Global water availability boosted by vegetation-driven changes in atmospheric moisture transport

Nature Portfolio (Springer Nature) | October 31st, 2022

Surface-water availability, defined as precipitation minus evapotranspiration, can be affected by changes in vegetation. These impacts can be local, due to the modificati

Surface-water availability, defined as precipitation minus evapotranspiration, can be affected by changes in vegetation. These impacts can be local, due to the modification of evapotranspiration and precipitation, or non-local, due to changes in atmospheric moisture transport. However, the teleconnections of vegetation changes on water availability in downwind regions remain poorly constrained by observations. By linking measurements of local precipitation to a new hydrologically weighted leaf area index that accounts for both local and upwind vegetation contributions, we demonstrate that vegetation changes have increased global water availability at a rate of 0.26 mm yr−2 for the 2001–2018 period. Critically, this increase has attenuated about 15% of the recently observed decline in global water availability. The water availability increase is due to a greater rise in precipitation relative to evapotranspiration for over 53% of the global land surface. We also quantify the potential hydrological impacts of regional vegetation increases at any given location across global land areas. We find that enhanced vegetation is beneficial to both local and downwind water availability for ~45% of the land surface, whereas it is adverse elsewhere, primarily in water-limited or high-elevation regions. Our results highlight the potential strong effects of deliberate vegetation changes, such as afforestation programmes, on water resources beyond local and regional scales.

GreenPlan-IT Tracker

San Francisco Estuary Institute (SFEI) | June 14th, 2018

This technical memo describes the purpose, functions, and structure associated with the newest addition to the GreenPlan-IT Toolset, the GreenPlan-IT Tracker. It also sh

This technical memo describes the purpose, functions, and structure associated with the newest addition to the GreenPlan-IT Toolset, the GreenPlan-IT Tracker. It also shares the opportunities for further enhancement and how the tool can operate in concert with existing resources. Furthermore, this memo describes a licensing plan that would permit municipalities to use the tool in an ongoing way that scales to their needs. The memo concludes with a provisional roadmap for the development of future features and technical details describing the tool’s platform and data structures. About the GreenPlan-IT Toolkit Municipalities across the state and beyond are carefully planning and implementing green infrastructure in their developed landscape to restore key aspects of the natural water cycle. Green infrastructure helps to achieve stormwater attenuation and contaminant filtration by increasing the pervious surfaces in often sophisticated ways. Additionally, green infrastructure features, as city dwellers have come to realize, demonstrate multiple benefits in addition to improving surface porosity, such as peak, volume, and load reductions, urban heat island mitigation, traffic calming, carbon sequestration, wildlife habitat, natural aesthetics, and others. The benefits are substantial, but so are the potential costs. GreenPlan-IT helps planners to make smart decisions in the types and locations of green infrastructure, minimizing effort and cost while maximizing the effectiveness of the public and private investments. GreenPlan-IT modules are focused on green infrastructure planning and assessment, including the Site Locator Tool, Modeler, and Optimizer tools. Together the modular toolkit can be used to take a city from a position of not knowing where to consider GI placement (a daunting position given the MRP C3 and C11/12 requirements), to a plan that includes a list and map of feasible locations and a map of baseline flow and pollutant load conditions, and a selected optimal set of placement locations for achieving flow and load reductions at minimal cost. Now, with the advent of the GreenPlan-IT Tracker, there is also a web based tracker for quantifying and communicating the locations, types, and treatment areas of GI installations (the outputs of all the planning efforts) and quantifying the peak flows, volumes, and loads reduced (the outcomes of all the implementation and cost expenditure that the community is asking for).

Groundwater and Urban Growth in the San Joaquin Valley

Public Policy Institute of California (PPIC) | September 20th, 2021

The San Joaquin Valley is ground zero for the Sustainable Groundwater Management Act (SGMA). It has the largest groundwater deficit in California and faces some of the

The San Joaquin Valley is ground zero for the Sustainable Groundwater Management Act (SGMA). It has the largest groundwater deficit in California and faces some of the worst impacts from overdraft, including land subsidence and drying wells. SGMA will help the region address these issues—while also building its climate resilience. But this will require hard work, not only by farmers—the largest groundwater users—but also by the valley’s urban water utilities, which serve a growing population while relying mostly on groundwater. As the valley confronts limits on groundwater pumping, urban utilities, local land use authorities, other water users, and state agencies must all engage to ensure a smooth transition for the region’s residents.

Guidebook for Implementation of SB 610 and SB 221 to assist water suppliers, cities, and counties in integrating water and land use planning

California Department of Water Resources (DWR) | October 10th, 2003

Senate Bills 610 (Chapter 643, Statutes of 2001) and Senate Bill 221 (Chapter 642, Statutes of 2001) amended state law, effective January 1, 2002, to improve the link bet

Senate Bills 610 (Chapter 643, Statutes of 2001) and Senate Bill 221 (Chapter 642, Statutes of 2001) amended state law, effective January 1, 2002, to improve the link between information on water supply availability and certain land use decisions made by cities and counties. SB 610 and SB 221 are companion measures which seek to promote more collaborative planning between local water suppliers and cities and counties. Both statutes require detailed information regarding water availability to be provided to the city and county decision-makers prior to approval of specified large development projects. Both statutes also require this detailed information be included in the administrative record that serves as the evidentiary basis for an approval action by the city or county on such projects. Both measures recognize local control and decision making regarding the availability of water for projects and the approval of projects.  Under SB 610, water assessments must be furnished to local governments for inclusion in any environmental documentation for certain projects (as defined in Water Code 10912 [a]) subject to the California Environmental Quality Act. Under SB 221, approval by a city or county of certain residential subdivisions requires an affirmative written verification of sufficient water supply. If coordinated and comprehensive water supply planning is underway at the time that the SB 610-water assessment is prepared, compliance with SB 221 will be greatly facilitated. SB 221 is intended as a ‘fail safe’ mechanism to ensure that collaboration on finding the needed water supplies to serve a new large subdivision occurs when it should – before construction begins. Not every project that is subject to the requirements of SB 610 would also require the mandatory water verification of SB 221 (e.g. if there is no subdivision map approval). Conversely, not every project that is subject to the requirements of SB 221 would also require the environmental document to contain an SB 610 water supply assessment. Projects approved before January 1, 2002 were not subject to the requirements of SB 610 or SB 221; however, some projects may have been subject to the requirement to prepare a water supply assessment as set forth in Senate Bill 901 of 1995 (Chapter 881, Statues of 1995). A foundational document for compliance with both SB 610 and SB 221 is the Urban Water Management Plan (UWMP). Both of these statutes repeatedly identify the UWMP as a planning document that, if properly prepared, can be used by a water supplier to meet the standards set forth in both statutes. Thorough and complete UWMPs will allow water suppliers to use UWMPs as a foundation to fulfill the specific requirements of these two statutes. Cities, counties, water districts, property owners, and developers will all be able to utilize this document when planning for and proposing new projects.

Hillslope Stability and Land Use

American Geophysical Union (AGU) | January 1st, 1985

Published by the American Geophysical Union as part of the Water Resources Monograph Series, Volume 11. This monograph compiles research findings on soil mass movement

Published by the American Geophysical Union as part of the Water Resources Monograph Series, Volume 11. This monograph compiles research findings on soil mass movement into a format usable by practitioners and students. Applications are stressed in the areas of extensive and management practices rather than engineering earthworks. Examples are included to illustrate various prediction, avoidance, and control measures used in managing unstable terrain. We use the term soil (i.e., soil mass movement) to mean the mantle of unconsolidated or poorly consolidated material of either residual or transported origin, that overlies bedrock and forms the surface of the land. This usage is consistent with the conventional civil engineering use of the word and is synonymous with the geological term regolith and with soil mantle.

Historical Ecology of the Los Angeles River Watershed and Environs, Infrastructure for a Comprehensive Analysis

University of Southern California (USC) | June 15th, 2020

Hydrologic Modeling of the Santa Clara River Watershed with the U.S. EPA Hydrologic Simulation Program - FORTRAN (HSPF)

Ventura County Watershed Protection District | January 24th, 2009

The purpose of the Santa Clara River (SCR) Watershed Feasibility Study as described in the PMP (October, 2003) is to determine the impact of the upstream urbanization, s

The purpose of the Santa Clara River (SCR) Watershed Feasibility Study as described in the PMP (October, 2003) is to determine the impact of the upstream urbanization, specifically in Los Angeles County, to the present natural state of the river in Ventura County and communities adjacent to the River that expect to develop close to the river banks. It is the goal of the watershed study to develop the necessary baseline data and analytical tools. In order to evaluate these impacts the feasibility study will include: • A comprehensive update of hydrologic, hydraulic, and sediment (yield and transport) models for a range of flow rates for existing conditions and future conditions within the Santa Clara River. The hydrologic model provides the flow data needed as input to the hydraulic and sediment transport models. • The hydrologic model will also be used to evaluate baseline and changes to water quality and pollutant loadings as a result of development or any proposed regional solutions to flooding or water quality problems. • Generate computer models that can simulate the impacts of land use changes under existing, natural and future conditions, and provide data to forecast the resulting changes to streamflow in the Santa Clara River. • Existing conditions include recently installed flood control and water supply/storage facilities. For future conditions, the modeling will include proposed land use changes, any additional flood control or sediment control facilities, and the effects of changes in sediment flow to the downstream areas as a result of proposed alternatives to mitigate flooding or water quality problems. The Natural Condition will be modeled by assuming the watershed has not been developed or subjected to extensive ranching or agricultural activities (pre-European). This document is the Final Report for the watershed hydrology model of the Santa Clara River Watershed using the U.S. EPA Hydrologic Simulation Program FORTRAN (HSPF). This effort was funded directly and wholly by contract with the Ventura County Watershed Protection District (VCWPD). This report identifies and describes the watershed characteristics and types of data required/available for the model, the segmentation of the watershed for modeling purposes, model calibration and validation efforts, and the results for the Baseline and Natural Conditions Scenario model runs. This effort has been designed to produce a comprehensive watershed model that meets the needs of the hydrologic model component of the SCR Watershed Feasibility Study as described above. This model was designed to: a. Represent hydrologic conditions throughout the SCR watershed for a wide range of flow conditions continuously for both high flows, low flows and individual storm events b. Provide continuous flow boundary conditions for the hydraulic and sediment transport models, at the appropriate spatial scales and boundary locations identified by the Feasibility Study participants c. Provide a modeling framework for subsequent sediment yield and water quality modeling requirements of the Feasibility Study d. Include a long-term database of 40 or more years of model input (e.g. precipitation, evaporation, diversions, POTWs) to allow long-term model simulations needed to develop the required flood (and low flow) frequency information at selected points throughout the SCR Watershed e. Provide long-term model simulations for both Baseline (current) and Natural Condition alternatives as a basis for assessing and comparing with planned Future Condition alternatives.

Increasing soil organic carbon to mitigate greenhouse gases and increase climate resiliency for California

California Natural Resources Agency (CNRA) | August 1st, 2018

Rising air temperatures are projected to continue to drive up urban, agricultural, and rangeland water use, straining both surface and groundwater resources. Scie

Rising air temperatures are projected to continue to drive up urban, agricultural, and rangeland water use, straining both surface and groundwater resources. Scientific studies have shown that managing farms, ranches, and public lands to increase soil carbon can increase soil water- holding capacity and increase hydrologic benefits such as increased baseflows and aquifer recharge, reduced flooding and erosion, and reduced climate-related water deficits. Coincident improvements in forage and crop yields are also indicated, while simultaneously sequestering carbon, reducing atmospheric greenhouse gases and mitigating climate change. This study was developed to consider the multiple benefits of increasing the organic matter content of soils across California’s working lands. Study results indicate that a one-time 1⁄4” application of compost to rangelands can lead to carbon sequestration rates in soils that are maximized after approximately 15 years, and more than offset greenhouse gas emissions stimulated by the compost addition for at least five decades longer. Modeled increases in total soil organic matter of 3% enhanced hydrologic benefits across 97% of working lands, and reduced climate change impacts. Economic valuation indicated all benefits increasing over time, demonstrating a large potential for the California carbon market to support incentives in regionalizing the impacts in the coming decades. Socioeconomic and related land use pressures pose barriers to implementing management practices to increase soil organic matter by driving conversion of rangeland to urban or to more greenhouse-gas emission intensive agriculture. Results can be effectively used with land use change scenarios to identify where on California’s working lands hydrologic benefits of soil organic matter enhancement coincide with development risk, highlighting counties in California in which there may be resilience to climate change when strategic soil management and land conservation are combined.

Influence of Urban Areas on Surface Water Loss in the Contiguous United States

American Geophysical Union (AGU) | February 7th, 2022

Inhabiting the Delta: A Landscape Approach to Transformative Socio-Ecological Restoration

University of California, Davis (UC Davis) | September 19th, 2017

Current legislation and plans for the Sacramento–San Joaquin Delta (Delta) call for large-scale restoration of aquatic and terrestrial habitats, which will require sign

Current legislation and plans for the Sacramento–San Joaquin Delta (Delta) call for large-scale restoration of aquatic and terrestrial habitats, which will require significant changes in waterways, land uses, and cultural patterns. These re-made landscapes will be subject to a variety of new human uses, which Delta planning and adaptive management literature has yet to adequately consider. Failing to account for human uses and evolving place values can lead to diminished performance and public support for Delta restoration efforts. Our empirical study examined restored and naturalized Delta landscapes using an integrative landscape approach that seeks to reconcile multiple goals and land-use agendas that span ecological, social, economic, and political domains. The research design consisted of six overlapping methods that included a planning, policy, and law review specific to the Delta; surveys and interviews with approximately 100 land managers, scientists, land-owners, law-enforcement personnel, agency representatives, and Delta residents; nine case studies of restored and naturalized delta landscapes; GIS mapping; and extensive field work. Findings derived from the synthesis of these methods show that human uses of the Delta’s re-wilded landscapes are diverse and pervasive. Given the infrastructural and urbanized context of the region, these environments are subject to multiple and sometimes conflicting uses, perceptions, and place values. Though these myriad uses cannot be fully predicted or controlled (nor should they be), findings showed that more proactive and inclusive planning for human uses can encourage or discourage particular uses while also building constituency, support, and active engagement in ecological restoration efforts. We conclude that reconciling human uses with ecological recovery in the Delta will require a more localized, multi-functional, and creative approach to designing and adaptively managing these emergent landscapes. We recommend that more resources and experimental prototyping be dedicated to such work.