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Water: Watershed Central

Set Goals and Identify Solutions - Identify Critical Areas

As part of your screening process you will want to identify which management practices can be implemented in the critical areas that you have identified, as required in element c of the nine minimum elements. Element c is "A description of the nonpoint source management measures that will need to be implemented to achieve load reductions and a description of the critical areas in which those measures will be needed to implement this plan." At this step, you will continue to refine the groupings as you conduct your loading analysis, target your management measures, and identify final critical areas. As you identify the pollutant sources and calculated the estimated load reduction needed, you identify which geographic areas are “critical” to implement management practices to achieve those load reduction.

In general, management practices are implemented immediately adjacent to the waterbody or upland to address the sources of pollutant loads. Streamside practices include streambank protection and riparian habitat enhancement to address the channel, floodplain, and riparian corridor of the waterbody. Upland management practices are typically divided into practices for agricultural lands, forestry, and urban developed lands.

You can use a geographic information system (GIS) or hand-drafted maps to conduct an analysis of management opportunities. A simple mapping analysis for a rural residential and farming area that has nutrient problems might include the following geographic information: location of section 303(d)-listed waterbodies, existing agricultural areas (using a GIS coverage of existing land use or land cover data that indicates grazing vs. cropland if possible), areas where existing management practices are being employed (if any), and the degree of riparian buffer disturbance. Most often, these maps can be generated using the land use/land cover databases and watershed tools from the scoping and watershed analysis.

For example, Figure 10-2 (PDF) (528 pp, 26K, About PDF) on page 10-15 of EPA's Watershed Handbook shows a map that was generated to identify the critical areas in which management practices are needed in the rural Troublesome Creek watershed. The map shows impaired waters with the percentage of disturbed buffer areas in the Creek. The subwatersheds with more than 15 percent disturbed areas indicate potential for riparian restoration efforts to limit sedimentation loading. In the map, these are T1, T6 and T8. The other subwatersheds have medium high potential for restoration efforts.

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