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The Soil Conservation
Service was born from a nightmare that whirled out of
the Plains states in the 1930s. Years of drought and
poor agricultural practices had stripped the earth of
natural ground cover that held the soil in place. When
powerful wind systems swept across the parched land,
they churned up clouds of dust, darkening the sky and
forcing the migration of hundreds of thousands of people,
as described by John Steinbeck in the novel The Grapes
of Wrath.
In the wake
of the Dust Bowl, the United States Department of Agriculture
(USDA) began to see soil erosion as a national menace.
The Interior Department handles public lands, but because
about 70% of land in the US is held by private landowners
- chiefly farmers and ranchers - USDA created an agency
dedicated to controlling erosion by promoting responsible
stewardship of private land.
That agency's name has since changed to the Natural
Resources Conservation Service (NRCS), and it has become
USDA's lead conservation agency. In addition to
monitoring soil quality and working with landowners
to ensure environmentally sensitive farming and grazing
practices, NRCS restores wetlands to foster animal and
plant life, reinforces streambanks, and designs terraces
to control flooding. The agency works to prevent runoff
of sediments and animal wastes, and it builds dams to
control the growth of gullies that have cut into the
slope of a hill over the years.
Strong
Local Presence
NRCS was conceived as a vast network of local offices
that could be active on the most "micro"
levels, engaged with individual landowners and properties.
As such, it maintains offices in 3,000 conservation
districts, virtually one for every county in the nation.
Along with NRCS, these USDA Service Centers usually
include staff from other USDA operations, such as the
Farm Service Agency, as well as the local county government's
own conservation division. They have had more than enough
work to do: Since 1993, these centers have experienced
an average 78% increase in workload while their staffs
have been reduced by 22%, according to USDA.
To boost the productivity and efficiency
of NRCS staff, a few years ago USDA instituted the Service
Center Modernization Initiative, which focused on bringing
labor-saving technologies to the field offices. These
include new computer servers, digital cameras, global
positioning system (GPS) devices for surveying, and
geographic information system (GIS) software for the
mapping and design tasks the field staff routinely handles.
Computer-aided design (CAD) products that draw upon
GIS and GPS mapping advances are one of the tools that
have allowed NRCS engineers to make complex measurements
more easily and generate designs for dams and wetland
restorations much faster than when their work was done
on paper.
The NRCS operation in Wisconsin offers a model snapshot
of the agency's use of engineering software. Wisconsin
has a higher percentage of privately owned farmland
than most other states, a robust network of local conservation
offices, and some unusual geographical challenges that
make erosion control a high priority.
Step
One Is Topography
Wisconsin's NRCS headquarters in Madison
is divided among technical areas, such as geology, forestry,
wildlife, and grazing, and the agency's engineering
division is overseen by John Ramsden. In 1998, Ramsden
began implementing electronic tools. "Whether
we're doing flood prevention, sediment retention,
or building a terrace, the common task they share is
that we need to have topographical maps of the area
we're going to design in," Ramsden says.
"So our technicians go to the project site and
they take measurements - it could be hundreds of
points. These are downloaded into Land Desktop, and
at that point we can very quickly turn out a map showing
surface topography." Land Desktop, from Autodesk,
works with the basic drawing platform AutoCAD.
"This map becomes the base on which we layer design
features, and the software gives us the freedom to adjust
volumes or dimensions. We can look at several possible
versions, which took much longer with paper drafting,"
Ramsden notes. "We can very easily make a dam
or an embankment higher or steeper. We can see what
an excavation would do to roads or make sure we're
not infringing on a wetland. If the curves on a stream
are too sharp and we need to reinforce the banks, we
can refer to the topography to get the best stream alignment."
Many of the Wisconsin NRCS field offices are co-located
with the local counties' Land Conservation Department
offices, and because the majority of these were already
using an Autodesk design standard, Ramsden says this
was another reason for the NRCS to use the same platform.
"We work closely together with our local counterparts - we
use the same federal manual for design specifications,"
he says. "We need to be able to pass files back
and forth; it has to be seamless."
Pinpointing
Site Locations
Mike Dreischmeier, an engineer in the NRCS Dodgeville
office who's one of the agency's more knowledgeable
AutoCAD users, learned the software in 1995 as a county
student intern. He remembers what field engineering
work was like before CAD: "You had to record horizontal
and vertical angles, stadia and rod readings, and then
back in the office you'd have to hand-plot them
all on a drafting table. Now you can just use a total
station [for surveying] and plug it into a computer.
Land Desktop shows you a plot of your survey, with coordinates
and elevations. We can create 3D digital terrain models
to show surface contours. When we move to design, we
can plot cross-section and profile views of storage
pits, berms, or drainage ditches we need to excavate."
Dreischmeier notes one feature that
has proved handy is the ability to move in reverse:
taking specific points from the map of an emerging design
and locating them out in the real world. "You
can upload points from your drawing back into your data
collector, go out to the job site, and figure out exactly
where the endpoints will be of the dam you designed,"
he explains. "It allows you to locate points that
aren't tied to objects - for example, if you're
building an embankment but you can't pull a tape
measure out to the end of it from the corner of a building.
So you put the instrument at the proper angle, and then
it directs you out to the right spot, accurate to a
tenth of a foot. I used to say you could put a quarter
on the ground and find it in the same place a few weeks
later."
Pilot
Dam Rehab Project
The Eau Claire
area office of NRCS is in the northwestern quarter of
Wisconsin, in a region that was named the "Driftless
Area" because it was missed by glaciers. Whereas glaciated
terrain is much flatter and speckled with lakes, the
topography of the Driftless Area is steep and hilly,
a high-relief landscape of grand bluffs, crags, and
ridges perched over narrow, twisting valleys. Those
factors mean more erosion as stormwater flows faster
down the hills, carrying sediments with it and carving
trenches into the land - and more challenges for NRCS.
CAD tools have become essential for Laurel Qualley, a
civil engineering technician in the Eau Claire office
who works primarily on larger "pilot dams"
that were built 25-30 years ago under a federally funded
project called PL 566. Those dams, which were built
to block gully erosion by channeling stormwater through
pipes dug under earthen berms, are now beginning to
fail; their pipe seams are separating and allowing sediment
to seep in. US Senator Herb Kohl won federal funds for
NRCS to rehabilitate the dams, and the first part of
each job entails creating all-new AutoCAD drawings to
replace a pilot dam's original Mylar plans.
"We resurvey everything - the surface contours,
the dam's pool area - and we calculate how
much grading we have to do, how much water will be going
through the pipe," describes Qualley. "Then
I'll go into Autodesk Civil Design and draw the
steel schedules, the grading areas, and the concrete
details. Every part of the design process has been streamlined
tenfold. I can change scales quickly, move a dam upstream
or downstream, recalculate everything."
Qualley says the Wisconsin NRCS maintains a popular Web
site where engineers can download AutoCAD templates
for "standard elements" of projects that
are frequently used, such as concrete walls, vegetative
covers, pipe supports, and the trash racks that cover
pipe inlets. "The site has more than 150 different
drawings, and I use it for everything. Before we would
use three-ring binders and copy drawings from file cabinets.
Now the final drawing packages look much more professional."
Restoring
Wetlands
Beth Kleisath, an engineer in the Eau Claire office,
works on the agency's Wetland Reserve Program
in which landowners receive a payment for granting an
easement on their land that allows NRCS to convert large
plots back into wetlands. If a farmer has dug ditches
and installed tiles to drain water from cropland, field
staff will break up the tiles and plug the ditches so
that the field returns to its native wetland state again.
NRCS will excavate "scrapes" that will become
small ponds and attract waterfowl. The scrapes need
to be built with varying depths, with deeper scrapes
holding water longer in a dry spell. "We try to
give the terrain a microtopography so it's not
all one level," says Kleisath. "Some plants
and animals like 6 inches of water, others like 2 feet."
If Kleisath is designing an earthen embankment in a wetland
or a gully, she uses a Land Desktop feature called Grading
Wizard to figure out volumes. "On the terrain
map, I'll draw the length and height of the embankment,
and it will show the total volume of fill that is necessary
for construction," she explains. "If we're
excavating a manure pit, the software calculates how
much earth we'll have to remove."
"It's important because we can give these
numbers to contractors and receive accurate cost estimates
for the projects," Kleisath notes. "It's
been a huge time-saver for us."
EC
- July/August 2003
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