SRA / DPA Acres, Population and Housing Units

Methodology:

Census data from 1990 and 2000 was used to quantify population and housing. CAL FIRE “migrated” the data, which involved recalculating average housing density for “habitable” lands within each census block. This required an assumption that certain public lands were not typically associated with permanent residences, and they were assigned a population and housing density of zero. This included lands such as National Forests, Bureau of Land Management holdings, and California State Parks. The calculation for habitable lands was simply total census block population and housing divided by habitable acres within the block.

Estimates of acres and population/housing were generated by overlaying data layers for migrated census, county boundaries, CAL FIRE Units, State Responsibility Areas (SRA), and Direct Protection Areas (DPA). Estimates of population and housing units for SRA and DPA were generated by multiplying the census block densities by the overlapping area value. A summary table was created on the year, county, and CAL FIRE unit fields. Values were rounded to the nearest hundreds.

Inter-decade population and housing estimates for 1995 and 2005 were generated by joining the 1990 and 2000 estimates to their respective Department of Finance tables of population estimates for unincorporated areas and adjusting them by the percent of population change during the intervening period. The county unincorporated area was used as a surrogate for SRA area because SRA can only be within unincorporated areas.

Sources:

Department of Finance (see http://www.dof.ca.gov/Research/Research.php):
E-4: Table 2 Population Estimates for Cities, Counties and State, 2001-2006
E-4: Table 2 Historical City, County, and State Population Estimates, 1991-2000, with 1990 and 2000 Census Counts

Department of Forestry and Fire Protection
SRA
1995: sra96_3
2000: sra03_2
2005: sra05_2

DPA
1995: dpa96_3
2000: dpa96_3 (dpa not redrawn in 2000)
2005: dpa05_2

CDF Administrative Units
1995: embedded in sra96_3
2000: cdfadmin03_1
2005: cdfadmin05_2




Please contact Robin Marose at (916) 324-1646 or Robin.Marose@fire.ca.gov if you have any questions about this project.