July 26, 2019 Update
Risk Assessment
We experience no significant additional flood risk due to the current lake levels, as expected both lakes have risen in response to last Thursday’s rain. Lake Monona is creeping up toward 847 feet, which poses concern for us.
Recall typically 1” of rain in the Mendota watershed gets you a 3” rise in the elevation of Lake Mendota.
Lake Mendota Today
Elevation = 850.89 feet
Change from one week ago = up 0.21 feet
Change from one month ago = up 0.08 feet
Above/below summer maximum: Above by 0.79 feet
Above or below 100 year elevation: Down 1.91 feet
Lake Mendota Statistics
Surface Area = 9,842 surface area acres
Summer Min = 849.6 feet
Summer Max = 850.1 feet
100-Year Record = 852.8 feet
Lake Monona Today
Elevation = 846.61 feet
Change from one week ago = up 0.15 feet
Change from one month ago = down 0.05 feet
Above/below summer maximum: above by 1.41 feet
Above or below 100 year elevation: down 1.09 feet
Lake Monona Statistics
Surface Area = 3,274 surface area acres
Summer Min = 844.7 feet
Summer Max = 845.2 feet
100-Year Record = 847.7 feet
The problem low ground elevations in the Isthmus area are at about elevation 848.5 to 849.00. These areas drain to Lake Monona and/or the Yahara River downstream of the Tenney Locks. The closer Monona rises to 847.00 the more ineffective our drainage system in these low areas becomes.