HomeMy WebLinkAboutFDP201800022 Study 2018-08-10100-YEAR FLOOD ELEVATION STUDY
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TR-55 HYDROGRAPH FOR PEAK FLOW
KEYS ACADEMY
TMP 76-12E
ALBEMARLE COUNTY, VIRGINIA
DRAINAGE AREA MAP
• PROJECT NARRATIVE
SCALE: 1 "=2000'
THE OWNER OF THE KEYS ACADEMY BUILDING AT 302D FONTAINE AVENUE EXTENDED IN ALBEMARLE COUNTY, VA IS
PROPOSING TO EXPAND THE CURRENT USE OF THE BUILDING TD USE THE LOWER LEVEL FOR CLASSROOMS. HOWEVER, THERE
IS A ZONE A FLOOD ZONE LOCATED ON THE PROPERTY AS SHOWN ON FEMA MAP 510D3CO269D, EFFECTIVE DATE 2/4/2003.
IN ORDER TO DETERMINE THE 100-YEAR WATER SURFACE ELEVATION ON THE PROPERTY, THE FOLLOWING PROCEDURE WAS
USED IN ACCORDANCE WITH 7HE FEMA GUIDANCE ON DETERMINING BFES IN ZONE A AREAS.
FIRST, SSS METHODOLOGY WAS USED TO COMPUTE THE PEAK 100-YEAR FLOW OF 2,030 CFS FOR THE 1,977-ACRE DRAINAGE
AREA FLOVANG TO THE DOWNSTREAM TRIPLE 8'W X TO'H BOX CULVERTS THAT CONVEY RUNOFF UNDER THE ROUTE 29/250
BYPASS, 1HEN, THE HEADWATER WAS COMPUTED AT THE TRIPE BOX CULVERTS FOR INLET CONTROL WHICH iS THE
CONTROLLING FLOW REGIME. BACKWATER WAS ASSUMED TO STEP UPSTREAM AT THE SAME SLOPE AS THE STREAM CHANNEE,
THE 1GO-YEAR WATER SURFACE ELEVATION AT THE KEYS ACADEMY BUILDING LOCATED 2E0' UPSTREAM WAS COMPUTED TO BE
435.3.
ITHE ELEVATION IN THE ADJACENT STREAM CHANNEL AT THE KEYS ACADEMY BUILDING WAS CHECKED USING THE MANNING'S
FORMULA TO ENSURE 7HE CONTROLLING ELEVATION WAS DERIVED FROM THE CULVERT HEADWATER ELEVATION.
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owner:
FONTAINE LAND TRUST
PO BOB 8147
CHARI,OTTESVILLE,VA 229U
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871 Justin Drive
Palmym'VA 22963
434.242.Z&"
m1Ke 30MMIO.CM
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. No.
840-2018
sS10NAt EKG
[ sheet if W.
i 100-YEAR
FLOOD
ELEVATION
SIdd DY
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Of 1
date: 08/10/2018