San Antonio River Flood Control

San Antonio River

n  Central Texas n  7th Largest City n  Edward’s Aquifer n  Springs n  Five mission complexes n  Seven Acequia systems built

to irrigate farmlands n  River Walk

http://www.edwardsaquifer.net/images/sariver.gif

Edwards Aquifer

n  Limestone n  Flows in the

direction of the San Pedro and San Antonio Springs

n  Artesian Zone n  water is discharged

to the surface due to high pressure (springs) without the need of a pump

area of concern

Diagram

San Antonio River

n  Olmos Creek n  Headwaters north of Loop 410

n  San Antonio Springs n  South of Olmos n  discharge at rates of 0 to 100 cfs

n  San Pedro Creek n  Drainage area of 45 square miles n  Fed by San Pedro Springs

n  Discharge at rates of 0 to 17 cfs

n  Joins San Antonio River at the Riverwalk

History

n  1691 first recorded settlement of the San Antonio River by Spanish missionaries as a protection against French attack

The Acequia Systems supplied San Antonio’s water for over 200 years

http://www.edwardsaquifer.net/images/1-054.jpg

n  1891 San Antonians began relying on wells for their water supply and the River level was significantly depleted

n  1910 Augustus Jones, mayor, developed the City Planning Committee and the re-beautification efforts

n  San Antonio River restoration and beautification project began

Beautification Proposals

n  Harvey L. Page, architect, proposed 13 miles of stone bridges and park

n  George Surkey, river commissioner, proposed “Surkey’s Sea Walls” downtown for flood control

n  Robert H.H. Hugman, architect, proposed the “Shops of Aragon and Romula” which had significant commercial benefits and became the River Walk of today

Flood Prevention: A Necessity

n  1914-1921 six major floods n  September 10, 1921 hundred-year-flood

n  City officials wanted to cement over the river

and turn it into a sewer system, citizens protested

•  2-10 ft of water •  50 deaths

http://www.edwardsaquifer.net/sariver.html

Olmos Dam Olmos Dam completed in 1926 at the cost of approx. $1.5 million

FACTS AND INFORMATION:

FLOOD CAPACITY:  5.1 billion gallons – crests at 728 feet

CREST HEIGHT: 

54 feet above Olmos Creek bottom.

SPILLWAY LENGTH: 

1,152 feet.

FLOOD GATES: Six, with standby generator.

http://www.floodsafety.com/texas/images/olmos-dam.jpg

http://sara-tx.org/site/flood_control/Complete_Flood_Cont/Olmos_Dam.html

Brackenridge Park

n  343.73 acres given to the city by George Brackenridge

n  Aquifer Recharge Zone – Olmos Dam n  San Antonio

Springs Source – Brackenridge

http://www.edwardsaquifer.net/bracken.html

Downtown

n  The “cutoff channel” completed in 1929 n  Designed to bypass the “Great Bend”

or River Walk n  controlled by a series

of floodgates located at two locations

http://www.edwardsaquifer.net/sariver.html

http://sara-tx.org/site/flood_control/Complete_Flood_Cont/Completed_flood_cont_images/flood_gates_images/sar-gate5.jpg

The Cutoff Channel

http://www.edwardsaquifer.net/sariver.html

San Antonio River Tunnel

n  The Olmos Dam and Great Bend cutoff were not enough to ensure protection of Downtown S.A.

n  Completed after 10 years in 1997 at the cost of $111 million

http://sara-tx.org

Facts

n  The tunnel is 16,330 feet long (approx. 3 miles)

n  24’4” diameter n  140 feet below the city n  carries 6,700 cfs peak rainfall runoff n  bypasses 1100 cfs via the San Antonio River

http://sara-tx.org

Inlet and Outlet Structures

n  The inlet structure located at Josephine St. is approximately 120 feet long (tunnel diameter 24 ft)

n  The outlet structure located

near the Lone Star Gallery enhances the natural flow of water, the tunnel diameter transitions from 24 ft to 35 ft.

http://sara-tx.org

Flood of October 1998

n  30 inches of rain in 48 hours (San Antonio’s avg. yearly rainfall!!)

n  $750 million in property damage n  31 deaths n  The tunnel functioned and the

River Walk and much of downtown was relatively unaffected by the flooding

http://blogs.mysanantonio.com/

New Changes and Renovations

n  2000 began use of recycled water rather than water from Brackenridge to maintain flow

n  2000 $12.5 million project from Houston St. to Lexington Ave.

n  2001 Civic Center Riverlink Project n  2002 River Park Upgrade $140 million

15 mile park from Brackenridge to Mission Espada (bike trails/green belt)

Paseo del Rio or The River Walk

n  The actuality of Robert H.H. Hugman’s vision

n  “the Venice of the U.S.” n  Restaurants n  Shops n  River Barges n  River Center Mall

www.travel-watch.com/historicriverwalk.htm

Fiesta

Every spring as a celebration of Texas’ freedom from Mexico San Antonians celebrate Fiesta a month long event of extravagant parades and parties.

Christmas Lights

In the month of December the River Walk is lit with over 60,000 Christmas lights and 2,500 candles.

www.travel-watch.com/historicriverwalk.htm

Conclusion

Works Cited

n  http://sara-tx.org/ n  http://www.edwardsaquifer.net/sariver.html n  http://www.usgs.gov/ n  http://www.floodsafety.com/ n  http://www.americanforests.org/