Greenhouse Gas Emissions Calculator for the Water Sector: User’s Manual

The Santa Ana Watershed Basin Study (Basin Study) is a collaborative effort by the Santa Ana Watershed Project Authority (SAWPA) and the Bureau of Reclamation (Reclamation), authorized under the Sustain and Manage America’s Resources for Tomorrow SECURE Water Act (Title IX, Subtitle F of Public Law 111-11).

The Basin Study complements SAWPA’s Integrated Regional Water Management (IRWM) planning process, also known as their “One Water One Watershed” (OWOW) Plan. It refines the watershed’s water projections, and identifies potential adaptation strategies, in light of projected effects of climate change. The Climate Change Analysis for the Santa Ana River Watershed (SARW) is a contributing section to the Basin Study.

The Greenhouse Gas (GHG) Emissions Calculator was developed as a tool to support the Climate Change Analysis. It was developed to evaluate mitigation strategies, while the Climate Change Analysis focused primarily on adaption and vulnerability analysis. Development of the tool began in 2012 and was completed in August 2013.

This report explains the methods used to develop the calculator and provides instructions on how to use it by introducing examples. The examples focus on the SARW to show how to develop a GHG emissions baseline, evaluate what it would take to meet specific GHG emission reduction goals, and illustrate how the GHG Emissions Calculator can be used to analyze projects.

Chapter 1 provides an introduction to the project, a literature review, and a summary of California’s GHG legislation. The methods used in the GHG Emissions Calculator can be found in Chapter 2. A guide showing users what data is needed and how to enter that data can be found in Chapter 3. Chapter 4 provides an introduction to the SARW, the GHG emission baseline for the SARW, discusses varies scenarios to reduce GHG emissions, and compares those reduction scenarios. In Chapter 5 SAWPA’s 20 finalist for the Integrated Regional Water Management (IRWM) funding were analyzed using the GHG Emissions Calculator.

The GHG Emission Calculator is a decision-making tool that can be used to explore the links between water resources, energy, and GHG emissions. It can be used to determine water supply and energy demands for the study area, in addition to GHG emissions from 1990 to 2050. It can be used to analyze a study area ranging from a city block to an entire watershed, regardless of the level of detailed data available. The GHG Emissions calculator is a vital tool for decision makers when developing water supply plans for the future. It is also equipped to evaluate long term GHG emission reduction potential for new projects that will alter the water supply portfolio.