Some Minneapolis bodies of water boast membership in the Chain of Lakes: Harriet has a bandshell and boats; Calhoun brags about being the biggest; Lake of the Isles surrounds itself with idyllic mansions. But a few miles east of this collection of water, where anyone throwing a rock can hit a lake to skip it on, public water is a scarcer resource. In the middle of this relative desert is the long-neglected, long-polluted Powderhorn Lake. The community around the lake prizes it as a valuable resource: It's the centerpiece of the surrounding park's many well-loved events, and in winter passersby can pick up rental ice skates for free. But for decades the 24-foot-deep, 12-acre lake hasn't been pretty. In the 1960s, I-35W construction cut off the lake, already carved out of a marsh, from its freshwater supply. By the late 1990s the storm- and aquifer-fed water had gotten gross enough that activists started rallying to rid it of floating trash, blooming algae, and deteriorating shoreline. The city sank more than $800,000 into infrastructure improvements like "grit chambers" to clean storm water. Through the 2000s the park system lined the lake with barley straw, and neighbors planted nearly 100 rain gardens. Their work has paid off: Today, two species of native plants have returned to the lake, plus new types of stocked fish, like channel catfish, that some anglers even eat. And though the lake still has a ways to go before a swimming beach gets installed, in September 2012 it was taken off the list of the state's most polluted waters.