Repairs to a 275-year-old aqueduct at San Antonio Missions National Historical Park are being performed by skilled craftspeople from the NPS Historic Preservation Training Center and San Antonio Missions National Historical Park with support from Texas Conservation Corps youth/NPS

Thanks to nearly $300,000 from the Great American Outdoors Act a 275-year-old aqueduct at San Antonio Missions National Historical Park in Texas is getting rehabilitated.

The aqueduct, the oldest Spanish aqueduct in the United States, is having leaks repaired and sediment and debris removed from its channel. The $290,000 project is expected to wrap up this month.

“Being able to preserve our community’s heritage, character, and sense of place is invaluable in experiencing and understanding the cultural identity of our past and future,” said San Antonio Missions Superintendent Christine Jacobs. “This project wouldn’t be possible without the team of skilled masons from San Antonio Missions National Historical Park and the National Park Service Historic Preservation Training Center who are providing the additional expert craftspeople needed to perform the work.”

The stone aqueduct, which spans a creek bed, was originally constructed between 1740 and 1745 as a part of a larger system of independent irrigation ditches called acequias that carried water from the San Antonio River to the sites of the mission communities and their nearby farm fields, according to the Park Service. Today, the Espada Aqueduct is a National Historic Landmark within San Antonio Missions National Historical Park which is also a World Heritage Site.

The work is being performed by skilled craftspeople from the NPS Historic Preservation Training Center and San Antonio Missions National Historical Park with support from Texas Conservation Corps youth.

GAOA funds several geographically based HPTC Maintenance Action Teams (MAT), trained in historic restoration and preservation work, who perform small, but critical, maintenance rehabilitation and repair projects on historic structures in national parks. MATs enable the NPS to complete projects that require consistent high-quality work at a time when fewer people are practicing traditional trades. San Antonio Missions National Historical Park has a long-standing relationship with American Youthworks, Texas Conservation Corps including apprentice programs in preservation masonry and cultural landscapes.

The project team drained the aqueduct using a diversion gate and then an open sluice to clear a heavy load of sediment from the masonry portion of the channel. An estimated 30 cubic yards of mud and soil was removed by hand, and the masonry channel was cleaned thoroughly. Now that the interior of the masonry channel is clear of water and sediment, the plaster surface will be assessed to locate small cracks and weak mortar joints in need of repairs. Deteriorated plasters and mortars will be removed and preservation treatments both inside the channel and on the exterior masonry will begin.

After proper cure times for mortars and plasters are achieved within the channel, water from the San Antonio River will be re-introduced, and repairs to the exterior of the structure will proceed.

Infrastructure funding from GAOA and the Bipartisan Infrastructure Law is part of a concerted effort to address the extensive deferred maintenance and repair backlog in national parks. Supported by revenue from energy development, GAOA’s Legacy Restoration Fund provides the National Park Service with up to $1.3 billion per year for five years to make significant enhancements in national parks to ensure their preservation and provide opportunities for recreation, education, and enjoyment for current and future visitors.