Insights into estuary habitat loss in the western United States using a new method for mapping maximum extent of tidal wetlands

PLOS | August 14th, 2019

Effective conservation and restoration of estuarine wetlands require accurate maps of their historical and current extent, as well as estimated losses of these va

Effective conservation and restoration of estuarine wetlands require accurate maps of their historical and current extent, as well as estimated losses of these valued habitats. Existing coast-wide tidal wetland mapping does not explicitly map historical tidal wetlands that are now disconnected from the tides, which represent restoration opportunities; nor does it use water level models or high-resolution elevation data (e.g. lidar) to accurately identify current tidal wetlands. To better inform estuarine conservation and restoration, we generated new maps of current and historical tidal wetlands for the entire contiguous U.S. West Coast (Washington, Oregon, and California). The new maps are based on an Elevation-Based Estuary Extent Model (EBEEM) that combines lidar digital elevation models (DEMs) and water level models to establish the maximum historical extent of tidal wetlands, representing a major step forward in mapping accuracy for restoration planning and analysis of wetland loss. Building from this new base, we also developed an indirect method for mapping tidal wetland losses, and created maps of these losses for 55 estuaries on the West Coast (representing about 97% of historical West Coast vegetated tidal wetland area). Based on these new maps, we estimated that total historical estuary area for the West Coast is approximately 735,000 hectares (including vegetated and nonvegetated areas), and that about 85% of vegetated tidal wetlands have been lost from West Coast estuaries. Losses were highest for major river deltas. The new maps will help interested groups improve action plans for estuarine wetland habitat restoration and conservation, and will also provide a better baseline for understanding and predicting future changes with projected sea level rise.

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 Environmental Modeling of Estuarine Systems: Lessons for the Sacramento-San Joaquin Delta

Delta Stewardship Council (Delta Council) | April 18th, 2017

Complexity in estuarine systems calls for integrated and community-based approaches for using and developing models and data. Environmental and hydrodynamic models have h

Complexity in estuarine systems calls for integrated and community-based approaches for using and developing models and data. Environmental and hydrodynamic models have helped organize and extend knowledge and predictions for physical, biological, and chemical aspects. However, specialization has often steered science and management to fragmentation among models, data, and management of estuarine systems. Integration of models and data in platforms that increase collaboration, interdisciplinary work, organization and transparency have been successful in other systems. Mathematical modeling developed in the past few decades to capture current understanding and inform immediate decisions and long-term strategies remains the most viable science-based approach for supporting management of these complex systems. Changes and uncertainties require that such technical activities occur in a long-term adaptive management framework. However, strategies and responsibilities for selecting, developing, and employing models and data, selecting modeling questions, and making the best use of multiple modeling efforts among diverse institutions remain unresolved. A new approach is needed to build and evolve scientific and technical understanding and analysis capability for policy and management for large estuarine systems across institutions, interests, and different areas of expertise. A modeling Collaboratory is proposed that has capacity to build, refine, maintain and upgrade models, compare and contrast different scientific approaches, quantify uncertainty in predictions, synthesize current data, and accelerate the discovery of knowledge to inform policy and management for these challenging problems. A Collaboratory will focus on specific problems with a defined time-line, with the intent of providing broadly credible information for the many parties involved in decision-making and management. For the Sacramento-San Joaquin Delta, a partnership of the federal government, the State of California, and contractors, perhaps hosted by an academic institution, would establish this center with access to computational and scientific resources from agencies, consultants, NGOs, and academics.  

Integrated Management of Delta Stressors: Institutional and Legal Options

Public Policy Institute of California (PPIC) | April 22nd, 2013

Despite some recent progress, the current institutional landscape for regulation and management of stressors in the in the Sacramento–San Joaquin Delta is highly fragme

Despite some recent progress, the current institutional landscape for regulation and management of stressors in the in the Sacramento–San Joaquin Delta is highly fragmented. A modest but powerful set of institutional changes can help produce better environmental outcomes while containing management costs—which are likely to exceed several hundred million dollars annually. This report lays out proposals for institutional reform.

Integrated Water Operations in California: Hydropower, Overdraft, and Climate Change

University of California, Davis (UC Davis) | July 16th, 2015

Several management and climate cases are evaluated with the updated CALVIN, a hydro-economic optimization model of California’s inter-tied water supply infrastructure.

Several management and climate cases are evaluated with the updated CALVIN, a hydro-economic optimization model of California’s inter-tied water supply infrastructure. Updates to the CALVIN model include new projected 2050 agricultural target demands and scarcity penalties, improvements to network-flow representation, especially agricultural, urban, and wildlife refuge demands, and extended surface and ground water hydrology, now covering an 82-year historical inflow hydrology. A new energy price scheme is applied to CALVIN, which incorporates hourly energy price variations into monthly CALVIN operations. Using one constant average price for a month underestimates hydropower revenue and overestimates pumping costs. Hourly-varying moving average prices improved representation of hydropower revenue without creating significant scarcities to agricultural and urban water users. Effects of ending long-term groundwater overdraft in the Central Valley are evaluated with several management cases using CALVIN. The cases include effects of Delta outflow and Delta exports from a “no overdraft” policy. The least cost overdraft that minimizes groundwater pumping and scarcity costs is calculated for the 82-year period. Prohibiting Delta exports result in severe water scarcities south of the Delta. Water operations are more economical when overdraft is ended with adaptations, such as more Delta exports, increased groundwater banking, and water trades, than historical operations with overdraft. Finally, climate change effects under a warmer and drier climate scenario are studied and results are compared to historical hydrology. A drier and warmer climate shifts the timing and magnitude of stream flows. Spring snowmelt decreases and winter flows increase. Modelled reduction in rim inflows averages about 28%. This warmer-drier climate increases water scarcities, but adverse effects can be diminished with water sales, higher Delta exports, more conjunctive use, and wastewater recycling. 

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.

Interagency Ecological Program Science Strategy 2020 – 2024: Investment Priorities for Interagency Collaborative Science

Interagency Ecological Program (IEP) | April 20th, 2019

The IEP Science Strategy is one of three organizing documents that together set the course for annual (IEP Annual Work Plan), 5-year (IEP Science Strategy), and 5

The IEP Science Strategy is one of three organizing documents that together set the course for annual (IEP Annual Work Plan), 5-year (IEP Science Strategy), and 5+ year (IEP Strategic Plan) organization planning for the Program. The Science Strategy is where the Science Management and Coordinators Teams articulate what they understand as the most pressing suite of subjects requiring additional data collection for management-relevant purposes for the IEP 9-Agency collective. The Science Strategy serves the additional purpose of providing a 5-year focus of planning effort to even-out short-term (annual) imperatives that change depending on mutable Agency directives.

Interagency Ecological Program Science Strategy: Needs for near-term science in five areas of emphasis

Interagency Ecological Program (IEP) | March 4th, 2016

The mission of the Interagency Ecological Program (IEP) is to provide and integrate relevant and timely ecological information for management of the Bay-Delta ecosystem a

The mission of the Interagency Ecological Program (IEP) is to provide and integrate relevant and timely ecological information for management of the Bay-Delta ecosystem and the water that flows through it. This is accomplished through collaborative and scientifically sound monitoring, research, modeling, and synthesis efforts for various aspects of the aquatic ecosystem. Building on the IEP Strategic Plan, which identifies the long-term goals and strategies to be implemented by the IEP to achieve its mission, the IEP Science Strategy provides direction to interagency science used to inform the management and ecological interests of IEP agencies in the near-term, and is one of a number of inputs used to shape the IEP Annual Work Plans. While the IEP Strategic Plan states that the Science Strategy be drafted for a 3-5 year horizon, a shorter 2-year timeframe for this first IEP Science Strategy has been adopted to allow for a more flexible internal development and review process, as well as feedback from the Bay-Delta research and stakeholder community.

Interagency Ecological Program’s Ability to Provide Science Supporting Management of the Delta

Delta Stewardship Council (Delta Council) | November 15th, 2019

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

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