Erik Porse

Fragmented Flows: Water Supply in Los Angeles County

In the Los Angeles metropolitan region, nearly 100 public and private entities are formally involved in the management and distribution of potable water—a legacy rooted in fragmented urban growth in the area and late 19th century convictions about local control of services. Yet, while policy debates focus on new forms of infrastructure, restructured pricing mechanisms, and other technical fixes, the complex institutional architecture of the present system has received little attention. In this paper, we trace the development of this system, describe its interconnections and disjunctures, and demonstrate the invisibility of water infrastructure in LA in multiple ways—through mapping, statistical analysis, and historical texts. Perverse blessings of past water abundance led to a complex, but less than resilient, system with users accustomed to cheap, easily accessible water. We describe the lack of transparency and accountability in the current system, as well as its shortcomings in building needed new infrastructure and instituting new water rate structures. Adapting to increasing water scarcity and likely droughts must include addressing the architecture of water management.

Network Analysis and Visualizations of Water Resources Infrastructure in California: Linking Connectivity and Resilience

AbstractConnectivity is important to the structure and function of systems. In water infrastructure systems, connections between components determine flow patterns and operational flexibility. Network theory can provide tools to assess and view connectivity in water resource networks that augment current methods in water resource systems analysis. This paper presents an analysis of connectivity and resilience in the network of California’s water resources infrastructure using network theory visualization and metrics. Applying these techniques to a link-node network used in a statewide hydroeconomic model of water management in California, the analysis shows how such metrics are useful to describe aspects of connectivity and identify important system components. Both the entire system and the San Francisco Bay Area subsystem are analyzed using measures of centrality, spacing, and linkage. The analysis also assesses the effects of network degradation by removing selected components, revealing complex relati...

Network structure, complexity, and adaptation in water resource systems

Infrastructure systems are often complex. Many have both natural and built components. For such systems, including water resource networks, resilience is a common policy goal. In the formalised study of complex systems, the structure and function of networks can contribute directly to system resilience. One branch of complex systems studies, network science, describes how connectivity between individual components can explain some system-wide properties of growth and reliability. Water resource systems analysis has only begun to apply techniques from network theory and complexity science to assess adaptability and resilience. We present an analysis of connectivity in a network model of Californias water infrastructure system using several network science techniques. Results indicate that nodes in Californias water system are clustered but without scale-free properties. The network originates from a mixture of top-down (centralised) and bottom-up (dispersed interactions of parties) planning. This structure provides managers greater flexibility to use local and distant water sources. We use the analysis to illustrate how several disciplinary notions of resilience apply to civil infrastructure planning. We also explore how adaptability, not just complexity, influences resilience in planning. Creating systems that can respond to future changes must be an important policy goal in planning civil infrastructure.

Systems Analysis and Optimization of Local Water Supplies in Los Angeles

AbstractLos 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 economic value of local water supplies in Los Angeles

Los Angeles imports water over long distances to supplement local supplies. Reduced reliability of the available imports is driving many local agencies to promote conservation and enhance local water sources. These include stormwater capture, water reuse and groundwater. But financial considerations are often a significant impediment to project development, especially when comparing new and existing sources. Here we demonstrate a comprehensive approach for evaluating the economic implications of shifting to local water reliance in Los Angeles County. We show that local water supplies are economically competitive. Results from integrated hydroeconomic modelling of urban water in Los Angeles identify cost-effective water supply portfolios and conservation targets. Considering costs across the ‘full-cycles’ of urban water supply that span agency boundaries yields better comparisons of planning alternatives. Throughout the region, many water retailers could successfully mitigate effects of imported water cuts while still supporting drought-tolerant landscapes, but some would suffer due to over-reliance on imports. Updating economic assessment methods would support needed innovations to achieve local reliance in Los Angeles, including infrastructure investments, institutional reforms, many more drought-tolerant landscapes and reallocated groundwater rights.A large-scale economic analysis of the economics of water supplies in the greater Los Angeles area, based on the ‘full-cycle’ costs of water sources such as imported water, groundwater, and reused and storm-water capture. The study showcases an updated model and framework for urban water studies that can be applied to other cities.

Open data and stormwater systems in Los Angeles: applications for equitable green infrastructure

ABSTRACT Urban stormwater systems traditionally used “grey” infrastructure to manage runoff. Contemporary designs now incorporate “green” infrastructure, which offers additional potential benefits such as urban amenities and health. Understanding how green and grey infrastructure investments are distributed across urban areas is important for new goals of promoting environmental justice in planning. In California, for instance, public investments increasingly require a percentage of funds to be spent in disadvantaged communities. Recent advancements in the availability of high-detail geographic data in cities can support prioritising investments to fulfil these multiple benefits. This paper analyses the distribution of stormwater infrastructure in Los Angeles (LA) County in relation to design criteria, urban structure and sociodemographic information. It demonstrates an approach for identifying projects that simultaneously address engineering needs and promote equity. Statistical analysis of high-detail sewer locations reveals geographic correlations with key local design parameters, urban characteristics and sociodemographic indicators. Watershed areas in LA County were identified that support multi-benefit projects, meeting dual criteria for infrastructure improvements and disadvantaged community status. As stormwater systems are increasingly designed for multi-benefit outcomes, new design frameworks can emphasise both performance and social equity.