HomeMy WebLinkAboutFDP202300002 Review Comments Floodplain Development Permit 2023-04-11 (2)�q oa rig 401 McIntire Road, North Wing
Charlottesville, VA 22902-4579
County of Albemarle Telephone:434-296-5832
COMMUNITY DEVELOPMENT DEPARTMENT WWW.ALBEMARLE.ORG
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Floodplain Development Permit Application (GLOMR) Review
Project title:
Meadowcreek Basin Trails & Bridges
Project:
FDP2023-00002
Plan preparer:
Daniel Hyer, PE - dhyer@line-grade.com
Ecosystem Services, 1102 Carlton Ave. /Charlottesville, VA
Kip Mumaw - kip@ecosystemservices.us
Owner /Applicant:
Republic Homes, Inc. 1885 Seminole Trail
Charlottesville, VA 22901
Also:
City of Charlottesville, Chris Gensic - eg nsicnas charlottesville.gov
P.O. Box 911, Charlottesville, VA 22902
Plan received date:
3 Mar 2023
Date of comments:
11 Apr 2023
Plan Coordinator:
John Anderson
Reviewer:
John Anderson, PE /CFM
Engineering has reviewed 2/28/23 Ecosystems Flood Study, and FEMA Forms: Riverine Structures,
Overview and Concurrence, and Albemarle FDP Application, and offers the following comments.
1. Please ref. p. 9-10 of ACDSM, Sec. A, Floodplain Impact Plans, and provide information, including:
a. A1.a: DA map (not provided)
b. A.1.b: plan drawing (not provided; also, items 2.d., 2.f.iii.4, below)
c. A.1.c: Actual measured cross -sections (provided as low-res hi -scale HEC-RAS printouts; unable
to evaluate design or impacts at scale provided). Also, there is little to no detail concerning
adjacent parcels, effect on structures or improvements in vicinity, natural resources, etc.
d. AAA: Proposed cross -sections, including any pipes, culverts, bridges, etc. Provided as low-res,
high -scale HEC-RAS schematics (Detailed Model Outputs), beginning p. 31 of Ecosystem Flood
Study. Pg. 4 of 51-p. Ecosystem Services Flood Study, February 28, 2023, Meadow Creek Basin
Trails & Bridges indicates "The proposed work is within the FEMA regulated Zone AE flood
hazard zone (including the floodway). This project will include grading activities that will alter
the topography of the floodplain and includes two bridges across Meadow Creek (see exhibit
below showing the project are outlined in red)." The exhibit identifies Meadow Creek stream
centerline and project area outlined in red. Bridge locations are not identified. Exhibit does
not delineate city -county boundary.
2. Pg.4, Ecosystem Flood Study, project summary, 1' sentence: 'Ecosystem Services has evaluated the
Meadow Creek Basin trails and bridges project in City of Charlottesville, Virginia: Please:
a. Confirm project location is partially within City of Charlottesville.
b. If project proposes change to BFE or horizontal limits of mapped floodplain or affects mapped
floodway of Meadow Creek or a tributary to Meadow Creek east of Hillsdale within Albemarle
County limits, please make this information clear across study, exhibit, in graphic plans, and
with narrative that clearly describes city v. county role relative to floodplain development
permit application, review, and coordination with FEMA.
c. Especially pis. clarify whether City of Charlottesville is coordinating proposed bridges with
FEMA for portions of floodplain within city limits. Meadow Creek is a city -county boundary
for -1000 ft. Tributary to Meadow Creek east of Hillsdale is entirely within Albemarle County.
d. On FDP plan (to -date, not provided), provide complete plan -profile design information for
proposed bridge crossings, per ACDSM guidance. This will be a detailed proposed design
Engineering Review Comments
Page 2 of 3
unlike the 700-ft. to 1800-ft. horizontal (stream x-section) scale, or 70-ft to 120-ft elevation
vertical scale (flood study HEC-RAS model outputs), which are relatively uninformative from a
detailed design or review perspective.
e. Provide HEC-RAS model profiles of Meadow Creek and its tributary between cross sections
that show increase or no increase in BFE from first to last riverine station. That is, show and
hatch difference between existing Eff. BFE and proposed revised BFE, should proposed
bridges be built.
f. Consider and discuss relevant 18-30.3 requirements, including:
i. 18-30.3.12.A: Floodplain Development Permit.
1. Structures: No bridge design data submitted, notwithstanding HEC-RAS low-
res schematics, which, Engineering cannot decipher; for example, whether
one or multiple bridge crossing options are presented with the flood study.
Clarify via narrative and graphic plan/profiles the options examined, and
which is preferred, for each bridge crossing location.
2. For preferred design, demonstrate preferred option is reasonably safe from
flooding; that structures adjacent to project area (2 bridges) will be or remain
reasonably safe from flooding (18-30.3.12.A.3), and that there is no adverse
effect on capacity of channels and floodways.
3. Provide evidence of coordination with USAGE, VMRC, and DEQ for any work
within Meadow Creek (below OHW), as applicable. Provide copies of permits
from outside agencies, as applicable.
ii. 18-30.3.13, Encroachment standards
1. A.2. Albemarle will not endorse C-LOMR based on information received to
date, since new construction activities are proposed to occur "within the
FEMA regulated Zone AE flood hazard zone (including the floodway)."
2. Given 2.f.ii.1, FDP Application will not be approved until FEMA approves the
C-LOMR, and Application to FEMA for C-LOMR will not be certified by
Albemarle floodplain administrator absent more detailed design information
for each proposed bridge crossing at Meadow Creek.
iii. Should project propose fill in the floodway fringe (18-30.3.14):
1. Provide readable -scale detailed plan -profile information for bridge approach,
abutments, any fill within FEMA mapped floodplain within Albemarle County.
2. Estimate fill (CY).
3. Consider and address 18-30.3.14.A.-D. Without evaluation of structures and
project impact on mapped floodplain (apart from HEC-RAS computational
evaluation) relative to these items (minimize obstruction, protect against
erosion, non-polluting) it is too soon for floodplain administrator to certify
that requirements A.-D. are met, or to furnish such certification to FEMA.
See FEMA Overview and Concurrence Form,
4. 18-30.3.14.E: Provide a site plan (FDP plan in this instance) for review.
iv. 18-30.3.15, Construction standards:
1. A. Structure and related improvements in any special flood hazard area;
general standards; items 1.-3.
a. Building code and required anchoring:
i. Apply for building permit
ii. Anchor structure to prevent flotation, collapse, or lateral
movement of the structure
b. Use materials resistant to flood damage
c. Use methods to minimize flood damage
3. General:
a. Please confirm:
i. FEMA'preliminary effective model ...provided by AECOM and developed by STARRII:
(Ecosystem study, p. 5)'The date of this preliminary effective model hydraulic report is
Engineering Review Comments
Page 3 of 3
January 2021, with a model study date of 2020.' Engr seeks to establish whether
AECOM preliminary effective model, 2021, is basis of FEMA Region III Changes Since
Last FIRM CSLF . If so, pis. confirm. If not, base flood study upon FEMA Region III
CSLF.
ii. Topography: Confirm and provide date on which additional field -survey stream cross -
sections were performed by Draper Aden. Since C-LOMR seeks to revise floodpiain
BFE, including fioodway limits, field -survey stream cross -sections are requisite (not
LiDAR). Please confirm flood study relies on field survey of x-sections; provide degree
of accuracy of field survey (0.1' ±, for example).
b. Provide and update Albemarle on City of Charlottesville review of project, and City
coordination with FEMA (if City coordinating). Albemarle must avoid circumstance where
county may inadvertently signal concurrence with C-LOMR application, inconsistent with City
of Charlottesville review of (similar) C-LOMR Application, and especially, inconsistent with any
concerns or issues City of Charlottesville may express to Applicant, or FEMA.
4. Emphasis: A'site plan' /FDP plan with graphic plan -profile, text/narrative, summary, labels, and detail
sufficient for fioodplain administrator to certify that project design (2 bridges) meets applicable
requirements of code, is required.
a. Pg. 9 of study is insufficient.
b. FDP plan must show, at readable -scale, parcel -by -parcel change to limits of mapped (pending
preliminary effective) fioodway/floodpiain, Meadow Creek or its tributary for areas within
Albemarle. Pg. 9 indicates both fioodplain and fioodway increase in certain locations in
Albemarle County (and within City of Charlottesville).
5. Note: FEMA Riverine Structures Form (Form 3) p. 2 indicates plans are attached. Plans were not
included with items submitted to Albemarle.
Please call if any questions — tel. 434.296-5832-0069, or email janderson2@albemarle.org.
FDP202300002—Meadowcreek Basin Trails & Bridges-041123