Integrating Water and Land Management: A Suburban Case Study and Locally Adaptable Tool

Managing the impacts of development on water resources is an urgent challenge in California. To support more efficient growth with fewer environmental impacts, the California Legislature and governor have adopted policies to better integrate land use and resource management. The Land Use Planning and Management Resource Management Strategy (RMS) located within California’s 2009 Water Plan Update calls for Low Impact Development (LID) and Leadership in Energy and Environmental Design (LEED) development approaches to reduce land use impacts on water resources. These strategies are suggested to decrease indoor/outdoor or residential water consumption, improve the quality of stormwater runoff, decrease the quantity and flow rates of stormwater runoff, and protect downstream riparian habitat.

The 2009 RMS set in motion a study to quantify costs and benefits associated with water-smart land use practices. Following this 2009 initiative, the charter for the RMS in the 2013 California Water Plan Update proposed a land use decision tool and demonstration of its application through pilot projects. For the first time since 1957, the Water Plan will also include a land use objective linked to corresponding actions.

Consistent with this approach, the California Department of Water Resources partnered with Sonoma State University’s (SSU) Center for Sustainable Communities and conducted four case studies of suburban development in Sonoma County. An “Integrated Water and Land Management Tool” was also designed and built as part of this project.

This tool may be downloaded free of charge at the website for the California Water Plan Update 2013. < http://www.waterplan.water.ca.gov/cwpu2013/index.cfm > Then navigate to Volume 4.

Although existing tools are available to guide practitioners, those that are easy to use generally could not be modified to reflect local conditions. And calculators that could be modified possessed challenging user interfaces that required extensive background knowledge. Thus, the project team determined that a user-friendly calculator with the ability to customize and save local data would be a valuable asset. The case studies were then compared and contrasted using the new tool. This allowed users to specify different residential land cover and infrastructure choices and compare development outcomes, especially at the lot and neighborhood levels.

Guiding principles for the study and creation of the tool were to:

• Create an open, locally modifiable, and user-friendly tool to help guide land use and land cover decisions
• Quantify relationships between land use alternatives and key water management benefits relating to water supply reliability, flood management, water quality, habitat value, and greenhouse gas emissions • Quantify the monetary costs of implementing LID and traditional development strategies, including long-term costs
• Compare and contrast outputs from different development approaches, as exemplified in four case study sites

This report, “Integrating Water and Land Management: A Suburban Case Study and Locally Adaptable Tool”, proceeds in two major parts: developing the tool, and then applying the tool to four residential developments in Sonoma County, California, as a proof of concept. While preliminary conclusions are made from the analysis of the case studies, the primary contribution of this research effort is a new, open-source Integrated Water and Land Management Tool, which will further grow and develop over time as additional case studies and applications are completed.