MM-4 (8/25/04 version)
Watershed Restoration And Protection Strategies:Overland Transport Of Pollutants
This restoration component, shown as item C in Figure 1, includes transport of contaminants both overland and via drainage outlets (including agricultural tile drains and stormwater drains) to receiving waters. Therefore, management practices to address chemicals and sediments may be necessary if:
- available data indicates that aquatic life use attainment is impaired or threatened; AND
- high magnitude causes and sources of impairment or threat include chemicals, bacteria and/or sediment
A considerable amount of jargon exists to describe the mechanisms to address nonpoint sources. Terms include best management practices (BMPs), management practices, management practice systems, management measures, and resource management systems (RMSs).
Management practices that focus on overland transport of pollutants, control the delivery of nonpoint source (NPS) pollutants to receiving water resources, and are generally designed to:
- minimize pollutants available (source reduction);or
- retard the transport and/or delivery of pollutants, either by reducing water transported, and thus the amount of the pollutant transported, or through deposition of the pollutant on land; or
- remediate or intercept the pollutant before or after it is delivered to the water resource through chemical or biological transformation.
Management practices that focus on overland transport are generally designed to control a particular pollutant type from specific land uses. However, there are situations where a management practice systems approach is desirable, particularly where:
- it is necessary to control more than one type of pollutant;
- sediment transport, or lack thereof, is a key factor hindering a self-sustaining stream channel.