|
 |
 |
Georgia
Restoration of a Riparian Forest -
An Agricultural Water Quality Improvement Project
Intensively farmed areas can maintain good water quality if riparian
forests are left in place along the streams draining agricultural areas. Such
forested areas are usually wetlands; they filter water and prevent excess
chemicals, dissolved solids, nutrients, and sediments from reaching downstream
waters. Therefore, the reestablishment of riparian forests that have been cut
or drained can also be expected to contribute to water quality
improvements.
Until now, the benefits of restored riparian forests on water quality have
not been demonstrated or evaluated in the Southeastern Coastal Plain. This 319
project a riparian restoration in the Sewanee River Basin near Tifton, Georgia,
became the first to focus on the efficiency of the restored forested wetland to
store and remove nutrients.
The project was designed to reestablish a riparian forest to ameliorate the
water quality impacts of applying liquid manure to cropland; that is, to
determine whether a restored riparian forest trees, shrubs, and native grasses
would improve the quality of runoff leaving the manure application site and
moving through the riparian area to the stream. It was conducted in conjunction
with an agricultural project at the University of Georgia's Coastal Plain
Experiment Station near Tifton.
The project demonstrated that riparian forested wetlands can be restored to
help prevent nonpoint source pollution from manure application sites.
The USDA Agricultural Research Service participated in the section 319 project
to restore a streamside riparian forest receiving runoff from the USDA-funded
liquid manure application and forage crop production site. The Tifton project
sought to demonstrate the conservation and water quality effects of using
minimum plowing and liquid manure to grow forage crops. It was funded by the
U.S. Department of Agriculture's Low Input/Sustainable Agriculture Program.
Obstacles and successes
Riparian vegetation was successfully restored in the project area, but not
before several obstacles had been overcome, for example, knowing which species
to plant. Yellow poplars were not a good choice for wet conditions; black gum
and green ash were effective substitutes. Within two months it was apparent
that there would be low survivorship among the poplars, since they were not
locally produced seedlings and did not thrive in wet, saturated soils. Black
gum and green ash were substituted since it was thought they would tolerate wet
conditions.
Project workers evaluated the effects of the riparian restoration by
measuring changes in surface and subsurface water quality indicators in the
field where manure was applied and again after the runoff had moved through the
restored riparian area toward the stream. Results of the monitoring
demonstrated that the restored riparian area removed nitrogen, phosphorus, and
sediment in the first two years of the project. Nitrate levels leaving the area
in shallow groundwater were higher than in mature riparian forest sites.
The project demonstrated that riparian forested wetlands can be restored to
help prevent nonpoint source pollution from manure application sites.
Information gleaned from this project, and others, has been incorporated in an
interim USDA Natural Resources Conservation Service and U.S. Forest Service
specification for Riparian Forest Buffer Systems. The guide recommends a
three-zone buffer system in riparian areas.
CONTACT: Frank Carubba
Georgia Department of Natural Resources
(404) 651-5492 |
Evaluating Best Management Practices -
A Farm Demonstration Project in Rayle, Georgia
Traditional methods of allowing livestock free access to streams and
pastures must change as modern farming methods intersect with environmental
concerns. With this commitment, the Georgia Resource Conservation and
Development Council, Inc., several conservation districts, federal agencies,
and the University of Georgia arranged a farm demonstration to teach area
cattlemen that new practices to keep livestock out of streams could be
cost-effective and practical. After selecting a dairy farm, the partners helped
install and monitor the following practices: proper grazing management,
nutrient management, animal waste management systems (including holding pond,
solid separator), loafing area, geotextile walkway, and livestock exclusion.
The dairy farm is located within a 385-acre watershed in northeastern Georgia's
Savannah River Basin near Rayle. In fact, it sits on an unnamed tributary that
flows into a pond next to the most heavily used section of the dairy. The
unnamed tributary continues through a wetlands (actually, another pond that had
been breached) and flows into the Broad River.
The 793,000 acres of agriculture land within the watershed contain the
following animals: 22,000 dairy cows, 185,000 beef cows, 95,000 swine, and
about 22 million poultry (layers and broilers). These animals potentially
contribute to the nonpoint source pollution problems in the watershed and river
basin. Direct access of livestock to streams and runoff from loafing areas have
degraded the watershed and impaired water quality, wildlife habitat, and
recreational activities.
The project managers planned an extensive water quality monitoring program
to demonstrate that the recommended best management practices were
cost-effective and practical. Water quality measurements included biological
oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids
(TSS), fecal coliform, fecal streptococci, nitrate, ammonia, and
orthophosphate. Additional in situ parameters monitored by an automated sampler
included pH, temperature, conductivity, ammonia plus ammonium, turbidity,
depth, and dissolved oxygen.
Comparing the results from post-BMP and pre-BMP monitoring show a marked
improvement in water quality. Statistical analyses have indicated significant
decreases (p 0.05) in ammonia, orthophosphate, TSS, COD, BOD, and fecal
streptococci. Extensive water quality monitoring has quantitatively
demonstrated that the recommended BMPs are both cost-effective and
practical.
CONTACT: Frank Carubba
Georgia Department of Natural Resources
(404) 651-5492 |
|