ARI Projects

The goal of this research is to develop improved methods to minimize runoff from irrigated landscapes. It is anticipated the results of this research landscape and irrigation designers as well as integrated into Best Management Practices (BMPs) for urban watersheds within California . For example the California Urban Water Conservation Council works with water purveyors to implement landscape best management practices that address address landscape water use issues. The Irrigation Association has developed a BMP's document. Their stated goal was to developed “ Turf and Landscape Irrigation Best Management Practices (BMPs) for policymakers and professionals who must save and extend our water supply while protecting water quality. The BMPs will help key stakeholders - policymakers, water purveyors, designers, installation and maintenance contractors, and consumers - to develop and implement appropriate codes and standards for effective water stewardship” ( www.irrigation.org . 2006, BMP for non-agricultural irrigation, Michigan State University, http://www.turf.msu.edu/docs/Non-g%20Irrigation%20BMP%20Oct%202005.pdf)

Runoff from urban landscapes in California has at least two areas of regulatory interest. The first is winter storm water runoff that is channeled to rivers and coastal waters. Runoff quantity, peak flows, and water quality from winter rains are important in watershed management. Urban runoff is related to infiltration; hardscapes such as roads, parking lots, and buildings decrease water infiltration resulting in more runoff. Landscape areas serve as infiltration areas and can attenuate peak flows.

A second area of regulatory interest of runoff from landscapes is runoff during the dry weather irrigation season. These surface flows, generally labeled nuisance flows, occur during the March through November irrigation season in Southern California . The quantity of runoff in an ideal world should be zero. However, the norm for most urban communities with existing landscapes is that there is significant summer runoff unto hardscapes, gutters and storm drains that ultimately degrade the quality of waters in streams, rivers and coastal waters. It is often assumed that chemical applications on landscapes and grass clipping contribute to pollution in urban runoff.

The focus of this research is the second area – dry season irrigation – runoff. With Southern California water supplies stressed, any runoff from landscape is considered a waste of this limited resource. This research will correlate the volume of runoff from narrow turf plots with two types of irrigation systems: sprinkler irrigation and surface flow irrigation.

This study would complement recent studies completed or in progress that include a residential runoff reduction study by the Municipal Water District of Orange County (MODOC), which showed a 49% reduction results in watershed runoff with the installation of ET controllers on residential sites. The city of Tustin and the Irvine Ranch Water District (2002 -03) installed a surface flow irrigation system on a large street median, which virtually eliminated runoff that had previously occurred at the same site with sprinkler irrigation.

It is anticipated this research would contribute to the ongoing development of guidelines to reduce or eliminate runoff by selection of the most appropriate sprinkler or surface flow irrigation system, and appropriate irrigation scheduling.

The investigators for this project have several related projects in landscape irrigation water management in progress.

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