One of the great messages to come out of the environmental movement of the 1960s and 1970s is that, while humans can cause pollution, they can also clean it up. Few success stories illustrate this point as clearly as that of Lake Washington. Lake Washington lies along the state of Washington's west coastline, near the city of Seattle. It is 24 miles (39 km) from north to south and its width varies from 2–4 miles (3–6 km).

For the first half of this century, Lake Washington was clear and pristine, a beautiful example of the Northwest's spectacular natural scenery. Its shores were occupied by extensive wooded areas and a few small towns with populations of no more than 10,000. The lake's purity was not threatened by Seattle, which dumped most of its wastes into Elliot Bay, an arm of Puget Sound. This situation changed rapidly during and after World War II...