“The huge Impounding Dam, the Diversion Dam, the miles of Reservoirs and Canals, all so aptly fitted into the titanic natural gorge of the Medina River as to make Nature bow to the will of Humanity, combine into a picture at once so enormous and so awe-inspiring that the imagination fails to provide for it a frame, until memory lends its aid. But once seen, this sight can never be forgotten. The first glimpse of the titanic Dam catches the breath in ecstatic surprise, the immense lake of water behind it, stretching for miles, holds one spell-bound. The views in this folder can give but a hint of the many marvels awaiting the visitor. “ c1920 Hotel Lobby Brochure: "Italian Scenery In Texas"
Medina Lake was constructed between 1911-1912 as an irrigation reservoir. An extensive canal system delivers water to 34,000 acres of Blackland Prairie farmlands below the Balcones Escarpment around Castroville. At the time it was constructed, it was the largest hydraulic engineering project west of the Mississippi River and was not only Texas’ largest dam, but the fourth-largest dam in the US.
The concrete behemoth soars 164 feet high, 128 feet wide at the base, 25 feet wide at the top, and 1,580 feet long, impounding 254,000 acre-feet of water at the spillway level. At spillway capacity, Medina Lake covers about 5,575 acres, has a length of 18 miles, a maximum width of three miles, and 110 miles of shoreline. In addition to the main dam, there is a smaller, solid concrete dam about four miles downstream that creates Diversion Lake, which discharges into the canal system.
As well as recognition from Texas ASCE as a Historic Civil Engineering Landmark of Texas, Medina Dam is listed on the National Register of Historic Places for its significance as an infrastructure project and its contributions to economic development of the county.
----
European immigrant Henri Castro explored the Medina River Valley in the 1840s and saw that its deep canyons could be used to irrigate farmlands to the south if water that periodically flooded the canyons could be contained. However, it was Alex Walton, a San Antonio civil engineer who first visited Box Canyon on a hunting trip in 1894 who lit a fire under the project. Despite detractors who claimed the limestone canyon would “leak like a sieve,” Walton foresaw the establishment of town sites and land that could be sold to prospective farmers. He joined forces with Terrell Bartlett and Willis Ranney, also civil engineers from San Antonio, and formed the Medina Irrigation Company. All that was needed was money. Finally, in 1910 they finally hit paydirt when they pitched the proposed project to Dr. Frederick Stark Pearson, an engineer renowned for his development of large-scale projects in New York, Boston, Canada, Cuba, Brazil, and Mexico. He deemed the idea feasible and turned to his British financiers, who purchased $6 million in bonds to support the project. [Unfortunately, on a subsequent voyage to England in 1915 to solicit additional funds, Pearson and his wife perished aboard the Lusitania.]
On August 19, 1910, the Medina Irrigation Company paid $149,200 for land to be placed under irrigation. Offices of the company had been established in San Antonio. Bartlett, Ranney, Walton, Thomas B. Palfrey, and Duval West, all of San Antonio, filed on August 19, 1910, for the appropriation of the waters of the Medina River for irrigation in Medina, Bandera, Kerr, and Kendall counties. The amount of land to be irrigated was estimated to be 150,000 acres.
The company also contracted with Southern Pacific Railway to build a 19-mile spur from Dunlay to the dam construction site near a huge limestone quarry. Then they began constructing and improving roads from San Antonio, Castroville, and Rio Medina to move equipment and manpower, much of it hauled by mule trains. Construction on the dam itself began in November 1911.
The pace of construction was frenetic. A crew of 1,500 men (approx. 3,000 employees total) worked twenty hours a day, six days a week, to pour the necessary 292,000 cubic yards of concrete. Limestone boulders from the aforementioned quarry added bulk to the massive concrete structure. Laborers received $2 a day, which were good wages for the time. Most were skilled laborers from Mexico who had prior experience building hydroelectric dams with Pearson, and most of them brought their families. A bitter note: at least 70 people were reported killed by accidents and disease during the year of construction.
The big push was fired by the builders’ expectation of large floods in the summer of 1913 that would fill the reservoir. But this is Texas – when it comes to water, boom or BUST. The floods never materialized, and though construction was complete in November 1912, it was 18 months before any significant rains fell. Medina Lake did not fill to capacity until September 1919.
This would prove prophetic: whether the designers overestimated the rainfall or the size of the watershed is not clear, but what is certain is wildly fluctuating levels have characterized Medina Reservoir throughout its entire history; unfortunately the watershed never supplied the flow originally envisioned.
Sitting partially on the Edwards limestone outcrop, the lakes contribute large amounts of water to Aquifer recharge. Seepage losses from Medina Lake and Diversion Lake have been documented by the USGS and other sources since completion of the irrigation structures in 1912. All of the water lost from the lakes has been assumed to enter the Edwards Aquifer, either directly or indirectly through the Trinity Aquifer. In 2004, the United States Geological Survey completed a water budget analysis and concluded that an average of about 3,083 acre-feet recharges each month, making Medina & Diversion Lakes the single largest recharge source for the entire Edwards Aquifer.
Today, the Bexar-Medina-Atascosa Counties Water Control and Improvement District No. 1 (BMA) owns and operates both Medina Dam and the Diversion Lake dam, as well as the 26 miles of irrigation canals that serve landowners growing various crops on 33,000 acres of farmland. “The dam works as well today as it did when it was built in 1912,” said BMA’s business manager, Ed Berger. The BMA & San Antonio River Authority (SARA) also recently completed a $5.6 million stabilization project in time for the 100th anniversary, the dam’s first major modification. In short, 32 anchors were installed: think in terms of nailing the dam to the ground. In addition concrete aprons were added to keep the dam from tipping and sliding.
Medina Lake Dam was designated a state historical landmark in 1976 by the Texas Historical Commission and was entered into The National Register of Historic Places at that time. Three historical markers currently stand atop the dam: one denoting the Mormon community that once existed 12 miles upriver, a second recalling the dam’s history, and a third recognizing Medina Dam as a Historic Civil Engineering Landmark of Texas. You’ll have to take my word on that: U.S. Department of Homeland Security regulations prohibit public access to the dam. There are plans calling for the markers to be moved to a public access site near the dam entrance.
-------------------------------------------------------------------------------------
Highlight of History!
“When Medina Lake was being constructed, there was a gravel toll road (built by an industrious landowner) leading from FM 471 to the construction site. Sightseers from San Antonio would travel up FM 471 in Packard touring cars and stop at a little rock house at the intersection, where a monkey wearing a tiny hat would come out and collect the tolls. The toll road was eventually paved and became FM 1283.”
-------------------------------------------------------------------------------------
Text of the Texas Historical Marker:
Henri Castro, who colonized this area in the 1840s, envisioned irrigated farms along the Medina River. The project was delayed, however, until after the turn of the century, when Dr. Fred Stark Pearson, an internationally known engineer, persuaded British investors to finance construction of a dam at this site. Completed in 1912, Medina Dam was hailed as the largest in Texas and the fourth largest in the United States. Limestone boulders from a nearby quarry added bulk to the massive concrete structure. Four miles downstream, a small diversion dam conducted water into a system of irrigation canals. Gravitational force delivered the water to fields. The outbreak of World War I (1914) disrupted ties with British investors. Seeking new capital, Dr. Pearson and his wife left for England in 1915 on the "Lusitania" and were killed when a German submarine torpedoed the ship. The irrigation network created by Medina Dam brought new prosperity to this region. Vegetables raised in irrigated fields became a valuable crop. Water and electricity were made available to rural residents. In 1925 voters established the Bexar-Medine-Atascosa Counties Water Improvement District No. 1 to manage the project. 1978
-----------------------------------------------------------------------------------
COORDINATES are for the dam itself. Viewing can be had from spots along Medina Dam Road which runs from Mico along the east side of the lower lake and dam, crossing the Medina River a few thousand feet below the dam. O’Connel Road turns north off Medina Dam Road just past the bridge, offering more viewing, or continue up Medina Dam Road to the higher ground. In this post 9/11 world, any viewing of the dam (even from upstream) will do. Be sure to tell where your photo was taken and give us a good log!
Further reading & references:
Medina Dam Construction Photo Gallery (
visit link)
Edwards Aquifer Website Medina Lake & Canal System (
visit link)
Excellent thumbnail history: Texas Highways “Speaking of Texas: Medina Dam at 100” (
visit link)
Medina Lake Conservation Society “Medina Lake History” (
visit link)
My San Antonio: “Medina Dam Revisited” (
visit link)
Kens5 “Construction underway for Medina Dam improvements” (
visit link)
Bandera County Courier “At 98, Medina Dam finally gets a facelift” (12/30/10) (
visit link)
Texas State Historical Association TSHA Online “Medina Lake” (
visit link)
Wikipedia Medina Dam (
visit link)
Medina Lake Preservation Society “History of the Medina Dam“ (
visit link)
Historical tidbits about Mico
and Medina Lake (
visit link)
Medina Lake Preservation Society Dam Memorial (
visit link)