Luna Leopold

"When one observes the many and great changes that have occurred in some s since the beginning of the , he is inclined to the belief that a longer period of time was involved than he had been led to believe. is an example where lakes of great depth once existed in a locality that is now a true desert. Segments of giant fans, some faulted, have been built out on the dried-up lake basin. Some large s on the surface are so deeply weathered that a hammer blow will reduce them to . We are rapidly learning that certain are much more rapid than we have been wont to believe. But only recently have s attempted to determine by actual measurement process rates formerly the subject of general reasoning or speculation. Such measurement programs have documented the fact that rates of landscape change are greater than had earlier been suspected."

"Over a period of ten years, simultaneous measurement of storm rainfall and resulting during individual storms were made in small basins in the , California. By simple measurement, without any recording devices, data collected define a relation of basin lag time to drainage area. This lag time, expressed as time between center of mass of rainfall and center of mass of runoff, is a specific measure of some basin characteristics including the effect of . Using lag time relations, synthetic hydrography construction shows the effect of urbanization on peak discharge from a given storm. The method applied to one storm shows that urbanization increased the peak discharge by two fold."

"The excess of over loss to the is a surprisingly small percentage of the average precipitation. The average amount of water that falls as precipitation over the United States annually is 30 es. Of this total, 21 inches are returned to the atmosphere in the form of through the process of evaporation and transpiration from plants. The balance of 9 inches contributes to the maintenance of and the ."

"The fate of rivers would evidently not be disregarded by Leopold’s watchful eye. In the late 1950s, he and W.B. Langbein initiated what came to be called the Vigil Network, consisting of sections in small s where natural changes would be recorded regularly. Some of these have been operating continuously for half a century, and similar schemes are in operation in Israel and Sweden. Just as productive were some of Leopold’s rafting expeditions down rivers for which he needed depth and velocity data. In 1965, he surveyed 450 km of the in this manner (and again many years later with his distinguished collaborator, the physicist, soldier, and desert explorer ). Besides feeding into the morphometric work, these investigations paved the way for a concerted attack on the problems of and , presaged in a joint study of flood control with T. Maddock Jr. in 1954 and developed with T. Dunne in 1978 and D.L. Rosgen in the 1980s."