3.11 Population 0610083.11 Population
Affected Environment
Consistent with Growth Management Act requirements for comprehensive planning, the Washington State Office of Financial Management (OFM) prepares a 20-year population projection for
each County that has adopted a Comprehensive Plan under the Growth Management Act, including Thurston County. Within Thurston County, the Thurston Regional Planning Council reviews the
OFM population projection for the entire County, and then projects population growth for each City and its associated Urban Growth Area, unincorporated Urban Growth Areas, and unincorporated
areas within Thurston County. This population allocation is utilized by each jurisdiction in its comprehensive planning process and by the County in establishing appropriately sized
urban growth areas.
The City of Yelm Comprehensive Plan was reviewed for consistency with the Growth Management Act in 2006. Several updates were adopted at that time, including updated population projections.
At that time, however, the most recent population projections available from the Thurston Regional Planning Council had been prepared in 2005 (see Table 3.8.11-1).
Table 3.11-1. Population projections for the City of Yelm and its UGA: 2005 (TRPC).
2005
2026
2030
Projected Population
5,590
10,560
11,480
Dwelling units needed to serve population
2,719
3,239
The Yelm Comprehensive Plan adopted these projections, but noted that the development of Tahoma Terra and Thurston Highlands would likely affect the official population forecasts in
the future.
The most recent population projections for Yelm and its Urban Growth Area were adopted by the Thurston Regional Planning Council in October of 2007 as part of the Buildable Lands Report
for Thurston County (TRPC 2002 and updates). These projections are reported in Table 3.11-2.
Table 3.11-2. Revised population projections for the City of Yelm and its UGA: October 2007 (TRPC).
2010
2015
2020
2025
2030
Projected Population
8,380
12,090
15,660
18,600
22,230
Dwelling units needed to serve population
3,500
5,120
6,990
8,640
10,670
The October 2007 projections, based on comparisons with other small cities in which Master Planned Communities have developed, project that the Thurston Highlands Master Planned Community
will be two-thirds built-out in 2030. This is a more conservative estimate than the City is using for its planning purposes, which assumes full build-out of Thurston Highlands by 2030.
Potential Construction Impacts
The physical impacts associated with constructing the Thurston Highlands Master Planned Community to serve the projected resident population are described throughout Chapter 3 of this
Draft EIS in relation to each element of the environment.
Developed Condition Impacts
For the purpose of the impact analysis, the full build-out population of each conceptual land use alternative was calculated using household sizes based on the 2006 Population Worksheet
for City of Yelm published by the Washington State Office of Financial Management (OFM), and the conservative assumption that household size would remain constant over the 10- to 30-year
build-out of the project.
Table 3.11-3. Population projections per household, by dwelling unit type (OFM).
Single-Family Dwellings (SFD)
2.912938
Duplexes
3.137255
Multi-family (3 and 4 units per building)
1.747368
Multi-family (5+ units per building)
1.280193
The build-out population and housing unit projections for each of the conceptual land use alternatives analyzed in this Draft EIS are presented in Table 3.11-4.
Table 3.11-4. Thurston Highlands build-out population and dwelling unit projections for the conceptual land use alternatives.
Projected
Population at build-out
SFD
Duplexes
Multi-family
(3 and 4 units/bldg)
Multi-family
(5+ units/bldg)
Total Housing
units
Preferred Alternative
12,548
3,000
546
509
945
5,000
Traditional Development
13,859
4,000
400
400
200
5,000
Urban Village
10,998
1,000
1,240
1,420
1,340
5,000
As the Thurston Highlands Master Planned Community has been included in the City of Yelm Comprehensive Plan, and has been considered as part of the City’s population projections, development
of this project over time will not significantly alter anticipated population growth within the City of Yelm or its UGA.
The difference in impact on population growth between the conceptual land use alternatives is relatively insignificant in relation to the City’s total projected population in the year
2030.
Possible Mitigation Measures
Because no adverse impacts to anticipated population growth are anticipated, no mitigation measures for such impacts have been identified.
Significant Unavoidable Adverse Impacts
From a City planning perspective, no significant unavoidable adverse impacts to population growth within the City of Yelm and its UGA would be anticipated.