Population Projections at the District · Methodology Overview • GIS-based small area population estimates and projections • Uses 2010 U.S. Census population cohort at the tract

Population Projections at the District

Corey C. Denninger, GISP

Senior GIS Analyst

Objectives

• History of Population Projections at the District

• Methodology Overview

• Deliverables

• Data usage

• Examples

History of Population Projections at the District

• Pre-2005 methodology = ‘Percent Shares’

– Calculate area of county

– Calculate area of utility (if known)

– Calculate utility area percentage of county

– Apply utility percentage to BEBR county-

wide projection

History of Population Projections at the District

• Example:

– County total area = 100,000 acres

– Utility X total area = 30,000 acres

– Utility X area percent of county = 30%

– BEBR 2030 population projection = 400,000

– Utility X 2030 population projection =

120,000

History of Population Projections at the District

• Issues with this methodology?– Does not consider numerous factors:

• Only at the county level (and some munis)

• Build-Out/Densities

• Conservation areas

• Future Land Use

• Existing Land Use

• Distance to roads

• DRIs/PUDs

• Historic Census Data

• Other boundary constraints (e.g. political)

History of Population Projections at the District

• District RFP in 2000

• Enters into contract with Ayers shortly

thereafter

• Issue, cause District to terminate the

contract in 2003

• District RFP in 2003, approved GISA

• First District-wide deliverables in

2006/2007

Methodology Overview

• GIS-based small area population estimates and projections

• Uses 2010 U.S. Census population cohort at the tract level as

starting point

• Calculates growth trends at the Census tract level

• Historic densities applied to appropriate land uses types

• Spatially distributes (or ‘disaggregates’) to the parcel-level

• Normalizes to BEBR (Bureau of Economic and Business Research)

county-level population estimates and projections

• Constrained by build-out estimates

Methodology Overview• Model considers

– Growth Drivers:

• Distance to roads

• Existing infrastructure

• Interchanges

• Commercial Land

• Waters

• Large developments (DRIs, PUDs)

– Future land use

– Existing land use

– Wetlands

– Conservation areas

– Historic Growth Trends

– Countywide Build-out

– U.S. Census data (including tract persons per household (pph))

– SWFMWD seasonal methodology

Methodology Overview

• Estimates previous year pop and projects future pop every 5 years to 2040

• Population Cohorts included:– Permanent (POP14)

– Peak Seasonal (POP14_P)

– Functionalized Seasonal (PERMSEAS14)

– Functionalized Tourist (POP14_T)

– Functionalized Net Commuter (POP14_NC)

– Total Functionalized* (TOTFUNC_14)

* PERMSEASyy + POPyy_T + positive POPyy_NC

Methodology Overview

• District model inputs:

– PS_SERVICEAREAS layer (annually)

– Lodging Facilities layer (annually)

– FLU layers District-wide (annually)

– Projections of Lodging Rooms - tabular (annually)

– Census Variables layer (decennial - once every 10 years)

Deliverables

• 18 feature classes and 1 Excel table

– 1 PS_SERVICEAREAS population fc

– 16 parcel-based countywide population fc’s

– 1 parcel-based Lee county population for areas permitted by

SWFWMD

– 1 Excel file with county and public supply service areas

summarized in tabular format (including DSS or non-served

areas)

– 2 pdf documents: Methodology and Updates

Data Usage

• Water Supply Planning & Forecasting

• Water Use Permitting

• Percent Shares (various jurisdictions)

• Total Pop (Finance Bureau)

• Potential Population Impacts (flooding due to storms or dam breeches)

• Total pop and demographics (COM)

• External requests

• Other ad-hoc

Examples

• Feature classes (poly’s and points)

• PSSA Population tables

• Percent Shares

One Parcel Example

Thank you!

Questions?

http://www.swfwmd.state.fl.us/data/demographics/

Credits:

• GIS Associates, Inc.,

• Bureau of Economic and Business Research

• U.S. Census Bureau