THE OCCURRENCE, DISTRIBUTION, AND REMEDIATION OF TRANSIENT POLLUTION EVENTS IN AGRICULTURAL AND SILVICULTURAL ENVIRONMENTS

Transient pollution events occur in runoff from both agricultural and silvicultural environments. In agricultural runoff, transient pollutio n events may be associated with sediment, nutrients, and pesticides. D epending 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 streams and reservoirs, limiting seasonal primary productivity, changing the bala nce of functional groups, and altering reproductive cycles. Transient pollution events are most noticeable in surface runoff, but are also o bservable in shallow ground water. Such occurrences in both runoff and shallow ground water may be associated with natural seasonal events i ncluding the fall leaching of crop residues, or with cultural activiti es 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 practi ces (BMPs) must be designed to remediate transient pollution in agricu ltural storm events. Not only must total storm agrichemical loading to aquatic ecosystems be reduced, but also the transient agrichemical co ncentration peaks occuring within the storm hydrograph. Copyright (C) 1996 1996 IAWQ. Published by Elsevier Science Ltd