Making Nature's City: A science-based framework for building urban biodiversity

San Francisco Estuary Institute (SFEI) | July 1st, 2019

Cities will face many challenges over the coming decades, from adapting to a changing climate to accommodating rapid population growth. A related suite of challenges th

Cities will face many challenges over the coming decades, from adapting to a changing climate to accommodating rapid population growth. A related suite of challenges threatens global biodiversity, and many species face potential extinction. While urban planners and conservationists have long treated these issues as distinct, there is growing evidence that cities not only harbor a significant fraction of the world’s biodiversity, but that they can also be made more livable and resilient for people, plants, and animals through nature-friendly urban design. Urban ecological science can provide a powerful tool to guide cities towards more biodiversity-friendly design. However, current research remains scattered across thousands of journal articles and largely inaccessible to practitioners. Making Nature’s City fills this gap, synthesizing global research to develop a science-based approach for supporting nature in cities. We identify seven key elements of urban form and function that work together to maximize biodiversity, and we illustrate these elements through a case study in California’s Silicon Valley. Using the framework developed in this report, urban designers and local residents can work together to link local parks, greenways, green roofs, street trees, stormwater basins, commercial landscaping, and backyards to support biodiversity while making cities better places to live. As we envision the healthier, and more resilient cities, Making Nature’s City provides practical guidance for the many actors who together will shape the nature of cities.

Managing An Uncertain Future: Climate Change Adaptation Strategies for California’s Water

California Department of Water Resources (DWR) | December 12th, 2008

For California water managers, the future is now. Climate change is already having a profound impact on water resources as evidenced by changes in snowpack, river flows a

For California water managers, the future is now. Climate change is already having a profound impact on water resources as evidenced by changes in snowpack, river flows and sea levels. The Department of Water Resources (DWR) will continue to play a leadership role in adapting to these changes. DWR is already engaged in a number of efforts designed to improve California’s ability to cope with a changing climate. However, more must be done. This report recommends a series of adaptation strategies for state and local water managers to improve their capacity to handle change. Many of the strategies will also help adapt our water resources to accommodate non-climate demands including a growing population, ecosystem restoration and greater flood protection. Several of the recommendations in this report are ready for immediate adoption, while others need additional public deliberation and development. Some can be implemented using existing resources and authority, while the majority will require new resources, sustained financial investment and significant collaborative effort. Many of California’s most important water resource investments remain dependent on bond funding approved by voters. As a result, they are well funded in some years, but underfunded in most. This history of uneven and irregular investment has delayed progress in areas that have the potential to yield substantial gains over short periods of time. DWR presents this report as part of the process of updating the California Water Plan, and as part of the California Resources Agency’s draft statewide Climate Adaptation Plan. Overall, this report urges a new approach to managing California’s water and other natural resources in the face of a changing climate.

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 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 retreat for sandy beach areas under sea level rise

Nature Portfolio (Springer Nature) | July 24th, 2023

Managing to End Groundwater Overdraft in California’s Central Valley with Climate Change

University of California, Davis (UC Davis) | July 14th, 2016

Several water management cases with climate change are modeled to assess the effects of ending long-term groundwater overdraft in the Central Valley using the Cal

Several water management cases with climate change are modeled to assess the effects of ending long-term groundwater overdraft in the Central Valley using the California Value Integrated Network (CALVIN) model, a hydro-economic optimization model of California’s water system. CALVIN optimizes water management decision-making for the lowest net operating and water scarcity cost over an 82-year period of unimpaired inflows. Recent updates to the CALVIN model include, input hydrology, network representation, agricultural demand and shortage penalties, and hydropower improvements. Management cases evaluated include changes in outflow and inflow requirements for the Sacramento-San Joaquin Delta (Delta), and prohibiting long-term groundwater overdraft. Cases were analyzed over an 82-year modified historical record with a warmer, drier climate, and compared to historical hydrology results. A modelled warmer, drier climate reduces average inflows overall by about 28% and shifts stream flows towards winter and away from spring. Results show large water scarcities south of the Delta without Delta exports, especially for agriculture. Allowing for increased water transfers, Delta exports, conjunctive use, and water recycling and desalination reduces the water supply effects of groundwater overdraft and climate change.

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.

Marine heat wave and multiple stressors tip bull kelp forest to sea urchin barrens

Nature Portfolio (Springer Nature) | October 21st, 2019

Extreme climatic events have recently impacted marine ecosystems around the world, including foundation species such as corals and kelps. Here, we describe the

Extreme climatic events have recently impacted marine ecosystems around the world, including foundation species such as corals and kelps. Here, we describe the rapid climate-driven catastrophic shift in 2014 from a previously robust kelp forest to unproductive large scale urchin barrens in Northern California. Bull kelp canopy was reduced by >90% along more than 350 km of coastline. Twenty years of kelp ecosystem surveys reveal the timing and magnitude of events, including mass mortalities of sea stars (2013-), intense ocean warming (2014–2017), and sea urchin barrens (2015-). Multiple stressors led to the unprecedented and long-lasting decline of the kelp forest. Kelp deforestation triggered mass (80%) abalone mortality (2017) resulting in the closure in 2018 of the recreational abalone fishery worth an estimated $44 M and the collapse of the north coast commercial red sea urchin fishery (2015-) worth $3 M. Key questions remain such as the relative roles of ocean warming and sea star disease in the massive purple sea urchin population increase. Science and policy will need to partner to better understand drivers, build climate-resilient fisheries and kelp forest recovery strategies in order to restore essential kelp forest ecosystem services.

Marine heatwaves need clear definitions so coastal communities can adapt

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