HomeMy WebLinkAbout5L Sanitary Sewer System ImprovementsPRIp
U er1
4646 Dakota Street SE
` INNES�� P Prior Lake, MN 55372
CITY COUNCIL AGENDA REPORT
MEETING DATE:
FEBRUARY 22, 2011
AGENDA #:
5L
PREPARED BY:
STEVE ALBRECHT, DIRECTOR OF PUBLIC WORKS
PRESENTER:
STEVE ALBRECHT
AGENDA ITEM: CONSIDER APPROVAL OF RESOLUTION AUTHORIZING
PREPARATION OF PLANS AND SPECIFICAITONS FOR 2011
SANITARY SEWER IMPROVEMENTS
DISCUSSION: Introduction
The purpose of this agenda item is for the City Council to authorize City
staff to proceed with design of the 2011 Sanitary Sewer System
improvements.
Hi story
The City of Prior Lake maintains more than 100 miles of sanitary sewer
mains that collect and convey sewage to the Met Council Sewer
Interceptor. This system includes nearly 8,000 sewer services and 39
sanitary sewer lift stations. Annually, the City completes improvements to
the infrastructure to ensure that it operates efficiently and correctly. Failure
to maintain this infrastructure can result in sewage backups and substantial
impacts to private property. The City's annual maintenance program is
detailed in the Sanitary Sewer Maintenance Policy. Annual sanitary sewer
system maintenance is required to meet the League of Minnesota's
insurance requirements and to reduce the City's liability associated with
sewage back -up incidents.
In addition to reducing liability, these projects allow the City to minimize and
prevent the inflow of ground water into the City's sanitary sewer system.
By minimizing this inflow the City minimizes sewer treatment costs with the
Met Council.
The annual improvements include sewer pipe lining, sewer main
replacement and lift station improvements.
Current Circumstances
For 2011 City staff has identified replacement of the existing sewer pipe
that runs under the lake between the southern terminus of Watersedge
Trail and the northern terminus of Glendale Avenue. This improvement will
be completed in conjunction with phase one of the Boudin's /Rutgers
neighborhood improvements.
Currently the sewer runs under the lake via an "inverted siphon" sewer
main constructed in 1975. This sewer serves more than 300 homes in that
area of the City. Over the last several years the City has experienced
several expensive sewer back -ups due to the malfunction of the siphon.
CADocuments and Settingstogreen\My DocumentslSharePoint Drafts12011 Sanitary Sewer Improvements Agenda.doc
Siphon's were used in the 1970's as a primary way to cross rivers and
streams prior to lift station technology becoming preferred. Due to minimal
grades this siphon does not operate efficiently and requires constant
monitoring and frequent maintenance. Replacing the siphon with a
forcemain under the lake will allow the City to lower the existing sewer in
the Boudin's /Rustic neighborhood to provide better flow and protection to
residences.
This option will also allow the City to preserve the siphon as an emergency
forcemain thus providing an emergency alternative for sewer service that
does not currently exist in this area of the City. Typically, the City can
bypass pump sewage past a blockage or sewer main break. In this case
the area is isolated and the nearest sewer lines for bypass are located
across the lake channel. In an emergency the City would need to pump to
trucks and haul the sewage.
Conclusion
Because the City is reconstructing Watersedge Trail in 2011 it is most cost
effective to make the improvements at this time. These improvements will
minimize sewer back -up concerns, provide long term dependable sewer
service to this area and provide an emergency alternative currently not
available.
ISSUES: If the City does not make this upgrade in conjunction with the 2011
reconstruction project the City will most likely need to tear up a portion of
the reconstructed Watersedge Trail to make repairs in the next 10 years.
Without replacement of the existing sewer crossing the City can't lower the
existing sewer lines to allow for better system flow.
Staff does not have in -house expertise to design the wet well and lift- station
components. The design services are not expected to exceed $15,000 and
will be solicited from the City's approved Consultant Pool.
FINANCIAL The 2011 Budget identifies $150,000 for sanitary sewer system
IMPACT: improvements and $60,000 for lift station panel and equipment installation.
Approval of this agenda item does not obligate the City to complete the
improvements; only to prepare the plans and specifications for future City
Council consideration.
ALTERNATIVES: 1) Approve a resolution authorizing preparation of plans and
specifications for the 2011 Sanitary Sewer Improvement Project.
2) Table this item for a specific reason.
3) Direct staff not to proceed with the project.
RECOMMENDED ,Alternative No. 1.
MOTION:
Revi6wed
Frank os,f`Cit Manager
r
CADocuments and Settings \cgreen \My Documents\SharePoint DraftsOl l Sanitary Sewer Improvements Agenda.doc 2
ti
U
�jNNESO�
4646 Dakota Street SE
Prior Lake, MN 55372
RESOLUTION 11 -xxx
A RESOLUTION AUTHORIZING PREPARATION OF PLANS AND SPECIFICATIONS FOR THE 2011
SANITARY SEWER IMPROVEMENTS
Motion By:
Second By:
WHEREAS, The City of Prior Lake maintains more than 100 miles of sanitary sewer main, nearly 8,000
sewer connections and 39 sanitary sewer lift stations; and
WHEREAS, In order to keep the system functioning properly and to meet League of Minnesota
Insurance guidelines and Met Council inflow requirements the City annually repairs and
replaces sections of the system; and
WHEREAS, Phase 1 of the Boudins /Rutgers Neighborhood Street Reconstruction Project requires
sewer improvements to the existing sewer running under the lake; and
WHEREAS, City Staff recommends the existing inverted siphon utilized between the southern terminus
of Watersedge Trail and Glendale Avenue be replaced in conjunction with the
Boudins /Rutgers Neighborhood Street Reconstruction Project; and
WHEREAS, The replacement of this crossing will improve sewer flow and eliminate the need for future
impacts to reconstructed streets for replacement of the sewer.
NOW THEREFORE, BE IT HEREBY RESOLVED BY THE CITY COUNCIL OF PRIOR LAKE,
MINNESOTA as follows:
1. The recitals set forth above are incorporated herein.
2. City Staff is authorized to prepare plans and specifications for the 2011 Sanitary Sewer
Replacement Project.
3. City Staff is authorized to utilize professional services from the Consultant Pool for an
amount not to exceed $15,000 for project design assistance.
4. Funding for design services shall come from account # 604- 49450 -303.
PASSED AND ADOPTED THIS 22 DAY OF FEBRUARY, 2011.
YES
NO
M ser
M ser
Erickson
Erickson
Hedberg
Hedber
Keeney
Keene
Soukup
Souku
Frank Boyles, City Manager
. . ... . . .. _
;
E \ §
■.� .
� \ � .
� :
� ,
2 `
y p :
_.
al69
.
�vR
-
^
;
2 `
y p :
_.
al69