In the late 18th and early 19th century Philadelphia, Boston, New York and other coastal cities in the United States grew rapidly, powered by increased trade, manufacturing and immigration. These changes led to increased demand for water and public health problems arising from polluted water supplies. The first U.S. city to confront this problem was Philadelphia, which grew from 41,000 in 1800 to 1.3 million in 1900. After outbreaks of yellow fever in the 1790s killed thousands of people, Philadelphia sought cleaner supplies. Its leaders turned to the engineer Benjamin Latrobe, who developed a waterworks by diverting the Schuylkill River and using steam engines to pump water to a high level to distribute to the population. Philadelphia completed the first section in 1801, but it quickly became inadequate and turned to an expanded system in what is now Fairmount Park between 1812 and 1815. (See above).
Urban areas have continually struggled to meet increased demand for water, but conservation has become an increasingly important tool. This is particularly true in the desert environments of the west and southwest of the United States. Las Vegas, one of the fastest growing urban areas of the last decade, annually receives only 4.5” of rain and has to rely on Lake Mead, a reservoir created by the Hoover Dam on the Colorado River, for 90% of its water. A severe drought threatens this supply and it is possible that the lake could run dry by 2021.
To look at the fountains on the strip in Las Vegas, the city and its economic engine appear to be profligate users of water, but the reality is different. For instance, the spectacular water show at the Bellagio Hotel uses recycled ground water so it places minimal strain on Lake Mead. On a larger scale, the Southern Nevada Water Authority recycles 40% of its wastewater to use in power plants, construction and irrigation, compared to a national average of 6%. With a growing population and worsening droughts that many scientists regard as due to global warming, the United States will have to increase conservation and wastewater recycling to maintain adequate supplies of water to cope with these changes.