Soil Investigations in the Bay-Delta Watershed of California.

The California Bay-Delta watershed is remarkable for its agricultural productivity, ecological diversity, and complexity.  It is home to one of the largest, most complex water delivery systems in the nation.  It provides drinking water to 22 million people and supports $28 billion in agricultural industry.  It is a National Priority Landscape Initiative for NRCS, with focus on water conservation, water quality improvements, and habitat restoration.

Soil survey research will center on select MLRA benchmark soil landscapes and catenas within the 38 million acre watershed.  Distinctive MRLA soil systems will serve as representative study units within the whole.  Potential projects include:  (1) Characterize benchmark soils (dominantly Histosols) in the fresh and salt water marshes, sloughs, river channels, and river deltas of the “Delta proper” (MLRA 16).  (2)  Characterize native vs. disturbed cropland soils on Merced/Tuolumne River terraces (MLRA 17) with research emphasis on soil hydrology, solute chemistry and reactions, and microbiology.  (3) Hydropedologic processes and properties in rangeland soils in the Sierra Foothills (MLRA 18) that interface between the agricultural and urban areas of the Delta and the wildlands of the mountains.  (4)  Soil moisture & temperature study in rangelands and lands recently converted to vineyards and orchards in the eastside Central Coast Range (MLRA 15).  (5) Soil climate study in toposequence from ~5,000 to ~11,000 feet elevation in the Sierra Nevada Mountains (MLRA 22B). 

Intent is to fill data gaps and increase understanding of climate, infiltration, permeability and runoff, all of which affect water quality, quantity, and wildlife habitat in line with the Bay-Delta Initiative.  The studies will increase understanding of patterns of pedogenesis and soil function, and help improve accuracy and precision of soil maps and interpretations in the MLRAs.  The soil survey research data will also inform future digital soil mapping and watershed modeling efforts.