Climate change and the Delta, San Francisco Estuary and Watershed Science

Anthropogenic climate change amounts to a rapidly approaching, “new” stressor in the Sacramento–San Joaquin Delta system. In response to California’s extreme natural hydroclimatic variability, complex water-management systems have been developed, even as the Delta’s natural ecosystems have been largely devastated. Climate change is projected to challenge these management and ecological systems in different ways that are characterized by different levels of uncertainty. For example, there is high certainty that climate will warm by about 2°C more (than late-20th-century averages) by mid-century and about 4°C by end of century, if greenhouse-gas emissions continue their current rates of acceleration. Future precipitation changes are much less certain, with as many climate models projecting wetter conditions as drier. However, the same projections agree that precipitation will be more intense when storms do arrive, even as more dry days will separate storms. Warmer temperatures will likely enhance evaporative demands and raise water temperatures. Consequently, climate change is projected to yield both more extreme flood risks and greater drought risks. Sea level rise (SLR) during the 20th century was about 22cm, and is projected to increase by at least 3-fold this century. SLR together with land subsidence threatens the Delta with greater vulnerabilities to inundation and salinity intrusion. Effects on the Delta ecosystem that are traceable to warming include SLR, reduced snowpack, earlier snowmelt and larger storm-driven streamflows, warmer and longer summers, warmer summer water temperatures, and water-quality changes. These changes and their uncertainties will challenge the operations of water projects and uses throughout the Delta’s watershed and delivery areas. Although the effects of climate change on Delta ecosystems may be profound, the end results are difficult to predict, except that native species will fare worse than invaders. Successful preparation for the coming changes will require greater integration of monitoring, modeling, and decision making across time, variables, and space than has been historically normal

Analyzing climate change adaptation in the agriculture and water sectors: screening risks and opportunities.

As part of the Mediterranean area, the Guadiana basin in Spain is particularly exposed to increasing water stress due to climate change. Future warmer and drier climate will have negative implications for the sustainability of water resources and irrigation agriculture, the main socio- economic sector in the region. This paper illustrates a systematic analysis of climate change impacts and adaptation in the Guadiana basin based on a two-stage modeling approach. First, an integrated hydro-economic modeling framework was used to simulate the potential effects of regional climate change scenarios for the period 2000-2069. Second, a participatory multi-criteria technique, namely the Analytic Hierarchy Process (AHP), was applied to rank potential adaptation measures based on agreed criteria. Results show that, in the middle-long run and under severe climate change, reduced water availability, lower crop yields and increased irrigation demands might lead to water shortages, crop failure, and up to ten percent of income losses to irrigators. AHP results show how private farming adaptation measures, including improving irrigation efficiency and adjusting crop varieties, are preferred to public adaptation measures, such as building new dams. The integrated quantitative and qualitative methodology used in this research can be considered a socially-based valuable tool to support adaptation decision-making

Participatory Modeling for Sustainable Development in Water and Agrarian Systems: Potential and Limits of Stakeholder Involvement

Resource /Energy Economics and Policy,

California Drought, An Update April 2008

TABLE OF CONTENTS CHAPTER 1. RECENT HYDROLOGIC CONDITIONS AND IMPACTS Introduction....................................................... 1 Water Year 2007 .................................................. 1 Drought in the Colorado River Basin ..................................................... 5 Drought and Dry Conditions in the Early 2000s .................................... 7 The 2001 Klamath Basin Drought Emergency ............................... 11 CHAPTER 2. PROGRAMMATIC AND INSTITUTIONAL UPDATES The San Francisco Bay-Sacramento/San Joaquin River Delta.................................................................. 15 The Colorado River .................................................................... 16 State Financial Assistance to Local Agencies.................................... 17 Urban Water Management Planning ................................................... 20 Water Transfers .............................................................................. 20 Small Water Systems and Drought Preparedness ................................. 2

Assessment of Climate Change Impacts on Water Quantity and Quality at Small Scale Watersheds

This book was inspired by the Hydrology–H030 Session of the 2019 AGU (America Geophysical Union) Fall Meeting. In recent years, simulating potential future vulnerability and sustainability of water resources due to climate change are mainly focused on global and regional scale watersheds by using climate change scenarios. These scenarios may have low resolution and may not be accurate for local watersheds. This book addresses the impacts of climate change upon water quantity and quality at small scale watersheds. Emphases are on climate-induced water resource vulnerabilities (e.g., flood, drought, groundwater depletion, evapotranspiration, and water pollution) and methodologies (e.g., computer modeling, field measurement, and management practice) employed to mitigation and adapt climate change impacts on water resources. Application implications to local water resource management are also discussed in this book

Participatory modeling for sustainable development in water and agrarian systems: potential and limits of stakeholder involvement

Public participation is increasingly advocated as a necessary feature of natural resources management. The EU Water Framework Directive (WFD) is such an example, as it prescribes participatory processes as necessary features in basin management plans (EC 2000). The rationale behind this mandate is that involving interest groups ideally yields higher-quality decisions, which are arguably more likely to meet public acceptance (Pahl-Wostl, 2006). Furthermore, failing to involve stakeholders in policy-making might hamper the implementation of management initiatives, as controversial decisions can lead pressure lobbies to generate public opposition (Giordano et al. 2005, Mouratiadou and Moran 2007)

An Integrated Framework for Modeling and Mitigating Water Temperature Impacts in the Sacramento River

Increasing demands on the limited and variable water supply across the West can result in insufficient streamflow to sustain healthy fish habitat. In addition, construction of dams and diversions along rivers for the purpose of storing and distributing the limited supply of water can further deteriorate natural flow regimes and, often, obstruct important migratory pathways for cold water fish reproduction and development. The thermal impacts on the ecology of river ecosystems have been well documented, yet there is no comprehensive modeling framework in place for skillfully modeling climate-related impacts. In regulated systems, such as the Sacramento River system, these impacts are an interaction of volume and temperature of water release from the reservoir and the subsequent exchange with the environment downstream. We develop an integrated framework for modeling and mitigating water temperature impacts and demonstrate it on the Sacramento River system. The approach has four broad components that can be coupled to produce decision tools towards efficient management of water resources for stream temperature mitigation: (i) a suite of statistical models for modeling stream temperature attributes using hydrology and climate variables of critical importance to fish habitat; (ii) a reservoir thermal model for modeling the thermal structure and, consequently, the water release temperature, (iii) a stochastic weather generator to simulate weather sequences consistent with long-range (e.g., seasonal) outlooks; and, (iv) a set of decision rules (i.e., rubric) for reservoir water releases in response to outputs from the above components. The statistical stream temperature models and stochastic weather generators are coupled to the reservoir thermal model and validated for their ability to reproduce observed stream temperature variability along with characterizing the uncertainty at a compliance point downstream. We develop and validate a Decision Support Tool (DST) developed by coupling the stream temperature forecast model with the stochastic weather generator to the decision rubric. The DST incorporates forecast uncertainties and reservoir operating options to help mitigate stream temperature impacts for fish habitat, while efficiently using the reservoir water supply and cold pool storage. The use of these coupled tools in simulating impacts of future climate on stream temperature variability is also demonstrated

Water Resilience Portfolio, January 2020

In April 2019, Governor Newsom directed state agencies through Executive Order N-10-19 to develop a “water resilience portfolio,” described as a set of actions to meet California’s water needs through the 21st century. The order identified seven principles on which to base this portfolio: Prioritize multi-benefit approaches that meet several needs at once » Utilize natural infrastructure such as forests and floodplains Embrace innovation and new technologies Encourage regional approaches among water users sharing watersheds Incorporate successful approaches from other parts of the world Integrate investments, policies, and programs across state government Strengthen partnerships with local, federal and tribal governments, water agencies and irrigation districts, and other stakeholders. In response, state agencies developed an inventory and assessment of key aspects of California water, soliciting broad input from tribes, agencies, individuals, groups, and leaders across the state. An interagency working group considered this assessment and public input and developed a portfolio, which can be defined as the integrated use of a broad range of actions. It is intended to strengthen the resilience of water systems, thereby helping communities prepare for disruptions, to withstand and recover from shocks, and to adapt and grow from these experiences. The pace at which we can carry out this diverse but connected set of actions will depend upon available resources, but taken together, they should allow us to thrive into an uncertain future

Bringing Water and Land Use Together: Final Report to the Community Foundation Water Initiative on the Equitable Integration of Water and Land Use

California is moving toward a more holistic approach to managing our water and land resources as the 21st century unfolds. This perspective recognizes the interconnectivity between two traditionally fragmented sectors.In 2005, the California Legislature passed new laws that enable communities to join together to adopt Integrated Regional Water Management (IRWM) policies and practices. This comprehensive planning approach considers water resources in the context of an interconnected watershed with a network of regional governance, rather than as a combination of fragmented parts. Unfortunately, the IRWM program is dominated by the water sector and in most regions has not pursued alignment with land use.Similarly, the Sustainable Communities Strategies (SCS) mandated through [legislation] establish a framework for aligning land use practices (predominantly housing and transportation) across jurisdictions within a larger geographic region. Yet very few SCSs have taken water resources into account.While water management and land-use planning remain highly fragmented across the state, we are making progress toward a more integrated approach, especially when setting new state-level policies, regulations and guidance. The 2014 Sustainable Groundwater Management Act (SGMA) is a leap forward in this direction. For the first time, local land use agencies have an opportunity to be full partners with water agencies in shaping groundwater governance. It is too soon to determine how well these two sectors are integrating under SGMA, but early results are promising

Application of Satellite Gravimetry for Water Resource Vulnerability Assessment

The force of Earth's gravity field varies in proportion to the amount of mass near the surface. Spatial and temporal variations in the gravity field can be measured via their effects on the orbits of satellites. The Gravity Recovery and Climate Experiment (GRACE) is the first satellite mission dedicated to monitoring temporal variations in the gravity field. The monthly gravity anomaly maps that have been delivered by GRACE since 2002 are being used to infer changes in terrestrial water storage (the sum of groundwater, soil moisture, surface waters, and snow and ice), which are the primary source of gravity variability on monthly to decadal timescales after atmospheric and oceanic circulation effects have been removed. Other remote sensing techniques are unable to detect water below the first few centimeters of the land surface. Conventional ground based techniques can be used to monitor terrestrial water storage, but groundwater, soil moisture, and snow observation networks are sparse in most of the world, and the countries that do collect such data rarely are willing to share them. Thus GRACE is unique in its ability to provide global data on variations in the availability of fresh water, which is both vital to life on land and vulnerable to climate variability and mismanagement. This chapter describes the unique and challenging aspects of GRACE terrestrial water storage data, examples of how the data have been used for research and applications related to fresh water vulnerability and change, and prospects for continued contributions of satellite gravimetry to water resources science and policy