State Water Project Research Articles

How reservoirs alter drinking water quality: Organic matter sources, sinks, and transformations

Within reservoirs, production, transformation, and loss of dissolved organic matter (DOM) occur simultaneously. While the balance between production and loss determines whether a reservoir is a net sink or source of DOM, changes in chemical composition are also important because they affect DOM reactivity with respect to disinfection by-product (DBP) formation. The composition of the DOM pool also provides insight into DOM sources and processing, which can inform reservoir management. We examined the concentration and composition of DOM in San Luis Reservoir, a large off-stream impoundment of the California State Water Project. We used a wide array of DOM chemical tracers including dissolved organic carbon (DOC) concentration, trihalomethane and haloacetic acid formation potentials (THMFP and HAAFP, respectively), absorbance properties, isotopic composition, lignin phenol content, and structural groupings determined by 13C nuclear magnetic resonance (NMR). There were periods when the reservoir was a net source of DOC due to the predominance of algal production (summer), a net sink due to the predominance of degradation (fall–winter), and balanced between production and consumption (spring). Despite only moderate variation in bulk DOC concentration (3.0–3.6 mg C/L), changes in DOM composition indicated that terrestrial-derived material entering the reservoir was being degraded and replaced by aquatic-derived DOM produced within the reservoir. Substantial changes in the propensity of the DOM pool to form THMs and HAAs illustrate that the DBP precursor pool was not directly coupled to bulk DOC concentration and indicate that algal production is an important source of DBP precursors. Results suggest reservoirs have the potential to attenuate DOM amount and reactivity with respect to DBP precursors via degradative processes; however, these benefits can be decreased or even negated by the production of algal-derived DOM. [Supplemental materials are available for this article. Go to the publisher's online edition of Lake and Reservoir Management to view the supplemental file.]

Isolated and integrated effects of sea level rise, seasonal runoff shifts, and annual runoff volume on California’s largest water supply

► We separate the impacts of three climate change factors on water supply in California. ► We provide another approach to reduce uncertainties in the impact estimate. ► Annual runoff change is the most dominant factor in the middle of this century. ► Sea level rise becomes the most critical factor in the end of this century. ► Seasonal runoff shift will add to but not dominate climate change impact. A 3-step perturbation ratio method is designed to facilitate the separation of seasonal pattern shifts of inflow to reservoirs from 2 other climate change factors: annual inflow change and sea level rise. The modeled region provides source water for the State Water Project and Central Valley Project of California. Four groups of the water planning simulation model CALSIM II run are implemented to isolate individual impacts of seasonal pattern shift of inflow to reservoirs, annual inflow volume change, and sea level rise on water supply in this region. Estimates of climate change impacts on water supply are made for the middle and end of the 21st century. These impacts are in terms of the ensemble means of CALSIM II simulation results for each of 12 climate model projections under the A2 or B1 emission scenario. The results indicate that around the middle of this century annual inflow changes contribute most to climate change impacts on water supply. But near the end of the century sea level rise of 61 cm in San Francisco Bay plays a major role in affecting water supplies.

Oxidation and volatilization of bromide by electrolysis in drinking water

To reduce the concentrations of brominated disinfection by-products, a process is presented here which removes bromide from a widely used surface water source, the California State Water Project (SWP). The process consists of oxidizing bromide to bromine and volatilizing the bromine. SWP water was passed through this unit under various conditions and the bromide was oxidized and volatilized under a variety of conditions. Five different reactor bodies with seventeen different configurations were tested. The reactors differed in the depth of the anode, in the distance between the anodes and, in the surface area of the anodes. Each reactor had SWP water pumped through the reactor at three or more different flows and at four or more different currents, producing 267 experimental conditions. Both reaction rates and removal efficiency increased with increasing current and were generally higher in the shallower reactors. The highest reaction rates were observed in the shallowest reactors and highest flow rates but the greatest efficiency was achieved is in a slightly deeper reactor at lower flows. This appears to have been the effect of the shallowest reactor having the smallest surface area that was easily saturated and but being closest to atmosphere, allowing the most rapid volatilization of bromine.

CalLite: California Central Valley Water Management Screening Model

The California Department of Water Resources (DWR) and U.S. Bureau of Reclamation Mid-Pacific Region (Reclamation) have developed a rapid, interactive screening model, named CalLite, for evaluating various Central Valley water management options. The CalLite model is being used as a computer-aided negotiations tool in a variety of stakeholder’s processes for improved understanding of water system operations and consensus-based decision making. CalLite was developed using the GoldSim system dynamics software that enables simulation of complex process through a buildup of simple object relationships, incorporates Monte Carlo stochastic methods, and includes dynamic, interactive user interfaces. The screening tool models much of the Central Valley of California that contributes flow to the Delta. The geographical coverage includes the Upper Trinity River, the Sacramento River Valley, the San Joaquin River Valley, the Sacramento–San Joaquin Delta, and the Central Valley Project and the State Water Project ser...

Identifying sources of dissolved organic carbon in agriculturally dominated rivers using radiocarbon age dating: Sacramento–San Joaquin River Basin, California

We used radiocarbon measurements of dissolved organic carbon (DOC) to resolve sources of riverine carbon within agriculturally dominated landscapes in California. During 2003 and 2004, average Δ14C for DOC was −254‰ in agricultural drains in the Sacramento–San Joaquin Delta, −218‰ in the San Joaquin River, −175‰ in the California State Water Project and −152‰ in the Sacramento River. The age of bulk DOC transiting the rivers of California’s Central Valley is the oldest reported for large rivers and suggests wide-spread loss of soil organic matter caused by agriculture and urbanization. Using DAX 8 adsorbent, we isolated and measured 14C concentrations in hydrophobic acid fractions (HPOA); river samples showed evidence of bomb-pulse carbon with average Δ14C of 91 and 76‰ for the San Joaquin and Sacramento Rivers, respectively, with older HPOA, −204‰, observed in agricultural drains. An operationally defined non-HPOA fraction of DOC was observed in the San Joaquin River with seasonally computed Δ14C values of between −275 and −687‰; the source of this aged material was hypothesized to be physically protected organic-matter in high clay-content soils and agrochemicals (i.e., radiocarbon-dead material) applied to farmlands. Mixing models suggest that the Sacramento River contributes about 50% of the DOC load in the California State Water Project, and agricultural drains contribute approximately one-third of the load. In contrast to studies showing stabilization of soil carbon pools within one or two decades following land conversion, sustained loss of soil organic matter, occurring many decades after the initial agricultural-land conversion, was observed in California’s Central Valley.

Factors Affecting Fish Entrainment into Massive Water Diversions in a Tidal Freshwater Estuary: Can Fish Losses be Managed?

AbstractWe examined factors affecting fish entrainment at California's State Water Project and Central Valley Project, two of the largest water diversions in the world. Combined, these diversions from the upper San Francisco Estuary support a large component of the municipal and agricultural infrastructure for California. However, precipitous declines in the abundance of several estuarine fish species, notably the threatened delta smelt Hypomesus transpacificus, have generated major concern about entrainment as a possible cause of the declines. We examined a 13‐year data set of export pumping operations and environmental characteristics to determine factors affecting entrainment (as indexed by salvage at fish screens) and the potential for manipulation of these factors to improve conditions for fish. Entrainment of three migratory pelagic species—delta smelt, longfin smelt Spirinchus thaleichthys, and striped bass Morone saxatilis—was primarily determined by the seasonal occurrence of particular life stages close to the export facilities. We also found that the direction and magnitude of flows through the estuary and to the export facilities were reasonable predictors of pelagic fish entrainment. Entrainment of resident demersal species (prickly sculpin Cottus asper and white catfish Ameiurus catus) and littoral species (Mississippi silverside Menidia audens and largemouth bass Micropterus salmoides) was not explained by diversion flows, although large numbers of individuals from these species were collected. Our study suggests that entrainment of pelagic species can be effectively reduced by manipulating system hydrodynamics.

Water Transport Charges and the California Divide: Implications of Ruling for Future State Capital Water Projects

This article discusses the recent case of Alameda County Flood Control & Water Conservation District Zone 7 et al v. State of California Department of Water Resources et al, Case No. 05AS01775, Sac. Sup. Ct. [Aug. 21, 2009], which centers around the California Department of Water Resources (DWR) use of revenues from the Hyatt‐Thermalito Dam, operated near the large storage facility of Lake Oroville, to offset the fees it charges contracting water agencies to the California State Water Project (SWP) for transporting water through the system. The article discusses the grave importance of these transportation charges to Southern California water agencies, along with how the court's decision was influenced by the ambiguity of the text of the contract. The court found that the state acted within its discretion in setting the fee structure in the first place. DWR has a statutory authority to sell power and set the price for it under California Water Code §11454. Other sections of the water code authorize DWR to cancel power sale contracts with utilities on the condition that it continued to pay at least as much for at least as long as the utilities paid for Hyatt‐ Thermalito power. DWR developed a policy regarding how it would value Hyatt‐Thermalito power for the purposes of calculating the credit to the SWP transportation charges, and the court held that this policy decision was entitled to deference.

Assessing reservoir operations risk under climate change

Risk‐based planning offers a robust way to identify strategies that permit adaptive water resources management under climate change. This paper presents a flexible methodology for conducting climate change risk assessments involving reservoir operations. Decision makers can apply this methodology to their systems by selecting future periods and risk metrics relevant to their planning questions and by collectively evaluating system impacts relative to an ensemble of climate projection scenarios (weighted or not). This paper shows multiple applications of this methodology in a case study involving California's Central Valley Project and State Water Project systems. Multiple applications were conducted to show how choices made in conducting the risk assessment, choices known as analytical design decisions, can affect assessed risk. Specifically, risk was reanalyzed for every choice combination of two design decisions: (1) whether to assume climate change will influence flood‐control constraints on water supply operations (and how), and (2) whether to weight climate change scenarios (and how). Results show that assessed risk would motivate different planning pathways depending on decision‐maker attitudes toward risk (e.g., risk neutral versus risk averse). Results also show that assessed risk at a given risk attitude is sensitive to the analytical design choices listed above, with the choice of whether to adjust flood‐control rules under climate change having considerably more influence than the choice on whether to weight climate scenarios.

Book Reviews

Book Reviews

Progress on incorporating climate change into management of California’s water resources

This paper presents preliminary efforts by agencies managing California’s water resources to incorporate climate change research into their planning and management tools. Projected increases in air temperature may lead to changes in the precipitation patterns, runoff timing and volume, sea level rise, and changes in the amount of irrigation water needed due to modified evapotranspiration rates. Historical observations of climate change related to California’s water resources are shown. Results from preliminary modeling studies of potential impacts of climate change to operations of the State Water Project and Central Valley Project, Delta water quality and water levels, flood forecasting and evapotranspiration rates are presented. Future directions to incorporate risk assessment are discussed.

Comparisons of Organic Carbon Analyzers and Related Importance to Water Quality Assessments

This study tested whether analyzers using different methods were equally capable of measuring organic carbon in diverse environmental water samples from California’s Sacramento/San Joaquin Delta and its watersheds. The study also evaluated whether the different instruments might provide differing organic carbon concentration measurements, which could in turn trigger (or not) a regulatory requirement for enhanced coagulation at a water treatment plant. In Phase 1, samples were collected in eight monthly events at five stations associated with California’s State Water Project and analyzed using three high temperature combustion and three chemical oxidation instruments. Significant differences between instruments occurred in only 20% of the analyses. However, 80% of the observed differences were attributed to one combustion instrument that reported higher values compared to the other instruments. In Phase 2, four certified standards were analyzed with nine instruments. Results suggested that the main contributor of the observed differences was some instruments’ inability to remove inorganic carbon, an important step in the analytical process. There were no significant differences in the frequencies at which different instruments would have prescribed enhanced coagulation at a water treatment plant. We concluded that properly operating instruments using any of the standard methods were equally capable of analyzing the diverse concentration levels of organic carbon in the Delta.

Electrochemical process for the removal of bromide from California state project water

Although bromide is generally considered non-toxic at concentrations found in most drinking water sources, it reacts with a variety of commonly used disinfectants, most notably ozone and chlorine, to produce by-products that are of serious public health concern. There are not currently any demonstrated technologies that can remove bromide in a cost effective fashion. This paper examines an electro-chemical process on a pilot-scale to remove bromide from a widely used surface water source, the California State Water Project (SWP). The process consists of oxidizing bromide to bromine and volatilizing the bromine. SWP water was passed through this unit under various conditions and the bromide removal was measured as well as the formation potential for various organic by products. This study shows up to 35% of the bromide was removed and there were up to 60% less disinfection by-products measured.

Seasonal Variations in Concentrations of Pharmaceuticals and Personal Care Products in Drinking Water and Reclaimed Wastewater in Southern California

Southern California imports nearly all of its potable water from two sources: the Colorado River and the California State Water Project (Sacramento-San Joaquin River Basin). Sewage treatment plant effluent (STPE) heavily impacts both of these sources. A survey of raw and treated drinking water from four water filtration plants in San Diego County showed the occurrence of several polar organic "pharmaceuticals and personal care products" (PPCP). These included phthalate esters, sunscreens, clofibrate, clofribric acid, ibuprofen, triclosan, and DEET. Several of these were also found in the finished water, such as di(ethylhexyl) phthalate, benzophenone, ibuprofen, and triclosan. Occurrence and concentrations of these compounds were highly seasonally dependent, and reached maximums when the flow of the San Joaquin River was low and the quantity of imported water was high. The maximum concentrations of the PPCPs measured in the raw water were correlated with low flow conditions in the Sacramento-San Joaquin Delta that feeds the State Water Project. The PPCP concentrations in raw imported water in the summer months approached that of reclaimed nonpotable wastewater.

CalSim: Generalized Model for Reservoir System Analysis

The California State Department of Water Resources and the United States Bureau of Reclamation Mid-Pacific Region have developed a general-purpose reservoir–river basin simulation model for the planning and management of the State Water Project and the federal Central Valley Project. The California Water Resources Simulation Model brings a fundamental change to modeling of these systems. Model users specify system objectives as input to the model. System description and operational constraints are specified using a new water resources engineering simulation language. A mixed integer linear programming solver efficiently routes water through the system network given the user-defined priorities or weights. Simulation cycles at different temporal scales allow for successive layering of constraints. The power and flexibility of the model is demonstrated by its ability to simulate the operation of complex new environmental water accounts.

Using Temperature and Salinity Tolerances to Predict the Success of the Shimofuri Goby, a Recent Invader into California

Shimofuri gobies Tridentiger bifasciatus recently invaded the San Francisco Estuary of California and appear to be physiologically well suited to the region. To assess the range expansion capability of the shimofuri goby, I used standard techniques to measure the critical thermal maxima (CTMax) at eight combinations of temperature (10°C and 20°C) and salinity (0, 5, 10, and 20‰) and I measured chronic upper salinity tolerance (CUST) at 20°C. Shimofuri goby CTMax was 37°C when acclimated to 20°C and was 31–34°C when acclimated to 10°C. These values surpass those of most other resident fishes and allow the gobies to survive in small isolated pools at low tide, where temperatures change quickly and often exceed 30°C. Shimofuri goby CUST was 17‰, typical for estuarine fishes, but insufficient to allow for range expansion through seawater. Shimofuri gobies have been transported via the California State Water Project into freshwater reservoirs, where they appear to have established reproducing populations. From these populations, they may disperse downstream into southern Californian estuaries, possibly threatening the federally endangered tidewater goby Eucyclogobius newberryi.

Ancient blue oaks reveal human impact on San Francisco Bay salinity

San Francisco Bay is one of the most important estuaries on the west coast of the Americas. Its water quality is controlled primarily by streamflow from the Sacramento and San Joaquin rivers. In fact, freshwater inflow from the Sacramento‐San Joaquin Delta explains 86% of the salinity variability at the mouth of the San Francisco Bay estuary [Peterson et al., 1989]. The massive diversion of streamflow by the California State Water Project and the Central Valley Project, part of the largest manmade water control system on Earth [Reisner, 1988], has raised salinity in the estuary on daily, seasonal, and annual timescales [Nichols et al., 1986; Peterson et al., 1989].

Oxidation of MTBE by ozone and peroxone processes

These two processes effectively remove MTBE but may also increase bromate.Initial pilot‐scale investigations demonstrated that both ozone alone and a combination of ozone and hydrogen peroxide (known as peroxone) can remove methyl tertiary butyl ether (MTBE) from water sources used by the Metropolitan Water District of Southern California. Under the tested conditions, peroxone more effectively removed MTBE than did ozone alone. In pilot tests, peroxone (here, 4 mg/L ozone and 1.3 mg/L hydrogen peroxide) removed an average of about 78 percent of the MTBE from water samples taken from the California State Water Project and the Colorado River. However, in peroxone‐treated samples from both water sources at ambient conditions, bromate was produced at concentrations above the maximum contaminant level of 10 μg/L for bromate in drinking water. A lower pH of 6.5 reduced bromate formation by about 20 percent in samples from both water sources, but it did not reduce the bromate concentration below 10 μg/L (the water sources contained about 0.1 mg/L bromide). Further optimization of the peroxone process may minimize bromate formation while providing acceptable MTBE removal and disinfection.

Build It And They Will Come: A Reexamination of the California State Water Project

Research Article| April 01 1998 Build It And They Will Come: A Reexamination of the California State Water Project Martin A. Nie Martin A. Nie Search for other works by this author on: This Site PubMed Google Scholar Southern California Quarterly (1998) 80 (1): 71–88. https://doi.org/10.2307/41171881 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Tools Icon Tools Cite Icon Cite Search Site Citation Martin A. Nie; Build It And They Will Come: A Reexamination of the California State Water Project. Southern California Quarterly 1 April 1998; 80 (1): 71–88. doi: https://doi.org/10.2307/41171881 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentSouthern California Quarterly Search This content is only available via PDF. Copyright 1998 Historical Society of Southern California Article PDF first page preview Close Modal You do not currently have access to this content.

Power input for the desalination plant in Santa Barbara, California

A new scheme for power input of the existing RO desalination plant in Santa Barbara, California, is described. This involves installing a new type of offshore water pump driven by ocean currents off Pt. Conception, CA. A financial comparison is made between three options for the consumer: (1) the cost of water using the State Water Project, (2) using the desalination plant as now built, powered by electricity from Southern California Edison Co., and (3) using the proposed new scheme.

Water conflicts in the Western United States

Water development and use in the Western United States has been fraught with conflicts, primarily because most areas west of the 100th meridian are water deficient. This is exemplified by California where the majority of available water is in the northern part of the state, while most of the population is concentrated in the semi‐arid south. Several examples of past conflicts are cited. Three current conflicts are examined in detail: the so‐called Miller‐Bradley Central Valley Project Improvement Act that instituted water marketing; the efforts by agricultural interests to reorder the allocation of water during shortages of the State Water Project pursuant to its contracts at the expense of urban interests; and the attempts by urban interest groups in Southern Nevada and Southern California to reallocate Colorado River water.