Blue Hole at Headwaters Sanctuary

Archaeological evidence places people around the San Antonio Springs for nearly 12,000 years. Indigenous communities depended on and regarded the springs as sacred.

Blue Hole was the largest outlet in a network of Edwards Aquifer springs. Traditional accounts describe a sacred gathering and pilgrimage place for the Payaya and other Indigenous peoples.

On June 13, Domingo Terán de los Ríos and Father Damián Massanet’s expedition camped near the headwaters with Payaya people. The Spanish named the place San Antonio de Padua.

The Spanish built the Alamo Madre acequia in 1745, then the Upper Labor dam and acequia around 1776, diverting spring and river water for settlement and irrigation.

Frederick Law Olmsted saw the spring before extensive aquifer pumping and wrote that “the whole river gushes up in one sparkling burst from the earth.”

Isabella Brackenridge purchased the estate in 1869. Beginning in 1877, the San Antonio Water Supply Company used spring flow to operate a pumping plant and supply the city.

Concerned that spring flow was unreliable, George W. Brackenridge drilled large artesian wells into the Edwards Aquifer for municipal water. Numerous additional wells followed.

Artesian pumping and prolonged drought dramatically reduced Blue Hole’s flow. Brackenridge reportedly lamented that the river was “dying” and attributed it to the wells.

Brackenridge sold approximately 280 acres, including the springs, to the Sisters of Charity of the Incarnate Word.

Increasing groundwater withdrawals made the spring intermittent. Blue Hole entered roughly three decades of dormancy before returning during exceptionally wet conditions in the 1970s.

Blue Hole became part of the National Register-listed Source of the River Historic District in 1978. The present octagonal limestone wall and walkway were installed in 1989.

The Edwards Aquifer reached a recorded high of 703.3 feet at the J-17 index well. Blue Hole flowed, though at only a fraction of the nineteenth-century volume.

San Antonio began using highly treated recycled water to conserve aquifer water and support dependable river flow during dry periods. It supplements the river downstream; it does not refill Blue Hole.

The 53-acre Headwaters Sanctuary was established to protect Blue Hole, its forest, and the headwaters landscape.

Wet periods raised the aquifer enough for Blue Hole to flow again temporarily. In September 2018, its water crossed the formerly dry channel and mixed with Olmos Creek water.

Blue Hole is an intermittent spring. Sources place its approximate flowing threshold around 670–676 feet above mean sea level at the J-17 index well.