Rainfall and relative losses in various forms

Abstract

Interest in rainfall and the consequent losses which‐occur from the land‐surface in various forms has been manifested for many, years by the membership of the Section of Hydrology as well as by other workers. During the past six years the Soil Conservation Service has been interested in this subject, recognizing that in the humid regions water is the primary agent of erosion and in the subhumid regions knowledge of the hydrologic cycle is important in connection with the conservation of water.At various times many different workers have reported separately the results of their work on the measurement of precipitation, losses in the form of runoff, transpiration from various kinds of plants under various conditions, and evaporation of water either from soils or free water‐surfaces. There has been very little work reported, however, in which these separate phases of the problem are studied in relation to each other. We have little information on the effect of the relative losses in one form upon the relative losses in some other form. It is desirable to know, for example, the effect of increased transpiration upon the relative movement of surface‐water to ground‐water, or the effect of reduced runoff upon consumptive use of water. It is desirable to know the relative effect, or at least the direction of trend of the effect of such factors as soil‐type, degree of land‐slope, length of land‐slope, characteristics of rainfall, vegetal cover, temperature, soil‐structure as affected by the chemical and physical properties of the soil and as affected by its mechanical treatment, and others of perhaps lesser importance upon the relative losses of precipitation from the land‐surface.