Annotated List of Articles Published in the Journal of Dam Safety ...

Subject terms: foundations, design, construction, seepage, case studies, failures, incidents, geotechnicalinvestigations, pipingLarson, Eric, Wilkes, John and Dreese, Trent. Geomembrane Installation at Salt Springs CFRDDam. Journal of Dam Safety - Winter 2006 (V. 4 N. 1)Salt Springs Dam, owned by Pacific Gas & Electric Co. (PG&E) is the fifth oldest Concrete Faced RockfillDam (CFRD) in the world and the first CFRD to reach 328 ft. (100 m) in height. It is located in California,south and east of Sacramento, high in the Sierra Nevada Mountain Range. In the 1930s, construction ofthe dam was halted at about mid-height due to winter weather. When rock placement resumed in thespring, the lift height was reduced and sluicing techniques were improved to gain better consolidation.These changes created a zone of differential settlement in the dam where the concrete face has requiredcontinual repairs over its 70+ year history. In 2001, seepage in this zone increased significantly,exceeding the limit set by the California Department of Water Resources, Division of Safety of Dams.Immediately, and at considerable expense, PG&E hired divers to make temporary repairs as it began toinvestigate how to permanently fix the upstream face at Salt Springs Dam. The conclusion was to installa PVC geomembrane system over the upstream face with the goal of reducing seepage to 12 cfs (340l/s). The work was done in two phases. In the spring of 2004, Phase I repairs began with the installationof the CARPI geomembrane system over the center of the face in the so called “transition zone” tomitigate the risk of significant seepage increases, as occurred in 2001.Geographic interest: CaliforniaSubject terms: rockfill dams, concrete, design, construction, temperature, seepage, rehabilitation,underwater investigations, seepage analysis, geosyntheticsSwaisgood, James R., Montgomery, Dr. Jerry and Kofoed, Val O., P.E. Mapping Seepage throughthe River Reservoir Dam No. 3. Journal of Dam Safety - Winter 2006 (V. 4 N. 1)The first step in addressing a problem with seepage is pinpointing its source. In the past, procedures fordetermining the exact location and nature of seepage flows have been both costly and time consuming.The approach to an emergency situation at River Reservoir No. 3, an arched earthen structure on theheadwaters of the Little Colorado River, proves that a combination of sound engineering consulting andmodern technologies can save time and money in response to emergencies.Geographic interest: ArizonaSubject terms: seepage, embankment dams, geophysical investigations, emergency management,rehabilitation, financial aspects, design, constructionToms, Ed, Poulter, Don, Samandi, Sam and Yonikas, Pat. Overholser Dam-Ambursen StructureRehabilitation. Journal of Dam Safety - Winter 2006 (V. 4 N. 1)Overholser Dam is a 125-foot-high (38.1m), 1,200-foot-long (366m) Ambursen structure constructed in1916 used for flood control and water supply for Oklahoma City. Safety issues discovered during routineinspection of the spillway section included: 1) buttress wall continuous cracks, 2) foundation seepage, 3)upstream shell seepage, 4) excessive upstream shell sediment loading, and 5) concrete deterioration.Issues complicating project design and construction included: 1) methods for dewatering the face of thedam to minimize impacts to the City’s water supply, 2) increased water supply treatment costs due todiminished water quality directly related to the lower reservoir level, 3) construction scheduling tominimize water supply and potential flooding impacts, 4) construction methods to enable competitive bidsfrom local contractors, 5) local, state, and federal environmental regulatory requirements to protectwetlands and aquatic habitats, and 6) preserving the historical aesthetics of the structure.