Written in an informal style for a nontechnical audience, this guide summarizes geologic features and history of McKinney Falls State Park, just south of Austin, Texas. Part guidebook and part geologic text, the book surveys Pilot Knob, the McKinney Gristmill, the Balcones Fault Zone, natural potholes, the Smith rock shelter, "Old Baldy," and the waterfalls in the park. Includes maps and photos.

Of the more than 19,000 documented leaking petroleum storage tank (LPST) sites in Texas, more than 6,000 have impacted ground water and resulted in fuel hydrocarbon (FHC) plumes. The sheer number of regulated facilities and their wide geographical distribution throughout the state, however, have made gaining a regional perspective on hydrocarbon plumes difficult.

This study used a numerical model to examine the playa-focused recharge theory by comparing it with the spatially uniform approach and with a zonal approach. Much recent hydrologic, geologic, and chemical evidence suggests that the approximately 19,250 seasonal lakes on the Southern High Plains of Texas and New Mexico, commonly known as playas, are the principal focal points of recharge to the Ogallala aquifer.