Managing diversions in unregulated streams using a modified percent-of-flow approach

Freshwater Biology (Wiley) | August 22nd, 2017

In Mediterranean-type river systems stream flows are naturally low in summer and autumn. This pattern is often exacerbated by over-exploitation of water resources during

In Mediterranean-type river systems stream flows are naturally low in summer and autumn. This pattern is often exacerbated by over-exploitation of water resources during the dry season, which has implications for managing flows for both environmental and human needs. Mediterranean systems are characterised by strong inter- and intra-annual variability with almost all precipitation occurring in winter months followed by summer droughts with little or no rainfall, and extreme year-to-year variation ranging from intense winter storms to year-round drought (Gasith & Resh, 1999; Power, Kupferberg, Cooper, & Deas, 2015; Power, Parker, & Dietrich, 2008). The seasonal pattern of precipitation in Mediterranean climatic regions results in water availability and demand being out-of-phase; precipitation and runoff occur (almost exclusively) in winter when human demands are lowest, and precipitation is virtually non-existent in summer months when human demand is greatest (Kondolf & Batalla, 2005; Merenlender & Matella, 2013). As a result, rivers in Mediterranean climates tend to have a high degree of alteration with streamsdiverted and dammed to provide scarce water for human use (Kondolf, Podolak, & Grantham, 2013; Marr et al., 2009; Moyle, 2013). While the biophysical responses to alterations of land use, vegetation and hydrology are similar in Mediterranean and other climatic regions, the magnitude of responses tends to be intensified in Mediterranean systems. For example prolonged dry season flows may result in lower dissolved oxygen, higher temperatures and concentration of contaminants among other impacts (Cooper, Lake, Sabater, Melack, & Sabo, 2013). Climate change and increasing frequency and severity of drought promise to increase the conflict between human needs and ecological needs over time (Arthington, 2012).

Managing Drought in a Changing Climate: Four Essential Reforms

Public Policy Institute of California (PPIC) | September 12th, 2018

California’s climate is changing. Hotter temperatures, a shrinking snowpack, shorter and more intense wet seasons, rising sea level, and more volatile precipita

California’s climate is changing. Hotter temperatures, a shrinking snowpack, shorter and more intense wet seasons, rising sea level, and more volatile precipitation—with wetter wet years and drier dry years—are stressing the state’s water management system. Recent climate projections indicate that the pace of change will increase. To avoid unwanted social, economic, and environmental consequences, the water system will need to adapt to greater climate extremes and growing water scarcity. While California is making good progress in some areas of drought management, a more focused plan of action is needed. Successful adaptation will require strong leadership at the state and local levels, and cooperation on all fronts. The 2012–16 drought—the hottest in the state’s recorded history and one of the driest—offered a window into the future under a warming climate and lessons for managing future droughts. Using these lessons as a starting point, this report offers a road map of essential reforms to prepare for and respond to droughts in California’s changing climate. Key reforms include: Plan ahead. Stronger drought planning is critically important for urban water management, groundwater sustainability, safe drinking water in rural communities, and freshwater ecosystems. Upgrade the water grid. California needs a comprehensive program to address above- and below-ground storage, conveyance, and operational challenges by mid-century, including repairing facilities that are broken, expanding conveyance and storage capacity, and modernizing and integrating operations. Update water allocation rules. California should comprehensively update its water allocation governance. The goals should be to find equitable and efficient ways to allocate limited supplies among competing demands during dry times while promoting efforts to capture and store water during wet times. Find the money. Reliable funding is crucial for adapting to climate change. New sources are needed to pay for necessary water-management investments and to fill funding gaps in the state’s water system. The focus of this reform agenda is on drought, because drought―more than any other aspect of California’s climate―reveals the vulnerabilities of watermanagement systems. Importantly, these reforms will improve drought resilience for today’s conditions, not just for the future.

Managing Floods in California

Legislative Analyst's Office (LAO) | March 22nd, 2017

This report is intended to provide basic information about floods and flood management in California. (Whereas previous generations referred to “flood control” or “

This report is intended to provide basic information about floods and flood management in California. (Whereas previous generations referred to “flood control” or “flood prevention” activities, experts now prefer the term “flood management” in acknowledgement that floodwaters are recurring and inevitable.) We begin by summarizing the history, causes, and risk of floods across the state. We then describe flood management agencies, infrastructure, and strategies, as well as how governmental agencies typically respond when floods occur. Next, we describe the spending levels and funding sources currently supporting flood management efforts, as well as estimates for how much additional funding may be needed to improve those efforts. We conclude by highlighting some key challenges confronting the state in contemplating how best to manage floods in California.

Managing for Change: Modernizing California's Water Governance

Little Hoover Commission | August 1st, 2010

In this study, the Little Hoover Commission focused on how California organizes the functions of water supply, planning, management and accounting. From the start, the go

In this study, the Little Hoover Commission focused on how California organizes the functions of water supply, planning, management and accounting. From the start, the goal was to take a statewide view of California’s water resources activities and recommend a governance structure that could position California and Californians for the decades to come. The focus deliberately was on statewide governance, in part because of the already intense focus on the Sacramento-San Joaquin River Delta and also because of the Commission’s view that the Delta’s problems could not be resolved without a stronger, more accountable water governance structure for the state as a whole.

Managing for Future Risks of Fire, Extreme Precipitation, and Post-fire Flooding

U.S. Bureau of Reclamation (USBR) | September 30th, 2016

On September 22–23, 2014, 23 scientists, resource managers, and urban planners convened in Las Vegas, Nevada, to discuss research and management needs related to seve

On September 22–23, 2014, 23 scientists, resource managers, and urban planners convened in Las Vegas, Nevada, to discuss research and management needs related to severe fires and post-fire flooding in the Intermountain West. The workshop was motivated by the concerns of water management agencies about the potential for a changing climate to exacerbate fire impacts through: 1) projected increases in acres burned; 2) potential changes in the intensity of future extreme precipitation; and 3) the frequency of extreme events, which the National Climate Assessment projects to at least double across the region. The workshop was convened by the University of Arizona with funding provided by the U.S. Bureau of Reclamation.

Managing Wastewater in a Changing Climate

Public Policy Institute of California (PPIC) | April 15th, 2019

California’s wastewater sector, which plays a crucial role in protecting publichealth and the environment, is at a turning point. Water supply and demand condit

California’s wastewater sector, which plays a crucial role in protecting publichealth and the environment, is at a turning point. Water supply and demand conditions are being affected by population growth, technology and policy changes, and drought. Climate change will bring new challenges. Wastewater agencies are tasked with reliably removing pollutants from water discarded to sewers, even as the quantity and quality of the water they treat declines. Of the multiple climate pressures that are likely to affect wastewater management, drought poses the biggest challenge for the sector. The unusually hot drought of 2012–16 provided a vivid demonstration of conditions that may become more common as the climate warms, and was a wake-up call for wastewater agencies. Many wastewater agencies are pursuing specific changes to their operations, infrastructure, or finances in response to the cascade of challenges they experienced during the latest drought. A PPIC survey of wastewater agencies done as part of this study found a high degree of concern in the sector about adapting to a changing climate. This report recommends policy and management changes to help build resilience in three broad areas: 1) Maintaining water quality in the face of changing water use.Wastewater management is challenged by short-term water conservation during droughts and longer-term reductions in water use from indoor efficiency measures—conditions which are largelybeyond the sector’s control. Reductions in indoor water use can damage infrastructure and reduce the effectiveness of existing treatment processes. Such challenges may grow as severe droughts become more frequent with climate change and as water efficiency increases. Better coordination and information sharing with water suppliers, and sector-wide planning for future droughts, are key to addressing these changes. 2) Making smart recycled water investments. Wastewater agencies produce highly treated water that is increasingly being reused as a water supply. Coordination among wastewater and water supply agencies is essential to respond to the increasing demand for recycled water. Formalized planning for recycled water projects at the regional level will likely lead to more efficient processes and better outcomes. New investments must be responsive to changing water use, climate change, and pending regulations. 3) Balancing conflicting objectives within watersheds. Most wastewater treatment plants discharge treated water into inland watersheds. Adapting to declining water use and meeting increased demand for recycled water may conflict with environmental objectives and the demands of downstream users. Rivers and streams are expected to experience lower flows and higher temperatures, which will heighten threats to aquatic ecosystems. Resources to identify areas most at risk of conflict over the use of treated wastewater are needed, as are tools to evaluate the impacts of water recycling projects on the environment and downstream water users. The state should also analyze its policies to identify tradeoffs and resolve conflicts between its water supply, water quality, and environmental goals. Advancements in engineering and technology can help wastewater agencies adapt to a changing climate―but shifts in policy and planning will facilitate a more efficient and effective path toward building resilience. The latest drought provided a window into the looming challenges facing the wastewater sector. Forging new partnerships and evaluating the full range of climate-related risks will help the sector determine the best adaptations and policy improvements needed to prepare the wastewater sector for a more volatile future.

Managing Water for the Environment During Drought: Lessons from Victoria, Australia

Public Policy Institute of California (PPIC) | June 16th, 2016

Over the past 30 years the Australian state of Victoria developed innovative approaches to planning and setting priorities for environmental water, along with new tools t

Over the past 30 years the Australian state of Victoria developed innovative approaches to planning and setting priorities for environmental water, along with new tools to manage it. These sweeping reforms were in part a response to the Millennium Drought, a decade-long record dry spell that severely affected all water use in Victoria. California—currently in its fifth year of drought—has many similarities with Victoria, including significant challenges in managing the health of rivers and wetlands during times of extreme water scarcity. In this report, we examine the reforms enacted by Victoria and compare them to current environmental water management policies in California. This comparison highlights some key lessons learned by Victoria that may help guide how California adapts environmental water management to address future droughts. The environmental policy reforms enacted by Victoria were difficult and at times highly controversial. While it will take years to fully understand whether these reforms had their intended effect, there is no doubt that the state’s new approach to managing environmental water avoided some serious biological losses during the drought. Additionally, it is clear that the state is much better prepared for the next drought.

Marine heatwaves need clear definitions so coastal communities can adapt

Nature Portfolio (Springer Nature) | April 3rd, 2023

Marsh Sediment in Translation: A Review of Sediment Transport Across a Natural Tidal Salt Marsh in Northern San Francisco Bay

University of California, Davis (UC Davis) | March 15th, 2025

Deposition of inorganic sediment is essential for the sustainability of tidal salt marshes. Understanding variability in sediment sources and the processes of sediment de

Deposition of inorganic sediment is essential for the sustainability of tidal salt marshes. Understanding variability in sediment sources and the processes of sediment delivery to salt marshes are high priorities for decision-makers responsible for managing sediment and conserving and restoring marshes.

Martis Valley Groundwater Basin Sustainable Groundwater Management Act Alternative Submittal

Truckee Donner Public Utility District (TDPUD) | December 22nd, 2016