surcharge by undertaking voluntary
I/I reduction programs that are funded at the same or greater level as the surcharge
amount. Under this approach, a community enters into an agreement with MCES to
obligate local funds to undertake the same or greater effort for I/I reduction.
Element 3—Limitation on Increases in Wastewater Service. Starting in 2013, the
Council will limit future increases in wastewater service within each community that has
not met the inflow and infiltration goal(s) set by the Council, until the problem is solved.
This limitation will be implemented by, among other possible means, the Council
recommending to the MPCA that no new sanitary sewer extensions should be approved
for such community until the community's I/1 problem has been resolved. Prior to taking
such a step, MCES will work with those communities not meeting I/I goals on a case-by-
case basis. The Council anticipates that all communities served by the MDS should be
able to reduce their excessive I/I and meet the established I/I goals by the end of 2012. If
a community's I/I program has not been effective, and its excessive I/I continues at a
level that either jeopardizes the ability of MCES to convey wastewater without an
overflow occurring or requires additional wastewater service capacity, MCES will notify
the community of the problem. Meetings with the community will be held and attempts
made to arrive at an acceptable local solution to the problem.
Element 4—Imposition of I/I Demand Charge. Starting in 2013, the Council will
institute a wastewater demand charge program for those communities that have not met
their inflow and infiltration goal(s). The intent of the program will be to defray the cost of
Page 11
providing attenuation within the MDS to avoid overloading downstream facilities. MCES
will continue to review communities' progress and work with them on a case-by-case
basis. The Council will design the needed storage and capacity improvements to avoid
overloading downstream facilities. Funds remaining in the surcharge reserve/contingency
fund will be available to defray the costs of these improvements. Any additional costs to
MCES to control, convey and treat the peak flow will be charged to the community as
demand charge(s).
Page 12
Vt , ^ Section Three
1/1 Costs in the MDS
Key Assumptions
The following assumptions address the costs of managing excessive I/I throughout the MDS.
Costs to store and treat excessive I/I were estimated, as were costs to reduce I/I at the
community level. Several key assumptions are needed to estimate these costs until more
information is available. These assumptions are as follows:
Excessive I/I that causes peak flows to exceed the basis of design of the interceptor
system would be stored underground at each point of connection to the interceptor system
rather than conveyed in larger sewers and pump stations.
The primary impact of high levels of I/I at the treatment plants is the increase of the
monthly average flow. Within the MDS, the peak monthly I/I flows at Seneca, Empire,
and Hastings are calculated to be about 30 gallons per capita per day (gpcd). For purposes
of estimating the cost of treating excessive I/I, monthly I/I flows exceeding 30 gpcd are
deemed excessive.
The capital cost of storage is estimated at $2 to $3 per gallon, depending on the size of
the storage basin required. Duluth recently constructed 2 million gallons (MG) of storage
for approximately $2 per gallon, but this did not include the engineering, legal and
administrative costs. In addition, the facility is near the ground surface and land costs
were not included.
The capital cost of treating I/1 is estimated at $2 to $3 per gallon per day (gpd), based on
actual costs of $3.50 to $5.00/gpd to expand large MCES treatment plants, and estimating
that 40% of the cost is associated with solids management and the strength of the
wastewater.
Most communities have addressed I/I in the publicly -owned system but have not
implemented effective programs to reduce I/I from private property (sump pumps,
foundation drains and leaky house laterals). For those properties contributing I/I, it is
estimated that, on average, the peak hour flow is increased about 6 gallons per minute
gpm) per connection.
Procedure for Estimating 1/1 Storage Volumes
The Interceptor Master Plan for MCES included characterizations of the sewersheds tributary
to the interceptor system relative to rainfall dependent I/I. These characterizations were used
as part of a hydrologic model to generate wet weather flow hydrographs for different design
storms. When added to the dry weather base flow, the combined hydrograph represents the
total flow entering the interceptor system. If the peak flow exceeds the peak flow allowed by
applying the correct MCES peaking factor, the difference is deemed "excessive". For
purposes of estimating the cost to manage the "excessive" I/I, the excess flow is assumed to
be diverted to below ground storage and subsequently pumped back into the interceptor after
the flows recede.
Page 13
The procedure used to estimate the storage volume starts with the sewershed
characterization. For each sewershed the ultimate average dry weather flow was calculated at
the net developable acreage and was multiplied by a wastewater generation rate. These
ultimate average dry weather flows were given a standard diurnal flow pattern, as indicated
below.
1.6
1.4
1.2
30
LL 1
mm
d
a 0.8
00
LL
0 0.6
Ua
0.4
0.2
Dry Weather Diurnal Pattern
01
12:00 12:00 12:00 12:00 12:00 12:00 12:00 12:00 12:00 12:00 12:00 12:00 12:00 12:00 12:00
AM PM AM PM AM PM AM PM AM PM AM PM AM PM AM
Time
A rainfall dependent hydrograph was simulated for each sewershed for a 25 -year rain event,
using the characterization of the sewershed developed as part of the Interceptor System
Master Plan. This I/1 hydrograph was added to the dry weather hydrograph to generate a wet
weather hydrograph reflecting ultimate development and current I/1 levels in the sewershed.
The wet weather hydrograph was compared to the allowable peak flow (ultimate average
flow times the appropriate MCES peaking factor). Flow above the allowable peak rate was
assumed to go into storage. The total storage estimated in this manner is about 300 million
gallons and the estimated capital cost for storage is approximately $700 million to manage
the current level of I/I for a 25 -year spring storm.
Additional metering data will help refine the estimates of storage needed. For example, the
characterization of the I/I from St. Paul is primarily based on one metershed.
Procedure to Estimate Treatment Plant Costs
Daily flow records for the regional plants were analyzed for a 10 -year period to estimate the
I/I contribution. For each plant analyzed, the wastewater generated from residences was
estimated as 70 gpd/capita times the estimated connected population. Commercial flow was
estimated as the employment population times 30 gpd/employee. The difference between the
recorded flow and the estimated wastewater generation was assumed to be I/I. As indicated
10
Page 14
below, the peak month I/I at Blue Lake WWTP reached 19 mgd in 2001. This was
approximately 80 gpd/capita. At the Metro Plant, the peak month I/I is estimated to have
reached 70 gpd/capita and at the St. Croix Valley WWTP, the value is near 60 gpd/capita.
For areas that do not have excessive I/I, the peak month I/I is approximately 30 gpd/capita.
Currently, systemwide excess I/I requiring treatment is approximately 80 million gallons per
day (mgd).
Inflow/Infiltration becomes part of the wastewater to be fully treated. Most of the liquid
treatment process in a wastewater treatment plant is sized based on hydraulics (flow rate),
and comprises approximately 60% of the capital cost of a wastewater treatment plant, or $2-
3 per gallon per day of capacity. Estimated capital costs for treatment is approximately $200
million (in addition to the costs for collection and storage of excess I/I).
20.00
18.00
16.00
14.00
12.00
E
10.00
Mv
0M
8.00
6.00
4.00
2.00
0.00
Blue Lake Peak Month 1/1
1992
1993
1994
1995
1996
1997
1998
111999
2000
2001
112002
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Month
Procedure to Estimate Local Cost for 1/1 Reduction
The cost to eliminate I/I from a foundation drain can range from several hundred dollars
disconnect the discharge from the sump pump) to $8,000 for installing a new outside sump
pump, curb side receiver, and yard restoration. For purposes of estimating the total cost of
eliminating I/I from private property, an average cost of $3,000 is assumed. The number of
private property sources within the MDS is largely unknown, but has been estimated from
the I/I characterization work done for the Interceptor Master Plan. The peak hour flow for a
25 -year rain event was simulated using a hydraulic model calibrated with MCES meter data.
Excessive peak hour I/I is estimated at 400 mgd, which is equivalent to 300,000 gpm. If each
connection is contributing 6 gpm to the peak hour flow (based on observed results in a
11
Page 15
2004/2005 I/I program in the City of Forest Lake), there would be about 50,000 connections
to repair. At a cost of $3,000 per connection, the cost to eliminate the I/I at the source could
reach $150 million.
This estimate can be refined as communities begin to assess the causes of high peak flows
associated with rainfall.
Total Costs for Surcharge Program
The lower of 1) the sum of MDS storage and treatment costs ($900 million) and 2) the
estimate of local costs to remove I/I ($150 million) was used as the target of
reserve/contingency funds for the MDS that must be raised through the Surcharge Program.
12
Page 16
i&'A Section Four
The Surcharge Program
Costs and Implementation
It has been estimated that if excessive I/I is not eliminated at its source it will cost the Region
approximately $900 million to construct storage facilities and expand wastewater treatment
plants to contain and treat the excessive I/I. MCES intends to begin collecting
reserve/contingency funds that will allow management of 1/I within the MDS, beginning with
the Surcharge program.
The modeling efforts of the Council show that during a 25 -year wet weather event the
projected peak hourly rate of I/I exceeds the allowable rate by approximately 300,000 gpm.
Staff has estimated that it will cost approximately $150 million for the communities and
private parties to eliminate the excessive I/I at its source or about 15% of what MCES would
have to pay to collect and treat it. Thus, MCES contingency fund raising can be targeted to
150 million in the 2007-2011 time frame. Should the Surcharge and other I/I programs not
succeed by 2012, the higher amount (adjusted by mitigation efforts to date) will need to be
raised through a Demand Charge that will be instituted in 2013.
The Surcharge Program
Using the $3000/connection average cost and the estimate of a 6 gallon per minute (gpm)
average reduction in peak flow for an average disconnection (see section 3), the estimated
exceedance cost of $500 per gpm was developed. Converted to million gallons per day (mgd)
this is approximately $350,000 per mgd of exceedance. $350,000 per mgd of excess I/I will
be the "Exceedance Rate" for 2007. This same rate will be applied to each municipality that
has one or more I/I exceedance events recorded for them since the measurement and notice
program began June 1, 2004.
2007 Surcharges
The 2007 Surcharge for each community will be equal monthly charges based on the
following:
Municipal 2007 Surcharge = Community's 1/1 Total Cost (IITC) Estimate / 60 months
Where:
Community's IITC Estimate = (Max Excess 1/1 Peak Flow Event) x (Exceedance Rate)
Max Excess 1/1 Peak Flow Event = Maximum Exceedance measured in the program
through June 30, 2006
Exceedance Rate for 2007 = $350,000 per mgd
The 2007 Surcharge will be imposed for 5 full billing years (2007-2011) and will not be
changed unless:
1) the municipality demonstrates to MCES, through the appeal process, that the amount is
not necessary to fix all the I/I problems in the municipality, or
2) that the full 2007 IITC has been spent earlier than 2011.
13
Page 17
These surcharges will appear on the monthly wastewater bills for 2007-2011 as "2007 I/I
Surcharge" unless offset by credits as described below.
2008 — 2011 Surcharges
New Surcharges will be initiated in subsequent years of the program if higher I/I peak events
occur in the intervening flow years (e.g. Billing year 2008 corresponds to flow from July 1,
2006 to June 30, 2007). The same Surcharge formula (as for 2007, above) will be applied
with the following changes:
Instead of 60 months, the number of months remaining in the program for which the
municipality may be surcharged will be used. For a Surcharge imposed in 2008 this will
be 48 months; for 2009, 36 months; for 2010, 24 months; and for 2011, 12 months.
The Exceedance Rate will be increased by inflation each year, using the most recently
available CPI -U for the Region per the federal Bureau of Labor Statistics. In addition, the
Council may increase or decrease the rate if subsequent engineering analysis determines a
materially different average cost.
The Max Excess I/I Peak Flow Event will be the increment over the Max used to
previously assess Surcharges, if any. If there were no prior Surcharges, then the entire
peak flow event will be used.
Municipalities should understand that the Surcharges will be based on actual wet weather
events. If little wet weather occurs in a particular municipality they may have little or no
Surcharges. However, a serious I/I problem may exist that will incur substantial expense
once the Demand Charges begin in 2013. The responsibility to fix the problems and avoid
such Demand charges resides entirely with the municipalities.
Surcharge Example
City X has had three I/I events occur since June 1, 2004 and to date, as follows:
June 9, 2004 .139 mgd
July 11, 2004 .120 mgd
July 23, 2005 .130 mgd
If no other I/I events occur before the close of the initial flow period (June 30, 2006), the
maximum event will be the .139 mgd event. This peak exceedance times the Exceedance
Rate ($350,000 per mgd for 2007) equals this city's IITC of $48,650. This implies a "2007
surcharge" of $9,730 per year for each year 2007 — 2011. Thus in 2007, in addition to the
municipal wastewater charge, the city will see an additional "2007 Surcharge" line item for
810.83 on its monthly bill.
If in the flow period for 2008 billing (July 1, 2006 — June 30, 2007), the only additional I/I
event(s) that occur are less than .139 mgd, then the 2008 billing will continue to include only
the "2007 Surcharge" of $810.83/month.
If during the flow period for the 2009 billing (July 1, 2007 — June 30, 2008), additional I/I
event(s) occur which exceed the prior max (of .139) then an additional surcharge will occur,
as follows:
New 1/1 events: August 1, 2007 .202 mgd
August 2, 2007 .215 mgd
14
Page 18
The new maximum event is the .215 mgd number which is .076 mgd higher (the increment)
than the prior max (which has already been surcharged). This incremental peak will be
multiplied by the then current Exceedance Rate. If the Exceedance rate is $370,000 (because
it inflated), the incremental IITC estimate is $28,120. As there would be only 3 years
remaining, the additional monthly surcharge would be $781.11. So on a monthly bill in 2009
there will be three line items: the municipal wastewater charge, the "2007 Surcharge" of
810.83, and the "2009 Surcharge of $781.11.
If during the flow period for the 2010 and 2011 billings there are no I/I events higher than the
215 mgd event, there will be no additional surcharges added. The 2007 and 2009 Surcharges
will be applied each month until the end of 2011.
Surcharge Reserve/Contingency Fund
All funds received by the Council under the Surcharge Program will be placed in a Surcharge
Reserve/Contingency Fund to be used for the purpose of managing I/I within the MDS
system if local efforts to remove I/I are unsuccessful. The Council will maintain separate
bookkeeping accounts for each community making surcharge payments. Each account shall
include any amounts paid by the community and a proportionate share of any interest earned
by the Surcharge Reserve/Contingency Fund.
Rebate or Avoidance of Surcharges
Communities subject to the Council's surcharges may recover or avoid all or a portion of
their allocated surcharge in two ways.
Option A (Rebates)
Municipalities may receive rebates of funds, including interest, in their bookkeeping account
in two situations:
1) Municipalities may receive a rebate of funds equal to the amount of eligible expenditures
made by the community. Eligibility requirements will be the same as for Option B
described below. Each municipality may apply at any time during a program year (but
only once a year) for a rebate from their community's bookkeeping account.
2) In the fall of 2012, 2013 or 2014, if no excess I/I events have been recorded for the
municipality in the three prior years, the full amount of any funds, including interest,
remaining in a community's bookkeeping account will be rebated to the municipality.
NOTE: The Council intends to begin a "Demand Charge" for excess I/I in 2013. Surcharge
accounts and rebates will not be altered by the initiation of the Demand Charges.
Option B (Credits)
MCES will prepare a standard I/I mitigation agreement that municipalities (that have been
surcharged) may sign to offset each Surcharge. This agreement will provide a credit against
the Surcharge amount for the coming year(s) and may entirely eliminate the billing. It will
require that municipalities spend other funds and/or require private party spending in an
amount equal to the credit. Eligible spending shall include budgeted direct staff costs for I/I
inspection or engineering (but not administrative overheads) as well as the cost of loans or
grants to private parties. Private party costs will be eligible based on standard costs
15
Page 19
determined by MCES (e.g. $5000 for a foundation drain or $500 for a sump pump
connection).
Appeals
Municipalities may appeal their Surcharges to the Regional Administrator of the Council,
within 90 days of being notified of the charges, in the following circumstances:
community expenditures (after June 2004, and before June 30, 2006) have fixed some
problems and should be taken into account,
extenuating circumstances caused the I/1 event(s) and the event(s) should not be counted
or should be reduced,
the Exceedance Rate is more than needed to fix the community's IITC, because the
specific fixes needed in the municipality, per an engineering study, will cost less than the
exceedance rate, or
the determination by MCES that some costs are ineligible costs, (if the community
believes these expenditures will contribute to the reduction of their IITC).
Community Exceedance Costs
In the I/I Task Force Report the Council provided a list of communities whose measured
peak flows during major wet weather events in 2001 and 2003 would have exceeded the
established I/I goals for their communities. Since June 2004, MCES has been monitoring
specific wet weather events and notifying those communities whose peak hour flows have
exceeded their I/I goals. The following table is a list of all communities whose peak hour
flows have exceeded the allowable I/I in either of these periods. Those communities that
have exceeded their I/I goals and received at least one letter from the Council since June
2004 are shown with the preliminary proposed surcharge listed. As wet weather events occur
the Council will continue to monitor the flows from all the communities within the
Metropolitan Disposal System and update the list through June of 2006 for the 2007
surcharge billing.
16
Page 20
Table 1. Preliminary IITC and 2007 Surcharge: Based on data through October 5, 2005
Municipalities not appearing on this list may also have excessive UI; it is recommended that
all municipalities adopt control strategies as discussed in Appendix B.
City
Actual Max
Flow Event(1)
mgd)
IITC at $350,000
per Excess
mgd
2007
Preliminary
Surcharge(1)
2007
Potential %
Inc. due to
Surchrg.(1)
High
Risk
of
Inc.
Apple Valley 2.94 1,029,000 205,800 9.7%
Arden Hills 1.43 500,500 100,100 17.2%
Bayport 0.28 98,000 19,600 6.5%
Bloomington 0.72 252,000 50,400 0.9%
Burnsville 0.26 91,000 18,200 0.6%
Chanhassen 4.46 1,559,600 311,920 21.7%
Chaska 0.82 287,000 57,400 4.5%
Columbia Heights 1.17 409,500 81,900 9.9%
Eagan 6.03 2,110,500 422,100 11.9%
Eden Prairie 3.95 1,382,500 276,500 10.2%
Edina 1.49 521,500 104,300 2.9%
Excelsior 0.79 277,900 55,580 42.6%
Farmington 0.80 280,000 56,000 6.9%
Forest Lake (2) 0 0 0 0.0%
Fridley 0.27 95,900 19,180 0.7%
Golden Valley 5.43 1,900,500 380,100 27.0%
Greenwood 0.24 84,000 16,800 44.2%
Hopkins 1.28 448,000 89,600 9.0%
Lakeville 3.09 1,081,500 216,300 9.5%
Lauderdale 0.31 108,500 21,700 20.5%
Lexington (2) 0 0 0 0.0%
Lilydale 0.36 126,000 25,200 58.6%
Little Canada (2) 0 0 0 0.0%
Long Lake 1.30 455,000 91,000 58.4%
Maple Grove 1.22 427,000 85,400 2.8%
Maple Plain 0.25 87,500 17,500 8.8%
Maplewood 3.36 1,176,000 235,200 9.5%
Medicine Lake 0.13 45,500 9,100 29.3%
Medina 0.43 151,550 30,310 25.4%
Mendota 0.04 15,400 3,080 30.9%
Minneapolis 103.00 36,050,000 7,210,000 24.7%
Minnetonka 4.90 1,715,000 343,000 10.0%
Analytical modeling shows a good chance for substantial increases.
17
Table continued on next page
Page 21
Table 1. Continued
City
Actual Max
Flow Event(1)
mgd)
IITC at
350,000 per
Excess mgd
2007
Preliminary
Surcharge(1)
2007
Potential %
Inc. due to
Surchrg.(1)
High
Risk
of
Inc.
Minnetonka Beach 0.38 134,400 26,880 73.9%
Mound 0.16 56,000 11,200 2.0%
New Brighton 0.39 136,500 27,300 2.3%
New Hope 0.14 49,000 9,800 0.8%
Newport 1.64 574,000 114,800 89.8%
North St. Paul (2) 0 0 0 0.0%
Oakdale 2.77 969,500 193,900 12.9%
Orono 1.28 448,000 89,600 29.3%
Plymouth 0.98 343,000 68,600 1.6%
Roseville (2) 0 0 0 0.0%
Savage 0.82 287,000 57,400 4.5%
Shoreview 1.23 430,500 86,100 5.6%
Shorewood 4.78 1,673,000 334,600 69.6%
South St. Paul 5.67 1,984,500 396,900 19.2%
St. Anthony 3.42 1,197,000 239,400 55.1%
St. Bonifacius 0.26 92,050 18,410 14.5%
St. Paul 93.70 32,795,000 6,559,000 50.8%
Stillwater 1.20 420,000 84,000 7.1%
Tonka Bay 0.13 45,500 9,100 6.4%
Vadnais Heights 0.84 294,000 58,800 7.9%
Waconia 2.14 749,000 149,800 31.4%
Wayzata (2) 0 0 0 0.0%
West St. Paul 1.89 661,500 132,300 10.4%
White Bear Lake (2) 0 0 0 0.0%
White Bear Township 0.09 31,500 6,300 1.1%
Woodbury 0.14 49,000 9,800 0.4%
Total 275 96,186,300 19,237,260
Notes: (1) These 2007 surcharge amounts will be increased if excessive 1/1 events occur after
October 5, 2005 and before July 1, 2006.
2) Municipalities that appear on the list with no actual flow event numbers, have exceeded
their 1/1 goals in 2001 or 2003 and, therefore, MCES believes they are vulnerable to
excessive 1/1 events.
Analytical modeling shows a good chance for substantial increases.
18
Page 22
Appendix A
Definitions and Acronyms
CMOM: Capacity, Management, Operations, and Maintenance federal regulations.
Regulates Sanitary Sewer Overflows (SSOs). Will become part of NPDES permit
requirements. Will require creation and maintenance of a plan to demonstrate a
governmental unit's ability to plan and manage its sewer system effectively, and maintain
its integrity so that it has adequate capacity and stays in good condition over the years.
Demand Charge: A demand charge is the amount that MCES will charge a community
starting in 2013) for the cost of excess capacity paid by MCES, because of the
community's excessive I/I. The charge is not a penalty; it is based on MCES' cost of
service for providing improvements that were the community's responsibility.
Design Average Flow: The design average flow is calculated as the product of the
developable area of the long-term service area times 800 gallons per acre per day. This
value represents an annual average flow from a service area at long-term development.
Design Peak to Average Flow Ratio: The ratio of the peak hour flow used for hydraulic
design divided by the design average flow. MCES has adopted a table (Attachment No. 1)
that identifies the Design Peak to Average Ratio to be used for ranges of design average
flows.
Exceedance Rate: The charge per mgd of excessive I/I (per Section 4 of this report).
Excessive VI: a ) I/I that results in the community's wet weather flows to exceed the
Metropolitan Council's established I/I goals for the community.
b) I/I that causes the peak hourly flow to exceed the value determined by
multiplying the average flow by the value of the peak to average ratio
used by MCES to design interceptors and pump stations.
c) I/I that exceeds 25 gallons per day per capita on a maximum monthly
basis (MPCA).
gpm: Gallons per minute
gpcd: Gallons per capita per day
I/I: Infiltration and Inflow is that component of sanitary sewage flow that originates from
clear water connections, i.e., sump pumps and foundation drains, stormwater entering
manholes and groundwater entering through pipe joints and cracks. It is water that would
normally not require any type of treatment. However, once it is co -mingles with sanitary
wastewater it cannot be separated, and must be treated along with the sanitary wastewater.
I/I Event: An hour when excessive I/I occurs as determined by MCES.
IITP: The Inflow/Infiltration Total Cost for each community.
Infiltration: The seepage of groundwater into sewer pipes through cracks or joints in the
pipes.
19
Page 23
Inflow: Inflow is typically flow from a single point, such as discharge from sump pumps and
foundation drains, or stormwater entering openings in the sewer access covers
Lateral: The small sewer pipe from buildings to the city sewers in the street.
MDS: Metropolitan Disposal System
mgd: Million gallons per day
MPGA: Minnesota Pollution Control Agency
Metershed: The area tributary to an MCES flow meter.
NPDES: National Pollutant Discharge Elimination System
Potential Peaking Event: The amount of flow (usually quoted in mgd) that would have
exceeded allowable flow (based on the Design Peak to Average Flow Ratio), had an
observed peak flow occurred at the diurnal peak (of the normal dry weather flow cycle)
instead of when it actually occurred.
SSO: Sanitary Sewer Overflow
Sewershed: The area tributary to the MCES interceptor system at a single point is a
sewershed.
Surcharge: A contingent charge to a local government unit for estimated costs of the MDS,
based on actual I/I events as described in Section 4 of this report.
WWTP: Wastewater Treatment Plant
zo
Page 24
Appendix 6
Possible Control Strategies
Options for Reduction of 1/1 in Local Collection Systems
New Facilities
The design and construction of new sewers and the connection of new buildings to the sewer
system should meet the industry standards for tightness and minimize the entry of I/I into the
collection system.
The state of Minnesota requires that new sewers be designed and installed so leakage into the
sewer is less than 100 gallons per day per inch -diameter per mile of sewer. For one mile of
12 -inch diameter sewer, the leakage into the new sewer must be less than 1,200 gallons per
day (less than 1 gallon per minute). Adherence to this standard depends on inspection during
construction and verification testing prior to acceptance by the owner. The task force agreed
that the Metropolitan Council should require certification by a professional engineer that new
facilities are installed in accordance with all specifications. Each community must retain
records of these certifications so that MCES can audit them.
The connection of a building lateral to the local sewer system is usually permitted by the
local building department. The steps taken to confirm that the connection is done correctly
vary among communities. Some communities require that a licensed plumber certify that the
connection was made in accordance with the building code.
Ordinances
All communities must have adopted ordinances that prohibit the connection of roof leaders,
foundation drain tiles, and sump pumps from new construction to the sanitary sewer system.
Cities should have ordinances that require the disconnection of any roof leaders, foundation
drain tile, or sump pumps currently connected to the sanitary sewer system.
Municipal Authority
M.S. 471.342 gives specific authority to Minnesota cities (but not to townships) to establish
I/I programs, including loans or grants to property owners. City and township funding can
come from Council Surcharge refunds as described in Section 4.
Disconnection of Foundation Drains and Sump Pumps
The disconnection of foundation drains and sump pumps from the sanitary sewer system is
one of the most difficult I/I reduction measures for a community to undertake. The
identification of the locations that should be disconnected is a major step and a difficult one
for most communities. Generally, the house to house inspection of the plumbing in the
basement does not cause much public concern if the program is well explained to the public
and they understand the reason for the inspections. These inspection programs take time and
a concerted communications effort. The inspection for connected gravity drains often
requires some form of dye testing around the foundation of a building. Dye is sprinkled
around a foundation and water is added to flush the dye down the wall of the foundation.
Concurrently, a TV camera is placed to observe the building lateral to see if dye is
discharged. The local ordinance must be written to allow for this type of testing.
21
Page 25
There are a range of options to address this and examples from other communities to follow.
Options to consider include the following.
Voluntary disconnection and reimbursement: Building owner is notified of connection
and offered some form of reimbursement for disconnection if performed within a
specified time frame. No penalty for remaining connected.
Point of sale: Seller must provide community proof that code is met prior to building
sale.
Age of structure: Some communities require new building lateral and confirmation of
disconnection if building permit is issued for building that is a certain age (40 years old,
for example).
Mandatory disconnection with reimbursement: Building owner is notified of
connection and offered some form of reimbursement for disconnection if performed
within a specified time frame. The owner is fined if remaining non-compliant after a
certain period.
In all cases the discommection should be certified by community staff or a licensed plumber.
These certifications should be on file and accessible for audit by the Metropolitan Council.
1// Reduction in Local Sewers
The investigation of 1/I sources in publicly owned sewer systems is fairly well developed and
the standard practices well documented on the basis of the sewer system evaluation surveys.
The basic steps included the following.
Flow monitoring and analysis: Locate areas generating high 1/1 and estimate 1/1 rates.
Smoke testing: Locate inflow sources.
Dye water flooding: Locate cross connections between drainage system and sanitary
sewer system.
Closed circuit TV inspection: Often conducted during the dye water flooding tests, the
TV inspection locates specific 1/1 sources and structural defects that should be
rehabilitated or replaced. Manhole inspections are usually done concurrently with sewer
inspections.
Most communities have ongoing sewer cleaning and inspection programs as part of the
routine maintenance of the collection system. 1/1 sources are often identified during
inspection and include open and leaking sewer joints, cracked pipes, missing joint gaskets,
broken house lateral connections, running services (problem likely on private property), pick
holes in manhole covers, and offset manhole frames. Many communities address these 1/1
sources as part of their infrastructure rehabilitation program.
Relief Sewers
Relief Sewers to convey excessive I/1 to the MCES interceptor system are not permitted.
MCES Toolbox Assistance
Additional information and resources on reduction actions/practices can be found in the
MCES 1/1 Reduction Toolbox located at:
http://www.metrocouncil.org/environment/Proj ectTeams/1-1-Home.htm
22
Page 26
Appendix C
Case Studies of 1/1 Related Costs
City of Milwaukee Case Study
The Milwaukee Metropolitan Sewerage District began a $2.3 billion sewer improvement
program in 1986 to store and treat I/I to comply with stricter federal water quality standards.
This program included a $716 million Deep Tunnel, put in operation in 1994, with a storage
capacity of 405 million gallons (this is $2.40 per gallon in 2005 dollars), and an interceptor
system of 153 overflow points from which untreated wastewater may be discharged into
local waterways during heavy rain. The District estimates that the Deep Tunnel has captured
more than 40 billion gallons of wastewater and prevented 240 sewer overflows since 1994,
with the average annual volume of sewer overflows reduced by 7.2 billion gallons annually,
or 81.3% from estimated pre -tunnel levels.
However, the Deep Tunnel, which was expected to virtually eliminate sewer overflows, has
not been as successful as planned, resulting in untreated wastewater overflows of 13.2 billion
gallons since 1994 (partly because capacity was exceeded during five large storms). The
District plans to address limitations of its sewer system by spending an additional $786.4
million to increase capacity through projects that include:
Project Cost
Improvements to the District's conveyance system 458.4m
Construction of 116 million gallons of additional
storage capacity for sanitary sewage 175.5m (or $1.50 per gallon)
Redesign siphons 96.2m
Purchase of enhanced storm tracking and real-time
flow monitoring equipment to improve the prediction of
storage capacity needs 16.5m
Increase treatment plant capacity 5.8m
Other (e.g. property acquisition, levee construction,
contaminated soil removal) 34.0m
Total 786.4m
Furthermore, in part to reduce the amount of stormwater entering the District's sewer system,
the Deep Tunnel, and treatment plants, the District has:
adopted new inflow and infiltration limits and funded $2.1 million in local demonstration
projects, in an effort to reduce I&I by 5% district -wide through 2010,
adopted rules that require municipalities to include runoff management systems as part of
any development plans, and
23
Page 27
planned to spend $410 million for watercourse improvement projects to reduce flood
damage to structures, improve water quality and reduce the inflow of stormwater into the
sewer system.
City of Forest Lake: Sump Pump Inspection Program
The interceptor system that provided wastewater service to the City of Forest Lake had
experienced capacity limitations during peak wet weather conditions. The City initiated a
sump pump inspection program in 2004 designed to locate and eliminate the illegal discharge
of sump pump water to the sanitary sewer system. The City has expended $120,000 to
inspect approximately 3,300 homes and has found approximately 370, or 11%, with sump
pumps illegally connected to the sanitary sewer system. The City estimates that the average
cost to disconnect a sump pump and direct it outside the building is $100. The City has not
had to provide additional discharge points for the clear water from the sump pumps to a local
collector.
City of St. Anthony: Drain Tile Inspection Program
The City of St. Anthony had experienced the backing up of sewage into homes during peak
wet weather conditions. The City completed an investigation as to the cause of the I/I
entering their system and determined that it was from passive drain tile connections to the
sanitary sewer system. The City passed an ordinance requiring homes to be inspected and
drain tile disconnected from the sanitary system at point of sale. The program began in 2001.
Currently, the City has inspected 340 homes for improper drain tile connections. The average
price to the home -owner for disconnecting the tile from the system, installing a sump basket,
and directing the pump outside the home is $1,200. As in Forest Lake, St. Anthony has not
had to provide additional discharge points for the clear water from the sump pumps to a local
collector.
24
Page 28
L
A endix D
y1 '
Appendix
Inflow/Infiltration Surcharge Program
2007 Option B Agreement
Draft of 9/27/05 (Conceptual)
Whereas, Excess Inflow and Infiltration (1/1) of clear water into the Metropolitan Disposal System (MDS) is
projected to cost the Metropolitan Council (Council) over $900 million for extra capacity over the next 25
years, and
Whereas, local efforts to mitigate this excessive I/1 are projected to cost approximately $150 million, and
Whereas, the Council has instituted an VI Surcharge Program, pursuant to M.S. 473.517, to encourage local
governments to solve this problem at the local level, and
Whereas, the municipality of (Municipality) has had excessive I/1 event(s) and thus has been
allocated a "2007 Surcharge" for each year 2007 to 2011 of $ per year, and
Whereas, the Council allows municipalities credit against this Surcharge by entering into this Option B
agreement, and
Whereas, Municipality prefers to mitigate 1/I within the municipality using other funds of Municipality or
through local regulation rather than paying the Surcharge,
Now, Therefore, Municipality and Council hereby enter the following agreement:
1.0 Municipality agrees to spend or cause to be spent on eligible 1/I mitigation costs, (as defined in section 3.0)
funds at least in the amount of $ during calendar years 2007-2011.
2.0 Council agrees to credit Municipality and thereby reduce the Surcharge by up to the amount listed in
section 1.0, but no more than the full amount of the Surcharge assessed to the Municipality for each year.
3.0 Municipality agrees that it will work to mitigate 1/I, as follows:
3.1 Municipality will spend its own funds on eligible 1/1 projects and costs. 1/1 projects shall be those
projects that are intended in whole or in part to reduce clear water entering the MDS. If part of a
project is UI mitigation then only the portion of the costs for I/1 work will be eligible. Eligible labor
costs for municipal staff will include only direct labor costs for inspection, engineering or
construction support on 1/1 mitigation projects. Fringe benefits for these employees may be included.
No administrative overhead shall be included. All contract services for 1/I mitigation shall be eligible.
The Municipality's plan for I/1 projects and costs is identified in Attachment A.
3.2 Private party costs incurred within the municipal borders as a result of the Municipality's I/I
project(s), for disconnections from the sewer, may be included on a standard cost basis for the
completion of disconnections on private properties as identified in Attachment A. Any municipal
costs for loans or grants to private parties, counted under section 3. 1, must be subtracted from these
standard private party costs, such that the local spending is counted only once.
3.3 Municipality may once each fall modify the plan in Attachment A, subject to the review and approval
of the Council. Such approval shall not be unreasonably withheld. In addition, failure of the Council
to object, in writing, within 30 days constitutes approval of the Plan modifications.
3.4 Municipality agrees to certify to the Council on a quarterly basis the "actual local funds spent" (i.e.
the expenditure of municipal funds on eligible I/I costs and the number of private party
disconnections actually accomplished).
3.5 Municipality agrees that if actual local funds spent on I/I projects on a cumulative basis are less than
the plan as described in Attachment A, at the end of each calendar year, the net reduction in local I/I
25
Page 29
spending (Attachment A plan less actual spent) shall be added to the Surcharge amount in the next
calendar year.
4.0 Municipality agrees that Council or its agents shall have reasonable access to its relevant records for the
purpose of auditing all records that pertain to this agreement.
5.0 Municipality agrees to indemnify and hold harmless the Council and its agents for all work performed
under this agreement.
6.0 Municipality acknowledges that the Council makes no representations as to the adequacy of this work to fix
the I/1 problems in the municipality, and that the Municipality may be subject to a Council Demand Charge
for excess I/I beginning in 2013 regardless of the work performed hereunder.
7.0 This agreement shall not change, in any way, other responsibilities of the Council or the Municipality under
state or federal laws, rules or regulations, or the Comprehensive Plan of the Municipality pertaining to I/1.
8.0 The term of this agreement shall be 5 years, through the end of 2011. Obligations in sections 3.2, 4.0 and
5.0 shall survive for an additional 3 years after the end of the term.
26
Page 30
Appendix D: Attachment A
The municipality plan to spend funds on PI mitigation projects and costs is described below:
1. Calendar Year = 2007
a) Municipal Costs:
attach additional sheets as necessary)
b) Private Party cost credits for work within the Municipal borders:
Sump Pump Disconnections @ $100 per dwelling = $
Foundation drain disconnections @ $3,000 per building = $
Rain Leader disconnections @ $100 per single family dwelling $
Rain Leader disconnections @ $3,000 per commercial or multi -family dwelling $
Service Lateral Repairs @ $5,000 $.
Other: (describe below)
Total to be spent by the end of 2007: $
ll. Calendar Year = 2008
a) Municipal Costs:
attach additional sheets as necessary)
b) Private Party cost credits for work within the Municipal borders:
Sump Pump Disconnections @ $100 per dwelling = $
Foundation drain disconnections @ $3,000 per building = $
Rain Leader disconnections @ $100 per single family dwelling $
Rain Leader disconnections @ $3,000 per commercial or multi -family dwelling $
Service Lateral Repairs @ $5,000 $
27
Page 31
Other: (describe below)
Cumulative Total to be spent by the end of 2008: $
III. Calendar Year = 2009
a) Municipal Costs:
attach additional sheets as necessary)
b) Private Party cost credits for work within the Municipal borders:
Sump Pump Disconnections @ $100 per dwelling = $
Foundation drain disconnections @ $3,000 per building = $
Rain Leader disconnections @ $100 per single family dwelling $
Rain Leader disconnections @ $3,000 per commercial or multi -family dwelling $
Service Lateral Repairs @ $5,000 $
Other: (describe below)
Cumulative Total to be spent by the end of 2009: $
IV. Calendar Year = 2010
a) Municipal Costs:
attach additional sheets as necessary)
28
Page 32
b) Private Party cost credits for work within the Municipal borders:
Sump Pump Disconnections @ $100 per dwelling = $
Foundation drain disconnections @ $3,000 per building = $
Rain Leader disconnections @ $100 per single family dwelling $
Rain Leader disconnections @ $3,000 per commercial or multi -family dwelling $
Service Lateral Repairs @ $5,000 $
Other: (describe below)
Cumulative Total to be spent by the end of 2010: $
V. Calendar Year = 2011
a) Municipal Costs:
attach additional sheets as necessary)
b) Private Party cost credits for work within the Municipal borders:
Sump Pump Disconnections @ $100 per dwelling = $
Foundation drain disconnections @ $3,000 per building = $
Rain Leader disconnections @ $100 per single family dwelling $
Rain Leader disconnections @ $3,000 per commercial or multi -family dwelling $
Service Lateral Repairs @ $5,000 $
Other: (describe below)
Cumulative Total to be spent by the end of 2011: $
29
Page 3 3
Appendix Chapter 9E
Cost and Funding
Information
A SEWERS AND LIFT STATIONS
1 REHABILITATION COSTS
Rehabilitation of sewers in disrepair improves flow through the sewers and reduces
maintenance expenditures on the system. The continued maintenance and
rehabilitation of existing sewers extend the life of the sewer and reduce costly
reconstruction of the system.
The VCP portions of the sewer system will monopolize a large portion of the
maintenance time and budget. It is estimated that in excess 60 percent of the
maintenance work effort and budget will be spent on 25 percent of the sewer system,
most of which are the VCP portions of the system.
The current VCP sewer rehabilitation should continue at a rate consistent with
available budgets. Televising will be concentrated in VCP areas for the first three
years to develop a prioritization for the continued rehabilitation program. Once a
prioritization is developed, the City may complete larger portions of the program
annually to accelerate the rehabilitation program.
It is estimated that two-thirds of the City's 30- to 40 -year old clay pipe is
experiencing significant root intrusion. A rehabilitation program to line two-thirds
48 miles) of the City's 12 -inch diameter and less clay pipe lines results in a total cost
of approximately $8.0 million. Lining the entire clay system would cost
approximately $12 million. A per mile cost of $150,000 - 165,000 per mile was used
to estimate the total cost of lining VCP sewers.
Page 1 of 4 Appendix 9E Plymouth Sewer Plan — April 14, 2009
Page 34
Developing a schedule to rehabilitate the clay sewer pipe depends on the annual
budget dedicated to the project. Below are examples of the timeframe the City can
expect, based on annual expenditures for rehabilitation:
500,000 per year achieves three miles per year (16+ year program).
1,000,000 per year achieves six miles per year (8+ year program).
1,500,000 per year achieves nine miles per year (5+ year program).
Reconstruction of sewers often results in costs that approach five to six times the cost
of lining. The amount of reconstruction cannot be determined without a review of
televising records. Areas that are scheduled for street reconstruction or major
rehabilitation should be reviewed to determine if reconstruction of the sewer would
be a feasible addition to the street project.
2 ESTIMATED COSTS FOR TRUNK SEWER OVERSIZING
The City should expect that over sizing of trunk sewers will be required with the
development in Northwest Plymouth. Over sizing costs will be included in future
budgeting. The actual costs and timing will be based on development planning,
staging and final design.
The City should also expect the need for over depth installation of trunk sewers in
part of Northwest Plymouth. Over depth costs will be considered as an alternative to
temporary lift station phasing.
Tables 9E-1 and 9E-2 show over sizing and over depth costs for Northwest
Plymouth.
Page 2 of 4 Appendix 9E Plymouth Sewer Plan —April 14, 2009
Page 35
TABLE 9E-4
ANNUAL EXPENDITURE
O&M AND CAPITAL IMPROVEMENTS
SANITARY SEWER SYSTEM YEARS 2008 - 2017
Parameter
Year
2008 2009 2010 2011 2012 2013 1 2014 1 2015 1 2016 1 2017
Annual O&M
Cleaning/Jetting Sewer 140,000 140,000 140,000 140,000 140,000 140,000 140,000 140,000 140,000 140,000
Televising Sewer 180,000 180,000 180,000 180,000 180,000 90,000 90,000 90,000 90,000 90,000
Lift Station Inspection 4,000 4,000 4,000 4,000 4,000 4,000 4,000 4,000 4,000 4,000
Annual O&M 324,000 324,000 324,000 324,000 324,000 234,000 234,000 234,000 234,000 234,000
Capital Imrovements
VCP Sewer Rehab 500,000 1,000,000 1,000,000 1,000,000 1,000,000 1,000,000 1,000,000 1,000,000 500,000 500,000
Lift Station Improvements 975,000 1,100,000 345,000 900,000 900,000 700,000 700,000 700,000 700,000 700,000
Total Annual Expenditure of
Capital Improvement 1 $1,475,000 2,100,000 1,345,000 1,900,000 1,900,000 1,700,000 1,700,000 1,700,000 1,200,000 1,200,000
Total Annual Cost to City 1$1,799,0001$2,424, 0001 1,669,0001 2,224,0001 2,224,0001$1,9324,0001 1,934,0001 1,934,0001 1,234,0001 1,234,000
Page 3 of 4 Appendix 9E Plymouth Sewer Plan - April 14, 2009
Page 36
MEMO
CITY OF PLYMOUTH
3400 PLYMOUTH BOULEVARD, PLYMOUTH, MN 55447
DATE: November 18, 2010
TO: Laurie Ahrens, City Manager
FROM: Diane Evans, Superintendent of Recreation
SUBJECT: Plymouth Skatepark Renovation —Focus Group
On Tuesday, November 9, 2010 the Plymouth Parks and Recreation department met with a focus group
of current skate park users and parents to discuss and gather input for a potential renovation of the
Plymouth Skate Park. We had 16 park users in attendance at the meeting ranging in age from 10 years
old through adult (3 parents were in attendance). They had an abundance of ideas to share regarding
both the existing park and potential renovations. The majority of attendees were teen's ages 12-18
years. This is a great representation of a teen interest in our community and our skate park.
Skate Park Backeround:
Built in 2001.
Skate park users — this park was built to appeal to beginning and intermediate skaters. Geared
toward middle school and high school teenagers but also attractive and appropriate for younger
developing skaters.
Skate park surface — asphalt pad.
Skate park features - park features are all 3' in height or lower, have a metal frame and riding
surfaces that consist of a series of metal plates fit together and they are all visibly worn.
Skate park attendance — daily skate park attendance has been declining over the last few years
but skate park programs (skate boarding camps/clinics and competitions) attendance has
remained strong.
Skate park renovations — no renovations or upgrades have been made to the park since its initial
construction. Currently scheduled for renovation in 2011.
At the meeting, we discussed the current skate park use, issues associated with the design and what
updates would really benefit the community users.
Focus group input on current skate park:
Skate surface — the asphalt is very weathered, it has developed a gravel texture that really slows
down skaters and reduces the functionality of the park. They stated that the paved parking lot
finished 2 % years ago provided a better ride.
Page 37
Skate park layout — the spacing and orientation of the features is very awkward, limiting skate
options and making skate rides and transitions difficult for users.
Skate park features — metal surfaces are not good, the numerous seams between plates create a
lot of bumps and slow downs. The seams cause a safety concern as you can catch and tear skin on
most of the corners. Also the park features have a vert skate style (lots of ramps) which is not very
popular in the mid -west. Street style skating is the most popular style in our community.
Amenities—there is no shaded area within the skate pad.
Skate park attendance — the focus group believes the poor shape the park is in is the biggest
reason the number of users have dropped in recent years. Slow surfaces, bad transitions and
outdated features are a major obstacles to having fun riding at the park and continuing to visit the
park. They can get a better ride and are less frustrated on sidewalks, plazas and at other parks
i.e., Hilde Stage & sidewalks).
Focus group input on desired renovations:
Skate surface — smooth concrete pad preferred, it provides the best ride. Possibly expand surface
5-7' on one side.
Skate park layout — incorporate new street -style features and improve spacing and orientation to
provide for easy transitions and maximum use of skate area by skater.
Skate park features —
o more variety in obstacles/features;
o transition to a street -style park, more rails, stairs, benches... that are made to be skated on;
o smooth continuous surfaces on features, poured concrete preferred, but Skatelite (pre -built,
modular skate park features) would work;
o increase feature height to new League of Minnesota Cities Tier 1 allowance of 4' (currently at
3'); and
o addition of movable kick boxes to adjust for different level skaters
Amenities — incorporated a shade canopy over part of the park.
Skate park attendance — the focus group believes that a skate park renovation that is done
properly will bring back the attendance levels. There are a lot of skaters in the Plymouth area that
are looking for a good place to skate locally.
Focus group identification of popular metro area skate parks:
Top Pick: Oakdale Skate Park — great design and construction. All concrete features and surfacing,
a wide variety of street -style features, optimal space/flow between features to gather speed and
allow room for tricks.
Newest Park: St. Cloud Skate Plaza- concrete features, street skating park with lots of stairs,
benches, rails and ramps. Opened November 13.
Focus group input on skate dots/pocket skate parks:
The focus group was very interested in the idea of skate dots in some of our neighborhood and
city parks. They thought that they would definitely make use of them if they were incorporated
into existing parks especially if they had a couple of smaller street style features. Although they
did state they would not want the skate dots to replace a skate park.
Group Consensus: The group really appreciates having a skate park in Plymouth and would like to
continue having one. But, they believe a renovation is definitely needed or the park will become
unused as the surface and features become even more worn out, outdated, unattractive and
unsafe.
Page 38