Independent Review Panel (IRP) Report for the 2015 Long-Term Operations Biological Opinions (LOBO) Annual Science Review

Delta Stewardship Council (Delta Council) | December 1st, 2015

This report presents findings and opinions of the Independent Review Panel (IRP) assembled by the Delta Science Program to inform the National Marine Fisheries Service (N

This report presents findings and opinions of the Independent Review Panel (IRP) assembled by the Delta Science Program to inform the National Marine Fisheries Service (NMFS) and the U.S. Fish & Wildlife Service (USFWS) as to the efficacy of water operations and certain regulatory actions prescribed by their respective Long-term Operations Biological Opinions’ (LOBO) Reasonable and Prudent Alternative Actions (RPAs) as applied from October 1, 2014 through September 30, 2015 (Water Year 2015).  This year’s annual review focused primarily on: (1) Shasta Reservoir and Sacramento River temperature monitoring, modeling, and management, (2) the River Assessment for Forecasting Temperature (RAFT) decision support tool (model), (3) an Enhanced Particle Tracking Model (E-PTM), and (4) a USFWS report on past, present, and future approaches to incidental take of Delta Smelt.  After reviewing a required set of written documents (Appendix 1), the IRP convened at a public workshop in Sacramento, CA on 5-6 November 2015. The first day of the 2-day workshop included agency presentations and provided a forum for the IRP to interact and consider information presented on water operations, temperature modeling, monitoring and RPA Actions as implemented in yet another critically dry 2015 water year. On the second day, the IRP deliberated in a private session beginning at 9:00 a.m. in order to prepare and present their initial findings at the public workshop at 2:00 p.m., after which there was an opportunity for agency representatives, members of the public, and the IRP members to comment and otherwise exchange impressions and information. Subsequent IRP communication and deliberations were conducted via email and conference calls in the course of drafting this final report. Click here for federal agency response letter

Independent Review Panel (IRP) Report for the 2017 Long-term Operations Biological Opinions (LOBO) Biennial Science Review (January 24, 2018)

Delta Stewardship Council (Delta Council) | January 31st, 2018

Influence of agricultural managed aquifer recharge on nitrate transport: The role of soil texture and flooding frequency

Soil Science Society of America (SSSA) | June 9th, 2021

Agricultural managed aquifer recharge (Ag-MAR) is a concept in which farmland is flooded during the winter using excess surface water to recharge the underlying groundwat

Agricultural managed aquifer recharge (Ag-MAR) is a concept in which farmland is flooded during the winter using excess surface water to recharge the underlying groundwater. In this study, we show how different recharge practices affect NO3− leaching and mineralization–denitrification processes in different soil systems. Two contrasting soil textures (sand and fine sandy loam) from the Central Valley, Califor- nia, were repeatedly flooded with 15 cm of water at varying time intervals in field and soil column experiments. Nitrogen species (NO3–, NH4+, total N), total C, dis- solved O2, and moisture content were measured throughout the experiments. Results show that when flooding occurs at longer intervals (every 1–2 wk), N mineralization increases, leading to an increase of mobile NO3− in the upper root zone and leach- ing of significant quantities of NO3− from both soil textures (137.3 ± 6.6% [sand] and 145.7 ± 5.8% [fine sandy loam] of initial residual soil NO3−) during subsequent flooding events. Laboratory mineralization incubations show that long flooding inter- vals promote mineralization and production of excess NO3− at rates of 0.11–3.93 mg N kg–1 wk–1 (sand) and 0.08–3.41 mg N kg–1 wk–1 (fine sandy loam). Decreasing the flooding frequency to 72 h reduces potential mineralization, decreasing the amount of NO3− leached during flooding events (31.7 ± 3.8% [sand] and 64.7 ± 10.4% [fine sandy loam] of initial residual soil NO3–). The results indicate that implementing recharge as repeated events over a long (multiple-week) time horizon might increase the total amount of NO3− potentially available for leaching to groundwater.

Initial Alternatives Information Report for the North/Central Delta Improvement Study (Delta Cross Channel, Franks Tract, and Through- Delta Facility Evaluation)

U.S. Bureau of Reclamation (USBR) | March 17th, 2010

The U.S. Department of the Interior (Interior) Bureau of Reclamation (Reclamation) and the California Department of Water Resources (DWR) are evaluating the feasibility o

The U.S. Department of the Interior (Interior) Bureau of Reclamation (Reclamation) and the California Department of Water Resources (DWR) are evaluating the feasibility of using conveyance and operations actions in the north and central region of the Sacramento–San Joaquin River Delta (Delta) to improve water quality and fish conditions. Specifically, Reclamation is evaluating the feasibility of these actions in the North/Central Delta Improvement Study (NoCDIS or Study). The Initial Alternatives Information Report (IAIR) identifies, discusses, and screens measures to address the problems and opportunities. These measures are used to develop initial alternatives. Initial alternatives from the IAIR will be incorporated into and refined in the subsequent Plan Formulation Report (PFR). Subject to continued appropriations and a determination of federal interest, the Study should culminate in an Environmental Impact Statement/Environmental Impact Report (EIS/EIR) and a Feasibility Report. Reclamation is the federal lead agency for National Environmental Policy Act (NEPA) compliance, and DWR is the state lead agency for California Environmental Quality Act (CEQA) compliance.

Initial Characterization of the Groundwater System near the Lower Colorado Water Supply Project, Imperial Valley, California

U.S. Geological Survey (USGS) | October 13th, 2015

In 2009, the U.S. Geological Survey, in cooperation with the city of Needles, began a study of the hydrogeology along the All-American Canal, which conveys water from the

In 2009, the U.S. Geological Survey, in cooperation with the city of Needles, began a study of the hydrogeology along the All-American Canal, which conveys water from the Colorado River to the Imperial Valley. The focus of this study was to gain a better understanding of the effect of lining the All-American Canal, and other management actions, on future total dissolved solids concentrations in groundwater pumped by Lower Colorado Water Supply Project wells that is delivered to the All-American Canal. The study included the compilation and evaluation of previously published hydrogeologic and geochemical information, establishment of a groundwater-elevation and groundwater-quality monitoring network, results of monitoring groundwater elevations and groundwater quality from 2009 to 2011, site-specific hydrologic investigations of the Lower Colorado Water Supply Project area, examination of groundwater salinity by depth by using time-domain electromagnetic surveys, and monitoring of groundwater-storage change by using microgravity methods. Prior to the completion of the All-American Canal in 1940, groundwater in the study area flowed from east to west, and groundwater was recharged primarily by underflow from the Colorado River Valley. After construction of the All-American Canal, groundwater elevations were altered in the study area as seepage of Colorado River water from the All-American Canal and other canals became the dominant recharge source. By 2005, groundwater elevations had increased by as much as 50–70 feet along the All-American Canal. Superimposed on the east-to-west groundwater gradient was groundwater movement away from the All-American Canal to the north and, most likely, to the south into Mexico. After lining the All-American Canal, from 2007 to 2010, groundwater elevations declined as seepage from the All-American Canal decreased. Between 2005 (the last complete groundwater-elevation survey prior to lining the All-American Canal) and 2011, groundwater elevations declined 20–40 feet along the All-American Canal and as much as 40–45 feet in the vicinity of Lower Colorado Water Supply Project pumping wells. Water-quality and isotope data were used to differentiate historically recharged groundwater from groundwater more recently recharged by seepage of Colorado River surface water from the All-American Canal. Prior to the completion of the All-American Canal in 1940, groundwater in the southern part of the study area was primarily sodium-chloride/sulfate type water that had relatively low total dissolved solids concentrations (500–820 milligrams per liter). During 2007–11, groundwater in the southern part of the study area, near the All-American Canal, ranged from sodium-chloride type water to mixed-cation-sulfate type water that had total dissolved solids concentrations generally less than 879 milligrams per liter. The stable-isotopic signature of groundwater near the All-American Canal sampled in 2009–11 indicated inputs of Colorado River water that had been affected by evaporation, and radioactive isotopes indicated that a substantial fraction of water had been recharged recently, within the past 60 years. This contrasted with historically recharged groundwater near the All-American Canal, which had higher sodium and chloride concentrations, and lower calcium and sulfate concentrations, than recent recharge from the All-American Canal. Groundwater at a distance from the All-American Canal, in the East Mesa, Algodones Dunes, Pilot Knob Mesa, and Cargo Muchacho Mountains piedmont, was found to have higher total dissolved solids concentrations (generally greater than 1,000 milligrams per liter) than recently recharged groundwater near the All-American Canal. Time-domain electromagnetic data indicated that low-salinity groundwater was present down to about 377 feet below land surface near the All-American Canal; groundwater salinity at depth increased with distance north from the All-American Canal. Groundwater several miles or more from the canal also did not contain tritium and had a residence time on the order of thousands to tens of thousands of years. The groundwater in the piedmont of the Cargo Muchacho Mountains had a distinctly light stable-isotopic signature indicative of recharge by runoff from local precipitation, whereas the stable isotopic signature of groundwater in the East Mesa and the Algodones Dunes indicated a mixture of local precipitation and historic Colorado River recharge sources. During and after lining the All-American Canal (2007–11), groundwater elevations in the Lower Colorado Water Supply Project area declined, while total dissolved solids concentrations remained relatively constant. The total dissolved solids concentrations in well LCWSP-2 ranged from 650 to 800 milligrams per liter during this study. Depth-specific water-quality and isotope sampling at well LCWSP-2 indicated the groundwater pumped from the deeper part of the screened interval (240–280 feet below land surface) contained a greater proportion of historical groundwater than the groundwater pumped from the shallower part of the screened interval (350–385 feet below land surface). Age-tracer data at well LCWSP-2 indicated that all depths of the screened interval had received recent recharge from seepage of Colorado River water from the All-American Canal.

Inland Empire Interceptor Appraisal Analysis

U.S. Bureau of Reclamation (USBR) | September 16th, 2013

The Santa Ana Watershed Project Authority (SAWPA) is a joint powers authority comprised of five member water districts that serve the vast majority of the Santa Ana Water

The Santa Ana Watershed Project Authority (SAWPA) is a joint powers authority comprised of five member water districts that serve the vast majority of the Santa Ana Watershed. The area served by SAWPA is located within Orange, Riverside and San Bernardino Counties of California, bounded by the Pacific Ocean on the west, the San Bernardino Mountains to the north, and the San Jacinto Mountains to the east. The five SAWPA Member Agencies are: • Eastern Municipal Water District (EMWD), • Western Municipal Water District (WMWD), • Inland Empire Utilities Agency (IEUA), • San Bernardino Valley Municipal Water District (SBVMWD), and • Orange County Water District (OCWD). These five agencies serve most of the Santa Ana Watershed. Population within the watershed has increased significantly in recent years, and this urban growth has put enormous pressure on the regional water supply, water quality and environmental/recreation resources. SAWPA’s mission is to plan and build facilities to protect water quality and enhance the water supply within the Santa Ana River Watershed. This mission includes the goal of achieving a salt balance in the upper Santa Ana Watershed. SAWPA developed the Inland Empire Brine Line (Brine Line), which was formerly known as the Santa Ana Regional Interceptor (SARI), for the purpose of exporting salt from the Santa Ana Watershed. Exportation of salt prevents its accumulation in the watershed and protects the quality of the potable water supply. The future of the potable water supply will continue to be dependent upon an economical means of collection, treatment and disposal of brine. The Brine Line collects and disposes of brine flow from the Santa Ana Watershed and is critical to SAWPA’s mission success. The Brine Line includes approximately 72 miles of pipeline in multiple branches which converge in the vicinity of Prado Dam near the City of Corona. It has a planned capacity of approximately 32.5 million gallons per day (MGD) and was planned for collection and exportation of approximately 271,000 tons of salt per year from the upper Santa Ana Watershed, east of the Santa Ana Mountains. Currently (2010 & 2011), average system flows are approximately 11.7 MGD and over 75,000 tons of salt are exported per year. An additional 21 miles of pipeline convey the combined flows to Orange County Sanitation District (OCSD) facilities for treatment and disposal by discharge to the Pacific Ocean. This pipeline has a nominal capacity of 30 MGD. The planned capacity of the Brine Line system (32.5 MGD) exceeds the hydraulic capacity of the pipeline from the Brine Line convergence near Prado Dam to the OCSD facilities. Furthermore, the present agreement between SAWPA and OCSD allows Brine Line flows to the OCSD system up to only 17.0 MGD, with a contractual right to purchase up to 30.0 MGD capacity.

Inner Workings: Big wildfires mobilize mercury. What are the risks to surface water?

National Academy of Sciences (NAS) | July 6th, 2021

The landscape was still smoldering in October 2020 as Jeff Prancevic and Charles Alpers, part of a multidisciplinary team of US Geological Survey (USGS) researchers, drov

The landscape was still smoldering in October 2020 as Jeff Prancevic and Charles Alpers, part of a multidisciplinary team of US Geological Survey (USGS) researchers, drove into the scorched hills above Lake Berryessa in California. Masked and traveling separately because of the pandemic, the team met up at EcoCamp Berryessa, a site that had recently hosted firefighters as they battled the LNU Lightning Complex fires in Northern California. The USGS team was there to sample soils and ash amidst the devastation.

Inorganic, isotopic, and organic composition of high-chloride water from wells in a coastal southern California aquifer

Applied Geochemistry (Elsevier) | August 1st, 2005

Chloride concentrations were as high as 230 mg/L in water from the surface discharge of long-screened production wells in Pleasant Valley, Calif., about 100 km NW of Lo

Chloride concentrations were as high as 230 mg/L in water from the surface discharge of long-screened production wells in Pleasant Valley, Calif., about 100 km NW of Los Angeles. Wells with the higher Cl− concentrations were near faults that bound the valley. Depending on well construction, high-Cl−water from different sources may enter a well at different depths. For example, Cl−concentration in the upper part of some wells completed in overlying aquifers influenced by irrigation return were as high as 220 mg/L, and Cl− concentrations in water sampled within wells at depths greater than 450 m were as high as 500 mg/L. These high-Cl− waters mix within the well during pumping and produce the water sampled at the surface discharge. Changes in the major ion, minor ion, trace element, and δ34S and δ13C isotopic composition of water in wells with depth were consistent with changes resulting from SO4 reduction, precipitation of calcite, and cation exchange. The chemical and isotopic composition of high-Cl− water from deep wells trends towards the composition of oil-field production water from the study area. Chloride concentrations in oil-field production water present at depths 150 m beneath freshwater aquifers were 2200 mg/L, and Cl− concentrations in underlying marine rock were as high as 4400 mg/L. High-Cl− concentrations in water from deeper parts of wells were associated with dissolved organic C composed primarily of hydrophobic neutral compounds believed to be similar to those associated with petroleum in underlying deposits. These compounds would not be apparent using traditional sampling techniques and would not be detected using analytical methods intended to measure contamination.

Installation of Bioretention Rain Gardens to Achieve Pollutant Reduction

San Francisco Estuary Institute (SFEI) | December 1st, 2019

Green infrastructure (GI) is a resilient approach to managing stormwater at its source while also delivering environmental, social, and economic benefits. GI uses vegetat

Green infrastructure (GI) is a resilient approach to managing stormwater at its source while also delivering environmental, social, and economic benefits. GI uses vegetation, soils, and other elements to restore more natural watershed processes that mimic nature to soak up stormwater, provide habitat, clean the air, and filter out pollutants from urban stormwater runoff. GI can reduce peak flows and stream erosion; recharge groundwater; and improve water quality in urban stormwater that drains to San Francisco Bay. 

Instream Flow Regime Recommendations, Big Sur River, Monterey County

California Department of Fish and Wildlife (CDFW) | September 23rd, 2016

The Department of Fish and Wildlife (Department) has interest in assuring that water flows within streams are maintained at levels which are adequate for long-term protec

The Department of Fish and Wildlife (Department) has interest in assuring that water flows within streams are maintained at levels which are adequate for long-term protection, maintenance and proper stewardship of fish and wildlife resources. The Department has developed recommended instream flow regimes for the Big Sur River, Monterey County for transmittal to the State Water Resources Control Board (Water Board) and consideration as set forth in 1257.5 of the Water Code. Submission of these flow recommendations to the Water Board complies with Public Resources Code (PRC) §10001-10002. The Department is recommending instream flow regimes for the lower Big Sur River from Pfeiffer Big Sur State Park at U.S. Geological Survey (USGS) Gage 11143000 downstream through Molera State Park. The recommendations are separated into six monthly hydrological condition types (i.e., critically dry, dry, below median, above median, wet, and extremely wet) and are presented in the form of an annual schedule for each of three mainstem river reaches (i.e., Lower Molera, Molera, and Campground). The recommended instream flow regimes are summarized in the current document, along with justification for the recommendations and reference to the data sources. The Department files the enclosed set of instream flow regime recommendations for the Big Sur River that we believe to be comprehensive and substantially complete. The recommendations were based upon information developed through recent PRC instream flow evaluations by the Department, and earlier information. The Department may revise its recommended instream flow regimes for the Big Sur River at a later date based upon any new scientific information that may become available.