20240462 Ver 1_Polk County - B13 - Hydro Report_20240325

FEMA DETAILED STUDY
r ITL r%ATA
INFORMATION TO BE SHOWN ON PLANS
BRIDGE SURVEY & HYDRAULIC DESIGN REPORT
N. C. DEPARTMENT OF TRANSPORTATION
DIVISION OF HIGHWAYS
HYDRAULICS UNIT
RALEIGH, N. C.
State Proj. Reference No. _ _ _SF-740013_ _ WBS Project No ------ BP14_R042.3_ _ _ _ _ Proj. Station _ _ _ 13+13
County _ _ _ _ _ _ _ _POLK_ _ _ _ _ _ _ Bridge Over _ _ _ _ _ _NORTH PACOLET RIVER _ _ _ _ _ Bridge Inv. No. - _740013
SR 1128 NC 108 SR 1123
On Highway_ _ (HOWARD GAP -RD.) Between _ _ _ _ (LYNN _ RD.) (CANE BREAK RD.
--- and ----------------------------
Recommended Structure 1@30', 1@70' (24" CORED SLAB) W/2'-6" DEEP CAPS
----------------------------------------------------
-----------------
-------------------------------------------------------------------------------------------
Recommended Width of Roadway_ _ _ _ _ _ _ _ _ _ 24'-6" CLEAR_ ROADWAY _ _ _ _ _ _ _ _ _ Skew _ _ _ _ _ 90_ DEG.
Recommended Location is ,At, Existing Crossing__________________________
Latitude _ _ _ _ _ _ _ _ 35.22593 _ _ _ _ _ _ _ Longitude -82.24063
Statewide Tier ❑ Regional Tier ❑ Sub -Regional Tier
Bench Mark is _ _ _ _ _ _ _ _ _ _ _ _ BY8-47: -L- STA_ 11_+09.28, 18.02'_RT (ALUMINUM _ CAP ON _ REBAR) _
Northing - _ - _ _ 552752.60 _ Easting _ _ _ 1032465.28 _ _ Elev. _ _ _ 921.45_ _ _ft. Datum: _ _ _ _ NAVD88
-------- ------
Temporary Crossing ______________________NONE=OFF-SITE DETOUR - -PROVIDED ---------------------------------------------
Designed b BEN HENEGAR, PE
g Y ----
------------
lus
Assisted by: _ _ _ RUSTY LASSITER, CODA BRANNAN, El
ENGINEERS
-'
�►�~`�H�CAROZ'i,.,
�a a� . • if,�:, Da------te 02-16-2024
. �FESS�� 9,
Q DocuSigned by:
= SEAL _( lit�AtMtl7t �, �t 17t t �AV
1fD7B6AA8B40FF437
044158 f �
�✓,F,(,� I NE��Oy� 2/16/2024 1 12: 50 PM EST
/�j�ii►ro`�`!,? QA Review bY------------------------------------
Date-------------
Drainage Area _ _ _ _ _ _ _ - _ 19.5 SQ ---------- Source ------ MI USGS-STREAM_ _STATS; USGS _QUAD
-----------
River Basin BROAD Character RURAL; BLUE RIDGE
Stream Classification (Such as Trout, High Quality Water, etc.) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _C,_Tr_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Data on Existing Structure _ _ _ _ _ _ _ _ _ _ _ 1927'-8",_1-941'-6",_TIMB--ER--
DECK ON STEEL I -BEAMS;
-----------------------------------
Waterway Opening
O. Al. =69.2-----------------------------------------------------
Total---- 454---- s.f.
Waterway Opening
Debris Potential: Low _ _ _ _ _Moderate _ _ X _ _High. _ _ _ _ Below 100yr. WS EL. _ _ _ _ - - - _ _ _ _s.f.
Data on Structures Up and Down Stream ______________________________________________________
U/S STRUCTURE: 1.0 MI. U/S ON US 176, NCDOT STR. #740052, 1@34'-3", 1@34'-6", 1@34'-3" RC DECK ON
RC_GIRDERS,_HT CR TO_BED=21.0',O.A.L.=103.0_____________________________________
6s STRUCTURE: 0.6 MI. DiS ON NC 108, NC -DOT- STR. �#740007, 3@40'-0" RC DECK ON RC GIRDERS
------------ HT CR_TO _BED=23.0',O.A.L.=120.0--------------------------------------------------
921.86 FEMA CORRECTED EFFECTIVE 100-YR WSEL
Design Control Elev_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ft. AT HEC-RAS RS 48744 (US TOE)
Gage Station No. _________ __________ Period of Records _______________WA
-------------------
Max. Discharge --------- WA--------- c.f.s. Date _______WA_______ Frequency ______WA
Historical Flood Information: (SEE ADDITIONAL INFORMATION
AND COMPUTATIONS) GARY CORN Period of
Date _5-18-18 Elev. _ 922 7 _ft. Est. Freq. _ 500 _yr. Source _ _ _ _ _ _ _ _ LOCAL RESIDENT
--------------------- Knowledge ---
30--yrs.
Period of
Date ------ Elev.___-__ft. Est. Freq ------- yr.Source-------------- - ___________ Knowledge ---- -__yrs.
Period of
Date ------ Elev.___-__ft.Est. Freq ------- yr.Source -------------- -_------------- Knowledge __- --- yrs.
Historical Scour Info: General _ _ _ WA_ _ _ -t. Contraction _ _ _ WA_ _ _ it. Local _ _ _ WA_ _ _ ft.
Channel Slope _ _ _ 0.0053 _ ft/ft Source - _ _ _ -USGS QUAD Normal Water Surface Elev. _ _ _ _ _ _912.0 _ _ _ _ _ ft.
EFFECTIVE MODEL /
Manning's n: Left O.B. 0.05-0.09_Channel _ 0.05 _ _ _ _ Right O.B. 0.05-0.09 Source _ _FIELD_ OBSERVATION
Flood Study /Status _ _ _ DETAILED (09-03-2008) / PANEL 0535
Flood Study 100yr. Discharge _ 4790 _c.f.s. WS Elev.: FlWith Without oodway_ _ _ 922.18_ _ ft. Floodway _ _ _ _ - - - - - _ _ _ft.
DESIGN DATA @ River Station 48781 (488)
Hydrological Method USGS SIR 2009-5158 RURAL REGRESSION EQUATIONS
--------------------------------------------------------------------------
Hydraulic Design Method HEC-RAS VER. 6.1.0, HEC-RAS PROJ. TITLE: SF-740013 NORTH PACOLET RIVER SR 1128
Floods Evaluated: Freq. Q Elev. Backwater Bridge Opening Velocity
(yr-) (c.f.$) (ft.) (ft.) (f.p.s.)
@ River Station Q10 2400 920.2 0.5 7.2
48744-------------------------------------------- -----------------
(U/S TOE) Q25 3400 920.9 0.3 5.4
-------
---- Q100--- ---- 4790--___ ---- 921.8---- --- 0.5--- ------- 4.8-------
---- Q500-------7020--------- 922.2---- --- 0.0--- ------- 6.4-------
----------- Waterway Opening Provided Below: Design W.S. Elev._ _ 554 _s.f.,100yr W.S. Elev. _ _ _619---- s.f.,Total _ _ _619_ _ _ _s.f.,
Average Channel Velocity (Design) _ _ _ _5.3_ _ _ _f.p.s. Average Overbank Velocity (Design) _ _ _ _ _ _1.5_ _ _ _ _ _f.p.s.
Computed Scour : General _ _ _ _ WA_ _ _ _ _ft. Contraction _ _ _ _ 3.3 _(OT) _ _ _ ft. Local _ _ _ _ _2.0 (OT) _ _ _ ft.
State Floodway Compliance Type _ _ _ _ _ _ _ _ _ SFC _ TYPE _B (MAX DECREASE_ OF 0.02' @_ _ RS 48744)
HYDRAULIC
DATA
DESIGN DISCHARGE
= 3400
C.F.S.
FREQUENCY OF DESIGN FLOOD
= 25
YRS.
DESIGN HIGH WATER ELEVATION
= 920.9
FT.
DRAINAGE AREA
= 19.5
SQ. MI.
BASIC DISCHARGE (Q100)
= 4790
C.F.S.
BASIC HIGH WATER ELEVATION
= 921.8
FT.
OVERTOPPING FLOOD DATA
OVERTOPPING DISCHARGE
= 2400
C.F.S.
FREQUENCY OF OVERRTOPPING FLOOD
= 10
YRS.
OVERTOPPING FLOOD ELEVATION*
= 920.2
FT
*CL @ SAG -L- STA. 16+31
WS EL. Taken @ River Station 48744 (U/S
TOE)
ADDITIONAL INFORMATION AND COMPUTATIONS
HISTORICAL FLOOD INFORMATION:
--------------------------------------------------------------------------------------------
GARY CORN, LOCAL NORTH PACOLET
------------------RESIDENT,-STATER--------------------------------------------------------------------
RIVER HAS FLOODED 5 TIMES IN THE 30 YEARS
HE'S LIVED NEXT TO THE BRIDGE. HE STATED THE
----------------------------------------------------------WATER----------------WAS------------------
HIGHEST FLOOD HE'S SEEN ON MAY 18, 2018
WHERE WATER WAS 1' FROM THE GRAVEL DRIVE AT HIS GARAGE ---------------------------------------
HYDROLOGY:
--------------------------------------------------------------------------------------------
USGS SIR 2009-5158 RURAL REGRESSION EQUATIONS, 7% REGION 1 (RIDGE &_ VALLEY /PIEDMONT)
-------------------------------------------------------------------------------------------
93% REGION 2 (BLUE DA=19.5 SQ. MI.
--------------------RIDGE-);-----------------------------------------------------------------------
0.617+0.00119 (PCT2) 0.0260 (PCT,) + 0.0246 (PCT2)
Q10 = (DA) 10 =
2,562 -> SAY 2,600 cfs; Q,o (FEMA) = 2,400 cfs
--------_-----------------------------------------
0.606+0.00118 (PCT2) 0.0273 (PCT,) + 0.0260 (PCT2)
Q = (DA) 10 =
zs
3,407 > SAY 3,400 cfs
--------------------------------------------------------------------------------------------
0.600+0.00118 (PCT2) 0.0282 (PCT,) + 0.0268 (PCT2)
Q50 = (DA) 10 =
-------_-----------------------------------------
4,031 -> SAY 4,000 cfs Q50 (FEMA)- 3,990 cfs
o.59a+o.00n9 (Pcr2)o.oz69 (Pcr,) + o.ovb (PCT2)
Q100 (DA)10_
4,766 -> SAY 4,800 cfs Q100 (FEMA) = 4,790 cfs
0.583+0.00121 (PCT2) 0.0303 (PCT,) + 0.0290 (PCT2)
Q500 = (DA) 10 =
------------------------------------------
6,403 -> SAY 6,400 cfs Q500 (FEMA)= 7,020 cfs
Q(FEMA) USED FOR DESIGN AND FEMA COMPLIANCE.
--------------------------------------------------------------------------------------------
OT SCOUR (10-YR)--------------------------------------------------------------------------------------------
CALCULATED PER HEC-18.
--------------------------------------------------------------------------------------------
CONTRACTION SCOUR (LIVE BED)
LOCAL SCOUR
-)-- -- -'-------=-----------------
Y2 =YQ=(W1)&YsY2YD
1[(Q------K---------------------------------
.43
--(-----------------))-�------
Ys=2.0(KL(KK(a) r,)---&---F-r1=--V14--(g-)t-Y-1- F
- --0.65(Y,)0 -0 --------
APPROACH XS RIVER STATION: 49176
CONTRACTED XS RIVER STATION: 48676 BR U
K, = 1 .0 Y, = 0.6'
---------------------------------------- ---------------------------------------------------
Y, =5.9' w, =63.9'
--------------------------------------------------------------------------------------------
K2=1.0 Fr,=0.9555
Q , = 2084 cfs w2 = 53.8'
---------------------------------------- ---------------------------------------------------
K 3 =1.1 V, = 4.2 ft/sec
Q2 =2391 cfs Yo=4.2'---------------
--- a=1.2'g=32.2 ft/sec2
K, = 0.69 Y2 = 7.5'
-----------------------------
Ys = 7.5'-4.2'= 3.3'