Mathematical models for nonpoint water pollution control

Abstract

“MATHEMATICAL models” have been used extensively since the late 1960s. During this same period, computers have become commonplace. And because mathematical models are expressed in a computer code, we can now understand what mathematical models are. While the term “mathematical model” may be new, all of us have used mathematical models since we took algebra in school. Such models are mathematical representaions of physical, chemical, biological, social, economic, and related processes. Many formulae that we use in our day-today activities are mathematical models. The expressions needed to provide a good assessment of nonpoint-source water pollution problems can be complex. But in most cases they are collections of relatively simple concepts put together in a way that can be used to study complex problems. One familiar model is the universal soil loss equation (USLE), a regression equation used to calculate long-term average annual soil loss from small areas ( 41 ). The USLE has been coded for solution by computer and is used in most Soil Conservation Service (SCS) field offices. The need for models Planning and control. Perspectives on water resource problems have changed in recent decades. The issues themselves have not changed, but knowledge …