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t~e lO-year a~G lOO-year floods. ~~is ~l=~ere~ce Goes not have a variat~or. grea~er than ~na~ i~d~ca~ed i~ t~e followir.g table fc~ ~ore tha~ 2C ?erce~~ o~ ~he react. Average Di=fere~ce Betwee~ 10- and lOO-year Floods Variatior: Less than 2 feet 2 to 7 feet 0.5 foot 1. 0 foot Eight reaches meeting the above criter~a were ~e~~ired for t~e =looding sources in the City of Lo~gno~t. 7~ese included two reaches for Dry Creek, one reach fer Le=t Hand Creek, three reaches for S?ring Gulch: a~d two reaches for the St. Vrain Creek. The locations of the reaches are shown files. ,....~ \....1-';' the :=lood ?ro- 5.2 Flood Hazard Factors The Flood Hazard ?actor (FH?) is the Federal Lcerge~cy Manageme~t Age~cy device ~sed to correlate flo8d ~,-=8r~a~~c~ with insurance rate tables. Correlations betwee~ p~ope~t7 da~age froe ~loods and t~eir FHF are used ~o set act~arial insura~ce ?reLiun rate tables based o~ ~3~s =ron 005 t8 200. The FHF for a reach lS the average weig~ted di=~ere~ce between the 10- and 100-year =loOQ ~a~er-s~r=ace eleva- tions expressed to the nearest o~e-half foot, and snow~ as a three-digit code. For example, if t~e difference betwee~ water-surface elevations of the lJ- and lOC- year flood is 0.7 foot, the PEF is 005: if t~e difference is 1.4 =eet, t~e FEF is 015: if the diffe~e~ce is 5.0 feet, the FHF is 050. Whe~ ~he di=fere~ce betwee~ ~he 10- and 100-year water-surface elevatio~s is greater tha~ 10.0 =eet, accuracy for the F?F is to t~e ~ea~est foot. 5.3 Flood Insurance Zones After the deter~inatic~ 0= reaches and their respective Flood Hazard Factors, the er.tire incor?orated and Pri~e Crbanizec A~eas 0= the C~ty of ~ong~on~ we~e divided into zones, each having a s?ecific =lood potential and hazard. Eac~ zone was assig~ed one of the followi~g =lood insura~ce zo~e designations: Zone AO: Special flood hazard areas inu~- dated by types 0= shallow flood- ing where depths are between 1.0 26