RAN: Redesigning the American Neighborhood Project
Stormwater Basics: Watershed Influences
Through soil analysis we can predict infiltration potential in the landscape. We can study the particular grain size of the soil, the actual pore space between the grains of soil, soil depth, and composition. All of these can speed or impede water filtration. This analysis can assist us in appropriate stormwater controls.
The geology of a watershed and its geomorphology (the science of surface landforms, geology, and climate) are of crucial importance in understanding the evolution of soils and conditions in a particular watershed. Through informed study of naturally occurring erosion and land patterns, we may better understand and predict the impacts of human influence.
Vegetation significantly affects watershed characteristics, both in regard to transpiration and infiltration, as the porosity of the soil can be greatly affected by root penetration. Filtration potential is also influenced by the physical pitch of the landscape.
Other significant factors include the size of the watershed compared to the tributary network (A large area draining into a small network will have more impact than a small area draining into a large tributary network).
The duration between storm events will also influence the amount of pollutants carried in stormwater runoff, as more pollutants accumulate over time during dry periods.
Last modified October 16 2009 10:38 AM