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Llano Watershed

“Conservation is a state of harmony between
men and land.”

Aldo Leopold

The headwaters of the South Llano River (Figure 1) begin about 2,300 feet above sea level in the heart of the Edwards Plateau, a 24,000 square mile upland region.  This region roughly extends from the Pecos River on the west to the Balcones Escarpment (Austin to San Antonio to Del Rio) on the east and south. Capping the Edwards Plateau is thick limestone rock that dissolved over time to form what is considered the largest continuous karst [i] areas in the United States.


The South Llano River flows intermittently in its first 35 miles across the plateau. But where the river and its tributaries have carved canyons into the limestone cap, the water stored in the karst features of the plateau emerges as springs along the canyon walls. The springs, located at an elevation of approximately 1,900 feet, have historically supplied constant flow for the river’s final 20 miles to Junction. At Junction, appropriately known as the “Land of Living Waters”, the South Llano joins the North Llano River, becoming the Llano River for the final 100-mile journey to Lake LBJ in the chain of water-supply reservoirs known as the Highland Lakes.


Figure 1. Map of North and South Llano Rivers and surrounding area




























The South Llano River flows through Edwards and Kimble counties. These counties can be characterized as agricultural, primarily consisting of ranches used for livestock production, and along the bottomlands, some pecan and hay production.  A large source of income for these ranches is hunting leases for white tail deer and exotic species. Tourism, primarily associated with recreation along the South Llano is also important aspect of the economy. Some natural gas production occurs in the headwaters of the river.


The current population of Kimble County is 4,570, with Junction, the county seat, accounting for about 58% of the county’s population. The 1,150 inhabitants of Rocksprings, the county seat of Edwards County, also make up 58% of that county’s total population (1,987). Kimble County has experienced a 2.3% growth rate since 2000, while Edwards County has experienced a 10.5% reduction in population since 2000.  However, population figures alone do not provide a clear picture of the demographics in these counties. For example, of the 9,000 parcels in Kimble County, non-Kimble county residents own 55% percent, and non-Texas residents own an additional 5%. Likewise, it is estimated that absentee landowners account for about 70% of the property owners in Edwards County.


[i] Karst areas include features such as caves, sinkholes, and subsurface drainage networks, or conduits.

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