SAN ANTONIO \u2013 Many people in San Antonio may have walked, biked or driven past one without even realizing it.<\/p>\n
Dozens of dams are hidden in plain sight across the city \u2014 tucked into parks, trails and green spaces \u2014 quietly protecting neighborhoods when heavy rain hits Flash Flood Alley.<\/p>\n
At one flood-control dam inside McAllister Park, people walk dogs and ride bikes nearby every day without realizing they are standing on critical infrastructure.<\/p>\n
\u201cThese were built when all of this was ranch land,\u201d said Wayne Tschirhart, a senior technical engineer with the San Antonio River Authority whose focus is dam safety.<\/p>\n
Many of San Antonio\u2019s dams do not look like traditional dams with large walls and reservoirs. Instead, they are mostly grassy, earthen structures designed to temporarily hold back floodwaters during major storms.<\/p>\n
\u201cMost of them are earthen dams with earthen auxiliary spillways,\u201d Tschirhart said. \u201cThey are earth and grass covered, and you really don\u2019t know they are there.\u201d<\/p>\n
At the dam at McAllister Park, Tschirhart said the concrete spillway almost never sees water.<\/p>\n
\u201cI\u2019ve been here 19 years, I\u2019ve never seen water go over this concrete,\u201d he said.<\/p>\n
The dam stretches more than a mile long through the park.<\/p>\n
\u201cWe\u2019re at the dam crest. This is the auxiliary spillway,\u201d Tschirhart said. \u201cThen the earthen part goes back into the park, and the total length is like 6,600 feet. So it\u2019s over a mile long.\u201d<\/p>\n
According to Tschirhart, there are 65 dams in Bexar County listed in the National Dam Inventory<\/a>. The San Antonio River Authority<\/a> operates 27 of them.<\/p>\n Those dams quietly hold back massive amounts of water during storms before it can rush into neighborhoods downstream.<\/p>\n \u201cThis and seven other dams upstream hold back a lot of, you know, thousands of acre-feet of water during a flood event that would normally impact people\u2019s homes downstream and community downstream,\u201d Tschirhart said. \u201cAnd so they don\u2019t make any noise. They fill and there\u2019s no sirens.\u201d<\/p>\n \u201cThey just sit here and operate and do what they do,\u201d he added.<\/p>\n Without the dam system, Tschirhart said neighborhoods including Terrell Hills, Alamo Heights and areas stretching to Roland Avenue could flood during major rain events.<\/p>\n The dams may not look impressive, but Tschirhart said they play a major role in keeping people safe.<\/p>\n \u201cThey are nothing fancy,\u201d he said.<\/p>\n But when asked whether they save lives in the community, Tschirhart had a simple answer: \u201cYeah, save lives and property.\u201d<\/p>\n Read also:<\/p>\n Copyright 2026 by KSAT – All rights reserved.<\/p>\n","protected":false},"excerpt":{"rendered":"SAN ANTONIO \u2013 Many people in San Antonio may have walked, biked or driven past one without even…\n","protected":false},"author":2,"featured_media":234849,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[82,84,83,15661,410],"class_list":{"0":"post-234848","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-san-antonio","8":"tag-san-antonio","9":"tag-san-antonio-headlines","10":"tag-san-antonio-news","11":"tag-san-antonio-river-authority","12":"tag-water"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us-tx\/wp-json\/wp\/v2\/posts\/234848","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us-tx\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us-tx\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-tx\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-tx\/wp-json\/wp\/v2\/comments?post=234848"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us-tx\/wp-json\/wp\/v2\/posts\/234848\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-tx\/wp-json\/wp\/v2\/media\/234849"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us-tx\/wp-json\/wp\/v2\/media?parent=234848"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-tx\/wp-json\/wp\/v2\/categories?post=234848"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-tx\/wp-json\/wp\/v2\/tags?post=234848"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}