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Implementing Best Management Practices to Reduce Agricultural Nonpoint Source Pollution in Support of the Arroyo Colorado WPP

Project Background: The Arroyo Colorado Watershed is located in the Lower Rio Grande Valley of South Texas and flows through the middle of Hidalgo and Cameron counties. The lower 16 miles of the Arroyo Colorado is the boundary between Cameron and Willacy counties. The Arroyo Colorado drainage area is a subwatershed of the Nueces-Rio Grande Coastal Basin, also known as the Lower Laguna Madre Watershed. The streams of the Nueces-Rio Grande Coastal Basin, including the Arroyo Colorado, drain to the Laguna Madre, which is considered to be one of the most productive hypersaline lagoon systems in the world. The Lower Rio Grande Valley comprises the northern part of the Rio Grande Delta, a broad fluviodeltaic plain laid down over tens of thousands of years by the ancestral Rio Grande. Just as the Rio Grande is the major source of freshwater for the Lower Rio Grande Valley, the Arroyo Colorado serves as the main drainage stream for this area of Texas.

The Arroyo Colorado currently has low dissolved oxygen levels within the tidal segment, not meeting the aquatic life use designated by the State of Texas and described in the Water Quality Standards. This has been the case for every 303(d) list prepared by the state since 1996. In addition, the Arroyo became impaired due to high bacteria levels in 2006.To address the Arroyo Colorado’s bacteria and dissolved oxygen impairment as well as nutrient concerns, the Arroyo Colorado Watershed Partnership developed A Watershed Protection Plan for the Arroyo Colorado – Phase I. Since the publication of the watershed protection plan (WPP) in January 2007, the Partnership has been working on implementation of management measures to improve water quality and natural habitat in the Arroyo Colorado. The objective of components of the Arroyo Colorado WPP addressing agricultural nonpoint source (NPS) pollution is to encourage the voluntary adoption of best management practices (BMPs) to reduce suspended sediment levels resulting from cropland erosion, BOD from runoff of crop residue, and nitrogen and phosphorus fertilizer runoff from irrigated cropland fields. The WPP concludes that approximately 300,000 acres of irrigated cropland lies within the Arroyo Colorado watershed. The WPP sets a goal to achieve the voluntary adoption of agricultural BMPs on 50% of the irrigated cropland (150,000 acres) by 2015.

Efforts that have been implemented or are in the process of being implemented that focus on the control of agricultural nonpoint source pollution include providing technical assistance to agricultural producers for the development and implementation of Water Quality Management Plans (WQMPs) that focus on reducing nutrient loadings from operations in targeted areas across the watershed. A WQMP is a site-specific plan developed through and approved by SWCDs which includes appropriate land treatment practices, production practices, management measures, and technologies that prevent and abate agricultural and silvicultural nonpoint source pollution. The BMPs prescribed in a WQMP are defined in the NRCS Field Office Technical Guide. TSSWCB and NRCS have various financial incentive programs to assist producers in implementing a WQMP.

The Environmental Quality Incentives Program (EQIP) is a voluntary conservation program that promotes production agriculture and environmental quality as compatible goals. EQIP is administered by the NRCS. Through EQIP, farmers and ranchers receive financial assistance to implement structural and management conservation practices on their land. EQIP is available to producers through 1) resource concern priorities established by Local Work Groups at the county level, and/or 2) State Resource Concerns established by the State Technical Advisory Committee. The State Resource Concern for Water Quantity-Irrigation in the Lower Rio Grande Valley is focused on improving the efficiency of irrigation systems in order to reserve more water for additional uses and to reduce inherent soil salinity problems. Note that more efficient irrigation systems also result in less irrigation return flows to the Arroyo Colorado thereby reducing nutrient, sediment and BOD loadings.

Specifically, in the Arroyo Colorado watershed, since 1999, the TSSWCB and local SWCDs have been developing WQMPs utilizing CWA §319(h) NPS grants (TSSWCB projects 99-03, Arroyo Technical Assistance, 02-12, SWCD WQMP Development, Implementation, and/or Maintenance Assistance, 02-16, Implementation Support in the Arroyo Colorado Watershed, 05-12, WQMP Implementation Assistance in the Arroyo Colorado Watershed, and 09-09 Implementing the Arroyo Colorado Watershed Protection Plan by Providing Technical and Financial Assistance to Reduce Agricultural Nonpoint Source Pollution ) and state appropriations (colloquially known as SB 503 funds). To date, a total of 422 WQMPs have been developed on approximately 36,000 acres. Including work done by NRCS through federal Farm Bill funding, a total of 906 farm plans have been developed in the Arroyo Colorado watershed covering over 73,308 acres. There continues to exist a need for technical assistance and financial incentives to implement BMPs through WQMPs in order to achieve the goal in the Arroyo Colorado WPP to restore water quality.

Project Goals/Objectives:

  • Provide technical assistance to agricultural producers for the development of Water Quality Management Plans (WQMPs) and implementation of Best Management Practices (BMPs) and track progress
  • Provide educational programs to increase stakeholders and citizens knowledge about water quality issues in the watershed
  • To conduct status reviews on WQMPs to track implementation success
  • To foster coordinated technical assistance between TSSWCB, SWCDs and NRCS
  • Inform and coordinate project efforts with the Arroyo Colorado Watershed Steering Committee and Partnership

Project Location: Arroyo Colorado Watershed located within Hidalgo, Cameron and Willacy Counties

Project Cost: Federal ($183,741); Non-Federal ($0): Total ($183,741)

Project Participant(s): TSSWCB, TSSWCB- Harlingen Regional Office, Southmost Soil and Water Conservation District, Hidalgo Soil and Water Conservation District, United States Department of Agriculture-Natural Resources Conservation Service (NRCS), Arroyo Colorado Watershed Partnership

Project Website:

Project Workplan: 13-10

Final Report: 13-10

"Protecting and Enhancing Natural Resources since 1939."

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