Hydraulic Transient Study of Mainstream & Des Plaines TARP Phase II Systems

Abstract

Numerical studies of hydraulic transients for the TARP Phase I system were conducted in 1988. and 1992. These studies revealed that due to storage and/or conveyance limitation of the TARP Phase I Mainstream system, inflow must be substantially reduced to avoid geysering problems induced by hydraulic transients. Different inflow control solutions to different cases of the TARP Phase I were suggested in the previous project reports. TARP Phase II is designed to add additional water storage and increase the conveyance ability. This study is to investigate the extent and nature of hydraulic transients in Mainstream/Des Plaines TARP Phase II and to evaluate its design performance using computer modeling. The fully dynamic transient mixed flow mathematical model (MXTRANS) developed at the University of Minnesota was used for this study. To evaluate the hydraulic performance of the TARP Phase II System, including the Phase I Mainstream tunnel, Phase II Relief tunnel, and Phase I Des Plaines tunnel with or without four planned reservoir stages, four groups of modeling configurations for the systems as listed below are being considered Group A: Stage I Mainstream (Mainstream alone) Tunnel System Group B: Stage II Mainstream (Mainstream. With Relief Tunnel) System Group C: Des Plaines With or Without Mainstream System Group D: Interconnected Des Plaines and Mainstream Systems (Mainstream with Relief Tunnel and Des Plaines Tunnel)