The Llano River ( ) is a tributary of the
Colorado River
The Colorado River ( es, Río Colorado) is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and northern Mexico. The river drains an expansive, arid drainage basin, watershed that encompasses parts of ...
, about long, in
Texas
Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...
in the United States.
It drains part of the
Edwards Plateau
The Edwards Plateau is a geographic region at the crossroads of Central Texas, Central, South Texas, South, and West Texas. It is bounded by the Balcones Fault to the south and east, the Llano Uplift and the Llano Estacado to the north, and the ...
in
Texas Hill Country
The Texas Hill Country is a geographic region of Central and South Texas, forming the southeast part of the Edwards Plateau. Given its location, climate, terrain, and vegetation, the Hill Country can be considered the border between the Ameri ...
northwest of
Austin
Austin is the capital city of the U.S. state of Texas, as well as the seat and largest city of Travis County, with portions extending into Hays and Williamson counties. Incorporated on December 27, 1839, it is the 11th-most-populous city ...
.
Two spring-fed tributaries, the North and South Llano, stretch across the otherwise arid lands of
West Texas
West Texas is a loosely defined region in the U.S. state of Texas, generally encompassing the arid and semiarid lands west of a line drawn between the cities of Wichita Falls, Abilene, and Del Rio.
No consensus exists on the boundary betwee ...
before merging just east of the small town of
Junction
Junction may refer to:
Arts and entertainment
* ''Junction'' (film), a 2012 American film
* Jjunction, a 2002 Indian film
* Junction (album), a 1976 album by Andrew Cyrille
* Junction (EP), by Basement Jaxx, 2002
* Junction (manga), or ''Hot ...
, in
Kimble County, forming the head of the Llano River proper.
[ The Llano River runs generally east-northeast through the rolling ]limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...
terrain of the Edwards Plateau as it flows through Kimble County and across rural Mason County, passing to the south of the town of Mason, Texas
Mason is a city in, and the county seat of, Mason County, Texas, United States. The city is an agricultural community on Comanche Creek southwest of Mason Mountain, on the Edwards Plateau and part of the Llano Uplift. The population was 2,114 ...
. Continuing in an easterly direction, the river carves its way through the Llano Uplift
The Llano Uplift is a geologically ancient, low geologic dome that is about in diameter and located mostly in Llano, Mason, San Saba, Gillespie, and Blanco counties, Texas. It consists of an island-like exposure of Precambrian igneous and m ...
, a roughly circular geologic dome of Precambrian
The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the ...
rock, primarily granite
Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...
, located in Central Texas
Central Texas is a region in the U.S. state of Texas surrounding Austin and roughly bordered by San Saba to Bryan and San Marcos to Hillsboro. Central Texas overlaps with and includes part of the Texas Hill Country and corresponds to a ph ...
. Flowing through Llano County
Llano County is a county located on the Edwards Plateau in the U.S. state of Texas. As of the 2020 census, its population was 21,243. Its county seat is Llano, and the county is named for the Llano River.
During the American Civil War, the c ...
, the river passes to the north of Enchanted Rock
Enchanted Rock is a pink granite mountain located in the Llano Uplift about north of Fredericksburg, Texas and south of Llano, Texas, United States. Enchanted Rock State Natural Area, which includes Enchanted Rock and surrounding land, spans th ...
and flows through the town of Llano, Texas
Llano ( ) is a city in Llano County, Texas, United States. As of 2010, the city population was 3,232. It is the county seat of Llano County.
Geography
Llano is located at (30.750953, –98.680038). It is on the Llano River, northwest of Aus ...
. Northeast of Llano, it turns sharply to the southeast, joining the Colorado from the northwest as an arm of Lake Lyndon B. Johnson, about southeast of Llano at Kingsland.
This river is one of the few popular fly fishing
Fly fishing is an angling method that uses a light-weight lure—called an artificial fly—to catch fish. The fly is cast using a fly rod, reel, and specialized weighted line. The light weight requires casting techniques significantly diffe ...
destinations in the state of Texas, and contains Guadalupe bass
The Guadalupe bass (''Micropterus treculii'') is a rare species of fish endemic to the U.S. state of Texas, where it also is the official state fish. It is restricted to creeks and rivers (including the Guadalupe River, hence the name Guadalupe ...
, the state fish of Texas. The Llano also contains largemouth bass
The largemouth bass (''Micropterus salmoides'') is a carnivorous freshwater gamefish in the Centrarchidae ( sunfish) family, a species of black bass native to the eastern and central United States, southeastern Canada and northern Mexico, but ...
, alligator gar
The alligator gar (''Atractosteus spatula'') is a ray-finned euryhaline fish related to the bowfin in the infraclass Holostei . It is the largest species in the gar family, and among the largest freshwater fish in North America. The fossil ...
, and various sunfish.
The river is also associated with the legend of the Los Almagres Mine. Translated from Spanish, ''almagre'' means red ochre. In 1756, the lieutenant-general of Texas (then still a province of New Spain
New Spain, officially the Viceroyalty of New Spain ( es, Virreinato de Nueva España, ), or Kingdom of New Spain, was an integral territorial entity of the Spanish Empire, established by Habsburg Spain during the Spanish colonization of the Am ...
), Don Bernardo de Miranda, launched an expedition from San Fernando (San Antonio
("Cradle of Freedom")
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, map_caption = Interactive map of San Antonio
, subdivision_type = Country
, subdivision_name = United States
, subdivision_type1= U.S. state, State
, subdivision_name1 = Texas
, s ...
), to ascertain whether rumors of rich mineral deposits to the north were true. As the legend goes, Miranda came across a cave in the side of a hill in the vicinity of the Rio de las Chanas (Llano River), and reported astounding quantities of silver to be found within.
2018 Flood
On October 9, 2018, a cold front
A cold front is the leading edge of a cooler mass of air at ground level that replaces a warmer mass of air and lies within a pronounced surface trough of low pressure. It often forms behind an extratropical cyclone (to the west in the Norther ...
swept through the hill country where it encountered the remnants of Hurricane Sergio The name Sergio has been used for four tropical cyclones in the Eastern Pacific Ocean.
* Tropical Storm Sergio (1978) – threatened Baja California.
* Hurricane Sergio (1982) – never threatened land.
* Hurricane Sergio (2006) – never threatened ...
. Mason County saw 10" of rain and Lake Travis
Lake Travis is a reservoir on the Colorado River in central Texas in the United States.
Serving principally as a flood-control reservoir, Lake Travis' historical minimum to maximum water height change is nearly 100 feet. In 2018 alone, it saw ...
saw a 3' rise. In Junction, Texas, the flow rate increased from its normal rate of 111 cubic feet per second (cfs) to 118,000 cfs.
Less than a week later the remnants of Hurricane Willa
Hurricane Willa was a powerful tropical cyclone that brought torrential rains and destructive winds to southwestern Mexico, particularly the states of Sinaloa and Nayarit, during late-October 2018. It was the twenty-fifth tropical cyclone, twenty ...
rolled into the area, followed by another front, on October 16, 2018. Upwards of a foot of rain fell in Llano, Texas. The flow rate of the Llano River, in Llano, had increased from its normal rate of 150 cfs to 275,000 cfs. The river crested at 39.9 feet, its highest level in more than 80 years and just 1.5 feet below its record high of 41.5 ft, set in 1935. The high flow rate caused the RM 2900 bridge in Kingsland to collapse. and what used to be a two-minute drive across town became a 40-50 minute drive.
The flooding was so intense that the Colorado River began to flow backwards briefly.
The flood waters entered into the Colorado River and flood gates on every dam on the Texas Highland Lakes
The Texas Highland Lakes is a chain of fresh water reservoirs in Central Texas formed by dams on the lower Colorado River. The Texas Colorado River winds southeast from West Texas to Matagorda Bay and the Gulf of Mexico.
The lower Colorado River ...
were opened. Lake Travis rose 25 feet in 24 hours and water flowed into it at a rate of 375,000 cfs. The flooding raised the turbidity
Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality.
Fluids can ...
of City of Austin
Austin is the capital city of the U.S. state of Texas, as well as the seat and largest city of Travis County, with portions extending into Hays and Williamson counties. Incorporated on December 27, 1839, it is the 11th-most-populous city ...
's water supply (which is sourced exclusively from the Colorado River) to untenable levels, forcing the city to issue a seven-day boil water notice
By December 2018 payments under the National Flood Insurance Program
The National Flood Insurance Program (NFIP) is a program created by the Congress of the United States in 1968 through the National Flood Insurance Act of 1968 (P.L. 90-448). The NFIP has two purposes: to share the risk of flood losses through floo ...
had exceeded $22 million
In the end, two people died as a result of the floods. The RM 2900 bridge in Kingsland was rebuilt less than a year later.
See also
References
{{authority control
Rivers of Texas
Tributaries of the Colorado River (Texas)
Rivers of Kimble County, Texas
Rivers Llano County, Texas
Rivers of Mason County, Texas
Texas Hill Country