The Musconetcong (New Jersey) and the Sudbury-Assabet-Concord (Massachusetts) are federally-designated Partnership Wild and Scenic Rivers, a model for river conservation under the Wild and Scenic Rivers Act. These two rivers are embedded in a patchwork of private and public land ownership. The Act has been used to facilitate partnerships among municipal, state, federal and local non-profit actors to implement river conservation plans. These partnerships have supported community science-based monitoring to make the case for dam removal and stricter water pollution controls. Two case studies examine using community science to provide actionable data to decision-makers. In New Jersey, a documented increase in macroinvertebrates post-dam removal supported additional dam removals, leading to the return of American shad to the river. Quality controls and training proved to be key components. In Massachusetts, stricter effluent discharge permits reduced instream Total Phosphorus from 0.8 mg/L in 1999 to the eutrophication threshold of 0.023–0.05 mg/L. Community engagement in river science and stewardship was an important co-benefit. As many US rivers evolve from generating hydropower and conveying waste into major recreational resources, local organizations are uniquely positioned to engage the public and generate quality-controlled data to use in advocating for major improvements in water and habitat quality. Useful policy and regulatory frameworks for broader applicability are suggested.