Stormwater May 2012 : Page 45
of them 32 feet in diameter—that hold as much as 521 million gal-lons of runoff until it can be sent through the wastewater treatment plant. The Deep Tunnels lie 300 feet below ground, blasted and drilled out of solid bedrock. Sha-fer has called the tunnel system “the biggest, most effective mea-sure we took to reduce CSOs.” Another type of hard infra-structure is the harbor siphons. This $138 million project saves room in the Deep Tunnels by get-ting more runoff into the Jones Island Waste Water Treatment Plant faster. MMSD is making some older sewer lines last for another 50 years by adding liners fi lled with a special resin. Hot water is sent through the pipes to turn the resin as hard as fi berglass, seal-ing any cracks. This project saves millions of dollars and keeps residents happy because entire streets don’t have to be torn up for weeks at a time. But MMSD needed a broader approach to deal with stormwa-ter, one that would focus on infi l-tration onsite and on prevention. The agency serves 28 communi-ties within 420 square miles and seven watersheds. The service area’s population is 1.1 million and growing. Back-to-back fl oods in 1997 and 1998 from 1% probability storms caused major damage in MMSD communities. The June 1997, fl ood forced hundreds of Milwaukee residents to leave their homes, closed freeways, and resulted in $90 million worth of damage. MMSW began buying and removing homes and other buildings in the areas that suf-fered the heaviest fl ooding. The department also built berms and fl ood walls. Years with the heaviest storms forced MMSD to cope with 50 combined sewer overfl ows (CSOs) per year. Shafer and other city offi cials knew they had to do something and, as expensive as grey infrastructure is, they had “Ten years ago, the idea of a regional sewerage district using a program like Greenseams for stormwater management was relatively unheard of.” to do something different. They knew that undeveloped land —which provides a natural green sponge to remove pollutants and absorb or slow the volume from heavy storms—would not stay va-cant forever. The undeveloped land that was needed now for stormwater to infi ltrate would be needed even more in the future. By then it would likely be devel-oped or otherwise unavailable. Protecting the watersheds in and around Milwaukee meant cleaner water beyond the met-ropolitan area. These water-sheds drain into the Milwaukee, Menomonee, and Kinnickinnic rivers. They also drain into Lake Michigan. Greenseams started in 2001. The program allows MMSD to purchase either undeveloped property or a permanent conser-vation easement to it. All but two properties have been outright purchases. Sales are voluntary only; no land is condemned. Properties must be 25 acres or more to be included in Green-seams, unless they are adjacent to already preserved conservations lands, parks, or municipal open areas. Priority is given to prop-erties that have water-absorbing (hydric) soils. One acre of hydric soil can hold 2 acre-feet of water. To date, Greenseams has ac-quired 75 properties totaling more than 2,200 acres. These properties hold 1.325 billion gal-lons of water. Some of the land was in agricultural use and about 400 acres have been restored to a precultivated state. Jessica Hrobar, a former proj-ect assistant for the Conservation Fund in Milwaukee, last year es-timated that by the end of 2011, Greenseams would have acquired about 100 to 150 more acres, in six or seven pieces of property, bringing the total amount of Greenseams land to 2,400 acres. Greenseams does more than acquire open land and leave it that way. More than 33,000 trees have been planted, to soak up rainfall and form riparian buffers that stabilize streambanks to pre-vent erosion. Greenseams is also part of MMSD’s ongoing efforts to educate government offi cials and the public about stormwater. “Working with the surround-ing municipalities has been a key component to the Greenseams program,” noted Hrobar. “Many Greenseams sites have been transferred to the local town, city, or village and become part of their comprehensive open space plan.” Greenseams has joined with area conservation organizations on particular projects. Such joint ventures offer MMSD additional opportunities to educate the public about stormwater. For ex-ample, the River Revitalization Foundation (RRF) has worked with Greenseams on the acquisi-tion of two properties along the Milwaukee River in highly urban, developed areas. And Green-seams and the Ozaukee Washing-ton Land Trust (OWLT) worked together to buy land in Mequon, including 34 acres of bald eagle habitat along Lake Michigan. Greenseams has spent $22 million, with $8 million coming from state and federal programs. Its main funding comes from MMSD’s annual budget. Another major source of funding is the May 2012 www.stormh2o.com 45
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