TOM CREEK. Tom Creek rises just northwest of Smithson Valley in central Comal County (at 29°49' N, 98°20' W) and flows northeast for 8½ miles to its mouth on the southwestern shore of Canyon Lake, on the Guadalupe River near Startzville (at 29°52' N, 98°16 W). Along its course are two small lakes, one of which is dammed, and it crosses an area of the Balcones Escarpment characterized by steep slopes and limestone benches that give a stairstep appearance to the landscape. Soil in the area is generally dark, calcareous stony clay and clay loam with rock outcroppings, and vegetation consists primarily of live oak and Ashe juniper woodlands. Since the completion of Canyon Dam in 1964, the lower reaches of Tom Creek have become the site of lakeside residential developments.