Baseline 2020: Water


 

Source and Assumptions

The Utah Division of Water Resources works with local water districts, municipalities, and other local entities to meet the water needs of the public. Water supply and demand projections are prepared by the Utah Division of Water Resources utilizing the Wasatch Front Water Demand/Supply Model. The Division also prepares the State Water Plan which directs the orderly and timely planning, conservation, development, protection and preservation of Utah's water resources. The projections of water supply and use prepared by the Division of Water Resources, in consultation with local water entities, inform decisions regarding water infrastructure and new water development. The fundamental logic of the modeling process used to makes these projections corresponds to the following general points. These points are followed by the main assumptions.

    Logic

  • A GIS modeling approach formulates individual demand estimates for water use and water supply within each service zone of a water service entity. There are 66 water service entities in the four metropolitan counties.
  • Residential demand for water is a function of persons per household, lot size, assessed value of the property, soil type, and season of the year.
  • Industrial and commercial demands are calculated as a function of employment by industry for both summer and winter months.
  • The water supply is provided by a single source such as individual wells and is allocated by a least cost method.
  • Both water supply and demand are modified for climatic conditions such as low rain and high temperatures. The model allocates supplies until all demands are satisfied and deficits are quantified.
  • The number of persons per household, conservation measures such as low flow plumbing and xeriscaping, water prices, and the number of multiple family residences are all inputs to the modeling process.

     Assumptions

  • All existing developed water supplies will continue to be available
  • Municipal and industrial supplies will be shared by all users in the Greater Wasatch Area without regard to current distribution networks and water rights
  • The Central Utah Project will be completed as now envisioned.
  • Additional groundwater will be developed
  • Considerable infrastructure development including water treatment plants and distribution systems will be developed.
  • New secondary systems in Davis, Weber, and Utah County will convert agricultural water to secondary use as agricultural land becomes urbanized.
  • Bear River water will be developed in some form
  • Conservation will reduce water demand by 12.5 percent by 2020 based on low flow plumbing, a gradual increase in xeriscaping by the new residential population, and price increases. None of these changes are considered to be major changes in human behavior, but rather a continuation of current trends.
  • The cost of most major water infrastructure developments in the State Division of Water Resources, water district, and large municipality plans have been included.

 

Characteristics and Trends

Water demand in the Greater Wasatch Area increases steadily from 699 thousand acre feet in 1995 to 954 thousand acre feet in 2020. Water supply increases in step quantities as new sources are developed. The supply of water in the Greater Wasatch Area increases from 853 thousand acre feet in 1995 to 1.04 million in 2020. The supply each year is sufficient to meet new demand, although for this to happen per capita consumption must decline and the price per gallon must increase. Per capita use is expected to decline from 319 gallons of culinary water per day in 1995 to 279 gallons of culinary water per day in 2020. Moreover, in order for supply to be sufficient, water providers with excess water must sell water to those with a supply problem. Water suppliers must build distribution systems to move the water from one provider to another.

 
Major Issues and Findings

The anticipated water supply and demand conditions in the Greater Wasatch Area introduce several major issues and findings that are relevant to the understanding of the baseline and the development of alternative scenarios. These include the following:

  • Water is not a constraint to growth in the Greater Wasatch Area through 2020. However, water will need to be shared across jurisdictional and legal lines and additional distribution systems will need to be built.
  • New sources of supply include development of additional groundwater supplies and expansion of water treatment plants to use more mountain stream water in Salt Lake County, irrigation conversion, treatment of Utah Lake/Jordan River water, and Bear River development.
  • Residents are expected to decrease per capita water consumption by 12.5 percent through 2020 and 25 percent through 2050. These conservation gains are based on a continuation of existing trends in the use of low flow plumbing, xeriscaping, and price increases and do not include major changes in human behavior.
  • Water rates are projected to continue to increase through 2020. Salt Lake City just announced a 50 percent increase in their water rates by 2002. Inflation adjusted water rates in Baseline 2020 are projected to increase by a similar amount in the Greater Wasatch Area through 2020.
  • The most significant water issue is the cost of paying for future new water infrastructure and water development. These costs are expected to be higher because of an aging delivery system in many areas that needs to be replaced, environmental and health regulations, less federal government financial assistance, and the costliness of the next new sources of supply.
  • Water infrastructure development is projected to cost more than $3.1 billion between 1995 and 2020 (current 1997 dollars). This equates to approximately $1,200 per person and $3,300 per household.(8) 

 

 

Footnotes

8. The $3.2 billion total is based on the long range plans of the 6 largest local water agencies in the region and Utah Division of Water Resources's share of the Bear River Project. Dozens of projects are identified in these plans. While the Bear River Project may ultimately cost several hundred million dollars, only that part of the project to be completed prior to 2020 has been included in the cost estimate. The projects range in size from a $400,000 drinking water upgrade to $220 million for Salt Lake County Water Conservancy District's share of the Bear River Project. In addition, the U.S. Environmental Protection Agency conducts a survey of all the drinking water systems in the nation. That survey identified $847 million of drinking water infrastructure needs in the Wasatch Mountain Area. Of that $847 million, it is estimated that $632 million has been programmed by the water agencies. Thus, it is estimated $215 million of drinking water projects are being planned outside the list developed from the six agencies and Utah Division of Water Resources. 

 

 

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