This is interesting stuff . . . things we take for granted and usually don’t have to think about cuz the engineers take care of it for us.
From: Nelson, Larry
Sent: Tuesday, August 28, 2007 11:00:44 AM
To: Dept Division Heads; ALL ALDERS; Ruckriegel, Ed; Cryan, Kathy;
Fahrney, John; Manning, Bryan; Dailey, Mike; Bachmann, Christy;
Hoffman, Jeanne
Subject: Lake ElevationsLake Monona has crested at elevation 847.48 at 3:00 pm, Monday afternoon, August 27, 2007. The regional flood elevation of Lake Monona is 848 but the highest level on record was sustained June 15, 2000 at 847.48.
As a result of the unexpected rainfall events of yesterday, Dane County has reduced the discharge from Lake Mendota to about 130 cfs (cubic feet per second), as measured on the Yahara River at E. Main Street. At 7:00 pm, Monday, August 27, 2007, there were 285 cfs flowing into Lake Mendota at STH 113.
Lake Mendota crested at 851.81 around 10:00 am Saturday, August 25, 2007. The Lake maintained an elevation of 851.80 at 7:00 pm, Monday, August 27, 2007. The 100 – Year Regional Flood is currently 852 but the WDNR has a proposal under consideration to increase that elevation to 853. The previous highest level on record was sustained June 7, 2000 at elevation 852.74.
The lakes are being managed in accordance with the long-term strategy of holding water in Lake Mendota and attempting to release water from Lakes Monona and Waubesa as quickly as possible.
The City of Monona has had to sandbag portions of its Belle Isle neighborhood and other areas. The City of Middleton has sandbagged areas along Lake Mendota north of James Marshall Park.
City Engineering has placed sand bags and sand at six locations. Engineering has a mechanical sand bagger, which was delivered to the Town of Windsor yesterday. We will retrieve the machine if required by City residents.We have had a few reports of damage to structures. FEMA will be assessing damage to Dane County today, preparatory to a disaster declaration by the federal government. Refer all reports of damage to Building Inspector George Hank and his staff.
What Can We Do to Reduce this Risk?
The lakes are operated in accordance with the order of WDNR which the following web page details:
http://co.dane.wi.us/landconservation/papers/lakes/DNR-3-SD-77-808.pdfLakes elevations are established to balance competing interests of the riparian owners, the boating /recreation interests and the environmental concerns, including fish propagation and protection of wetlands. The high water elevations, which cause “bogs” to dislodge from the bottom and float with the current, have significantly diminished the Cherokee wetlands.
We believe that this current situation would have been less of a concern had we been able to maintain a lake elevation one-foot lower than the maximum summer elevation established for both Lakes Monona and Mendota. We have sent a letter to the WDNR requesting a review of the order and that review is underway.
Another action that we need to develop additional information is the railroad bridge at the mouth of the Yahara River and Lake Waubesa. Kevin Connors, Director of the Dane County Land Conservation Department, reports that the bridge (railroad trestle) restricts the flow of the river as much as 0.5 feet. During high water periods, the “head loss” at the bridge increases the elevation of Lake Monona over Lake Waubesa. It has been proposed to install a new bridge that would increase the capacity of channel, facilitate boating, and widen the bridge to accommodate bike/pedestrian traffic.
