Portfolio | Water Quality | Tetra Tech R&D

McMullin On-Farm Flood Capture and Recharge Project

The San Joaquin Valley (SJV) faces two large hydrologic issues: severe and chronic groundwater overdraft and flooding risks along major rivers. Capturing sufficient flood flow volumes for groundwater recharge could help address these two pressing issues of groundwater overdraft and flood risks. Howe ..... More >>

Evaluation of Rice Cultivation in the Sacramento-San Joaquin Delta- Rio Vista, CA

About two thirds of the 740,000 acres in the Sacramento-San Joaquin Delta (Delta) are in agriculture. The drained peat soils of the Delta have provided fertile soils for agriculture since the late 1800s when these lands were reclaimed from existing wetlands. Since then, the Delta environment has dra ..... More >>

Focusing on demonstrating cost effective agricultural BMPs (On-Farm Flood Flow Capture) to retain and infiltrate storm waters, Kings Basin, CA

A Survey of Water Use and Sustainability in the United States with a Focus on Power Generation

This study presented an assessment of current and future water withdrawal requirements compared with water availability, resolved at the level of counties across the continental US. Various metrics characterizing water use are computed and mapped. These metrics represent, for example, water availabi ..... More >>

Selenium TMDL for North San Francisco Bay

Selenium has been a concern in the Central Valley and San Francisco Bay for several decades, a region with selenium sources from San Joaquin Valley and various point sources including refineries. A TMDL project is underway to address selenium toxicity in North San Francisco Bay led by the San Franci ..... More >>

Use of Alternate Water Sources for Power Plant Cooling

With increasing competition for good quality water resources and restrictions on withdrawals from natural water bodies and aquifers, it is becoming more commonplace for electric utilities to evaluate alternate water sources for cooling power plants. This study considered the use of alternate, degrad ..... More >>

Mokelumne River Watershed Land Use Master Plan

Tetra Tech supported the East Bay Municipal Utility District (EBMUD) during the information gathering process and prepared an updated land use master plan for approximately 29,000 acres that it owns in the Mokelumne River watershed. The Mokelumne Watershed Land Use Master Plan (Master Plan) establis ..... More >>

Conceptual Models of Constituents of Drinking Water Concern in the Central Valley

Tetra Tech worked closely with EPA Region IX and a multiple-agency stakeholder group called the Central Valley Drinking Water Policy Workgroup to develop conceptual models that represent the sources, transformation, and transport of the critical constituents of drinking water concern in the waters o ..... More >>

Guadalupe River Watershed Mercury TMDL

The Guadalupe River Watershed is a large (440 sq. km.) complex hydrologic system, comprised of six major reservoirs and over 130 km of streams and rivers. The upper portion of the watershed contains the New Almaden mercury-mining district, the largest mercury producer in North America. From 1846 to ..... More >>

Low Intensity Chemical Dosing of Agricultural Runoff in the Delta

This project broadly studies the LICD technology at a site in the Delta. Replicated studies are testing the efficacy of aluminum and iron based coagulants to remove DOC, DBPPs and Hg; subsidence and accretion rates and soil bulk densities in wetland cells with coagulant treatments; net ecosystem eff ..... More >>

Suisun Marsh: Low DO project and Blacklock Marsh Restoration

Tetra Tech has been involved with improving water quality in Suisun Marsh under a variety of State Water Quality Control Board and DWR funded projects. Current land use in Suisun Marsh is managed wetlands. Low dissolved oxygen levels and elevated Hg levels have been attributed in part to land manage ..... More >>

Strategy for Resolving MeHg and Low Dissolved Oxygen Events- Northern Suisun Marsh

The 116,000 acre Suisun Marsh is the largest contiguous brackish water marsh remaining on North America’s west coast and represents a critical part of the San Francisco Bay-Delta estuary ecosystem. Almost half of the marsh is comprised of managed wetlands that experience seasonal flood-drain-flood cycles depending on environmental conditions and property manager objectives. In northwestern areas of the Marsh, fall flooding cycles cause ..... More >>

Evaluation of Rice Cultivation in the Sacramento-San Joaquin Delta- Rio Vista, CA

This project builds upon the earlier rice investigation [1]. Current agricultural uses in the Sacramento-San Joaquin Delta cause subsidence when organic soils are drained and exposed to oxygen. Previous research indicates rice cultivation will stop and may reverse subsidence. This project, which began construction in October 2008, ..... More >>

Methyl mercury (MeHg) cycling and export from agricultural and natural wetlands in the Yolo Bypass

Water is becoming increasingly scarce in California and is not meeting current needs, requiring actions to more efficiently manage California’s water supply. Among these actions are conjunctive use and groundwater recharge. In developing a strategy to increase groundwater banking, solutions have typically focused on public agencies ..... More >>

San Jose Water Pollution Control Plant Mercury Study

The San Jose/Santa Clara Water Pollution Control Plant (SJ/SC WPCP or “Plant”) conducted a multi-year study of mercury fate and transport from October 2004 to May 2007. This was one of the largest focused studies of mercury behavior in a wastewater treatment plant. The study was focused on examining ..... More >>

South San Francisco Bay Total Maximum Daily Loads (TMDLs) for Copper and Nickel

Water quality standards in the southern portion of San Francisco Bay were being exceeded in spite of the point source controls in place at water treatment facilities. A watershed-wide assessment addressed both point and non-point pollutant sources, such as urban runoff, upstream inputs, air depositi ..... More >>

Groundwater and Soil Investigation at Former Steel Company Site, Union City, California

A field sampling program was designed and implemented for a proposed, below grade roadway (State Highway 84) across a former steel company property. The area where the road was planned had concrete building pads; subsurface foundations sumps filled with sludge, slag, and oily liquids and large pipes ..... More >>

March Air Force Base Basewide Groundwater Modeling Program Riverside, California

Tetra Tech has been under contract to the Air Force Center of Environmental Excellence (AFCEE) since 1992 to assess the effects of past waste management practices on the regional groundwater quality at March Air Force Base and surrounding communities. ..... More >>

Soil and Groundwater Evaluation and Modeling at Large MGP Site, Los Angeles, California

The 256-acre former Aliso Street manufactured gas plant (MGP) site is located in downtown Los Angeles. MGP operations began in 1874 and used both coal-based processes and oil-based processes. When natural gas became available in 1922, the gas plant was placed on standby. In 1942, the facilities were ..... More >>