HomeMy WebLinkAboutFDP201900006 Review Comments Floodplain Development Permit 2021-02-19@I
COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road, North Wing
Charlottesville, Virginia 22902-4596
Phone (434) 296-5832 Fax (434) 972-4126
February 19, 2021
Scott Collins, PE
Collins Engineering
200 Garrett St., Suite K
Charlottesville, VA 22902
RE: FDP201900006 — Pleasant Green
CLOMR-F for Powell's Creek Stream Crossing
Dear Mr. Collins,
The referenced application cannot be approved at this time. Please refer to comments below.
1. Please reference "FDP201900006 — Pleasant Green" on all documents.
2. The Fish and Wildlife Service certification is no longer valid. The letter is dated 12/16/16 and
states it is valid for 1 year. It was also issued for the West Glen project. Please provide an updated
letter with the current project name from the Fish and Wildlife Service.
3. LOMR Case No. 20-03-1533P was approved by FEMA on 02/04/21, which included a revision to
the floodplain IimitsBFE of Powell's Creek just north and south of Jarman's Gap Road. Please
confine tie-in data does not overlap. If it does, update the models to account for the previously
approved revisions. Update maps to show the approved revisions just downstream of Section F
and reference "LOMR 20-03-1533P, effective date June 23, 2012." Refer to attached
FIRMETTE. Contact me for modeling data if needed.
4. Please provide a copy of the USACOE permit for proposed stream impacts associated with the
stream crossing.
5. Project narrative on plan and in letter states:
a. "The fill associated with the road crossing occurs within the floodplain fringe only."
The floodway width at section G4 is shown as 75-ft for the existing condition and
48-ft for the proposed condition, approximately. The floodway width at section
G3 is shown as 116-ft for the existing condition and 56-ft for the proposed
condition, approximately. The floodway is reduced at both cross -sections under
the proposed condition; therefore, the floodway is being impacted and fill is
occurring within the floodway and floodplain. Please clarify and revise as
needed.
b. "There is a zero -rise in the BFE associated with the proposed fill. "
Is this statement intended to refer to a no rise on adjacent properties, because
there is a rise directly upstream and downstream of the new box culvert? Please
clarify.
Page 1 of 2
c. "There is a nominal expansion of the floodway limits due to the fill on the fringes of the
floodplain, but this does not impact the BFE. "
The BEE is impacted upstream and downstream of the culvert. Please clarify how
the BFE is not impacted by the proposed fill. Or is this referring to the BEE on
adjacent properties? This appears to be a carry-over note from the previously
approved CLOMR. Please confirm this statement is accurate.
6. Provide a list of parcels affected by the change in BFE. Clearly show and identify existing
property boundaries on all sheets.
7. Two or three lots are partially within the floodplain. Remove or adjust the lots so that they are not
within the floodplain.
8. Show the 100-yr and 500-yr flood elevations on the Rambling Brook Lane profile (Sheet 4).
9. Submit HEC-RAS modeling data files.
10. How was the 1% annual flood flowrate determined or confirmed? Streamstats reports an
estimated flowrate (Q) for the 1% flood to be approximately 3,040 cfs. The flowrate used in the
model for this application is approximately half this amount. Please confirm and explain the
discrepancy.
11. Pleasant Green Phase 2 includes grading and improvements within the floodplain. Either include
those activities/improvements with this CLOMR-F or submit a separate FDP application to
address those activities within the floodplain.
12. For information:
a. Letter of Map Revision ("LOMR') or Conditional Letter of Map Revision (CLOMR),
required. If the owner has or will be requesting a required Letter of Map Revision or
Conditional Letter of Map Revision as provided in subsection (A)(3), the administrator
or any other county official or body shall not act on any pending application and no use
shall begin until the Federal Emergency Management Agency issues the Letter of Map
Revision (or CLOMR) and all requirements of 44 CFR § 65.12 are satisfied. [18-
30.3.10.C.3].
b. FDP application cannot be approved until the DBIZ issues are resolved.
Don't hesitate to let me know if you have any questions or comments.
Sincerely,
Fl V.F 1. PECFY wWmn.a ruv`ew
Frank V. Pohl, PE, CFM
County Engineer
Copy: Jeremy Swink, SMC (via email)
Page 2 of 2
National Flood Hazard Layer FIRMette
Legend
0101 FEMA
SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT
Without Base Flood Elevation (BFE)
Zane A, V, A99
SPECIAL FLOOD With BFE or Depth
HAZARD AREAS Regulatory Floodway Zone AE, AD, AN, VE AR
0.2%Annual Chance Flood Hazard, Areas
of 1%annual chance flood with average
depth less than one foot or with drainage
areas of less than one square mile zone x
Future Conditions 1%Annual
Chance Flood Hazard zone x
Area with Reduced Flood Risk due to
ITHER AREAS OF
Levee. see Notes. zone x
FLOOD HAZARD
Area with Flood Risk due to Levee ZOMD
xo scaEEx Area of Minimal Flood Hazard zonex
Q Effective LOMRs
OTHER AREAS
Area of Undetermined Flood Hazard zone D
GENERAL
---- Channel, Culvert, or Storm Sewer
STRUCTURES
umnllllll Levee, Dike, or Floodwall
e p'z Cross Sections with l%Annual Chance
Water Surface Elevation
o- — — Coastal Transact
.....Fu Base Flood Elevation Line (BFE)
Limit of Study
Jurisdiction Boundary
-- --- Coastal Transact Baseline
OTHER _ Profile Baseline
FEATURES Hydrogrephic Feature
Digital Data AvailableNl
El Digital Data Available
MAP PANELS ® Unmapped
This map complies with FEMA's standards for the use of
digital flood maps if it is not void as described below.
The base map shown complies with FEMA's base map
accuracy standards
The flood hazard information is derived directly from the
authoritative NFHL web services provided by FEMA. This map
was exported on 2/26/2018 at 4:13:38 PM and does not
reflect changes or amendments subsequent to this dale and
time. The NFHL and effective information may change or
become superseded by new data over time.
This map image is void if the one or more of the following map
elements do not appear. base map imagery, flood zone labels,
legend, scale bar, map creation date, community identifiers,
FIRM panel number, and FIRM effective date. Map images for
unmapped and unmodembed areas cannot be used for
regulatory purposes.
0 250 500 1,000 1,500 2,000