HomeMy WebLinkAboutFDP202100001 Other 2021-03-16Albemarle County Floodplain Development Permit No.:
ENGINEERING "NO -RISE" CERTIFICATION
Community: Scottsville County: Albemarle
Applicant: Let It Go, LLC Date: 03-02-2021
Address: 724 Jefferson Mill Lane
Telephone: 434-979-8900
Engineer: David A. Krisnitski, PE
VA
Address: 1734 Seibel Drive, N.E., Roanoke, VA 24012
540.344.7939
SITE DATA
1. Location: NA /4; NA /4; Section NA ; Township NA ; Range NA
Street Address: 724 Jefferson Mill Lane, Scottsville, VA 24590
2. Panel(s) No. of NFIP map(s) affected: Lot 123-26 Deed Book/Page = 3340/466
3. Type of Development: Filling Grading ❑ Excavation Q Minor Improv. 0
Substantial Improv. ❑ New Construction ❑ Other ❑
4. Description of Development: The project proposes to rehabilitate the existing
powerhouse with a new turbine and generator. An intake structure will be excavated into the
riverbank, within the 100 year flood zone. Water will flow through a penstock into the
powerhouse, pass through the turbine, and return to the river just downstream of the dam.
5. Name of Flooding Source: Hardware River
COMMENTS: The intake structure will be built mostly below the existing grade with only a small
portion of the structure extending above the current ground elevation. The reduction in flow area
due to the proposed structure is 10.8 square feet that will be placed within the floodplain.
Additionally the flow area at this cross section will be increased by a minimum of 11.7 s.f. that will
be removed from the riverbank providing a net increase in the available flow area. The result is no
net increase in fill placed within the floodplain.
This is to certify that I am a duly qualified engineer licensed to practice in the State of Virginia. It is
to further certify that the proposed development as described in the Jefferson Mill Dam Design
dated March 2021, has an area of less than 5 acres and that construction of the proposed design
will not result in an increase in flood elevations for any adjacent property owners along the
Hardware River. This conclusion is based on the geometry of the proposed intake strucct
site grading. Xt a t,Tak
Name: David A. <risnitski r
Signature:'Oel
Date:
3/11/2021
Title: Water Resource Engineer License No.:
R7-No Rise (Converted to Adobe Form by State of Virginia)
JEFFERSON INTAKE
NO RISE CALCULATION
FILL=10.8SF CUT=11.7SF
STRUCTURE WIDTH = 12 FT
FILL=130CF CUT=140CF
PVC ENCASED IN CONCRETE
FOR STEM (LOCATION AND
325 SIZE TO BE COORDINATED
WITH SLUICE GATE SUPPLIER)
GROUNDSURFACE
TOP OF WALL ELEV. 32Z3 ------ 7
ELEV. 323.0 /
36" DIP
PENSTOCK
CONDUIT
P-7CONCRETE
CRADLE
SLUICE GATE OPERATOR
SLUICEGATE
CLOF PENSTOCK
\ ELEV. 315.5 \bs
-#5 REBAR@ e•Y'�
'1 8" SPA (TYP)
NORMAL POOL/
TOP OF DAM
ELEV. 319.7
TRASH RACK
ASSUME ROCK
RIVERBED
,1SECTION - PENSTOCK INLET STRUCTURE
p \1J/
Lat = 37.8413 Long =-78.4746
71 j
0% ", --
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National Flood Hazard Layer FIRMette 3, FEMA
0 250 500 1,000 1,500 2,000
Basemap: USGS National Map: Orthoimagery: Data refreshed October, 2020
Legend
SUMS REPORT FOR DETAILED LEOENDAND INM MAR MR FIRM PANEL LAYOUT
Without Base Flood Elevation (BFE)
Zone A. V. A99
SPECIAL FLOOD With BFE or Depth zone AE, Ao, AR, W, AR
HAZARD AREAS Regulatory Floodway
OTHER AREAS OF
FLOOD HAZARD
0.2%Annual Chance Flood Hazard, Areas
of 1%annual chance flood with average
depth less than one font or with drainage
areas of less than one square mile zone x
Future Conditions 1%Annual
Chance Flood hazard zneex
Area with Reduced Flood Risk due to
Levee. See Notes. zoncx
Area with Flood Risk due to Leveezone D
NOSCREEN Area of Minimal Flood Hazard zonex
Q Effective LOMRs
OTHER AREAS Area of Undetermined Flood Hazard zoom D
GENERAL ---- Channel. Culvert, or Storm Sewer
STRUCTURES 11111 I I Levee, Dike, or Floodweill
e 2aa Cross Sections with 1%Annual Chance
tvs Water Surface Elevation
v- - - Coastal Transact
---r°--- Base Flood Elevation Line (BFE)
Limit of Study
>` Jurisdiction Boundary
- — --- Coastal Transact Baseline
OTHER - Profile Baseline
FEATURES Hydrographic Feature
Digital Data Available N
No Digital Data Available
MAP PANELS Unmapped
4 The pin displayed on the map Is an approximate
point selected by the user and does not represent
an authoritative property location.
This map complies with FEMA's standards for the use of
digital flood maps if it is not void as described below.
The basemap shown complies with FEMA's basemap
accuracy standards
The flood hazard information is derived directly from the
authoritative NFHL web services provided by REM A. This map
was exported on 3/2/2021 at 4:02 PM and does not
reflect changes or amendments subsequent to this date and
time. The NFHL and effective information may change or
become superseded oy new data over time.
This map image is void if the one or more of the following map
elements do not appear: basemap Imagery, flood zone labels,
legend, scale bar, map creation date, community Identifiers,
FIRM panel number, and FIRM effective date. Map Images for
unmapped and unmodernized areas cannot be used for
regulatory purposes.
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