Current information on the water requirements of landscape plant materials is based on observational data and limited research information. There is little research information developed on the quantitative water needs of traditional landscapes, Xeriscape plantings and those that employ the use of native and other landscape plant materials which exhibit drought tolerant characteristics. This project would determine the need for refinement of 'guestimates' and focus on the promotion of quality landscapes with reduced water applications. In addition, implementation of water conserving practices may significantly reduce green waste and runoff contributing to water quality concerns. The project directly addresses PPAC Agricultural Resources target issue #6, Urban Landscapes.

UC personnel have the expertise and are the source of current research-based information in this field in California. There are also academics in Utah, Arizona, and Nevada with similar objectives. We know the scope of complexity and the many factors involved in determining irrigation amounts required for acceptable landscape performance. However, urban landscape plants produce no marketable yield, so it is only necessary to closely estimate the minimum water a species needs to provide its intended function. Research is needed to better understand the minimum water needs of urban landscape plants and how the factors involved relate to one another so that water-conserving irrigation management strategies can be identified and disseminated. For example, we know from previous research experiments that reduced irrigation frequency and intentional water stress placed on landscape plants can drastically reduce water applications to landscapes with little or no loss in quality. Unfortunatly, this information is not currently employed in water conservation programs.

This project would not only help supply the industry with much needed information, but would give increased credibility to UC as a source of reliable and practical information for urban audiences, particularly in implementing effective landscape irrigation best management practices (BMPs). In addition, this project would be a politically correct move for UC to show that we are committed to this issue and are willing to provide a leadership role. With initial funding through the workgroup, we can initiate the project; then we feel that industry and agencies will help with additional funding and acceptance of the program into current water conservation programs.

Knowledge of plant performance under reduced irrigation has the potential to drastically reduce the amounts of landscape irrigation water applied throughout the state of California. Reduction of both green waste and water quality (runoff) problems may also be realized. Changes in the skills and attitudes of landscape irrigators should also be achieved, especially since evapotranspiration (ET) based irrigation scheduling is gaining acceptance by the industry. Through the initial phase of the project, research methodologies and characteristics of landscape plant materials will be identified, which will lead to more confidence in water use research experiments.

Phase I (Year 1):During the initial phase of the project, applicable research information will be assessed together with the needs of clientele. Contact with agencies such as water districts, the Department of Water Resources, USBR, the Irrigation Association, the California Urban Water Conservation Council (CUWCC) and industry groups has already been initiated in order to identify needs and to establish inroads into funding sources and mechanisms to get the information to clientele. A second objective is to identify research methodologies available to refine water needs, assess plant water stress and drought resistance, as well as plant performance under reduced irrigation. This would also involve contact with interested AES plant physiologists to determine if physiological processes can be identified or simplified testing of plant materials can be performed to rank or catagorize the drought tolerance of commonly utilized plant materials. Assessing the need for this information, garnering industry and agency support, and identifying research methodologies is to be completed during the first year of the project by the team of Landscape workgroup members. After assessing the available research-based information and clientele needs, it is likely that one or more educational publications and/or events will be initiated.

Phase II (Year 2+) It is anticipated that methodologies exist to perform research experiments to refine landscape water needs. During the second phase of the project, research experiments would be planned and established in 3-6 climatic regions of the state implementing the protocol developed in phase I. These field experiments, perhaps initiated at UC Research and Extension Centers, would entail an establishment period and two to three years of data collection and analyses. We anticipate that the irrigation and nursery industries will provide much of the needed irrigation equipment, supplies and plant materials.

Phase III (Year 5) At this time, publications and other means to disseminate the results and recommendations would be developed. Utilizing industry and agency support, UC personnel would extend the information to clientele.

Since the CUWCC has the responsibility and authority to monitor and certify the conservation programs of water agencies and their successes, we will work closely with CUWCC to generate data on urban landcape water use and the adoption of irrigation BMPs.