Lagoon

LAGOON

As part of the 1906 O.C. Simonds Master Plan for Vilas Park, the lagoon was utilized to build land for park uses. The La Crosse Dredging Company created a lagoon with one island named Wild Rice. In the period between the original 1906 dredging and the creation of a City Map of 1914, the lagoon was expanded to create a second, much larger island. There are no records to indicate when the lagoon was expanded. The result was a lagoon with two islands. This lasted until 1955-57 when Lake Wingra was filled and the smaller island was removed. This filling is documented in aerial photographs taken during that time period.

In 2019, the City of Madison contracted with CGC, Inc. of Madison to probe the lagoon to determine the depth of the water and the amount of lose sediment at the bottom.75 The findings show the lagoon is shallow, with a maximum water depth of 3.75 feet. The depth of sediment to firm bottom has a range of 0.75 feet to 4.5 feet. The data shows the lagoon system does not have the depth to reduce vegetation growth, which may factor into the continued seasonal plant growth in the lagoon. The soil profile consists of dark gray organic silt; medium stiff to stiff, gray lean clay with occasional thin seams of silt; little to some clay and sand partings; dark gray organic silt with trace sand, clay and shell fragments; stiff, brown to gray lean clay; and trace sand.76

The original lagoon had two connection points with Lake Wingra. This resulted in the creation of an island where the current park shelter is. Access to the island at both entry points was provided by the construction of bridges. Funding for the bridges was donated by the Vilas family. The west bridge crosses the remaining connection of the lagoon to Lake Wingra, whereas the east bridge is now within the zoo’s boundary fence. The 1955-57 filling of Lake Wingra closed this second open-water connection and turned the island into a peninsula. In 2012, Lauren V. Brown, a community fellow at Edgewood College77 suggested in her work that a secondary connection be reopened near the existing boat launch.

75 CGC Inc., Probe Location Plan, January 2019. 76 CGC Inc., Log of Sediment Core, March 2019. 77 Vilas Park/Lake Wingra Shoreline Vision, Sustainability Leadership Graduate Certificate Program, Edgewood College, 2012.

Figure 5.141. Lagoon in Summer Figure 5.142. Lagoon in Fall

Figure 5.143. Lagoon in Fall with Event in the Meadow

Figure 5.144. Lagoon in Winter (Skating) Figure 5.145. Lagoon in Spring