The great focal points of civilization placed their roots along streams and in sheltered harbors because man needed to be near water for navigation and housekeeping and because it provided protection. There was little thought of caring for the bountiful supplies of water which seemed endlessly renewable. Within living memory the supplies of fresh water in the beautiful streams and lakes of North America were legendary. But suddenly in the 20th century we have at last begun to sense that both the water and soil of the earth are limited. We now realize that we cannot run off to a clean new place each time we have fouled our nest. We shall have to learn to manage our affairs and our immediate environment. We are sickened by the spectacle of the trash and refuse of our own activity. We become uncomfortable in our role as stewards of this wonderful resource, for we do not understand how we may both use and protect it. While we have been engaged elsewhere, the rampant growth of aquatic weeds has come to be one of the symptoms of our failure to manage our resources. We assign values to the depreciation of property, to the pollution of municipal water supplies, to the loss of navigable streams, and to the failure of irrigation and power systems because of aquatic weeds. But we must also judge the worth of clean water for man in other, quite different ways. Some of the loveliest places on earth are at the water's edge. These may be the sites of our dwellings or the places that we choose for rest and renewal. As we spoil these, one by one, we shall know that we have surrendered a great part of our humanness, and we shall be anxious because we cannot trust ourselves. Now we must abandon our view that streams and lakes are great self-cleansing reservoirs that can receive our wastes forever and return to us always as cool, clear water. Many of the water-courses of Asia and Africa, and of Wisconsin and Florida, are now so fertile and so well innoculated with aquatic weeds that they can no longer correct themselves. In many of these places, it is now too late to talk about an equilibrium or the balance of nature. Human activity and neglect have driven the equation far to the right. Within the combinations of mechanical, biological, and chemical methods of aquatic weed control we can find the tools to help with their restoration. We can keep the waterways open so that they can be useful to man and so that he may enjoy them. We can buy the time we need to learn to manage not only the vegetation but each of the resources in an entire watershed.
