Museum going green to control storm water

The Milwaukee Public Museum plans to start building storm-water controls in mid-July at its W. Wells St. entrance plaza disguised as gardens of native flowers, grasses and sedges along meandering paths made of porous pavement.

Where concrete slabs now form a hardened, gray entry, Hillary Olson expects flowering rattlesnake master, swamp milkweed and purple coneflower to invite butterflies and people to spend some time there.

If the fragile pollinators show up, the urban museum will have both outdoor and indoor butterfly exhibits next to each other, said Olson, a museum vice president of community engagement. The Puelicher Butterfly Vivarium with its glass-enclosed tropical garden opened in 2000.

Honey locust trees at the Wells St. entry will remain in place to form a canopy over the new gardens and shade all visitors, including young students.

“Our educators will be able to go outside with some of our school groups and show them monarch butterflies on milkweed,” Olson said.

The Milwaukee County Board on Thursday will be asked to approve construction of the project. The board’s finance committee recommended approval at its May 18 meeting.

Pending board approval, construction would start by July 15 and be completed by the end of August, according to Olson.

Before the new gardens can be planted, contractors will install cisterns below new porous pathways with the capacity to store 32,000 gallons of water in a heavy rainstorm.

This water will be sprayed on the gardens to sustain the plants. But the primary purpose of the storage system is to keep that much water out of the combined sanitary and storm sewer that serves the museum, according to Ellen Censky, a senior vice president and academic dean.

Collecting the water where it falls will reduce the risk of sewer backups during storms, she said.

For that reason, both the Milwaukee Metropolitan Sewerage District and the Fund for Lake Michigan have contributed a total of $161,870 to pay the full cost of the museum’s green infrastructure project.

MMSD awarded an $81,870 grant to the museum for the project’s water storage capacity, and the opportunity to demonstrate green infrastructure measures that could be built just about anyplace else, including industrial, commercial and residential properties, Olson said.

Rain-capturing measures — such as rooftop plantings, gardens next to downspouts, cisterns, barrels and porous pavement — are described as green infrastructure because they supplement the capacity of traditional metal sewer pipe.

MMSD’s goal is to encourage property owners throughout the metropolitan area to build 740 million gallons’ worth of storage capacity by 2035. That volume is 42% more than the total deep tunnel system storage capacity of 521 million gallons.

The Fund for Lake Michigan provided an $80,000 grant to support the project.

One section of the museum entrance garden will showcase the five varieties of sedum, a groundcover plant, on the building’s roof. The green roof was installed in October 2001.

About 4,100 square feet covered with sedum can capture an estimated 90,000 gallons of storm water a year and keep it out of the combined sewers, Censky said. There is no estimate of the amount of water it collects in a single storm.

A solar energy wall was installed on the museum building in October 2014. The wall’s 230 solar panels generate enough electricity to run the butterfly vivarium for a year, including the energy needed to maintain its high tropical indoor temperatures throughout each winter, according to Censky.