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.
- 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.
- 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
- 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)
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.