Reconstruction and operation of the El Paso Solar Pond with a geosynthetic clay liner system

After the original XR-5 membrane liner failed in 1992, the El Paso Solar Pond was reconstructed and operated with a geosynthetic clay liner (GCL) system. The solar pond is approximately 3000 m² in surface area, and 3.2 meters deep with a 15° side-wall slope. A new heat extraction system includes 15-cm (6-inch) rubber hoses and two redesigned polypropylene diffusers. A new automated instrumentation system was developed for monitoring pond status. It uses a newly developed scanner combined with a computer for both position control and data logging. The salinity gradient was established using a new scanning method, as opposed to the previously used fixed point method. Fresh water was injected into brine through a newly designed PVC bar shaped diffuser, which scans automatically within preset regions. After two months, the pond bottom reached 80 °C and heat extraction began. The performance of the GCL system, characterized by its hydraulic conductivity, has been monitored, and to our knowledge, generates the first full scale, elevated temperature data for a GCL system. Preliminary hydraulic conductivity data indicate values comparable with other clay liner systems.