Wauwatosa landscape continues to change

Drive around the County Grounds and Wauwatosa's public lands long enough and you'll notice a number of depressions in the landscape - bowls, basins, drainage features of different kinds. The largest is the huge Milwaukee Metropolitan Sewerage District basin that starts just across Underwood Parkway from the Hansen Golf Course clubhouse and stretches west under Swan Boulevard and east along the Menomonee River.

The newest landscape drainage feature is the pond near the corner of Underwood Parkway and Watertown Plank Road, just north of the High Pointe office building at 1200 N. Mayfair Road.

Bicyclists who head west on the Oak Leaf Trail from the parkway will recognize it as the pond on the left that the trail curves around.

There was always was a pond there, city engineer Bill Wehrley said, but it has been enlarged. It filled with water immediately after it was finished last week.

Unike the MMSD basins, "it's a pond that's designed to stay wet," Wehrley said.

The pond is connected to the storm sewers that drain the streets, "so it should have water in it normally," he said.

The water level will fluctuate with the amount of precipitation.

When the water level reaches the height of a drain visible above the level of the pond, the water will drain off and be piped to Underwood Creek, just a few feet away.

The pond is "what we call inline," Wehrley said. "If the pond wasn't there, the street runoff would run directly into the creek, but now it runs through this pond on its way to the creek, so that some of the suspended solids, and some of the pollutants and some of the sands and gravels and dirt and pollutants can settle out in the pond to improve the water quality before it discharges into Underwood Creek."

The widening of the roadways related to the state Department of Transportation's Zoo Interchange project will create more runoff, making enlarging the pond necessary, he said.

In contrast to the MMSD basin, which was built for flood control, the pond is designed to improve water quality, he said.

The pond was enlarged by the DOT on land that belongs to the county.

DOT communications manager Emlynn Grisar said the pond will accommodate runoff from the roads as well as the County Grounds, the railroad tracks just west of Mayfair Road, a portion of the High Pointe parcel, and even, at least temporarily, Innovation Park.