STORY LEAD:
High-Tech Surveillance Nabs Water Weeds
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ARS News Service
Agricultural Research Service, USDA
May 24, 1999
Ben Hardin, (309) 681-6597, bhardin@asrr.arsusda.gov
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The thickest patches of exotic weeds clogging the lower Rio Grande River
can't hide any longer and could get their comeuppance, thanks to high-tech
aerial mapping technology developed by Agricultural Research Service
scientists.
Beginning last year, the technology helped the Texas Natural Resource
Conservation Commission (TNRCC) and the Texas Parks and Wildlife Department
detect tons of hydrilla and water hyacinth growing on the river so they
could be removed. During last year's drought, these weeds were sucking up
scarce water and obstructing the flow of irrigation water.
Hydrilla, native to Asia, and water hyacinth, native to South America, share
a notoriety for clogging marinas, snarling fishing lines and interfering
with flood control and hydroelectric power generation. The weeds grow so
competitively with other aquatic plants that biological diversity may be
threatened in many lakes and streams through southern parts of North
America.
ARS and TNRCC researchers used aircraft to acquire color-infrared video
imagery that pinpointed locations where the alien vegetation had infested
the Rio Grande. The imagery makes water hyacinth appear orange-red and
hydrilla appear reddish-brown. The scientists measured the area of
infestations by computer analysis of the imagery.
Verification of the data by boat helped advance other research that's aimed
at conducting wider-scale surveys of weed infestations using additional
remote sensing, global positioning system and geographic information system
technologies. These technologies may help scientists make timely assessments
of experimental weed control measures.
ARS is the chief scientific arm of the U.S. Department of Agriculture.
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Scientific contact: James H. Everitt, ARS Subtropical Agricultural Research
Center, Weslaco, Texas; phone (956) 969-4824, fax (956) 969-4893,
j-everitt@tamu.edu.
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