Storm rainfall conditions for floods and debris flows from recently burned areas in southwestern Colorado and southern California

Geomorphology (Elsevier) | April 15th, 2008

Debris flows generated during rain storms on recently burned areas have destroyed lives and property throughout the Western U.S. Field evidence indicate that unli

Debris flows generated during rain storms on recently burned areas have destroyed lives and property throughout the Western U.S. Field evidence indicate that unlike landslide-triggered debris flows, these events have no identifiable initiation source and can occur with little or no antecedent moisture. Using rain gage and response data from five fires in Colorado and southern California, we document the rainfall conditions that have triggered post-fire debris flows and develop empirical rainfall intensity–duration thresholds for the occurrence of debris flows and floods following wildfires in these settings. This information can provide guidance for warning systems and planning for emergency response in similar settings. Debris flows were produced from 25 recently burned basins in Colorado in response to 13 short-duration, high-intensity convective storms. Debris flows were triggered after as little as six to 10 min of storm rainfall. About 80% of the storms that generated debris flows lasted less than 3 h, with most of the rain falling in less than 1 h. The storms triggering debris flows ranged in average intensity between 1.0 and 32.0 mm/h, and had recurrence intervals of two years or less. Threshold rainfall conditions for floods and debris flows sufficiently large to pose threats to life and property from recently burned areas in south-central, and southwestern, Colorado are defined by: I = 6.5D− 0.7 and I = 9.5D− 0.7, respectively, where I = rainfall intensity (in mm/h) and D = duration (in hours). Debris flows were generated from 68 recently burned areas in southern California in response to long-duration frontal storms. The flows occurred after as little as two hours, and up to 16 h, of low-intensity (2–10 mm/h) rainfall. The storms lasted between 5.5 and 33 h, with average intensities between 1.3 and 20.4 mm/h, and had recurrence intervals of two years or less. Threshold rainfall conditions for life- and property-threatening floods and debris flows during the first winter season following fires in Ventura County, and in the San Bernardino, San Gabriel and San Jacinto Mountains of southern California are defined by I = 12.5D−0.4, and I = 7.2D−0.4, respectively. A threshold defined for flood and debris-flow conditions following a year of vegetative recovery and sediment removal for the San Bernardino, San Gabriel and San Jacinto Mountains of I = 14.0D−0.5 is approximately 25 mm/h higher than that developed for the first year following fires. The thresholds defined here are significantly lower than most identified for unburned settings, perhaps because of the difference between extremely rapid, runoff-dominated processes acting in burned areas and longer-term, infiltration-dominated processes on unburned hillslopes.

Stormwater Funding Options Providing Sustainable Water Quality Funding in Los Angeles County

California Contract Cities Association (CCCA) | May 21st, 2014

The Los Angeles region faces critical, very costly, and seriously underfunded stormwater and urban runoff water quality challenges. The Los Angeles County Flood Control D

The Los Angeles region faces critical, very costly, and seriously underfunded stormwater and urban runoff water quality challenges. The Los Angeles County Flood Control District (LACFCD) led a multi-year effort to develop a sustainable revenue source for municipalities to manage stormwater programs and implement water quality improvement projects. This effort included special legislation and development of a proposed parcel fee, the “Clean Water, Clean Beaches Measure,” to fund clean water programs. At extended protest hearings on a proposed parcel fee in January and March of 2013, the Board of Supervisors heard concerns about the fee and the fee program from public schools, the business community, other stakeholders and the public. The Board moved to close the public hearing and determined to “not proceed at this time with the Clean Water, Clean Beaches measure as proposed.” In June 2013, the Board adopted a motion requesting collaborative participation with the County Sanitation Districts of Los Angeles County (LACSD) and other wastewater management agencies to evaluate methods, assess the a potential model governance structure, and to help identify and secure other sources of funding. In response to the Board’s actions, the City Managers Committees of the California Contract Cities Association (CCCA) and the League of California Cities, Los Angeles County Division (League) convened a City Managers meeting with representatives from public schools, environmental organizations, and the business community on June 27, 2013 to hear stakeholders’ concerns and suggestions directly. The City Managers attending the meeting authorized a Work Group to review stormwater funding options after the County’s proposed Clean Water, Clean Beaches funding initiative failed to move forward. The City Managers Work Group actively sought the input of key stakeholders from the environmental, public education, and business communities, and prepared this report to assist the Board, local decision makers, stakeholders, and the public in reaching a common understanding of the issues at hand and the potential solutions. The Managers found that to fully understand the issues, improved communication and education is necessary. This report describes the stormwater regulatory requirements speci c to the greater Los Angeles area, the complexities of funding stormwater programs, and the LACFCD’s funding initiative. It examines the regulatory framework for stormwater management, including the requirements of the National Pollution Discharge Elimination System (NPDES) MS4 permit (stormwater permit) and the total maximum daily load (TMDL) programs. The report also summarizes the impacts of the federal TMDL Consent Decree for the Los Angeles Region signed in 1999, which has indirectly regulated the LACFCD, 85 cities, and the unincorporated County since that time. Further, it reviews estimated stormwater program compliance costs, the “pros and cons” of various funding options, and evolving opportunities. The report concludes with a series of recommendations agreed upon by the City Managers. Suggestions from an Elected Officials Committee and individual City Attorneys are also included in this report. The Work Group found that funding urban runoff programs is so complex and dynamic, and the solutions so costly, that the County and the Cities cannot follow a single funding strategy at this time. One option, for example, is to examine institutional roles to determine whether other agencies, such as the County Sanitation Districts, either provide a useful governance model or could play a new or different role in managing stormwater in the future. During the report development process, the Sixth Appellate Court clarified the application of Proposition 218 regarding the imposition of fees for the capture and use of stormwater for groundwater recharge (Griffith v. Pajaro Water Management Agency). This ruling could have major implications on funding options. These are only two examples of the changing nature and complexities in charting a path forward. The City Managers Work Group recommends a “multi-pronged” approach to address urban runoff funding issues, since our communities may encounter several dead-ends. A number of the recommendations require active management and a higher degree of organization by local government. The recommended actions are voluntary. The report is not advocating that any city, group of cities, or the County adopt stormwater fees. The managers are committed to local control; if a regional fee moves forward, each community should make its own decision whether or not to participate in the regional effort. However, there are steps that local governments can take that will assist in funding the new stormwater mandates. For example, cities should organize and be active in the water bond discussions. This report suggests a voluntary framework through Contract Cities and the League to organize those communities that desire to engage in implementing the recommendations found in this report. It should be noted that the recommendations involving California Contract Cities, the Los Angeles County Division of the League of California Cities, and the State League of Cities have not been of cially endorsed by these organizations at this stage of the process. The City Managers Work Group and the Elected Of cials Committee held detailed discussions with staff from both organizations in order to re ect their input and concerns. Recommendations involving these organizations, such as changes in State legislation, would need to be reviewed and approved by each organization.

Strategic Plan for the Future of Integrated Regional Water Management in California

California Department of Water Resources (DWR) | April 24th, 2013

Integrated regional water management (IRWM) was officially embraced by the State of California in 2002 with the passage of the Integrated Regional Water Management Planni

Integrated regional water management (IRWM) was officially embraced by the State of California in 2002 with the passage of the Integrated Regional Water Management Planning Act (SB 1672). Thanks to voter-approved bond funds, California has since made profound improvements in water resource management. The Department of Water Resources (DWR) has supported IRWM with grants and technical services to regional water management groups (RWMGs) statewide. Forty-eight RWMGs now cover 87% of the state’s geographic area and 99% of the population. The names and locations of individual IRWM regions and RWMGs, along with other information, can be found at www.water.ca.gov/irwm/grants/fundingarea.cfm. DWR is developing the Strategic Plan for the Future of IRWM in California. The need for the strategic plan and the specific tasks that will be completed for the plan’s development are described herein. Information on how groups and individuals can be involved in the plan’s development are also included.

Strategic Plan for the Future of Integrated Regional Water Management in California: Review of IRWM Planning and Implementation in California

California Department of Water Resources (DWR) | February 20th, 2015

Integrated Regional Water Management (IRWM) has become a water management standard throughout most of California following passage of the 2002 IRWM Planning Act (SB 1672)

Integrated Regional Water Management (IRWM) has become a water management standard throughout most of California following passage of the 2002 IRWM Planning Act (SB 1672). The dedicated efforts of regional water management groups and the support of state bond funds have resulted in 48 IRWM regions identifying and implementing integrated regional water management solutions to improve public safety, foster environmental stewardship, and support economic stability throughout the state. Under the principles of IRWM, individuals and agencies have built strong working relationships, identified regional water management needs, and defined crucial steps to meet those needs together.  IRWM is essential for California's future and is a key part of the California Water Action Plan. As the Department of Water Resources works with its partners to produce a Strategic Plan for the Future of IRWM in California (Strategic Plan), we have surveyed the IRWM landscape to identify key characteristics and trends in IRWM planning and implementation. Survey results were presented to stakeholders at the second round of Strategic Plan development workshops in October and November 2013 and subsequently updated to reflect IRWM planning and implementation efforts as of October 2014. These updated results, along with additional information, are presented in this technical memorandum. Please visit the Strategic Plan website at http://www.water.ca.gov/irwm/stratplan/ to learn more about the Strategic Plan development effort. For more information about the California Water Action Plan, please visit http://resources.ca.gov/docs/california_water_action_plan/ Final_California_Water_Action_Plan.pdf.

Strategic Plan to Protect California Coast and Ocean 2020-2025

California Ocean Protection Council (COPC) | February 26th, 2020

Strategic Salt Accumulation Land and Transportation Study (SSALTS) Final Phase 1 Report – Identification and Characterization of Existing Salt Accumulation Areas

Central Valley Salinity Alternatives for Long-Term Sustainability (CV-SALTS) | December 13th, 2013

The purpose of the Strategic Salt Accumulation Land and Transportation Study (SSALTS) is to identify the range of viable Central Valley alternatives for salt disposal to

The purpose of the Strategic Salt Accumulation Land and Transportation Study (SSALTS) is to identify the range of viable Central Valley alternatives for salt disposal to provide input for consideration during development of the Salt and Nutrient Management Plan (SNMP) for the region under the jurisdiction of the Central Valley Regional Water Quality Control Board (Central Valley RWQCB). The findings will be used to guide discussions regarding establishment of regional salt management policies and the need for changes to the existing Central Valley RWQCB Water Quality Control Plans (Basin Plans) to facilitate salt disposal in a manner that is most beneficial to the region and consistent with the State Water Resource Control Board (SWRCB) Recycled Water Policy. This work is being conducted under the direction of the Central Valley Salinity Alternatives for Long- Term Sustainability (CV-SALTS) initiative, which is developing the SNMP for the Central Valley. The SSALTS project is being conducted in three phases: Phase 1: Identify and Characterize Existing Salt Accumulation Study Areas–Selection of representative Study Areas to serve as prototype situational examples to facilitate discussions regarding salt accumulation and disposal in the Central Valley. Each of these Study Areas is being characterized to establish baseline information that may be used to support development of salt disposal alternatives in subsequent project phases. Phase 2: Develop Potential Salt Management Strategies–SSALTS will develop potential long- term salt disposal alternatives in three parts: (1) In-Valley alternatives; (2) Out-of-Valley alternatives; and (3) hybrid alternatives that combine In-Valley and Out-of-Valley salt disposal options. Phase 3: Evaluate Potential Salt Disposal Alternatives to Identify Acceptable Alternatives for Implementation – Alternatives developed under Phase 2 will be evaluated using selected feasibility criteria (e.g., regulatory, institutional, economic, technological, etc.). The outcome of this evaluation will be the identification and prioritization of acceptable salt disposal alternatives for potential incorporation into Central Valley SNMP as salt management implementation measures. This draft report represents the findings of Phase 1. Subsequent phases of SSALTS will be implemented following completion of this phase.  

Strategic Salt Accumulation Land and Transportation Study (SSALTS) Final Phase 2 Report – Development of Potential Salt Management Strategies

Central Valley Salinity Alternatives for Long-Term Sustainability (CV-SALTS) | October 1st, 2014

The purpose of the Strategic Salt Accumulation Land and Transportation Study (SSALTS) is to identify the range of viable Central Valley alternatives for salt disposal to

The purpose of the Strategic Salt Accumulation Land and Transportation Study (SSALTS) is to identify the range of viable Central Valley alternatives for salt disposal to provide input for consideration during development of the Salt and Nutrient Management Plan (SNMP) for the region under the jurisdiction of the Central Valley Regional Water Quality Control Board (Central Valley RWQCB). The findings will be used to guide discussions regarding establishment of regional salt management policies and the need for changes to the existing Central Valley RWQCB Water Quality Control Plans (Basin Plans) to facilitate salt disposal in a manner that is most beneficial to the region and consistent with the State Water Resource Control Board (SWRCB) Recycled Water Policy. This work is being conducted under the direction of the Central Valley Salinity Alternatives for Long- Term Sustainability (CV-SALTS) initiative, which is developing the SNMP for the Central Valley. The SSALTS project is being conducted in three phases: Phase 1: Identify and Characterize Existing Salt Accumulation Study Areas–Selection of representative Study Areas to serve as prototype situational examples to facilitate discussions regarding salt accumulation and disposal in the Central Valley. Each of these Study Areas is being characterized to establish baseline information that may be used to support development of salt disposal alternatives in subsequent project phases. Phase 2: Develop Potential Salt Management Strategies–SSALTS will develop potential long- term salt disposal alternatives in three parts: (1) In-Valley alternatives; (2) Out-of-Valley alternatives; and (3) hybrid alternatives that combine In-Valley and Out-of-Valley salt disposal options. Phase3: Evaluate Potential Salt Disposal Alternatives to Identify Acceptable Alternatives for Implementation – Alternatives developed under Phase 2 will be evaluated using selected feasibility criteria (e.g., regulatory, institutional, economic, technological, etc.). The outcome of this evaluation will be the identification and prioritization of acceptable salt disposal alternatives for potential incorporation into Central Valley SNMP as salt management implementation measures. The Phase 1 report was finalized in December 2013. This report summarizes the findings of Phase 2. Phase 3 work will begin after the stakeholders have reviewed the Phase 2 report and provided comments.

Stratigraphic controls on seawater intrusion and implications for groundwater management, Dominguez Gap area of Los Angeles, California, USA

Hydrogeology Journal (Springer) | May 30th, 2009

Groundwater pumping has led to extensive waterlevel declines and seawater intrusion in coastal Los Angeles, California (USA). A SUTRA-based solute-transport model was dev

Groundwater pumping has led to extensive waterlevel declines and seawater intrusion in coastal Los Angeles, California (USA). A SUTRA-based solute-transport model was developed to test the hydraulic implications of a sequence-stratigraphic model of the Dominguez Gap area and to assess the effects of water-management scenarios. The model is two-dimensional, vertical and follows an approximate flow line extending fromthe Pacific Ocean through the Dominguez Gap area. Results indicate that a newly identified fault system can provide a pathway for transport of seawater and that a stratigraphic boundary located between the Bent Spring and Upper Wilmington sequences may control the vertical movement of seawater. Three 50-year water-management scenarios were considered: (1) no change in water-management practices; (2) installation of a slurry wall; and (3) raising inland water levels to 7.6m above sea level. Scenario 3 was the most effective by reversing seawater intrusion. The effects of an instantaneous 1-m sealevel rise were also tested using water-management scenarios 1 and 3. Results from two 100-year simulations indicate that a 1-m sea-level rise may accelerate seawater intrusion for scenario 1; however, scenario 3 remains effective for controlling seawater intrusion.

Strawberry Case Study: What If Farmers Had to Pay for Water?

New York Times | December 29th, 2023

While American farmers elsewhere have watered their crops by freely pumping the groundwater beneath their land, growers in Pajaro must pay hefty fees for irrigation water

While American farmers elsewhere have watered their crops by freely pumping the groundwater beneath their land, growers in Pajaro must pay hefty fees for irrigation water — making it one of the most expensive places to grow food in the country, if not the world. The cost: Up to $400 per acre-foot, a standard measurement equal to water covering one acre, one foot deep. The fees bring in $12 million a year, which is used to recycle, restore and conserve the region’s groundwater.

Submittal of 2015 Agricultural Water Management Plans and Implementation of Efficient Water Management Practices Report

California Department of Water Resources (DWR) | September 22nd, 2017

Senate Bill X7-7, the Water Conservation Act of 2009 (SB X7-7), requires agricultural water suppliers who provide water to more than 25,000 irrigated acres (excluding acr

Senate Bill X7-7, the Water Conservation Act of 2009 (SB X7-7), requires agricultural water suppliers who provide water to more than 25,000 irrigated acres (excluding acreage irrigated by recycled water) to adopt and submit Agricultural Water Management Plans (AWMPs or Plans) to the Department of Water Resources (DWR) and to implement Efficient Water Management Practices (EWMPs), including two critical EWMPs: the measurement and volumetric pricing of water deliveries. These AWMPs were due by January 31, 2016. Governor Brown’s Executive Order B-29-15 required agricultural water suppliers that provide water from 10,000 to 25,000 irrigated acres to submit AWMPs by July 1, 2016. California Water Code (CWC) §10845(a) and (b) directs DWR to report on the following: • The status of adopted AWMPs • Exemplary elements of adopted plans • An evaluation of the effectiveness of implemented AWMPs in promoting efficient agricultural water management practices • Recommendations relating to proposed changes to the AWMP reporting requirements and EWMPs Additionally, CWC section 10608.48(g) directs DWR in consultation with the State Water Resources Control Board (SWRCB) to prepare and submit to the Legislature a report on: • EWMPs that have been implemented or are planned to be implemented, and • An assessment of the manner in which the implementation of an EWMP has affected and will affect agricultural operations and an estimation of water use efficiency improvements, if any. This legislative report addresses the above requirements in a single report and documents the status of AWMP submittals and the implementation of associated EWMPs or best management practices (BMPs) for those water suppliers submitting a United States Bureau of Reclamation (Reclamation) plan in lieu of a plan meeting SB X7-7 criteria.1 A table comparing the SB X7-7 EWMPs and Reclamation BMPs is in Appendix B. Further information on SB X7-7 requirements and legislative reports are available at http://www.water.ca.gov/wateruseefficiency/sb7/.