GaugingUrban Growth BoundaryEffectiveness in King County

By Gabe Thum

CEE 498 E GIS for Civil Engineers

What is an Urban GrowthBoundary (UGB)?

Regional Boundary used to designate where growth is intended to take place Inside the UGB: High density urban

growth Outside the UGB: Low density rural,

agricultural, wilderness, or open space

Established by local, regional, or state governmentIn King County, established in 1995

Why use an Urban Growth Boundary?

Efficient use of landMaximize infrastructure investments

Water Electric Transportation

Preserve existing farmland or wildernessControl growth / Prevent sprawl

Strategies used in the analysis

Using Residential Building Permits, 1991 – 2002, database of housing types

Multi-Family(apartments, condos, ect.) Single Family(classic suburban home)

Distinguishing which building permits fell within the UGB vs. building permits which fell outside of the UGB

GIS

Strategies

Determining the number of housing units per building permit (for MF only)Statistical analysis One-sided T-test Comparing levels of housing units,

before and after UGB implementation

Expected Results if the UGB is Successful

An increase in MF housing units Especially inside the UGA

A decrease in SF housing units Especially outside the UGA

Results:

0

2000

4000

6000

8000

10000

Building Permits

1991 1993 1995 1997 1999 2001

Year

MF Housing Units Inside UGB

MF Building Permits

Urban Growth Boundary Enacted

-500

50100150200250300350

Building Permits

1991 1993 1995 1997 1999 2001

Year

MF Housing Units Outside UGB

MF Housing UnitsOutside UGB

Urban Growth Boundary Enacted

0

1000

2000

3000

4000

5000

6000

Building Permits

1991 1994 1997 2000

Year

SF Housing Inside UGB

SF Housing Inside UGB

Urban Growth Boundary Enacted

0

200

400

600

800

1000

Building Permits

1991 1994 1997 2000

Year

SF Housing Outside UGB

SF Housing Outside UGB

Urban Growth Boundary Enacted

Results

MF Housing Inside has IncreasedMF Housing Outside has IncreasedSF Housing Inside has Remained SteadySF Housing Outside has Decreased

Conclusions

The UGB has had an effect There has been an increase in MF

housing units More substantially inside UGB

While SF Housing inside UGB remained constant, outside it has dropped substantially