HomeMy WebLinkAboutWPO201300043 Review Comments Erosion Control Plan 2014-05-23Mpg A
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COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road, Room 227
Charlottesville, Virginia 22902 -4596
Phone (434) 296 -5832 Fax (434) 972 -4126
Project: Contractor Storage Yard — Final Touch Tree Service
Plan preparer: Anhold Associates, PLC
Owner or rep.: Final Touch Tree Service, LLC
Plan received date: 9 Apr 2014
Date of comments: 23 May 2014
Reviewer: Michelle Roberge
RE: Erosion & Sediment Control Plan and SWM Plan (WP0201300043)
Engineering has completed the review for WP0201300043. Please address the following
comments.
[Comment] It appears the 18' gravel driveway is not necessary. Please remove the future
18' gravel driveway.
[Revision 1] Comment addressed.
2. [Comment] The professional seal shall be signed and dated. [Section 18- 32.6.1]
[Revision 1] Once comment #4 is addressed please submit 4 signed, sealed and dated
plans.
3. [Comment] The pro -rata fee for the use of Lickinghole Basin is $596.84. After the plan is
approved, please process the E &S bond, SWM bond, SWM agreement, and Lickinghole Basin
fee. You may contact Ana Kilmer (Albemarle County Department of Community
Development) at ext. 3246 for further information on bonding procedures and Maintenance
Agreements.
[Revision 1] This fee was acknowledged by applicant. However, the rate has increased
1.5% and is now $605.78. Please make the payment prior to the plan approval.
[Revision 2] Payment is pending.
4. [Comment] Please address MS -19.
[Revision 2] A detention basin is proposed to show post development peak rate for 10 yr
storm is less than pre - development peak rate. However, this does not address MS — 19.
Here are some options to prove adequate channels.
a) Prove the one percent rule.
i. Based on area. Prior to any land disturbance, the site's contributing drainage area to a point of
discharge from the site is less than or equal to 1.0% of the total watershed area draining to that
point of discharge; or
ii. Based on peak flow rate. Based on the post - development land cover conditions prior to the
Engineering Review Comments
Page 2 of 3
implementation of any stormwater quantity control measures, the development of the site results
in an increase in the peak flow rate from the one -year 24 -hour storm that is less than 1.0% of the
existing peak flow rate from the one -year 24 -hour storm generated by the total watershed area
draining to that point of discharge.
b) Prove adequate channels and adequate manmade conveyance system to the basin.
Your analysis stops at the existing underground pipe.
c) If downstream is inadequate or you do not wish to prove downstream analysis, meet
all of the following:
i. Detain the WQV (1" runoff) and release over 48 hours.
ii. Detain the 1 year 24 -hour storm and release over 24 hours.
iii. Detain and reduce the peak flow for a 1.5, 2 and 10 year 24 -hour storm, to the
following level; peak flow <= I.F. *Qf (VfNpost), where Qf is flow from the site in a well forested
condition (C = 0.25, or CN = 51), and Vf is volume from the site in a well forested condition. I.F.
is an improvement factor (0.8 for sites > 1 acre or 0.9 for sites < 1 acre.
New Comment based on new design:
5) Provide the title page. Title page should state E &SC plan and SWM plan since you are now
proposing a basin. This will require a SWM fee on next submittal.
6) Show DA -SCC #3 on post development DA map. Label acres, CN, and Tc.
7) If you decide to pursue option c from comment 4, provide all calcs and analysis.
Engineering Review Comments
Page 3 of 3
8) Provide easement for SWM facility. Also, show vehicle access to facility with minimum 10'
wide access easement over access.
9) Provide cross sections of swm facility to scale.
Sincerely,
r&T-
Michelle Roberge