Sediment accumulation in the Barton Springs complex

Ellen Geismar

Abstract

The four springs located in the Zilker Park area of Austin, Texas are the only known habitat of the endangered species Eurycea sosorum and E.waterlooensis. Sediment deposition in these springs contributes to the temporary degradation of salamander habitat due observed during salamander counts. The sediment transport in the area of the springs is dynamic with deposition/resuspension rates varying spatially and temporally over the substrate. Accumulation of sediments in these habitats has been a concern because sediment loading is anticipated to increase as a result of human activities in the Barton Springs watershed. This study documents the baseline rate of sediment accumulation in 3 of the 4 springs under low flow conditions over varying periods of time during 2002-2003. Sedimentation rates varied from 0.5 to 2.2 inches/year across the tests performed with an average of 0.9 inches/year. Results indicate that during low rainfall (decreasing flows), the sediment accumulation rates decrease. As rainfall and flows increase the sediment accumulation rate increases. Transport of sediment out of spring areas during runoff events and maintenance cleaning of spring outlets prevents these sedimentation rates from being problematic for maintenance of salamander habitat. Open Access - Permission by Publisher See Extended description for more information.