Land use substantially affects the type and extent of nonpoint source pollution of water bodies. For example, soil erodes naturally from undisturbed land, but the amount of erosion can increase manyfold when trees are cut or the land is farmed. In addition, when land is used for housing or urban development, erosion from land clearing and excavation during construction can increase tremendously. Moreover, land use activities can also produce toxic pollution. For example, pesticide use in farming has resulted in toxic runoff, and mining has produced leaching of heavy metals and acid mine drainage. Nonpoint source pollution can have long-lasting impacts. For instance, a heavy rain can wash tons of soil from a field, and the material can either scour a streambed or settle out and cover gravel that fish spawn in. Long after the water itself clears, populations of fish and other aquatic life may still not have recovered. Similarly, when trees and bushes are cut next to stream banks, debris falling into the stream or washing into the water may initially degrade the water, but a longer-term problem may be caused by persistent elevated water temperatures resulting from the removal of shade. In time, altered water temperatures can make the stream a less sustainable habitat for fish and other animals or may make it totally uninhabitable. For nearly 40 years, the Clean Water Act has played a critical role in reducing water pollution and improving the health of the nation’s waters, including rivers, lakes, and streams. The purpose of the law is to restore and maintain the chemical, physical, and biological integrity of the nation’s waters. Passed by Congress in 1972, the act marked a shift in clean water policy, establishing a significant federal role in controlling point sources of water pollution. Through the 1980s, EPA issued a series of reports, including a key 1984 report to Congress, finding that in the decade following passage of the act, control of point sources had resulted in significant achievements toward water quality goals but that these point source reductions had illuminated the nonpoint source contribution to For example, at that time, a majority of EPA water quality problems.regions identified nonpoint sources as the principal remaining cause of water quality problems. In 1987, Congress amended the Clean Water Act, adding section 319 and creating the nonpoint source management program. Section 319 provides for annual grants to be administered by EPA and incentives for states to develop and implement nonpoint source management programs. Section 319 includes various minimum conditions that states must meet to receive grants, including the development of nonpoint source management programs—which EPA must approve—and annual reports on states’ progress in achieving the goals of their management programs. States must also obtain a determination from EPA that they made “satisfactory progress” in meeting their goals from the prior year. For its part, EPA has discretion by statute to add terms and conditions to grants; to require additional information on applications; and to request additional information, data, and reports it considers necessary to determine continuing state eligibility for grants. The 1987 amendments to the Clean Water Act created the nonpoint source program, but EPA did not receive an appropriation to implement the program until fiscal year 1990. In the early 1990s, EPA focused on developing technical support for states’ use in developing and implementing their programs. During these initial stages, some states and EPA regions focused their nonpoint source programs narrowly on demonstrations of particular pollution control technologies. In response to EPA program guidelines issued in 1996, states upgraded their programs, and in so doing, several states incorporated watershed-based approaches as a significant and sometimes central organizing theme. These states focused their pollution reduction efforts in specific watersheds—areas of land through which all the rainfall and streams flow downhill toward a main river channel (see fig. 1). According to EPA documents, state nonpoint source programs that adopted this approach improved their capacity to solve nonpoint source pollution problems. In the early 2000s, EPA encouraged states to sharpen the focus of their nonpoint source management programs toward impaired water bodies. Specifically, EPA and the states determined they needed to target their efforts to reduce nonpoint source pollution within defined geographic areas representing the most severe water quality problems. According to EPA documents, the two key steps states need to solve nonpoint source problems at the watershed level are the development of a watershed- based plan that addresses water quality needs within a watershed and the actual implementation of the plan. In 2003, EPA issued Federal Register guidelines for the section 319 program, which remain in use today. These guidelines followed a substantial increase in appropriated funds. Key features of the guidelines include the following: The guidelines direct states to use about half their section 319 grants to develop and implement watershed-based plans for impaired watersheds. Beyond targeting funds to geographic areas in need of restoration, the guidelines also allow states to fund activities that generally support section 319 goals, such as technical assistance, staffing, projects that demonstrate innovative approaches to pollution reduction, and education programs that promote awareness and changes in behavior. EPA’s 10 regional offices, which provide oversight of the section 319 program, are to place special emphasis on reviewing states’ progress in developing and implementing watershed-based plans according to the guidelines. Regional offices are to review and discuss with states the projects states select for section 319 funding to ensure the plans’ effective implementation. It is through this review process that regional offices have the opportunity to influence the types of projects states select if they believe that the projects selected by a state are not adequate to effectively reduce nonpoint source pollution. States are encouraged to leverage section 319 funds with projects from other federal programs that have water quality objectives, including USDA’s Environmental Quality Incentives Program (EQIP).This program is designed to fund conservation practices on working agricultural land to achieve national priorities, including reducing soil erosion and nonpoint source water pollution. The guidelines state that section 319 funding is especially suitable for supporting activities that either are ineligible for or typically do not receive significant USDA funding, including developing watershed-based plans in impaired watersheds, monitoring water quality, and funding staff to work with local communities to help assist and promote the development and implementation of watershed-based plans. Under EPA’s section 319 program, states retain the primary role for addressing nonpoint source water pollution. EPA’s 10 regional offices annually distribute program funds to the states using a formula that is weighted heavily toward state population and the number of acres in agricultural crop production. States develop their own project selection processes and the criteria that their nonpoint source management programs will consider when determining what projects to fund. Annually, each state submits its list of selected projects to the EPA regional office for incorporation into the state’s work plan, which describes what projects will be funded through section 319. Organizations that apply for section 319 funds—often including conservation districts, local governments, and nonprofit organizations—submit project proposals to states’ nonpoint source management programs and, if selected, are responsible for implementing their proposed nonpoint source pollution projects under an agreement with the state. Section 319 is a nonregulatory program, and many states therefore rely primarily on voluntary approaches to address nonpoint source pollution. The programs’ nonregulatory status, combined with private ownership of much of the nation’s land, means that securing voluntary landowner participation is a key aspect of nonpoint source pollution control and, according to EPA, can introduce significant uncertainty in how and when projects are implemented. Under EPA’s section 319 program, states have funded many projects that have helped successfully address nonpoint source pollution and restore and protect water bodies across the country, but states have also funded projects that have encountered significant challenges—including many that could have been prevented. This section discusses (1) the types of projects states have selected to address various categories of nonpoint source pollution, (2) the successes some section 319-funded projects have achieved in restoring impaired water bodies, and (3) projects states have funded that encountered preventable challenges. States’ nonpoint management programs have used their annual section 319 grants from EPA to fund projects that address different categories of nonpoint source pollution. The scope of individual section 319 projects varies considerably; common activities include direct implementation of conservation practices, education and outreach efforts, water quality monitoring, and funding of state nonpoint source management program staff. According to data from EPA’s Grants Reporting and Tracking System, from fiscal year 2004 through fiscal year 2010, states awarded more than $1.2 billion in section 319 funds to more than 5,800 projects. Projects have been funded in all 50 states and by many tribes and have been targeted to seven different categories of nonpoint source pollution, mainly agricultural, urban and stormwater runoff, and hydromodification (see fig. 2). States funded section 319 projects that supported a mix of direct and indirect approaches to help restore, protect, or prevent further degradation of water quality. Direct approaches generally involved projects implementing conservation practices or other corrective actions to directly reduce or eliminate pollutants entering a water body. Common direct approaches included, but were not limited to, agricultural conservation practices, such as the installation of fences to exclude cattle from shorelines or stream banks; erosion control projects; and stormwater discharge projects such as the installation of surfaces in parking lots that absorb rainfall rather than allow it to run off into urban streams. Indirect approaches typically involved activities to help build state and local capacity to address nonpoint source pollution, raise public awareness, and assess water quality in particular places of concern and commonly involved methods such as education and outreach, watershed planning, and staffing. According to our analysis of EPA data, approximately 45 percent of projects that states funded in fiscal years 2004 through 2010 under section 319 involved direct approaches and were designed primarily to implement activities to directly restore, protect, or prevent further degradation of water quality. The categories of pollution that were the most common focus of direct restoration approaches—such as implementing agricultural conservation practices, stabilizing stream banks, or restoring a stream’s natural channel configuration—include agricultural pollution and pollution resulting from urban and stormwater runoff (see fig. 3).