Systems Analysis and Optimization of Local Water Supplies in Los Angeles

Abstract

Los Angeles, which relies on large infrastructure systems that import water over hundreds of miles, faces a future of reduced imports. Within Los Angeles and its hundreds of water agencies, the capacity to adapt to future changes is influenced by laws, institutions, and hydrogeology. This paper presents a systems analysis of urban water management in metropolitan Los Angeles County to assess opportunities for increasing local water reliance. A network flow model was developed to investigate management tradeoffs across engineered, social, and environmental systems. With an aggressive regional demand target, increased stormwater capture (300%), and prioritized water reuse from existing facilities, imported water supplies can be cut by 30% while maintaining landscapes, economic productivity, and groundwater resources. Further reducing imports (by 40-50%) is possible through actions to promote additional reuse, recharge, conservation, and groundwater access. Reducing imported water without significant conservation results in likely groundwater overdraft. Fragmented networks of agencies in Los Angeles create an uneven landscape of vulnerability to water shortages. The paper discusses model applications, research needs, and policy implications of results for dry-climate cities.

Energy use for urban water management by utilities and households in Los Angeles

“…Future work could further validate and refine the approach by comparing to real-world water network operations. Finally, the underlying water resource model using simulation and optimization is subject to limitations that have been outlined previously (Porse et al 2017(Porse et al , 2018b.…”

“…A diverse and fragmented network of water agencies is responsible for providing and disposing of water supply (figure S1 in supporting information is available online at stacks.iop.org/ERC/2/015003/mmedia) (Ostrom 1962, DeShazo and McCann 2015, Pincetl et al 2016. The majority of residents and businesses are served by a hundred sizeable water supply agencies (>3000 connections) that report water supply and demand, while additional agencies provide wastewater, flood control, and stormwater management services (Porse et al 2017).…”

“…A network flow model with simulation and optimization was used to evaluate effects of regional water management decisions on energy use, both system wide and for individual water agencies (Porse et al 2017). The model incorporates sociologic, environmental, hydrologic, and economic parameters to evaluate the benefits and drawbacks of management options.…”

System Modeling, Optimization, and Analysis of Recycled Water and Dynamic Storm Water Deliveries to Spreading Basins for Urban Groundwater Recharge

“…Representative recent studies have focused on optimizing existing water infrastructure systems (Cherchi et al, ; Perelman et al, ), optimizing designs for nonpotable recycled water systems (Kavvada et al, ; Lee et al, ), designing direct potable reuse systems (Guo & Englehardt, ; Vitter et al, ), siting and costing new recharge facilities (Dillon & Arshad, ; Fournier et al, ; Pedrero et al, ; Russo et al, ), optimizing recharge and recovery well systems that receive storm water (Clark et al, ; Marchi et al, ), and optimizing new recycled water distribution systems (Fournier et al, ; Lan et al, ; Lee et al, ; Zhang et al, ). In addition, several studies—for example, Newman et al (), Porse et al (), Wu et al (), and Xiong et al ()—investigate optimizing urban water supplies portfolios that include recycled water, but none of these studies consider both the engineering and economic considerations within our study's scope.…”

Use of alternative water sources in irrigation: potential scales, costs, and environmental impacts in California

“…Though the primary foci of stormwater management are flood control and water quality protection, California has begun to promote the use of stormwater for local water supply. Stormwater filtering or treatment facilities have been built in many cities, including Los Angeles and San Francisco [24,25]. From 1986 to 2016, about 400 million m 3 of stormwater have been annually captured and used for groundwater recharging in the metropolitan area of Southern California [26].…”