Vacant Buildable Lands Model
Vacant Buildable Lands Model .PDF

The Vacant Buildable Lands Model (VBLM) is a planning tool developed to analyze residential, commercial, and industrial lands within urban growth areas. The model serves as a tool for evaluating urban area alternatives during Clark County 20-year Comprehensive Growth Management Plan updates and for monitoring growth patterns during interim periods. The VBLM analyzes potential residential and employment capacity of each urban growth area within the county based on vacant and underutilized land classifications. This potential capacity is used to determine the amount of urban land needed to accommodate projected population and job growth for the next 20 years during plan updates and to analyze land consumption or conversion rates on an annual basis for plan monitoring purposes.

In 1992, Clark County began evaluating vacant lands as part of the initial 20-year growth management plan. At that time, County staff met with interested parties from development and environmental communities to examine criteria and establish a methodology for computing potential land supply available for development. A methodology relying on the Clark County Assessor’s database and Geographic Information System (GIS) as primary data sources was developed. As a result the VBLM is a GIS based model built on geoprocessing scripts.

In the spring of 2000, the Board of Clark County Commissioners appointed a technical advisory committee consisting of local government agencies, Responsible Growth Forum members, and Friends of Clark County to revisit this process. They reviewed definitions for each classification of land and planning assumptions for determining potential housing units and employment.

Another comprehensive review of the VBLM criteria and assumptions was undertaken in 2006 as part of the growth management plan update. This review compared the 1996 prediction to the 2006 model. This review demonstrated that for the most part the model was a good predictor of what land would develop. However, changes were made to the model based on results of this review. Important changes to the model include:

Underutilized land determination for all models was changed to a building value per acre criteria.

The industrial model and commercial model now have consistent classifications. The industrial model was revised to match the commercial process.

Environmental constraints methodology changed from applying assumptions to parcels based on percentage of critical land to simply identifying constrained and non constrained land by parcel and applying higher deductions to constrained lands.

Example Map of Constrained Lands

Benefits of the current improvements are more consistency and easier monitoring of the model. Better accounting for private open space, constrained lands, and exempt port properties. And calculations for underutilized lands are more dynamic.

Model Classifications

The model classifies lands into three urban land use categories--residential, commercial, and industrial. Lands are grouped into land use codes based on comprehensive plan designations for model purposes. Lands designated as parks & open space. public facility, mining lands, or airport within the urban growth areas are excluded from available land calculations. Additionally, all rural and urban reserve designated lands are excluded from the model. Table 1 lists a breakdown of the land use classes.

Table 1: Land Use Classes

LU	Comprehensive Plan Classification	VLM Model
1	Urban Low Density Residential	Residential – Urban Low
1	Single-Family_Low	Residential – Urban Low
1	Single-Family_Medium	Residential – Urban Low
1	Single-Family_High	Residential – Urban Low
2	Urban Medium Density Residential	Residential – Urban High
2	Urban High Density Residential	Residential – Urban High
2	Multi-Family_Low	Residential – Urban High
2	Multi-Family_Medium	Residential – Urban High
2	Multi-Family_High	Residential – Urban High
3	Neighborhood Commercial	Commercial
3	Community Commercial	Commercial
3	General Commercial	Commercial
3	City Center	Commercial
3	Regional Center	Commercial
3	Downtown	Commercial
3	Commercial	Commercial
4	Mixed Use	Commercial
4	Town Center	Commercial
5	Office Park/Business Park	Commercial
5	Employment Center	Commercial
5	Light industrial/Business park	Commercial
5	Employment Campus	Commercial
5	Office commercial industrial	Commercial
6	Light Industrial	Industrial
6	Heavy Industrial	Industrial
6	Railroad Industrial	Industrial
6	Industrial	Industrial
33	Mixed use - Residential	Residential
34	Mixed use - Employment	Commercial

The model classifies each urban parcel as built, vacant, or underutilized by the three major land uses. Additionally lands with potential environmental concerns and/or geologic hazards as consistent with the applicable section of the Clark County and other municipal codes are classified as constrained (critical lands) lands. Constrained lands are identified by parcel in the model.

Constrained lands include:

100 year floodplain or flood fringe

wetlands inventory (NWI, high quality, permitted, modeled) with 100 foot buffer

slopes greater than 15 percent (>25% for City of Vancouver)

land slide area that has active or historically unstable slopes

200 foot shoreline buffers

hydric soils with 50 foot buffer

habitat areas with 100 foot buffer

species areas with 300 foot buffer

riparian stream buffers by Stream Type:

Type S (Shoreline) : 250 feet

Type F (Fish bearing): 200 feet

Type NP (Non-fish bearing, perennial): 100 feet

Type NS (Non-fish bearing, seasonal): 75 feet

Residential Model

Important residential classifications include vacant, vacant critical, underutilized, and underutilized critical. These classes are used to determine gross acres available for development. Vacant exempt, vacant lots less than 5,000 square feet, and all other classes are excluded from available land calculations. Table 2 lists all residential classes.

Table 2: Residential Classifications

RESCLASS	Description
0	Not Residential
1	Built
2	Unknown
3	Vacant
4	Underutilized
5	Roads and Easements
6	Mansions and Condos
12	Built Exempt
13	Vacant Exempt
14	Vacant Critical
18	Underutilized Critical
19	Less than 5,000 sqft
20	Private Openspace
21	Parks and OpenSpace

Criteria for classifying residential lands are as follows:

Residential Vacant Criteria

Building value less than $13,000

Not tax exempt

Not an easement or right of way

Not a state assessed or institutional parcel

Not a mobile home park

Parcel greater than 5,000 square feet

Underutilized

Same as Vacant except building value criteria is replaced with a building value per acre criteria.

Building value per acre of land is below the 20^th percentile of building value per acre for all residential parcels within all UGAs. The 20^th percentile is calculated by the model for each year and for each UGA alternative.

Parcel size greater than 1 acre

Mansions and Condos

Parcel size greater than 1 acre

Building value per acre greater than the 20^th percentile.

Residential Exempt

Properties with tax exempt status

Easements and right of ways

Constrained (Critical lands)

All classifications may be subdivided into constrained vs. not constrained. Constrained lands are described above.

Commercial and Industrial Models

Commercial and industrial lands are classified using consistent criteria with one exception; industrial classes include exempt port properties in the current model.

Important commercial classes for determining gross acres available for development include vacant, vacant critical, underutilized, and underutilized critical. Vacant exempt and vacant lots less than 5,000 square feet are excluded from available land calculations. Table 3 lists all commercial classes.

Table 3: Commercial Classifications

COMCLASS	Description
0	Not Commercial
1	Built
2	Vacant
3	Underutilized
5	Vacant Lot less than 5,000 sq feet
7	Vacant Critical
9	Underutilized Critical
10	Vacant Exempt

Important industrial classes for determining gross acres available for development include vacant, vacant critical, exempt vacant port property, exempt vacant port property critical, underutilized, underutilized critical, exempt underutilized port property, and exempt underutilized port property critical. All exempt not port properties are excluded in the available land calculations. Table 4 lists all industrial classes.

Table 4: Industrial Classifications

INCLASS	Description
0	Not Industrial
1	Vacant
2	Underutilized
3	Vacant Critical
4	Underutilized Critical
6	Built
7	Exempt Vacant Port Property
8	Exempt Vacant Not Port
9	Exempt Vacant Port Property Critical
10	Exempt Underutilized Port
11	Exempt Underutilized Port Critical
12	Exempt Underutilized Not Port
15	Easements

Commercial and industrial models classify vacant and underutilized land as follows:

Vacant land

Building value less than $67,500

Not “Assessed With”- Some parcels are assessed with other parcels. These parcels are often parking lots, or multiple parcels comprising a single development. All assessed with parcels are considered built.

Not Exempt.

Port property is exempt, and is included as a separate classification in the Industrial land model.

Not an Easement or right of way

Parcel greater than 5,000 square feet

Not a state assessed or institutional parcel

Underutilized Lands

Same as vacant except building value criteria is replaced with a building value per acre criteria of less than $50,000.

Constrained (Critical lands)

All classifications may be subdivided into constrained vs. not constrained. Commercial and industrial constrained lands are defined the same as residential constrained lands and are listed above.

Exempt Port Properties in the Industrial Model

Includes lands that are under port ownership and available for development. Buildable exempt port properties are included in available land calculations.

Port properties can be classified as vacant, underutilized, or constrained.

The model produces a summary of gross residential, commercial, and industrial acres available for development. Gross acres are defined as the total raw land available for development prior to any deductions for infrastructure, constrained lands, and not to convert factors.

Planning Assumptions

The next step in the buildable lands process is applying planning assumptions to the inventory of vacant and underutilized gross acres in order to arrive at a net available land supply. These assumptions account for infrastructure, reduced development on constrained land, and never to convert factors. Use factors along with employment and housing units per acre densities are applied to derived net acres to predict future capacities.

Residential Model Planning Assumptions:

27.7% deduction to account for both on and off-site infrastructure needs. 20% infrastructure deduction for mixed use lands.

Never to convert factor

10% for vacant land

30% for underutilized

50% of available constrained (critical) land will not convert

60% of mixed use land will develop as residential, 85% residential for Battle Ground mixed use - residential and 25% residential for mixed use - employment.

Commercial and Industrial Model Planning Assumptions

25% infrastructure factor applied for both commercial and industrial lands.

20% of available constrained (critical) commercial and mixed use land will not convert

50% of available constrained (critical) industrial land will not convert

40% of mixed use land will develop as commercial, 15% commercial for Battle Ground mixed use - residential and 75% commercial for mixed use - employment.

Employees and unit per acre density assumptions are applied to net developable acres to predict future employment and housing unit capacities. Densities are set by the Current Planning staff based on observed development and comprehensive plan assumptions for each UGA.

Applied residential densities vary by land use and UGA. Residential classes are grouped into urban low, urban high, and mixed use densities. Table 6 lists the range of units per acre by land use.

Table 6: Residential units per Acre

Land Use	Units per acre Range
Urban Low	4 - 5
Urban High	9 - 16
Mixed Use	4 - 18

Applied employment densities vary by land use as well. Commercial classes which includes commercial, business park, and mixed use categories apply 20 employees per acre while industrial classes apply 9 employees per acre.

Applying residential and employment planning assumptions to the VLM results produce housing units and employment carrying capacity estimates for urban growth areas. These estimates help monitor growth on an annual basis and is part of the criteria used for setting UGA boundaries during growth management plan updates.

Current model layers and reports are available for viewing in Clark County’s GIS MapsOnLine web application at http://gis.clark.wa.gov/imf/imf.jsp?site=vblm.

Underutilized land classes are grouped with vacant classes by land use in MapsOnLine and on other map products. Table 5 lists the group classes used for mapping.

Table 5: Group Classes

GRPCLASS	Description
1	Built
2	Built w/Critical
3	Residential Vacant
4	Residential Vacant w/Critical
5	Commercial Vacant
6	Commercial Vacant w/Critical
7	Industrial Vacant
8	Industrial Vacant w/Critical
9	Public Facilities
10	Public Facilities w/Critical
11	Parks and Openspace
12	Parks and Openspace w/Critical
13	Roads and Easements

For more information on the model inputs, structure and outputs, please contact Clark County Community Planning at (360) 397-2280 or Clark County Department of Assessment and GIS at (360) 397-2391.