What is this tool intended for?

WEST is intended to support decision-making in water supply planning by quantifying environmental impacts. It provides insights into the energy consumption and emissions associated with different water supply alternatives, helping utilities and planners make informed choices that minimize environmental burdens. The tool is particularly useful in regions facing water scarcity, where alternative sources such as desalination and water recycling need to be evaluated in terms of their sustainability.

How does this tool work?

WEST employs a life cycle assessment methodology to analyze the full environmental footprint of water supply systems. It quantifies material and energy inputs as well as emissions across different life-cycle stages, including material extraction, infrastructure construction, system operation, and maintenance. The tool integrates process-based LCA for assessing system-specific impacts and EIO-LCA for evaluating upstream material production effects. It considers three main water supply phases: supply, treatment, and distribution, and accounts for key environmental indicators such as greenhouse gas emissions, nitrogen oxides (NOx), sulfur oxides (SOx), particulate matter, and volatile organic compounds. Users input data related to the water system, including materials used, construction details, and operational parameters, which are then processed to generate environmental impact assessments.

Who might use this tool and with which types of stakeholders?

WEST is primarily used by water utilities, municipal and regional water planners, and policy-makers involved in water supply decision-making. It is also relevant for environmental consultants, researchers, and regulatory agencies assessing the sustainability of water management strategies. The tool can help utilities compare the environmental trade-offs between importing water, desalination, and recycling, providing a valuable resource for long-term infrastructure planning.

What stages of a process can this tool support?

The tool supports early-stage planning and evaluation of water supply options, helping decision-makers assess the sustainability of different alternatives before committing to infrastructure investments. It is particularly useful for policy formulation, regulatory planning, and impact assessments that require a holistic understanding of the environmental implications of water management decisions.

What skills, capabilities, and resources are required to use this tool?

Users need a basic understanding of life cycle assessment principles and water supply systems to effectively interpret the tool’s results. Familiarity with environmental data analysis and Microsoft Excel is beneficial, as the tool operates in an Excel-based environment. Access to detailed system data, including energy consumption, material use, and operational parameters, is necessary for accurate assessments.

Where can this tool be used?

WEST is applicable in various contexts, including urban and regional water supply planning, water resource management, and infrastructure development. It has been used in California and can be applied to other regions facing water scarcity and evaluating alternative water supply options.

Case examples of where this tool has been used

WEST has been applied in two case studies in California: Marin Municipal Water District (MMWD) in Northern California and Oceanside Water Department (OWD) in Southern California. The analyses compared the environmental impacts of importing water, desalination, and recycling. The results showed that desalination had significantly higher energy demands and emissions compared to the other options, with energy consumption in the treatment phase being the dominant factor. The findings highlighted that water recycling, where feasible, is often a more environmentally sustainable alternative to desalination.