2030 Growth Forecasts for Employment, Housing, and Transportation Analysis Zones (TAZ) for Spokane County
Draft Demographic Information provided by Intermountain Demographics
Purpose
The purpose of this analysis is to independently forecast population, housing units, and employment for Spokane County and to allocate changes in those variables to smaller areas in the valley known as traffic analysis zones.
Major Findings
Using an independent population forecasting technique, Intermountain Demographics (IMD) predicted that Spokane County’s population will increase from 441,600 persons in 2005 to more than 563,700 by 2030. All of Spokane County is forecast to increase by more than 122,000 residents, a gain of more than 22 percent.
Intermountain Demographics population forecast of 563,767 for 2030 compares favorably with the 2029 population forecast of 562,877 prepared by the AVISTA Corporation. The two population forecasts were prepared using different methodologies.
Forecasts prepared by The State of Washington’s Office of Financial Management (OFM) show that Spokane County’s population will reach 561,627 by 2025 in the intermediate series forecast, a population forecast consistent with IMD and the AVISTA Corporation. The OFM high series population forecast for Spokane County in 2025 is 657,946 persons and is about 95,000 persons higher than the AVISTA forecast for 2029 and the IMD and forecast for 2030. That 95,000 person population gain is in addition to the 122,000 population gain forecast by IMD for 2030. The difference of 95,000 persons between the two forecasts is larger than Spokane Valley’s current population of about 85,000 residents.
The number of housing units in the entire county will reach more than 240,600 units, a gain of more than 53,000 units over the same time period.
Spokane County employment will increase by about 90,000 employees and reach a total of more than 339,000 employees by 2030.
Areas experiencing major future residential growth are on the eastern, western, and northern edges of the existing urbanized area, particularly the Liberty Lake area, the Airway Heights/West Plains area, and the northern portion of the North South Corridor.
More than 1,000 housing units at Fairchild Air Force Base are removed from the forecasts as the Air Force will no longer provide on-base housing in the future. However, employment at the Air Force Base is forecast to increase by 2,000 employees during the forecast period.
Other areas gaining significant shares of future employment include Airway Heights/West Plains, the northern portion of the North South Corridor, and the traffic zones north of Liberty Lake.
Conclusion
Forecasts prepared in this analysis are used for transportation planning and travel forecasting. The forecasts also may be used for other public sector facility planning (water, wastewater, and parks) and public service planning (police, fire, and emergency services). These forecasts also affect economic development as the private sector may use this information in determining future demand for goods and services and for locating or expanding retail and service establishments.
Methodology
Population forecasts for Spokane County are prepared by using the cohort-survival population forecasting technique, which factors in births, mortalities and migration information to produce population projections. In the cohort-survival methodology, the base year (2000) population is divided into 5-year age groups and forecast into the future. Each 5-year age group is factored by its mortality rate and placed into the next oldest age group over a 5-year time frame. (For instance, number of persons in the 25 to 29 year old age group in 2005 is factored by a mortality rate and is aged into the 30 to 34-year-old age group in 2010.) That process is repeated for each age group for each 5-year time period from 2000 to 2030. Births occurring in the under five year old age group are based on the number of births in Spokane County and age data provided by the Census Bureau. Mortality rates for each age group also are derived from Spokane County mortality information.
The number of persons moving to Spokane County for each age group is determined from the Census Bureau’s 2000 population count and its 2004 county population estimate. The number of persons migrating to Spokane County in that time period is extrapolated to 2005 and adjusted for the age of persons moving to the county. The 2000 to 2005 level of in-migration to Spokane County is assumed to occur for each 5-year time frame from 2000 through 2030.
Housing unit forecasts are calculated on population projections and are adjusted for factors such as vacancy rates and family size.
Long-range countywide employment forecasts are produced for each employment sector of the economy based on a combination of short and long- term historical trends and on national forecasts for various industries.
The allocation of housing units and employment from the county level of geography to the more than 400 traffic zones in the county is based on factors including interviews with persons familiar with past and current development trends, existing development proposals, Spokane Regional Transportation Council’s (SRTC) building permit history file, Spokane County’s Land Quantity Analysis, local comprehensive plans and development policies, a “windshield” survey of the county, and Spokane Valley’s traffic zone allocation.
INTERVIEWS & DATA SOURCES
Representatives from the following agencies were interviewed in preparing this analysis:
AVISTA Corporation
The City of Spokane Planning Services
The City of Spokane Valley
Spokane County Development Services
SRTC Transportation Technical Committee
Spokane Transit
Washington State Department of Transportation
Data sources for the analysis include the following:
Bureau of Economic Analysis Regional Information System
City of Spokane Comprehensive Plan/Environmental Impact Statement
City of Spokane Valley Comprehensive Plan
City of Spokane Valley Long Plat Subdivision History
City of Spokane Valley Housing Unit and Employment Distribution by Traffic Zone
Center for Business Research and Services, Idaho State University
Office of Financial Management, Washington State County Population Projections
Policy Research Institute, University of Kansas
Population Division, U.S. Census Bureau
Real Estate Research Committee, The Real Estate Report, 2005
Spokane County Development Services Land Quantity Analysis
Spokane County Comprehensive Plan
SRTC Residential Building Permit History, 1990 – 2004
SRTC Housing Unit and Employment Inventory, 2005
Woods and Poole Economics, Spokane County Washington 2005 Data Pamphlet
Zimmerman/Volk Associates, Market Potential Study, Downtown Spokane
Links to Maps and Excel spreadsheets
Summarization
By Land Use Category
- Employment Growth Forecast for LU4: Agriculture, Forestry Mining, Industrial, Manufacturing and Wholesale
- Employment Growth Forecast for LU5: Retail Trade (Non-Central Business District)
- Employment Growth Forecast for LU6: Services and Offices
- Employment Growth Forecast for LU7: Finance, Insurance, and Real Estate Services
- Employment Growth Forecast for LU8: Medical
- Employment Growth Forecast for LU9: Retail Trade (Central Business District)
- Employment Growth Forecast for LU10: Schools
Housing Growth Forecasts
- Total Housing Unit Growth Forecast for 2030
- Total Multiple Family Housing Unit Forecast for 2030
- Total Single Family Housing Unit Forecast for 2030
Transportation Analysis Zone (TAZ) Forecast Spreadsheet