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Pesticide Education in the Coastal Zone of the Arroyo Colorado Watershed Final Report

T. Allen Berthold

The Arroyo Colorado is an ancient channel of the Rio Grande River that extends eastward for about 90 miles from near the city of Mission, Texas through southern Hidalgo County to the city of Harlingen in Cameron County, eventually discharging into the Laguna Madre near the Cameron-Willacy County line. The tidal segment of the Arroyo Colorado, as classified by the Texas Commission on Environmental Quality (TCEQ), is between the confluence with Laguna Madre in Cameron/Willacy County to a point 100 meters (110 yards) downstream of Cemetery Road, south of Port Harlingen in Cameron County. This part of the river is also defined as a coastal natural resource area (CNRA) and a coastal wetland in the Coastal Coordination Act.

Water quality monitoring over the past decade has confirmed low oxygen levels and escalated ammonia and nitrate concentrations that have contributed to multiple fish kills in the tidal segment. These sub-optimal aquatic conditions resulted in this portion of the Arroyo Colorado being placed on the Texas Water Quality Inventory and 303(d) List for high aquatic life use impairment in 2002. Numerous urban sources, such as point source wastewater discharges, have contributed to this impairment; however, according to the Arroyo Colorado Watershed Protection Plan (ACWPP), nonpoint source agricultural runoff accounts for much of the water quality issues in the tidal segment.

These coastal issues and other water quality issues in the watershed have been addressed by the more than 715-member Arroyo Colorado Watershed Partnership in the ACWPP. The plan identifies needs specific to water quality protection and improvement for the agricultural community as well as addressing nonpoint source pollution from the urban environment such as landscapes. In response to the ACWPP, Texas Water Resources Institute (TWRI) proposed to work with the Texas AgriLife Extension Service to implement an educational program aimed at agricultural producers, which included turfgrass producers and local independent school districts that manage athletic fields. The agricultural effort was an integrated farm management program focused on pesticide education and proper nutrient management for Cameron and Willacy counties to address water quality issues related to agricultural production in the tidal segment of the Arroyo Colorado. While the turfgrass and athletic field managers were invited to the educational programs provided through the agricultural effort, a separate educational workshop was held for turf producers and managers to increase awareness of how nutrient, pesticide and irrigation management can reduce the amount of nonpoint source pollution.

This education plan helps fulfill two goals of the Texas Coastal Management Program. First, agricultural and turfgrass producers and managers in Cameron and Willacy county were educated on water quality issues and how the proper application of pesticides meets current laws and regulations, and can improve the water quality and fish community in the Arroyo Coastal Natural Resources Area (CNRA). Second, the producers and managers were taught that implementing proper pesticide application practices will reduce the potential for nonpoint source pollution, which will improve the water quality in the Arroyo CNRA. This project also enhances the area's ability to continue to support valuable aquatic life and meet water quality goals outlined in the ACWPP. An additional environmental success for this area, given the over-allocation and availability of clean surface waters, will be the added water savings attributed to the irrigation management educational program provided through this effort.

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