Flooding

Risk Assessment

We experience no significant additional flood risk due to the current lake levels.

Current extended forecast is for approximately a 50% chance of rain every day next work week. We will watch levels closely.

Recall typically 1” of rain in the Mendota watershed results in a 3” rise in the elevation of Lake Mendota.

Lake Mendota Today

Elevation = 850.28 feet

Change from one week ago = up 0.08 feet

Change from one month ago = down .21 feet

Above/below summer maximum: by .18 feet

Above or below 100 year elevation: below 2.52 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 = 846.16 feet

Change from one week ago = up .17 feet

Change from one month ago = up 0.21 feet

Above/below summer maximum: above by .96 feet

Above or below 100 year elevation: down 1.54 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, 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.