HomeMy WebLinkAboutResolution No. 146-09 •
RESOLUTION
BE IT RESOLVED by the Common Council of the City of Rochester that the City does
hereby approve the revised emergency warning plans for the South Zumbro Watershed Joint
Powers Board reservoirs as explained in the attached memorandum.
PASSED AND ADOPTED BY THE COMMON COUNCIL OF THE CITY OF
ROCHESTER, MINNESOTA, THIS A�Q/ff DAY OF, , 2009.
i
PRESIDENT OF SAID COMMON COUNCIL
ATTEST- � r
,/CITY CLERK
APPROVED THIS Z/sr DAY OF , 2009.
MAYOR OF SAID CITY
(Seal of the City of
Rochester, Minnesota)
ResUS Approve.EmerWarning Plan 1
•
M.e o
To: South Zumbro Watershed Joint Powers.Board
From: Gary Neumann
Date: February 25,2009
Re: Reservoir Emergency Warning Plans— Revisions
An emergency warning plan has been in place for each of the reservoirs since
construction. Periodically over the years these plans have been revised. .The staff of
the emergency response and public works departments of the City, County and the
• NRCS (SCS) have reviewed and revised the emergency warning plans for each of
the reservoirs and recommend that the Board approve the revised plans. The format
for each*plan is consistent with the attached plan for the WR-6A reservoir.
During the August 2007 major rainfall event that affected SE Minnesota several of
the reservoirs received and stored significant amounts of rainfall. It was a good test
of the reservoir system and of the emergency warning plans that had been adopted.
The reservoirs performed their function as planned and expected. There were a few
plan items that we revised and there were a few changes in our procedures that
resulted from this test of the system as follows:
1) The warning plans stated that the initial inspection and continued monitoring
of the water levels in the reservoirs would be conducted by the Sheriffs
Department. During the 2007 event, however, the Deputies were completely
occupied in responding to other water related emergencies and were
unavailable for the inspection and monitoring of reservoirs. So instead the
Rochester Public Works Department personnel performed the inspections
and monitoring on 6 reservoirs and the Chester Woods Park on-site
personnel did that for BR-1/Chester Woods. The revised warning plans
include that change and incorporates what actually happened and worked in
2007.
• 2) During 2007, for the first time, the level of the water stored in a reservoir, in
this case BR-1, reached an elevation that required notification of downstream
property-owners. All of the reservoirs are designed to hold and store at least
• a 200 year storm event without any water flow through the emergency
spillway that is designed into each reservoir structure. At the point at which
the water level comes within 2 feet of the bottom elevation of the emergency
spillway, the plan requires a notification of downstream properties. A notice
similar to the following was issued in 2007 to residents along Bear Creek:
"The BR-1 Chester Woods Flood Control Reservoir on Bear Creek is nearly
full to the emergency spillway elevation. The flood control structure remains
structurally sound. However, continued rains may cause an overflow of the
emergency spillway. This is not a warning to evacuate."
In 2007 this "watch" was.issued utilizing the reverse 911 automatic phone
dialing equipment to property-owners in the potentially affected area. In the
event of future flood warning notification situations we have upgraded our
capacity to provide such notices in a much more timely manner. We can call
approximately 10,000 phone numbers in 60 minutes under this enhanced
system. We can access 200 phone lines. The areas to be contacted are
automated. This is an upgrade that resulted from the 2007 event.
3). Accurately determining water level elevations during and after the 2007 was
accomplished by survey data. A better and preferred`method of obtaining
elevation data and for historical comparison is to install electronic elevation
' monitoring gauges: We have installed an electronic real-time monitoring
gauge at Chester Woods in 2008. That has been working very well, so we
plan to install similar monitoring equipment at the remaining 6 reservoirs in
2009. The City has agreed to fund this cost.
Board Action Requested.
Approve the revised warning plans for the NRCS 7 reservoirs.
•