San Joaquin River Restoration Program Geophysical Analysis for Seepage Management and Channel Capacity Improvement
Effects of Sedimentological and Geophysical Characteristics of Fluvial Deposits on Seepage
The Seepage Management Plan (SMP) of the San Joaquin River Restoration Program (SJRRP) includes locations of identified risks, fields or parcels that may experience seepage impacts due to Interim or Restoration Flows. Some locations experience seepage at flows below full Restoration Flows. The SMP provides initial locations to evaluate for seepage projects to increase capacity to convey Restoration Flows. Projects may include a variety of real estate or physical actions, including license agreements, acquisition, interceptor drains, relief drains, drainage ditches, slurry walls, shallow groundwater pumping or channel conveyance improvements.
Physical projects from the list above depend on a variety of site-specific conditions including soil types. Soil textures along the San Joaquin River include alluvial deposits from both the Sierra Nevadas and the coast range. Thick clay and hardpan layers are found along with sand deposits from former river channels. Topography in the area is such that the Riverside, Poso, and Columbia canals are on the high ground, the river channel is between them, and elevations slope off to either side. Sand deposits may carry surface water from the San Joaquin River underground and create problems further away from the river channel, necessitating changes in project design. This research proposal would address this question through the use of geophysical exploration techniques in a pilot project.
Need and Benefit
The San Joaquin River Restoration Program has a need to analyze the appropriateness of and develop physical projects to prevent seepage adjacent to the San Joaquin River. This need may be common across other Reclamation projects including both river and canal seepage. This project will evaluate soil textures adjacent to the San Joaquin River for the purpose of enabling cost effective and technically accurate projects. Benefits include:
" Drainage evaluation evaluate fine soil texture locations to know potential for drainage impairment
" Identify sand channels that daylight, channeling water further away from the river than may be expected
" Inform need to protect local landowners further away from the river channel,
" Increase effectiveness of physical seepage projects through design and construction
Contact the Principal Investigator for information about partners.
The research project will be documented with a Technical Memorandum (TM) in approximately January 2013. The TM will include a description of the background information and hypothesis tested, the methods used and results. The TM will also discuss any limitations of the research, any lessons learned which may be extrapolated to other locations along the San Joaquin and other rivers, and any potential for assumptions to be made and general results used in other areas. Finally, the report will discuss any conclusions on geophysical and sedimentological characteristics of fluvial deposits in the pilot project area, potential design considerations for physical projects in the area, and conclusions that may be drawn for other locations on the San Joaquin and other rivers.