Since the beginning of the industrial revolution, inadequate treatment of human, animal, and industrial wastes has challenged those charged with providing potable water.1–3 In 1993, more than 100 people in Milwaukee died from Cryptosporidium, which underscored the reality that our treatment technologies for water supplies are not foolproof.3 Yet, leaking landfills, industrial lagoons, feedlots, and terrorists are perceived as greater threats to public health than runoff is.Building on green lands leads to paving those lands. As a result, rain that would otherwise fall into streams and recharge an aquifer are diverted. The impact of diversion can be seen when the areas downstream become flooded after heavy storms. Water quality is affected by uncontrolled development that leads to runoff from cars, houses, shopping malls, gasoline stations, and the other accoutrements of urban development.4 Water supplies can be damaged to the point of abandonment by residual debris, oil and grease, animal manure, tire residue, heavy metals, de-icing compounds, and pesticides that are washed into watercourses during precipitation events.Uncontrolled development has already threatened potable water supplies across the United States. The most prominent examples are New York City’s 1900-square-mile Croton and Catskill watersheds. Research has found that the major reservoirs, once characterized as producing the best drinking water in the United States, are now threatened by the sprawl-related runoff of street salts, nutrients, and hazardous contaminants.5A proactive policy option is to turn sensitive watershed land into a green buffer by purchasing it or by permitting the transfer of development rights to other less sensitive parcels. Building engineered structures that control runoff is another proactive policy option. We used an important public, potable, surface water supply in New Jersey to illustrate the need to proactively make land use, design, and engineering decisions in support of public health. Specifically, the research answered two questions: (1) What configurations of residential and light commercial land uses pose the most serious threat to water supplies? (2) What land use, design, and engineering options can be used to prevent degradation of water supplies?
