NRCS Applications
Most NRCS applications fall within the categories
of:
(a) conservation planning,
(b) project planning,
and
(c) inventory and assessment.
Conservation Planning
In NRCS conservation planning,
the major application of this erosion prediction technology
is to predict sheet and rill erosion,
concentrated flow erosion,
and sediment yield
at specific field sites.
These predictions are made for
existing conditions
and for a proposed
set of alternative conservation practices
to provide erosion estimates used to guide the selection
of a resource management (soil conservation) system
for the specific site.
A resource management system is usually being chosen to control: (a) erosion
to a tolerable rate
for productivity maintenance,
(b) on-site deposition to prevent
excessive adverse effects from deposition,
(c)
sediment yield from fields to allowable rates
that prevent excessive off-site sedimentation, and
(d)
sediment yield
from fields to prevent excessive degradation of
off-site water quality.
Conservation planning in occurs at the field office level,
and it usually takes place in the field with the conservationist
working directly with the land user.
Not only does the prediction procedure
provide the erosion estimates
needed to develop the conservation plan,
it is a communication tool
that
helps the conservationist describe the erosion process
and
how
soil conservation practices work to control erosion.
Thus the technology must be based on concepts and principles that
can be easily understood and described
by the conservationist
to the client.
In this application,
the major need is to provide "accurate"
estimates using as few resources as possible and
to maximize the quality and quantity of service that NRCS field personnel provide to clients.
Project Planning
In NRCS project planning,
the prediction technology is used most frequently as a tool
to help:
(a)
determine the erosion control measures
and their distribution over a project area
needed
to meet specific project objectives,
(b)
estimate sediment yield and sediment characteristics
needed to design off-site water conveyance and
impoundment structures
and to evaluate off-site impacts from sedimentation,
and
(c)
estimate sediment yield and sediment characteristics needed to
develop erosion control plans for
improvements in downstream water quality.
The prediction procedure is applied
in the office using field data collected by field personnel,
and the application may be more computer intensive than
for conservation planning.
Comparing project planning to conservation planning,
project planning allows:
(a)
more expenditure of time and effort for collecting input data,
(b) more emphasis
on
detail for representative subareas
where computed results are expanded to
the
entire project area,
(c) more emphasis on
sediment delivery from fields,
and (d) greater use of
interdisciplinary teams,
although field personnel typically
collect field data for input.
Inventory and Assessment
As opposed to planning, which considers
"what if" questions,
NRCS
inventory and assessment activities are concerned
with determining erosion and sediment yield for
the present state.
Also,
rather than application to
specific fields, watersheds,
and project areas,
the analysis is usually computing erosion and
sediment yield at selected sample points and areas
and aggregating these results for county,
regional, state,
and national areal units.
The technology is usually applied in a
"national"
office where considerable computer and data base resources are available.
The inputs frequently come from
existing data bases
(e.g., climatic and soil files),
remotely sensed data,
and
surveys conducted by field office personnel.
The use of the technology and the analysis is
usually conducted by and under the direction
of an NRCS national assessment staff.
Any Comments Would Be Appreciated
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