middle-fork-surge-shaft

After 50 years in service, the 3 meter diameter surge shaft for the 122 Mega Watt Middle Fork Hydro Power Plant had deteriorated and was cracking, perhaps due in part to seismic activity. The water leakage was believed to be seeping into the hillside and at one point had been named as the cause of a landslide which resulted in significant hydro power plant damage at a lower elevation.

The property owner was Placer County Water Agency and ATS, Inc. was subcontracted through Kiewit Pacific.   The pH of the water in the surge shaft and at the seepage points was monitored during the project so that there would be no discharges of water not in compliance with Water Board guidelines. All process water and seepage water was treated for turbidity and pH before discharged through a spray field. The discharge method was used to reduce any erosion to the mountainside. Redundant systems were used to eliminate downtime from a system problem and to assure that water would be treated under all conditions. Over a period of 3 months all water was discharged within regulatory guidelines. Water treatment data was available real time on the internet.