What would the University of Wisconsin be without University Bay?  The Bay makes the University and the Campus Natural Areas unique.  University Bay supplies recreation and scenery.  It also supports a diverse group of animals.  Without the Bay, there would be no Picnic Point.

Looking across University Bay from Picnic Point (photo by Glenda Denniston)

Unfortunately, this shallow 260-acre Bay has been under pressure for over a hundred years.  Once raw sewage from Madison was dumped into the Bay.  Most of the marsh, which filtered and cleaned water flowing into Bay, was drained and farmed and now is parking lot and playing field. Today a straightened Willow Creek dumps the untreated storm water and pollutants from much of the near West side of Madison directly into the Bay.  A box culvert built in the late 1950s connects the storm sewers of the area along University Avenue below Midvale to Willow Creek.  As the area along Midvale and University Avenue was developed (Hilldale was developed in the early 1960s) and most of the open area was built upon, more and more water flowed rapidly off the impenetrable pavement and buildings.  Now, when heavy rains occur, leaves, dirt, salt, and fertilizer are all carried directly into the Bay.  At a Village of Shorewood Hills Storm Water Task Force meeting in 2001, David Wolmutt estimated that 282 tons, or 564,000 pounds, of sediment was dumped into University Bay through Willow Creek every year.

The addition of large amounts of sediment has several effects on University Bay.  First, this sediment accumulates throughout the Bay, making the Bay more shallow.  The sandbar near the mouth of Willow Creek, where the gulls sit, is a result of the deposition of this sediment.  Gradually the Bay is filling up with sediment and becoming land.  Second, the inflow of warm, dirty, fertilized water has changed the plant composition of the Bay over time.  In the past a diverse underwater plant community existed in the Bay.  Today water Eurasian milfoil is the main underwater plant.  This decrease in plant diversity leads to a decrease in the diversity of animal life in the Bay.  Once many diving ducks used the Bay in the fall.  They ate wild celery and other submerged plants.  Today few diving ducks feed in the Bay.  Finally, the increased nutrients from fertilizers and other sources throughout the watershed cause algae blooms.  The low oxygen levels of the lake in mid-summer cause fish kills.  Both of these make it unpleasant to be around Lake Mendota in the summer.