Guadalupe-Blanco River Trust Preservation Matters


Aransas National Wildlife Refuge - Myrtle Foester Whitmire Unit

The restoration and construction of a canal and laterals will help to provide an efficient delivery of freshwater to impoundments located on the Myrtle Foester Whitmire Unit (Whitmire Unit). The 3,440-acre Whitmire Unit in the Aransas National Wildlife Refuge (Refuge) is located in Calhoun County on lands that were once part of the historic Indianola port area. That port was an important point of entry for European immigrants in the 19th century, but was destroyed by devastating hurricanes in the 1880's. The Whitmire Unit now serves as an important environmental project by providing food, water, and shelter for a significant portion of the Central Flyways waterfowl population migrating to the Texas Gulf Coast.

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The Trust, GBRA and the Refuge have formed a partnership to provide a more reliable and efficient method to deliver freshwater to approximately 750 acres of wetland impoundments within Refuge. The Whitmire Unit is located at the end of the Guadalupe-Blanco River Authority's (GBRA) Calhoun Canal System (Bolling Canal). The Bolling Canal was built in the early 1950s and provides water to the Whitmire Unit. The canal stretches over 18,000 feet on flat pastureland. Maintenance and repair of the levees is difficult and expensive due to extensive levee damage from livestock and limited access to the canal. To further complicate matters, rice farming has declined significantly in this area, resulting in reduced water usage within the canal system. This reduced water flow increases silting in the existing canal and allows invasive aquatic plants to proliferate.

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The Whitmire Unit contains 750 acres of impoundments that require flooding at critical times for wintering and breeding waterfowl dependent on this wetland habitat. Because of the inefficient delivery of water from the Bolling Canal, the Whitmire Unit is not able to flood these impoundments in a timely manner thus reducing the quantity and quality of migratory bird habitat. The Whitmire Unit also has an additional 100+ acres of impoundments that are not in use as a result of the inability to efficiently deliver water. Wetland habitat, that is vital for at least 300 species of birds and wetlands on the Texas Coast, are declining at an alarming rate. Coastal marsh habitat often becomes too deep for optimal dabbling duck forage and is not always available during critical times. This project is providing an efficient and reliable delivery system of water necessary for quality habitat that will help sustain waterfowl populations at levels recommended in the North American Waterfowl Management Plan (NAWMP).

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The late flooding period (November through March) is typically when the Whitmire Unit is most important for wintering waterfowl. The Whitmire Unit is a major wintering area for northern pintails and a significant breeding area for mottled ducks. Both species have seen a significant decline in population in recent years.

The Whitmire Unit lies within the Texas Mid-Coast Initiative area of the Gulf Coast Joint Venture. The Gulf Coast is the terminus of the Central Flyway and Mississippi Flyways and is therefore one of the most important waterfowl areas in North America, providing both wintering and migration habitat for significant numbers of the continental duck and goose populations. The coastal wetlands of Texas are the primary wintering site for ducks using the Central Flyway, wintering more than half of the waterfowl population.

The Whitmire Unit project is a logical result of efforts by the GBRA, Trust and Refuge to seek practical solutions in a cooperative manner addressing the need to preserve the area's natural resources and heritage.

Public outreach includes local schools and environmental organizations. Local schools have taken field trips to the Whitmire Unit, providing opportunities for students to get involved with an important project while increasing the student's awareness of natural resources and its impact on the environment and habitat.

Project Partners and Contributors include:

  • Conoco Phillips – SPIRIT of Conservation Migratory Bird Program
  • National Fish and Wildlife Foundation Coastal Coordination Council of Texas’ Coastal Management Program
  • Friends of Aransas Wildlife Refuge
  • Formosa Environmental Trust Fund
  • Tetra-Tech


The Whitmire Unit/Calhoun Canal System project is a logical result of efforts by the GBRA, the Trust and the Refuge to seek practical solutions in a cooperative manner addressing the need to preserve the area’s natural resources and heritage and to provide an economically beneficial infrastructure in the Guadalupe River watershed.

Additional benefits from this cooperative effort include:

  • Metering of water usage in the Unit so water deliveries are based on measured flow. This will provide research data that could benefit similar resource management efforts and encourage water conservation;
  • Monitoring of the Unit’s internal canal system and associated water deliveries;
  • Opportunity for educational projects. For example, a partnership has been formed with Travis Middle School in Port Lavaca, (Calhoun County ISD). Students will use field technology, and conduct evaluative studies to determine the location and extent of the invasive species within the canals at the Whitmire Unit. The Unit could also provide a valuable opportunity for local schools to observe shorebirds and waterfowl;
  • Record keeping on the operational and maintenance activities related to the Unit’s canals and laterals. This will facilitate analysis of its water requirements and help to promote research regarding the efficient use of water for wildlife management;
  • Collaborative efforts to document the results of research and water management projects conducted on the Unit;
  • Cooperative efforts to address issues like the control of water hyacinth and other aquatic vegetation in the Calhoun Canal System and Whitmire Lake.

To learn more about this project and its anticipated benefits, please contact Dan Alonso at the Refuge (361-286-3559), or Carrie Kasnicka () at the Trust (830-379-5822).