Surface transport of microorganisms by water

Several studies have reported on the quality of runoff from land that has received either an application of livestock waste or been utilized as a pasture for livestock. Unfortunately, these studies have not directed their efforts to understanding and developing the relationships among several of the important parameters that influence runoff quality. One of the reasons for this deficiency is that the list of influencing parameters is quite long. Nevertheless, it is important to identify the parameters and their probable impact on movement of organisms in water. The microbiological aspects are influenced by the fate of organisms in the environment. Radiant energy (sunlight), temperature, available nutrients, presence of toxic materials, available moisture (precipitation and humidity), and soil pH all influence the death/growth rate of the organisms in question. Site characteristics, such as slope, vegetative cover, antecedent moisture content, soil type, organic matter content, infiltration rate, and surface condition of the soil, all influence microorganism movement. Hydrologic factors, such as frequency, duration, and intensity of rainfall, are very critical in determining the characteristics of runoff events that provide the transportation to move introduced organisms from their application site. There are very few models today that can be used to calculate the microorganism population in runoff. While many of the influencing parameters have been identified, there has been little research on the surface transport of microorganisms.