better, results as land-based systems (underground storage tanks, stormwater treatment systems, biofilters, etc.). the proper lid solution is one that balances the desired results (controlling runoff and pollution) with the associated costs (loss of usable land for land-based systems versus capital cost of manufactured solution). green (vegetated) roofs are also another low-cost solution. iwm as a movement can be regarded as being in its infancy and brings together elements of drainage science, ecology and a realization that traditional drainage solutions transfer problems further downstream to the detriment of the environment and water resources. regulations federal requirements map of municipal separate storm sewer systems in the united states, the environmental protection agency (epa) is charged with regulating stormwater pursuant to the clean water act (cwa). the goal of the cwa is to restore all "waters of the united states" to their "fishable" and "swimmable" conditions. point source discharges, which originate mostly from municipal wastewater (sewage) and industrial wastewater discharges, have been regulated since enactment of the cwa in 1972. pollutant loadings from these sources are tightly controlled through the issuance of national pollution discharge elimination system (npdes) permits. however, despite these controls, thousands of water bodies in the u.s. remain classified as "impaired," meaning that they contain pollutants at levels higher than is considered safe by epa for the intended beneficial uses of the water. much of this impairment is due to polluted runoff, generally in urbanized watersheds (in other us watersheds, agricultural pollution is a major source).: 15 to address the nationwide problem of stormwater pollution, congress broadened the cwa definition of "point source" in 1987 to include industrial stormwater discharges and municipal separate storm sewer systems ("ms4"). these facilities are required to obtain npdes permits. in 2017, about 855 large municipal systems (serving populations of 100,000 or more), and 6,695 small systems are regulated by the permit system. state and local requirements a silt fence, a type of sediment control, installed on a construction site epa has authorized 47 states to issue npdes permits. in addition to implementing the npdes requirements, many states and local governments have enacted their own stormwater management laws and ordinances, and some have published stormwater treatment design manuals. some of these state and local requirements have expanded coverage beyond the federal requirements. for example, the state of maryland requires erosion and sediment controls on construction sites of 5,000 sq ft (460 m2) or more. it is not uncommon for state agencies to revise their requirements and impose them upon counties and cities; daily fines ranging as high as $25,000 can be imposed for failure to modify their local stormwater permitting for construction sites, for instance. nonpoint source pollution management further information: agricultural wastewater treatment and erosion control agricultural runoff (except for concentrated animal feeding operations, or "cafo") is classified as nonpoint source pollution under the cwa. it is not included in the cwa definition of "point source" and therefore not subject to npdes permit requirements. the 1987 cwa amendments established a non-regulatory program at epa for nonpoint source pollution management consisting of research and demonstration projects. related programs, such as the environmental quality incentives program are conducted by the natural resources conservation service (nrcs) in the u.s. department of agriculture. public education graphic distributed by epa public education campaigns education is a key component of stormwater management. a number of agencies and organizations have launched campaigns to teach the public about stormwater pollution, and how they can contribute to solving it. thousands of local governments in the u.s. have developed education programs as required by their npdes stormwater permits. one example of a local educational program is that of the west michigan environmental action council (wmeac), which has coined the term hydrofilth to describe stormwater pollution, as part of its "15 to the river" campaign. (during a rain storm, it may take only 15 minutes for contaminated runoff in grand rapids, michigan to reach the grand river.) its outreach activities include a rain barrel distribution program and materials for homeowners on installing rain gardens. other public education campaigns highlight the importance of green infrastructure in slowing down and treating stormwater runoff. dupage county stormwater management launched the "love blue. live green." outreach campaign on social media sites to educate the public on green infrastructure and some other best management practices for stormwater runoff. articles, websites, pictures, videos and other media are spread to the public through this campaign. history since humans began living in concentrated village or urban settings, stormwater runoff has been an issue. during the bronze age, housing took a more concentrated form, and impervious surfaces emerged as a factor in the design of early human settlements. some of the early incorporation of stormwater engineering is evidenced in ancient greece. a specific example of an early stormwater runoff system design is found in the archaeological recovery at minoan phaistos on crete.