Optimal Selection and Placement of Green Infrastructure in Urban Watersheds for PCB Control

American Society of Civil Engineers (ASCE) | May 1st, 2019

San Francisco Bay and its watersheds are polluted by legacy polychlorinated biphenyls (PCBs), resulting in the establishment of a total maximum daily load (TDML) that req

San Francisco Bay and its watersheds are polluted by legacy polychlorinated biphenyls (PCBs), resulting in the establishment of a total maximum daily load (TDML) that requires a 90% PCB load reduction from municipal stormwater. Green infrastructure (GI) is a multibenefit solution for stormwater management, potentially addressing the TMDL objectives, but planning and implementing GI cost-effectively to achieve management goals remains a challenge and requires an integrated watershed approach. This study used the nondominated sorting genetic algorithm (NSGA-II) coupled with the Stormwater Management Model (SWMM) to find near-optimal combinations of GIs that maximize PCB load reduction and minimize total relative cost at a watershed scale. The selection and placement of three locally favored GI types (bioretention, infiltration trench, and permeable pavement) were analyzed based on their cost and effectiveness. The results show that between optimal solutions and nonoptimal solutions, the effectiveness in load reduction could vary as much as 30% and the difference in total relative cost could be well over $100 million. Sensitivity analysis of both GI costs and sizing criteria suggest that the assumptions made regarding these parameters greatly influenced the optimal solutions.

Optimizing the dammed: Water supply losses and fish habitat gains from dam removal in California

Journal of Environmental Management (Elsevier) | April 1st, 2014

Dams provide water supply, flood protection, and hydropower generation benefits, but also harm native species by altering the natural flow regime and degrading aquatic an

Dams provide water supply, flood protection, and hydropower generation benefits, but also harm native species by altering the natural flow regime and degrading aquatic and riparian habitat. Restoring some rivers reaches to free-flowing conditions may restore substantial environmental benefits, but at some economic cost. This study uses a systems analysis approach to preliminarily evaluate removing rim dams in California's Central Valley to highlight promising habitat and unpromising economic use tradeoffs for water supply and hydropower. CALVIN, an economic-engineering optimization model, is used to evaluate water storage and scarcity from removing dams. A warm and dry climate model for a 30-year period centered at 2085, and a population growth scenario for year 2050 water demands represent future conditions. Tradeoffs between hydropower generation and water scarcity to urban, agricultural, and instream flow requirements were compared with additional river kilometers of habitat accessible to anadromous fish species following dam removal. Results show that existing infrastructure is most beneficial if operated as a system (ignoring many current institutional constraints). Removing all rim dams is not beneficial for California, but a subset of existing dams are potentially promising candidates for removal from an optimized water supply and free-flowing river perspective. Removing individual dams decreases statewide delivered water by 0–2282 million cubic meters and provides access to 0 to 3200 km of salmonid habitat upstream of dams. The method described here can help prioritize dam removal, although more detailed, project-specific studies also are needed. Similarly, improving environmental protection can come at substantially lower economic cost, when evaluated and operated as a system.

Oroville Dam Safety Comprehensive Needs Assessment Summary

California Department of Water Resources (DWR) | October 30th, 2020

Oroville Dam, located on the Feather River in Butte County, is a key facility of the California State Water Project (SWP). Completed in 1967, it is owned and operated by

Oroville Dam, located on the Feather River in Butte County, is a key facility of the California State Water Project (SWP). Completed in 1967, it is owned and operated by the California Department of Water Resources (DWR). In February 2017, both the gated main spillway and the ungated emergency spillway suffered significant erosion scour damage while releasing flood waters that had flowed into Lake Oroville. Concerns for the stability of the spillway crest structures resulted in the temporary evacuation of 188,000 residents downstream of the dam. Over the next few months, flood waters were successfully managed by making controlled reservoir releases down the damaged gated main spillway through May 2017 when the gates were closed for the year and DWR began repairs to the two spillways. By the fall of 2018, the entire 3,000-foot-long chute for the gated main spillway had been completely reconstructed, and major erosion-resistant armoring had been added to the emergency spillway. The repairs resulted in making these two spillways robust structures meeting modern engineering standards. 

Oroville Dam: A key unit of the State Water Project

California Department of Water Resources (DWR) | July 1st, 1973

Patterns, drivers, and a predictive model of dam removal cost in the United States

Frontiers in Ecology and Evolution (Frontiers) | July 24th, 2023

Paying for California's Water System

Public Policy Institute of California (PPIC) | May 31st, 2021

Paying for Infrastructure: California’s Choices

Public Policy Institute of California (PPIC) | January 16th, 2009

PPIC’s At Issue series focuses on issues important for California now and in the future. Financing infrastructure has traditionally been difficult for the state, and cu

PPIC’s At Issue series focuses on issues important for California now and in the future. Financing infrastructure has traditionally been difficult for the state, and current economic woes are likely to make it even more challenging. In this At Issue, PPIC research director Ellen Hanak analyzes the impediments to infrastructure financing and describes funding reforms such as loosening the supermajority rules for local infrastructure funding, financing investment through user fees, and expanding public-private partnerships. She outlines how these reforms could improve the state’s ability to build for the future.

Paying it Forward: The Path Toward Climate-Safe Infrastructure in California

Climate-Safe Infrastructure Working Group | September 1st, 2018

Physical water system consolidation alone cannot resolve drinking water failure in California’s San Joaquin Valley

Nature Portfolio (Springer Nature) | July 2nd, 2026

Small community water systems in California’s San Joaquin Valley disproportionately fail to provide safe drinking water, with most serving disadvantaged communities and

Small community water systems in California’s San Joaquin Valley disproportionately fail to provide safe drinking water, with most serving disadvantaged communities and lacking the technical, managerial, and financial capacity to maintain compliance. The State Water Board designates such systems as failing when they have documented violations of drinking water standards or cannot reliably deliver safe water. Physical consolidation, which involves connecting a smaller failing system to a larger provider through new pipeline infrastructure, is the primary long-term solution promoted by state regulators. Here, we assess consolidation feasibility and capital costs across four counties (Kern, Kings, Tulare, and Fresno) via the state’s 2024 screening methodology. The methodology identifies smaller failing and at-risk systems as candidates for joining a larger receiving system with sufficient capacity. Among the 210 eligible systems, 114 (54%) matched a receiving system within three miles, with an estimated total capital need of $413.5 million. Nearly all identified pairs met state funding viability thresholds. The remaining 96 systems, including 49 classified as failing, lacked an eligible receiving partner and will require alternative solutions. Physical consolidation is necessary but insufficient for achieving safe drinking water access across the region.

Planning for America’s Water Infrastructure Needs

Stanford University | May 31st, 2018