Water Demand Projections

 

Authors

  • Mazdak Arabi – Colorado State University
  • Jorge Ramirez – Colorado State University
  • Thomas C. Brown – USDA Forest Service

Purpose

Projections of water demand during the 21st century can be used to determine water shortage indicators such as water supply scarcity, vulnerability, reliability, and resiliency; water use per capita, water import per capita, reservoir storage, groundwater depletion under alternative future climate, population and land use scenarios. It showed that, in the absence of adaptation, serious water shortages are likely in some regions of the United States. Comparison of projected demands with projected future supplies indicates where and when adaptations to changing conditions would be needed. Further improvements in water use efficiency, following established efficiency trends in various water use sectors, can significantly ameliorate impending water shortages.

A1-1_Arabi_Water_Demand_OK
Download

Description

Water demand was estimated as the net amount of water depletion (equal to withdrawal times a consumptive use factor, or essentially withdrawal minus return flow) that would occur if water supply were no more limiting than it has been in the recent past. Water demand was estimated by summing projections for six water use sectors: domestic and public; agricultural irrigation; thermoelectric; industrial, commercial and mining; livestock; and aquaculture. Data on past water use (from surface and groundwater sources) came from the quinquennial USGS water use circulars for years 1960 to 2010 and for thermoelectric use from Diehl and Harris [2014]. Future water withdrawals in each sector were estimated as the product of a water use driver (e.g., population, irrigated area) and a water withdrawal efficiency factor (e.g., domestic withdrawals per capita, irrigation withdrawal per unit area). Effects of climate change were then added to some of the projections: domestic and public and irrigation demands were modeled as affected by future changes in precipitation and potential evapotranspiration, and thermoelectric demand was modeled as affected by future changes in ambient temperature.

 

Climate Model Used

  • BCC-CSM1.1 (BCC)
  • CanESM2 (CAN)
  • CSIRO-Mk3.6.0 (CSIRO)
  • GFDL-ESM2M (GFDL)
  • IPSL-CM5A-LR (IPSL)
  • MIROC-ESM (MIROC)
  • MPI-ESM-LR (MPI)
css.php