|
|
||
 4.2 WATERSHED TECHNIQUES
The agricultural perspective of watershed management is multidisciplinary and multiagency in
nature. Farm history, rural sociology, economics, planning, agronomy, soil science, and engineering are
typical disciplines found in successful watershed water quality projects. Agency participants may
include the Soil and Water Conservation District, the United States Department of Agriculture-Natural
Resources Conservation Service (USDA-NRCS), Cooperative Extension Service, USDA-Farm
Services Agency, and others. Agency representatives having experience in a total of many disciplines
often work together to plan and implement a watershed project.
A one to two year pre-implementation planning period is needed to identify and document the
water quality problem, develop objectives and goals, garner community and farmer support, and target
critical areas for treatment (Gate et al, 1993). Pre-implementation planning may also include advance
information and education programs, surveys to identify needs, and writing BMP implementation plans
for farms already identified for treatment. Watershed planning may proceed as the result of a voluntary
or legislative initiative.
4.2.1 TARGETING OR COMMAND AND CONTROL
A proven approach to achieving management objectives is to set priorities and direct resources
to the greatest need. Land treatment must be targeted to critical areas or pollutant sources where the
greatest improvement in water quality can be achieved for the least investment in BMPs (Maas et al.
1987). Defining critical areas involves identifying the greatest pollutant sources and assessing the
hydrologic transport system, beginning at the water resource and moving upgradient to pollutant
sources near major tributaries, lower order waterways, and then headwater streams. Land treatment
can then be targeted by first estimating the magnitude of the pollution potential of the sources and then
ranking them with respect to the quantity of pollutant(s) expected to affect the water resource. In this
way, the resources of the project can be focused on the major sources of pollution, thereby increasing
the probability of reducing pollutant exports and reversing the water quality impairment.
Develop scientific criteria for identifying critical areas and apply the criteria consistently. For
watersheds with animal waste issues, evaluate the pollution potential of cattle lounging in streams,
untreated animal operations, exposed manure piles, and land application areas. For sediment problems
resulting from eroding cropland, evaluate erosion potential, existing BMPs, the distance of the source to
the receiving water body, and the potential for pollutant trapping in the stream system. Pollutant
transport models such as AGNPS (Young et al. 1995) may be used to develop scientific criteria to
identify critical areas.
Command and control results when BMPs are mandated by the federal or state government.
For example, the federal government has imposed the CAFO regulations for confined animal
operations. In North Carolina, the Environmental Management Commission proposed rules in the
4.2-1
|
||
|
||
