|Smith Jr, Sammie|
Submitted to: Water Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 1, 1996
Publication Date: N/A
Interpretive Summary: Single rainfall generated storm events may be responsible for most of the yearly yield of sediment, nutrients, and pesticides, and may have a profound effect on the ecological health of streams and reservoirs. As best management practices (BMPs) are used more and more in the agricultural arena, the ambient or average environmental quality will improve. Legislation with respect to surface and ground water quality standards is becoming more stringent. Proper watershed planning demands that we better understand a major cause of offsite contamination from agriculture - the transient event. This manuscript examines the attributes, occurrence, distribution, possible biological effects, and the remediation of transient pollution events in the agricultural environment. The concepts presented in this paper will help to provide a better understanding of the effects of storm events and solutions to some problems for watershed planners, farmers, and pollution officials.
Technical Abstract: Transient pollution events may be associated with sediment, nutrients, and pesticides, and can occur not only on a storm to storm basis, but also within the storm hydrograph itself. Depending upon hydrological conditions, these events may be responsible for most of the yearly yield of sediment, nutrients, and pesticides, and may have a profound effect on the ecological health of steams and reservoirs, limiting seasonal primary productivity, changing the balance of functional groups, and altering reproductive cycles. Transient pollution events are most noticeable in surface runoff from either agricultural or forested environments, but are also observable in shallow ground water. Such occurrences in both runoff and shallow ground water may be associated with natural seasonal events including the fall leaching of crop residues, or with cultural activities including the application of fertilizers and pesticides. In either case, rainfall distribution and intensity become important factors in the magnitude of the transient pollution event. Best management practices (BMPs) must be designed to remediate transient pollution in agricultural storm events. Not only must total storm agrichemical loading to aquatic ecosystems be reduced, but also the transient agrichemical concentration peaks occurring within the storm hydrograph.