Odana Pond is a wet retention pond, built on an old wetland

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"The Lake Wingra watershed contains eight major wet retention ponds:  the Odana Hills Park pond, the Nakoma Golf Course pond, and six ponds in the UW-Arboretum. Approximately 60% of the watershed’s storm sewers convey runoff to wet retention ponds, which are among the most effective stormwater treatment methods available." "Each pond provides a single, discrete location for removing sediment, pollutants, and nutrients from runoff originating from a broad, diffuse area."

"These ponds require careful management; effective ponds trap sediment, therefore requiring periodic dredging. As a pond fills with sediment, its water depth decreases. Once water depth is below four feet, the pond’s efficiency to trap sediment decreases dramatically."


"The Odana pond is the only city-owned wet retention pond. It was built in the 1950s when the city Parks Department dredged a wetland area to create the pond. The pond (actually three connected ponds) has not been dredged since that time, although the city Department of Public Works has unsuccessfully requested funding from the city to do so for the past three years. The city Engineering Division estimates that once the pond is dredged, it may be 60 years or more before it needs to be dredged again.

Much of the sediment currently in the pond originated from construction activity that occurred since the pond was originally built. Because the area drained by the pond is now completely developed, the major sources of sediment are automobiles, winter road sand, and atmospheric deposition."

Quoted from this 1999 source.