The Engineering Division is monitoring lake levels and the potential to flood year round. To keep people informed, we’re sharing a weekly update with you, and as frequently as needed, should a major rain event happen. We are not sending these to elevate concern, this is just a new communication option for us to keep you informed as flooding deeply impacted our community last summer, and may be top of mind when rain moves through our area.
June 14, 2019 Update
Mendota is at elevation 850.36, this is down from 850.49 last week. The summer max by the Wisconsin Department of Natural Resources order is 850.10 (So, we are approximately three inches over summer max). The 100-year elevation is 852.8, but we can only currently effectively rise to approximately 852.0.
Monona is at 845.92, down from 845.95 last week. The summer max by WDNR order is 845.20 (So, we are approximately nine inches over.). The 100-year is 847.7.
The problem, low-ground elevations in the Isthmus area are at about elevation 848.5 to 849.00. These areas drain to Lake Monona, or the Yahara River downstream of the Tenny Locks. The closer Monona rises to 847.00 the more ineffective our drainage system in these low areas becomes.
We experience no significant additional flood risk due to the current lake levels.
The extended forecast looks mostly dry with just scattered rain predicted for Saturday, mostly dry after that for the next week. Recall, typically one inch of rain in the Mendota watershed gets you a three-inch rise in the elevation of Lake Mendota.