Water conservation initiatives seldom quantify the volume of water that is at stake in lawn watering. In many communities, including those in South Florida, outdoor water use, which includes lawn irrigation, is not metered separately from indoor water use and is indistinguishable from indoor water usage. A large number of residents use self supply non-potable wells for lawn irrigation that are not regulated by the South Florida Water Management District. The result is that residential lawn water use is difficult to account for and quantify. This thesis project addressed these difficulties by combining semistructured interviews, daily watering observations and irrigation system audits to ascertain how much public supply water and self supply (well) water was being used for residential lawn irrigation. The study also examined lawn watering practices and how factors such as: precipitation, the minimum plant needs of St. Augstinegrass, and how local watering restrictions influenced watering behavior.

Turfgrass lawns are widely used in residential and commercial landscapes, providing many environmental, aesthetic, and recreational benefits. However, concerns and scrutiny arise with perceived maintenance requirements, particularly with regards to irrigation. It is important to manage irrigation in order to maximize water conservation without significantly reducing lawn quality. A series of field and greenhouse studies were conducted to investigate how water usage might be reduced in irrigation practices with the following proposed objectives: 1) evaluate the use of rain and soil moisture sensors in a humid transition zone environment; 2) evaluate the effects of chronic drought stress between drought-resistant and drought-sensitive varieties of tall fescue (Festuca arundinacea Schreb.; TF) and Kentucky bluegrass (Poa pratensis L.; KBG) under field conditions; 3) investigate field performance differences between KBG varieties, varying in drought-resistance, under variable amounts of deficit irrigation; 4) evaluate the impact of irrigation frequency on the establishment of seeded cool-season turfgrasses varying in drought resistance; 5) and evaluate the impact of deficit irrigation for establishing seeded TF cultivars, varying in drought resistance, in the field. On average, rain sensors reduced irrigation by 22.5% and soil moisture sensors reduced irrigation by 66.5% with no decline in turfgrass quality with no decline in lawn quality. Environmental conditions greatly influenced the impact of chronic drought stress on TF and KBG, as intense and timely rains occurred. As a result, minimal differences in turfgrass quality or green turfgrass coverage were observed. Under prolonged, chronic drought stress, drought-resistant KBG exhibited greater coverage than drought-sensitive KBG at lower levels of deficit irrigation. During establishment, drought-resistant perennial ryegrass (Lolium perenne L.), TF, and KBG varieties irrigated every two days, exhibited similar turfgrass coverage to when irrigated daily. Intraspecific drought-resistance differences of mature TF and KBG in previous findings were not consistently observed during establishment. Tall fescue irrigated at 75% of reference evapotranspiration exhibited similar coverage as irrigation replacing 100% reference evapotranspiration, which could be a useful guideline regarding irrigation requirements for establishing TF from seed. Overall, these findings demonstrate the great potential to reduce water use in irrigation practices used in establishing and maintaining turfgrass lawns.

This compilation provides guidelines that facilitate the successful planning and operation of water reuse projects. Offering the information, analysis and proven experience for agricultural and landscape irrigation, it bridges the gap between fundamental science and relatively uncharted areas of economic, institutional and liability issues. It delivers a synthesis of information recently emerging in both science and in the practice of irrigation with reclaimed water. The book compiles guidelines, recommendations and codes of best practices from around the world for all types of recycled water uses, and it examines recent concerns about adverse effects on plants, groundwater and public health.

Climate change impacts in eastern Washington are expected to alter the timing and volume of precipitation received. These changes could have significant impacts on residential outdoor water use particularly if water supply systems are unable to meet the forecasted demand due to both declining water resources and rising climate-driven water use. Residential lawns often require relatively large volumes of water to maintain and demands have increased as green lawns have become more pervasive in residential areas as the population expands. Such increases in water demand can have severe consequences for water management in counties in eastern Washington which are relatively arid. Understanding the potential consequences of the relationship between climate change and lawn maintenance will be necessary for understanding how lawn irrigation can be more efficient in a drier future. As outdoor water use is more elastic than indoor use, residential lawn irrigation is also attractive for achieving water savings. Although lawns are widespread, the impact of climate change on consumptive use of municipal water is relatively understudied. To accomplish this, Chapter 2 details our use of VIC-CropSyst, a coupled framework consisting of a macroscale hydrologic model and agricultural model. The model output is used to explore gaps related to the potential impacts of climate change and atmospheric CO2 increases on irrigation demand on a regional scale in eastern Washington counties. In this study, we ran 17 General Circulation Models (GCMs) and future Representative Concentration Pathways (RCP) scenarios with different lawn management events to determine what likely future lawn irrigation rates will be in the face of climate change. The result shows that the need for lawn irrigation will increase and management guidance, like clipping events, and grass height maintenance could be the best practice for estimating the right amount of water with changing future climate. Chapter 3 explored the impacts of precipitation variability and watering restrictions on lawn irrigation practices in the City of Moses Lake. Results showed that households were responsive to precipitation change using more water in dry years and less in wet years and the restrictions were an effective tool for reducing outdoor water use.