Nutrient Export in Relation to Land Use

Abstract

Nutrient yield of land surface will be considered here in relation to land use. The central information base for this purpose is the representative watershed program, in which nutrient loss was measured for individual small watersheds dominated by particular land uses. The names and locations of the representative watersheds are shown in Figure 54. The watersheds represent eight different land uses: undisturbed (background), roads, interstate highways, residential development on sewer (nonpoint component), urban development on sewer (nonpoint component), residential development on septic, ski areas, and Climax Molybdenum operations. The nutrient yields from these representative watersheds are considered in sequence below. For each of the watershed types except the undisturbed type, the background nutrient yield is subtracted from the total yield and the residual is related quantitatively to the intensity of land use by some index such as the number of persons per unit area or the percentage of affected area. After the nonpoint sources have been treated in this way, consideration is given to the contributions per capita from small and large point sources (wastewater treatment plants).