Research

Water use by urban landscapes

Although outdoor water use is thought to constitute a large fraction of urban water budgets, the amount of water actually used by irrigated urban landscapes is not well quantified. Most water taken up by plants roots gets transpired through leaf pores (stomata). Evapotranspiration, the total flux from vegetated surfaces to the atmosphere, is comprised of evaporation and plant transpiration. Urban evapotranspiration is difficult to measure and model, particularly in cities with diverse plant composition.

In the United States, turf grasses cover an area larger than any cultivated crop. In arid and semiarid cities, where up to 75% of household water is spent for irrigation, turfgrass lawns may claim a substantial portion of municipal water budgets. However, water use by irrigated lawns have seldom been directly addressed in real urban environments.

In addition to turfgrass lawns, urban landscapes often contain large variety of non-native trees that originate from multiple geographic regions. Their exposure to urban environments results in transpiration patterns that are hard to predict a priori. This further complicates predictions of urban evapotranspiration.

The goal of this research is to identify key parameters and general relationships that would simplify predictions of landscape water use in urban environments.