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February 2009 cover image of Davis Mountains State Park

Whitmire Wetlands

New freshwater delivery system enhances habitat for waterfowl and shorebirds.

By Todd Votteler

Indianola, once an important point of entry for European travelers in the 19th century, was destroyed by devastating hurricanes in 1875 and 1886. Today, the nearby Myrtle Foester Whitmire Unit (Whitmire Unit), a satellite component of the Aransas National Wildlife Refuge, serves as an important port for feathered travelers, in some years providing food, freshwater and shelter for up to 18 percent of the Central Flyway waterfowl that annually migrate to the Texas Gulf Coast. However, the wetlands habitat of the Whitmire Unit has waxed and waned from year to year with hit or miss rainfall.

The 3,440-acre Whitmire Unit was acquired by the U.S. Fish and Wildlife Service (USFWS) in 1993. It is located at the end of the Guadalupe-Blanco River Authority’s (GBRA) canal system in Calhoun County. In 2004, the Guadalupe-Blanco River Trust, GBRA and the refuge began an effort to make the Whitmire Unit an unmatched habitat for waterfowl and shorebirds year in and year out. The partnership is accomplishing its goal by establishing a reliable freshwater delivery system for the Whitmire Unit through a new canal that is 2.65 miles in length, benefiting 750 acres of impoundments. Construction of the canal overcame a number of obstacles, such as 20 inches of rain in July 2007. The partnership is also improving the efficiency of water delivery within the Whitmire Unit and controlling invasive aquatic plants such as water hyacinth that have clogged the canals.

The Whitmire Unit is a major wintering area for northern pintails and a significant breeding area for mottled ducks; both species have declined significantly in recent years. It has been identified in the North American Waterfowl Management Plan as one of the most important wetland habitats on the Texas Gulf Coast. Nearly every waterfowl species using the Central Flyway benefits from this high-value wintering habitat at the Whitmire Unit, as do current and former threatened and endangered species such as the whooping crane, peregrine falcon, aplomado falcon, wood stork and brown pelican. Because coastal marsh habitat often becomes too deep for optimal dabbling duck forage, this type of habitat is not always available during critical times.

The old water supply canal, built in the early 1950s, stretched over 18,000 feet on flat pastureland. Maintenance and repair of the levees was 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 that allowed increased silting in the canal and invasive aquatic plants to proliferate. The old canal was often unable to flood the Whitmire impoundments in a timely manner, reducing the quantity and quality of migratory bird habitat.

A number of entities provided financial and in-kind support for the project, including the North American Wetlands Conservation Council, Formosa Plastics, Alcoa, Tetra-Tech, and Friends of Aransas National Wildlife Refuge. The majority of funding was provided through the National Fish and Wildlife Foundation, ConocoPhillips and the Coastal Coordination Council, which awarded the Guadalupe-Blanco River Trust grants totaling over $400,000.

The trust and its lead partners, USFWS and GBRA, are now pursuing a project to install water control structures at strategic locations within the Whitmire Unit to optimize water distribution to the existing impoundments as well as another 100 acres of impoundments that will be added to benefit hundreds of thousands of wintering waterfowl and shorebirds.

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