Instream Flow Studies for the Protection of Public Trust Resources: A Prioritized Schedule and Estimate of Costs

California State Water Resources Control Board (SWRCB) | February 18th, 2011

Chapter 5 of the 2009-10 Seventh Extraordinary Session (SB X7 1, Simitian) directs the State Water Resources Control Board (State Water Board) to submit to the Legislatur

Chapter 5 of the 2009-10 Seventh Extraordinary Session (SB X7 1, Simitian) directs the State Water Resources Control Board (State Water Board) to submit to the Legislature, by December 31, 2010, a prioritized schedule and estimate of costs to complete instream flow studies for two categories of rivers and streams, by two specific deadlines: 1) high priority rivers and streams in the Delta watershed that were not covered in the Board’s “Final Report on Development of Flow Criteria for the Sacramento-San Joaquin Delta Ecosystem” by 2012; and 2) all major rivers and streams outside the Sacramento River watershed by 2018. The definition of the two stream categories is ambiguous. There are a number of tributaries that are both in the Delta watershed and outside the Sacramento River watershed, including the San Joaquin, Calaveras, Cosumnes, and Mokelumne Rivers. The State Water Board interprets the first category to mean all Delta and Sacramento River tributaries not covered under the Board’s “Final Report on Development of Flow Criteria for the Sacramento-San Joaquin Delta Ecosystem.” Two additional schedules are prioritized for “all major rivers and streams outside the Sacramento River watershed.” This report identifies 138 rivers and streams for instream flow studies. The total estimated cost to conduct scientific instream flow studies for the high priority rivers and streams tributary to the Delta is $32.46 million. The total estimated cost to conduct scientific instream flow studies for the high priority rivers and streams outside the Delta watershed is $107.25 million. The detailed schedules and costs are preceded with a few short discussions on the timelines given in the directive, the organization of schedules, the cost estimates for instream flow studies, and cost estimates for the next logical step: setting instream flow objectives.

Integrated Coastal Groundwater Monitoring Program and Plan

Monterey County Water Resources Agency (MCWRA) | May 19th, 2019

California American Water Company (CalAm) is working to increase sustainability of their water supply portfolio to meet the long-term needs of customers in their

California American Water Company (CalAm) is working to increase sustainability of their water supply portfolio to meet the long-term needs of customers in their service area on the Monterey Peninsula. Accordingly, CalAm has proposed the Monterey Peninsula Water Supply Project (MPWSP). The MPWSP includes a desalination plant, distribution pipelines, aquifer storage and recovery and in-lieu use of desalinated water. Feedwater for the desalination plant would be from a seawater intake system consisting of slant wells constructed into the shallow aquifers at the coastal margin of the Salinas Valley Groundwater Basin (SVGB). The objective of the MPWSP is to meet CalAm’s long-term water demands and comply with state imposed regulatory requirements1. A MPWSP Test Slant Wells Study (HWG, 2017) was conducted to evaluate project effects and support preparation of a draft and Final Environmental Impact Statement/Environmental Impact Report (EIR/EIS) (ESA, 2017). CalAm has received a Certificate of Public Convenience and Necessity CPCN) for the MPWSP from the California Public Utilities Commission (CPUC)2. The EIR/EIS supported the CPUC decision. This document presents a proposed Coastal Monitoring Plan (Monitoring Plan) to continue observing the MPWSP effects, if any, on the SVGB.

Integrated Regional Water Management: Stakeholder Perspectives

California Department of Water Resources (DWR) | April 18th, 2017

Integrated regional water management (IRWM) is the application of integrated water management principles at the regional level. IRWM brings local agencies and other stake

Integrated regional water management (IRWM) is the application of integrated water management principles at the regional level. IRWM brings local agencies and other stakeholders, with a range of water-related roles and interests, together to address water management needs collaboratively within self-identified regions accepted by the State. The practice of IRWM is rooted in the principle of regional control, recognizing that local and regional water managers and other stakeholders, working together in a collaborative, open, and transparent manner, are best suited and best positioned to manage water resources in their regions. Issues including limited groundwater and surface water supplies, drought, flooding, climate change, water quality, environmental degradation, aging infrastructure, economic constraints, recreation, and cultural considerations are addressed through coordinated and integrated actions. IRWM is helping California move away from a legacy of fragmented, divisive, conflict prone, and sometimes ineffective water management practices by supporting cooperation among agencies and other stakeholders. Integrated water management at the regional level: Helps provide for public safety. Supports a healthy economy. Supports ecosystem vitality. IRWM benefits accrue at the local and regional level, but also “roll up” to the state level, helping California meet its collective water management needs. When IRWM succeeds, California succeeds.  

Inter- and intra-ethnic variation in water intake, contact, and source estimates among Tucson residents: Implications for exposure analysis

Journal of Exposure Science & Environmental Epidemiology (Springer) | January 7th, 2002

Water-related exposures among Hispanics, particularly among Mexican Americans, are relatively unknown. Exposure and risk assessment is further complicated by the

Water-related exposures among Hispanics, particularly among Mexican Americans, are relatively unknown. Exposure and risk assessment is further complicated by the absence of good time–activity data (e.g., water intake) among this population. This study attempts to provide some insight concerning water-related exposure parameters among Hispanics. Determining the extent to which non-Hispanic whites and Hispanics living in the Tucson metropolitan area differ with respect to direct water intake and source patterns is the primary purpose of this investigation. Using random digit dialing, researchers conducted a cross-sectional telephone population survey of 1183 Tucson residents. Significant ethnic variation was observed in water intake patterns among this sample, particularly in terms of source. Hispanics reported much higher rates of bottled water consumption than did non-Hispanic whites. Ethnic variation in exposure parameters such as that observed in this study increases the potential for measurement error in exposure analysis. Erroneous assumptions that exposure estimates (i.e., water intake source) are generalizable across various ethnic groups may lead to both overestimation and underestimation of contaminant exposure.

Inter-population differences in salinity tolerance of adult wild Sacramento splittail: osmoregulatory and metabolic responses to salinity

Conservation Physiology (Society of Experimental Biology) | December 10th, 2020

The Sacramento splittail (Pogonichthys macrolepidotus) is composed of two genetically distinct populations endemic to the San Francisco Estuary (SFE). The allop

The Sacramento splittail (Pogonichthys macrolepidotus) is composed of two genetically distinct populations endemic to the San Francisco Estuary (SFE). The allopatric upstream spawning habitat of the Central Valley (CV) population connects with the sympatric rearing grounds via relatively low salinity waters, whereas the San Pablo (SP) population must pass through the relatively high-salinity Upper SFE to reach its allopatric downstream spawning habitat. We hypothesize that if migration through SFE salinities to SP spawning grounds is more challenging for adult CV than SP splittail, then salinity tolerance, osmoregulatory capacity, and metabolic responses to salinity will differ between populations. Osmoregulatory disturbances, assessed by measuring plasma osmolality and ions, muscle moisture and Na+-K+-ATPase activity after 168 to 336 h at 11 salinity, showed evidence for a more robust osmoregulatory capacity in adult SP relative to CV splittail. While both resting and maximum metabolic rates were elevated in SP splittail in response to increased salinity, CV splittail metabolic rates were unaffected by salinity. Further, the calculated difference between resting and maximum metabolic values, aerobic scope, did not differ significantly between populations. Therefore, improved osmoregulation came at a metabolic cost for SP splittail but was not associated with negative impacts on scope for aerobic metabolism. These results suggest that SP splittail may be physiologically adjusted to allow for migration through higher-salinity waters. The trends in interpopulation variation in osmoregulatory and metabolic responses to salinity exposures support our hypothesis of greater salinity-related challenges to adult CV than SP splittail migration and are consistent with our previous findings for juvenile splittail populations, further supporting our recommendation of population-specific management.

Interactions between snow cover and evaporation lead to higher sensitivity of streamflow to temperature

Nature Portfolio (Springer Nature) | December 4th, 2020

Estimates of potential evaporation often neglect the effects of snow cover on evaporation process. Here, we present a definition of potential evaporation that explicitly

Estimates of potential evaporation often neglect the effects of snow cover on evaporation process. Here, we present a definition of potential evaporation that explicitly accounts for landscapes that are partially covered by snow. We show that, in the presence of snowpack, our evaporation estimates differ from conventional methods that assume evaporation from a free water surface. Specifically, we find that conventional methods overestimate potential evaporation as well as aridity, taken as the ratio of atmospheric water demand to supply, in landscapes where snowfall is significant. With dwindling snow-cover, actual aridity increases, which could explain the reduction in streamflow with decreasing snowfall. We suggest that streamflow, and hence water availability, is more sensitive to temperature changes in colder than in warmer regions.

Interagency Fish Passage Steering Committee 2014 Annual Report Focusing on the Shasta Dam Fish Passage Evaluation

Delta Stewardship Council (Delta Council) | July 1st, 2014

Interim instream flow criteria for the protection of fishery resources in the Scott River watershed, Siskiyou County

California Department of Fish and Wildlife (CDFW) | February 6th, 2017

This document describes the methods and results of an analysis using historical flow data and regional regression relationships to develop interim instream flow criteria

This document describes the methods and results of an analysis using historical flow data and regional regression relationships to develop interim instream flow criteria suitable for anadromous fish in the Scott River watershed in Siskiyou County. The Scott River watershed provides aquatic habitat for four species of anadromous fish; Chinook Salmon (Oncorhynchus tshawytscha), Coho Salmon (O. kisutch), steelhead trout (O. mykiss), and Pacific Lamprey (Lampetra tridentata). Specifically, the Scott River is one of the most important Coho Salmon spawning and rearing tributaries in the Klamath River watershed. Instream flow requirements can be generated from flow standard setting techniques or from the results of site specific studies. The interim instream flow criteria presented for the Scott River were developed using flow standard setting techniques. Stream flow standards derived from standard setting techniques are designed to identify the environmental resource in need of flow protection, identify biologically significant criterion that can be used to measure potential flow related impacts, and specify the amount of flow required to protect the resource. Most individual standards evaluate only one or more, but not all the criterion needed to fully evaluate the flow needs of an aquatic species. This limitation can lead to prescribing a single minimum threshold or “flat-line” affect (Poff et al. 1997). The seasonal and inter-annual variability in the hydrograph must be maintained to protect stream ecology and provide an ecosystem based standard (Annear 2004). To account for the seasonal and the inter-annual hydrologic variability of the Scott River, the Department applied a detailed hydrologic analysis along with application of three standard setting methods to evaluate the life history flow needs of salmonids in the Scott River near Fort Jones. Adult fish passage was estimated using the equation developed by R2 Resources (R2 2008) for the State Water Resources Control Board’s (SWRCB) North Coast Instream Flow Policy (SWRCB 2014), spawning and juvenile rearing were evaluated using the Hatfield and Bruce regional equations (Hatfield and Bruce 2000), and the results were adjusted monthly based on estimates of unimpaired hydrology using Tessmann’s adaptation (Tessmann 1980) of the Tennant or Montana Method (Tennant 1975).

Interpretation of Hydrostratigraphy and Water Quality from AEM Data Collected in the Northern Salinas Valley, CA

Marina Coast Water District | March 15th, 2018

Groundwater management, in the Monterey area of California, requires an accurate understanding of the hydrostratigraphy of the coastal aquifer system, as well as an unde

Groundwater management, in the Monterey area of California, requires an accurate understanding of the hydrostratigraphy of the coastal aquifer system, as well as an understanding of the groundwater quality variability within that system. The hydraulic properties of, and connectivity between, the individual units in the aquifer system determine potential routes for the movement of groundwater within and between aquifers. An understanding of the distribution of water quality within the aquifer system and an understanding of the hydrostratigraphy of the system are needed to evaluate the current state of groundwater resources, and to assess the potential impact of any proposed activity on the groundwater resources in the area. The focus of this study is the Northern Salinas Valley. Figure 1 shows the specific region of interest outlined in pink. The orange contour shows the extent of saltwater intrusion into the uppermost aquifers in this area, as determined from well data by the Monterey County Water Resources Agency as the regions where groundwater contains concentrations of chloride greater than 500 mg/L. But there is some question as to whether this contour accurately captures the extent of saltwater intrusion into these aquifers. The detection of water with anomalously low concentrations of total dissolved solids in five newly constructed monitoring well clusters suggests the presence of isolated lenses of fresher groundwater in the Dune Sand Aquifer and Perched Dune Sand Aquifer (outlined in light blue) and in the 180-Foot Aquifer (outlined in dark blue) (Hopkins Groundwater Consultants, 2016). The locations of seven wells from the Monterey Peninsula Water Supply Project (MPWSP) are also shown in Figure 1 as red diamonds, and wells owned by the Marina Coast Water District (MCWD) are shown as green circles. The two groundwater subbasins in the region of interest—the Monterey Subbasin and the 180/400 Aquifer Subbasin—are outlined in purple and blue, respectively. The objective of this study was to use the geophysical method, airborne electromagnetics (AEM), to evaluate the current understanding of the hydrostratigraphy in this area and to interpret the distribution of groundwater quality indicated by available well data. To evaluate the understanding of the hydrostratigraphy, a hydrostratigraphic model of the region of interest was first built using existing data, and was then updated with the information supplied by the AEM data. This approach was followed for two separate initial models. The first initial model was based on the North Marina Groundwater Model (NMGWM), developed by Geoscience Support Services as part of the MPWSP. The second initial model was built in-house using lithology data and hydrostratigraphic interpretations from a variety of previously published reports. Our interpretation of the distribution of groundwater quality in the region is based on statistical relationships built between water quality samples and borehole geophysical data collected in the wells shown in Figure 1.

Investigation on the Feasibility of Developing Uniformwater Recycling Criteria ror Direct Potable Reuse

California State Water Resources Control Board (SWRCB) | December 1st, 2016

The population of California is projected to increase from 38 million to 50 million by the year 2049. This population increase will have a dramatic impact on the water ne

The population of California is projected to increase from 38 million to 50 million by the year 2049. This population increase will have a dramatic impact on the water needs of the State. To address this increased water need, the State will take a variety of actions as outlined in the Governor’s California Water Action Plan, first released in 2014 and recently updated in 2016 (CA Natural Resources Agency, 2016). One component of that plan is to increase the use of recycled water. The State Water Board has set a mandate of increasing the use of recycled water by 200,000 acre-foot per year (AFY) by 2020 and an additional 300,000 AFY by 2030. Although the use of recycled water for non-potable uses such as agricultural and landscape irrigation is already well established and has been regulated for decades in California, increasing the use of recycled water for both non-potable uses as well as a source of potable water (“potable reuse”) is important for the State to be able to meet this mandate. For example, groundwater replenishment (groundwater recharge), which is an indirect form of potable reuse, has the capacity to reuse 200,000 acre-feet of recycled water a year via just eight projects throughout California. Accordingly, the State Water Board revised and adopted uniform water recycling criteria for groundwater replenishment in 2014 and is in the process of establishing uniform water recycling criteria for the augmentation of surface water reservoirs used as a source of drinking water supply, which is another form of indirect potable reuse.