HomeMy WebLinkAboutWPO201800027 Review Comments WPO VSMP 2020-06-05COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road, Room 227
Charlottesville, Virginia 22902-4596
Phone (434) 296-5832 Fax (434) 972-4126
Project:
Project file#:
Plan preparer:
Owner or rep.
Developer:
Plan received date:
(Rev. 1)
(Rev. 2)
Date of comments:
(Rev. 1)
(Rev. 2)
Reviewer:
VSMP Permit Plan Review
Martha Jefferson Hospital Apartments — VSMP Plan Amendment 1
WP02018-00027
Scott Collins; Collins Engineering [200 Garrett St., Suite K, Charlottesville, VA
22902, scott(a)collins-en ing eerieg com]
Martha Jefferson
6015 Poplar Hall Drive, Suite 214 / Norfolk, VA 23502
Alan Taylor [ alanAriverbenddev.com ]
23 Apr 2020
2 Jun 2020
5 Jun 2020 (digital—6/5/2020 1:04 PM email)
26 May 2020
4 Jun 2020
5 Jun 2020, Approved
John Anderson
Also, please see emails sent 5/25/2020 12:41 PM, 5/26/2020 12:06 PM.
Also (Rev. 1), ref email sent 5/27/2020 10:21 AM.
County Code section 17-410 and Virginia Code §62.1-44.15:34 requires the VSMP authority to act on any
VSMP permit by issuing a project approval or denial. This project is denied for reasons listed below. The
VSMP application content requirements can be found in County Code section 17-401.
A. Stormwater Pollution Prevention Plan (SWPPP)
The SWPPP content requirements can be found in County Code section 17-405. A SWPPP must contain
(1) a PPP, (2) an ESOP, (3) a SWMP, and (4) any TMDL measures necessary.
1. Revise WP0201800027 SWPPP
a. Include SWPPP title reference to WP0201800027 Amendment 1. (Rev. 1) Addressed.
b. Include rev. ESC and SWM plan sheets, once comments addressed. (Rev. 1, D Persists.
Applicant response, 6/1/20: `The revised ESC and SWM plan sheets will be inserted into the
SWPPP once the comments have been addressed.'
2. Engineering needs two (2) print copies, once Plan Amendment is approved.
B. Pollution Prevention Plan (PPP) — See, above. Revise Exhibit, as needed. (Rev. 1) Addressed.
The PPP content requirements can be found in County Code section 17-404.
C. Stormwater Management Plan (SWMP)
VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a SWMP. This
Amendment plan is approved.
1. Provide design features required with a Level Il wet pond, including aeration (see VA DEQ Design
Specification 14, p. 3, Level 11 Design Guidance, table 14.2).
Note: MJH Apartments contributing DA is insufficient for proposed wet pond to function reliably as a
Level 11 wet pond, but the practice was approved with WP0201800027.
Ref. VA DEQ Stormwater Design Specification No. 14, .55, Contributing Drainage Area: `A contributing
drainage area of 10 to 25 acres is typically recommended...' (Rev. 1) Withdrawn/ref. Applicant response:
Engineering Review Comments
Page 2 of 4
`Sheet 7 has been revised to show a circle representing the proposed aeration. The upper -right plan entitled
`Level II Wet Pond detail' has also been revised to provide a label that reads `Proposed Aeration, see
details on sheet 9.' Also, sheet 9 has been revised to include notes and details for the proposed aeration.
With respect to the contributing drainage area (CDA), the applicant believes the proposed subarea is
acceptable and meets minimum VA DEQ requirements. Specification #14 states "...wetponds can still
function with drainage areas less than 10 acres...." The applicant has also provided additional protective
measures for this pond. To prevent clogging, trash racks are provided for the riser and low orifice. Also, a
sluice gate is provided to serve as a dewatering orifice if it is required in the future for maintenance.
Additionally, a drought tolerant /water balance calculation in accordance with VA DEQ specification #14
was submitted, reviewed and approved with WPO201800027. A copy of this was provided with the
amendment, with no revisions made to the sheet. These items address potential concerns related to a CDA
less than 10 acres. Also, an example of where a CDA of less than 10 acres can be maintained is when a
sediment trap maintains a permanent pool in Albemarle County during summer months when droughts are
more likely to occur, and where subareas are less than 3 acres. Furthermore, these sediment traps often
have more vegetative ground covers that absorb runoff and further diminish the runoff entering the trap.
This is conservative when compared to the final build out of the wet pond's impervious watershed, which
will have a greater CDA with less ground absorption.'
2. Provide calculation or table showing that wetlands constitute > 10% of level II pond area. Withdrawn.
Ref. sheet 7. As follow-up: List surface area of wet pond at elev. 380' on sheet 7.
3. Provide water balance calculation to assess whether the wet pond will draw down by more than 2 feet after
a 30-day summer drought. (Contributing Drainage Area (spec. 14)) Withdrawn, see email sent 5/26/2020
12:06 PM. Also, p. 20 Calc. packet, 4/22/20.
4. If wet pond level drawdown exceeds 2-ft during a 30-day summer drought, provide remedy. See equations
in Sec. 6.2 of VA DEQ Stormwater Design Specification No. 14. Withdrawn, pond drawdown does not
exceed 2-ft.; see email sent 5/26/2020 12:06 PM.
5. On -site requirement: Consider 9VAC25-870-69.B.3. which requires 75% of phosphorus nutrient reductions
be achieved on -site. (Rev. 1) Addressed. Also, item 14.
6. Provide 75% on -site reduction, else demonstrate that alternative site designs have been considered to
accommodate on -site best management practices. (Rev. 1) Addressed. Also, item 14.
7. Consider additional on -site practices; for example: biofilters or Filterra units. Filterras offer promise since
they may be installed in 100% impervious parking areas. (Rev. 1) Addressed. Also, item 14.
8. Note: Albemarle request does not penalize developer or designer, or create new requirements; rather,
request is to comply with 9VAC25-870-69.B.3., a requirement applicable to initial application. (Rev. 1)
Addressed. Also, item 14.
9. Note: Initial third -party comments should have noted requirements listed at 9VAC25-870-69.B.3., and
requested demonstration satisfying requirements at 9VAC25-870-69.B.3. We regret we did not catch it,
then. (Rev. 1) Addressed. Also, item 14.
10. Reviewer is of the opinion that while WPO201800027 Approval stands, initial approval does not grant or
convey approval to an Amendment that must meet applicable design requirements. (Rev. 1) Addressed.
Also, item 14.
11. At present, VRRM.xls New Development worksheet indicates 13.60 lb. reduction required. Amended
limits of disturbance=17.17ac. (sheet 413); therefore, the project is ineligible to purchase more than 25% of
total reduction required, or more than 3.4 lb. (Rev. 1) Addressed. Also, item 14.
12. By bill of sale dated 15 May 2020, project provides 6.24 lb. nutrient credits to be applied to
WPO201800027. These credits are accepted as applicable to approved plan WPO201800027. (Rev. 1)
Addressed. Also, item 14.
13. While 6.24 lb. purchase is accepted, sheet 6 of Amended plan states that `the remaining water quality
balance of 6.68 lbs/year of phosphorus will be met by the best management practice of purchasing nutrient
credits.' There is a 0.441b. deficit. (Rev. 1) Addressed. Also, item 14.
14. Engineering requests that at a minimum, design be revised to propose additional on -site best management
practices (filterra units, for example) that provide, at a minimum, 0.44 lbs./fir. phosphorus reduction. (Rev.
1) Partially addressed. As follow-up: Sheet 8A, please: (Rev. 2) Addressed.
a. Label bioretention forebay and main cell (L X W) dimensions (plan view).
b. Transfer elev. data that may be listed with bioretention basin profile notes to basin section;
indicate invert elevations for:
i. 12" stone layer
Engineering Review Comments
Page 3 of 4
ii. Choker stone (pea gravel)
iii. Bioretention soil media
iv. Shredded hardwood mulch
v. Also, top of mulch elev. (0.25' higher than iv.)
c. Please show building 6 roof drain pipe outfall to SWM practice /profile view. Drain tie-in
elevation /geometry unclear.
15. Provide sheet 1 Narrative explaining Amendment to approved WP0201800027. (Rev. 1)
Withdrawn. Review error. A comprehensive detailed description explains proposed changes to the
approved plan, sheet 1.
16. Engineering encourages consistency between WPO and Final Site Plan titles: one reads Martha Jefferson
Hospital Apartments while the other reads Martha Jefferson Hospital Presidio Apartments. Also, owner
listed with final site plan (Presidio Pantops, LLC /Castle Development Partners, LLC) differs from owner
listed with WPO plan. (Rev. 1) Addressed.
17. Incorporate pond aeration included with Fig. 14.1 (sheet 9) in plan view of level 11 wet pond on sheet 7.
(Rev. 1) Addressed.
18. Sheet 7: Revise Aquatic bench (Zone 1) Planting Schedule for SWM Facility table to include quantities
estimated required to provide listed coverage (sf). (Rev. 1) Addressed.
19. Cale. packet p. 10: DA A + DA B area =11.71 Ac. Cale. packet /Site Information (VRRM.xls), p. 30, lists
17.17 Ac. project site. Provide narrative description and calculations addressing compliance for site areas
not included with DA A or DA B.
Note 1: Sheet 6 indicates proposed grading /project activity outside DA A and DA B. These areas appear to
discharge (as sheet flow) without detention. Consider these areas. Provide narrative relative to 9VAC25-
870-66. (Rev. 1) Addressed. Applicant response: `Sheet 6 was revised, under the `watershed summary'
tables in the middle -right portion of the page, to include a note that reads `The disturbed areas outside of
subarea A & B's limits release runoff in a sheet flow manner and are not released in a concentrated
fashion.' In accordance with a phone conversation between County Engineering and Mr. Murray of Collins
Engineering on May 27th, this was deemed an acceptable method for addressing this comment.'
Note2: Area of wet pond calculated at elev. 380' should be listed (in future project) tables of post -
developed impervious areas. (Rev. 1) Discussed with Applicant via tel. 5/27/20 —confirmed statement
applies to future projects and does not request modification to plan or calculations for this Amendment.
20. Sheet 7: Include labels requiring Warning /'No trespassing' signs (unless overlooked) since permanent
pools present risk of drowning, esp. to youth /children. Signs must be prominent, lettering highly visible.
Text, sign material /type, and placement are at Applicant's discretion, but Engineering recommends several
signs at approaches to wet pond at each end of tiered retaining walls. (Rev. 1) Addressed. Applicant
response: `Sheet 7 has been revised to address this comment. The sheet's plans show the signs, and the
upper -right `Level 11 Wet Pond Detail' now includes two labels that read "Proposed Sign, See `General
SWM Note' #5 on this sheet." Additionally, the referenced `General SWM Note' #5, shown in the bottom -
center portion of sheet 7 was added and reads "Contractor shall install two (2) signs with prominent letters
that are highly visible and reflective. The locations of the signs are to be placed at the end of the retaining
walls where the 10' wide dam is located, as shown, to increase pedestrian awareness. Signs to read
`Warning /No Trespassing.'
D. Erosion and Sediment Control Plan (ESOP) — Approved with WP0201800027 / Amendment, NA
Virginia Code §62.1-44.15:55 requires the VESCP authority to approve or disapprove an ESOP. This
Amendment does not substantially revise or affect the Approved ESC Plan. See WP0201800027.
Please reference transmittal email for next -step requests, and PROCESS section, below. Thank you
Process:
Once review comments addressed:
• SWM Facility Maintenance Agreement recorded at bk.-pg. 5263-485.
• 6.24 lb. Nutrient credits are purchased /valid for use with this project. (15 May 2020)
Note: Project must provide a minimum 0.44lb/yr. additional phosphorus reduction on -site.
Engineering Review Comments
Page 4 of 4
• SWM Facility Easement plat recorded at bk.-pg. 5276-400, 2/12/20.
• VAR10 permit required prior to receiving a Grading Permit.
• VSMP /WPO plan bond is prerequisite to a Grading Permit.
• Engineering understand WPO plan bond is in process.
County forms can be found on the county website forms center under engineering;
hllp://www.albemarle.oriz/deptfonns.asl2?department--cdenoMo
WP0201800027 MJH Apts_VSMP Plan Amend-1 _060520rev2Approv