Population Projections

State of Utah population projections hit the mark

LeRoy W. Hooton, Jr.

December 4, 2002

Population projections play an important role in planning for the future. These projections provide information for numerous state and local policy and decision makers to prepare and meet the demands of growth.  This is especially true in planning for public utilities. Developing capital improvement construction programs for both water and sewer facilities depend on solid population projections. If growth is not anticipated and the necessary facilities are not in place in a timely manner, communities could be faced with either building moratoriums or shortages, or both.

In some cases, failure to meet federal and state regulations result from poor planning and delays in the construction of new facilities.  This more often happens when sewage treatment facilities are not on line ahead of the growth curve. Overloaded treatment plants can lead to violation of federal Clean Water Act standards. The lead time to plan, finance and construct new capacity can take years.

So how did the population projections used in Salt Lake City Department of Public Utilities’ (DPU) long-range master planning and capital improvements program actually turned out? Did the projections come close to the prognostications?

DPU’s 1976 water master plan was based on population projections provided by the State Planning Coordinator’s Office.  Prepared by The Pitometer Associates Engineers of New York, N.Y., the master plan provided for the construction of over $26 million (1975 dollars) in water distribution system improvements. State population projections were estimated to be 1.8 million people by the year 1990. According to 1990 census figures, the actual population was 1,722,850, or only 4.3 percent below the projection. The population projection for the urban areas of Salt Lake County was 750,000. Census figures for 1990 showed 725,956, only missing the projection by 3.2 percent.

The population projections for 1970 – 90 were near perfect, but how did they match 1980 – 2000?  In 1980, the State Planning Coordinator’s Office projected that the state’s population in the year 2000 would reach 2,274,000. Population figures from the 2000 census counted 2,233,169, missing the projected figure by a scant 1.8 percent. EPA’s projection of 1,688,000 didn’t do as well, at 24 percent below their projected figure.

In 1997, DPU completed its next master plan for water system improvements. Prepared by CH2M Hill, the Plan addresses future water demand, transmission, distribution and storage needs for the Salt Lake City water service area to the year 2025. Population projections for the city’s service area are expected to increase from 332,581 in 1995 to 432,026 in the year 2025.  Based on these population projections, DPU entered into an agreement with Sandy City and the Metropolitan Water District of Salt Lake and Sandy to construct over $200 million (2000 dollars) in water treatment and conveyance facilities to provide reliable water deliveries during the planning period. Besides providing a means of utilizing 20,000 acre-feet of petitioned water from the Bonneville Unit of the Central Utah Project, the new facilities will provide redundancy and treatment technology capable of meeting future water quality standards. Furthermore, the facilities will be the centerpiece of coordinated water deliveries to other water entities in Salt Lake and Utah Counties.

The most recent  planning effort has been spearheaded by Envision Utah. Focusing on the Greater Wasatch Front, a million more residents will live in this fast growing area of Utah.  This area, bounded by Brigham City to Nephi and Kamas to Grantsville, will experience the brunt of Utah’s growth during the next 20 years. Established in 1997, Envision Utah was formed to develop a quality growth strategy.

The Governor’s Office of Planning and Budget is projecting the state’s population in 2025 will increase to 3,428,230.  If these population projections are as accurate as those provided in the past, policy and decision makers will have the tools necessary to efficiently plan and construct the necessary infrastructure to serve this growth.