City Detention Basin Maintenance ProgramTHE CITY C7 ~ C ~~-^
DUB E MEMORANDUM
Masterpiece on the Mississippi
July 10, 2007
TO: The Honorable Mayor and City Council Members
FROM: Michael C. Van Milligen, City Manager
SUBJECT: City Detention Basin Maintenance Program
City Engineer Gus Psihoyos has provided an update on the work being done on the
stormwater detention facilities at Fremont Heights and Harvest View.
This is provided for your information and no action is requested.
~; i~'
Michael C. an Milligen
MCVM/jh
Attachment
cc: Barry Lindahl, City Attorney
Cindy Steinhauser, Assistant City Manager
Gus Psihoyos, City Engineer
THE CITY OF
DuB E MEMORANDUM
Masterpiece on the Mississippi
July 9, 2007
TO: Michael C. Van Milligen, City Manager
FROM: Gus Psihoyos, City Engineer
SUBJECT: City Detention Basin Maintenance Program
INTRODUCTION
The purpose of this memo is to provide updated information about the City's Detention
Basin Maintenance Program.
BACKGROUND
Over one hundred detention basins have been constructed since the City started requiring
detention basins in the mid-1990s. The City has an interest in ensuring that all are properly
maintained. Currently, the City is responsible for maintaining seventeen of them. And five
of those, the City can assess the costs back to the property owners within the subdivision
that the basin serves.
On June 4, 2007, Ms. Betty Leibfried and Ms. Veronica Bender addressed the City Council
about the condition of the Fremont stormwater detention basin behind their homes on
Barbaralee Drive.
City staff presented an update on the maintenance and improvements to the Harvest View
and Fremont Heights detention basins in June of 2007. As reported, Arensdorf Excavating
was awarded a contract to install the improvements. The improvements include adding
260 feet and 675 feet of drain the in the Fremont and Harvest View basins respectively.
The drain the will be buried in free draining clean stone to increase its effectiveness to
drain the soil. Above the drain the and stone will be a topsoil/compost mix. And finally sod
will be placed throughout the basin regarded to better drain. They were to complete the
improvements to the Fremont Detention Basin by June 29 and the Harvest View Detention
Basin by July 20, 2007.
The City Council directed staff to report back in 45 days as to the progress of the City's
Detention Basin Maintenance Program.
DISCUSSION
Since last summer, City staff has inspected one hundred fifteen (115) detention basins.
Again, the City is responsible for maintaining seventeen of the facilities. And even though
the maintenance of the other ninety eight basins is the responsibility of private property
owners, inspections are necessary to ensure that all detention basins will function as
designed during rains. Mowing, removal of volunteer trees, and rip-rap repair were the
main maintenance deficiency sited. In of themselves, they would not prevent a detention
basin from performing its primary function -flood control. However, they present other
undesirable conditions.
The inspections revealed that Fremont Heights and the Harvest View Detention Basins
were identified as requiring more than just maintenance. Improvements to the design were
required to prevent the recurring/constant occurrence of standing water in what were
intended to be dry bottom detention basins. Incidents of erosion were discovered at a few
others that will require minor grading and rip-rap repair.
The contractor finished constructing the improvements to the Fremont Detention basin in
June. The original design called for sod in the detention basins. However, due to the
nature of the compost/soil mixture, seed, fertilizer, and mulch were placed instead. The
concern with the sod was that the grass roots would .not grow into the compost/soil
mixture. The seed will be watered this summer and over seeding will be done this fall if
necessary. Work has started on the Harvest View Detention basin and should be
completed by the July 20 deadline.
In addition to the work performed on the Harvest View and Fremont Detention basins, a
contractor was hired to perform the first wave of maintenance as needed on the remaining
fifteen basins. Primarily they are mowing the basins and removing volunteer trees. This
work will be completed by July 20. After that, the basins will be inspected again. And
based on those inspections, a contractor will be hired to bring them to the condition that
they were originally designed by the end of August.
BUDGET IMPACT
The detention basin maintenance will be funded from the annual Detention Basin
Maintenance CIP (#7201359) with a current balance of $34,252.20. The FY2008 budget
includes an addition $29,000 for routine detention basin maintenance.
ACTION TO BE TAKEN
There is no action requested. This memo is intended to provide information.
Prepared by Deron Muehring
cc: Barry Lindahl, City Attorney
Cindy Steinhauser, Assistant City Manager
Deron Muehring, Civil Engineer II