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The Village at Chestnut Grove
Albemarle County,Virginia
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Stormwater Management Cover
14 April 2014
Revised 13 May 2014
The existing basin appears to be roughly a constructed detention basin having steep slopes and excess volume.
It is used as a stormwater basin primarily for Sienna Lane runoff,but includes some lot area as well. Rain
gardens were approved for lots.Terra Engineering was asked by Cathcart Properties to redesign the basin shape
into something acceptable to the Lot 3 property owner,Paul Corridon.To do that,a copy of the previous
County approved Stormwater Computations prepared by Kurt Gloeckner dated May 15,2000 was obtained.
This report used the rational method for basin design.To the contrary,this redesign uses the 24-hr storm
distribution and SCS TR-20(as requested by the County)to comply with changes to the computation
methodology as supported by the Department of Environmental Quality.
The proposed basin was routed for the 2, 10 and 100-year,24-hour,Type 11 storms. The computations are
attached The basin contains a primary 15-inch RCP outlet with an 11V2-inch orifice plate and a higher
secondary 15-inch RCP pipe outlet.Both outlets are existing pipes.
In summary,the routed 2, 10 and 100-year storms have a peak discharge of 3.11;1.27 and 47.89 cubic feet per
second,respectively.The respective peak stages are 1:26,4.61 and-728 feet.The respective storage volumes
arc 81,2 149,and 9628 cubic feet.The pond was enlarged and accommodates the 100-year storm.
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The basin is designed without a riser,with 3:1 and 4:l side slopes, including a 4-foot shoulder along the
maintenance drive and decorative stone at the pond invert all at the request of the Lot 3 property owner.
Nyloplast inlets are used to extend and transition the existing basin inflow pipes and reduce flow velocities.
Class I rip-rap(EC-1)is used at the new pipe ends to dissipate energy.
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Review Comments
Project Name: The Village mt Chestnut Grove
Date Completed: Monday, June 30, 2014
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DepertmentiD|v|a|on�4g*ncy: Engineering �1
Reviews Comments:
application signed by Mr Corridon �
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Review � S�� []
Appro^n�� |-|
Page: 11 County of Albemarle On: J123-Y2014
Review Comments
Project Name: The Village at Chestnut Grove Stormwater ManagemenVBMP Pl,,F]
Date Completed: Friday. May 30. 2014
Reviewer: Glenn Brooks F-I
D e p a rtm e nt'D ivi s i o W.Ag e n cy: Engineering
Reviews Comments:
Review Status: Pending F-I
Page: 9 Count of A.1 b e m a rl e On: '1213'U20 14
OF Al
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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: Village at Chestnut Grove stormwater basin revision
Plan preparer: Terra Engineering [sdriver @terraengineering.net]
Owner or rep.: Paul Corridon [1022 Lucust Avenue, Charlottesville VA 22901]
Plan received date: 18 Apr 2014
Date of comments: 28 Apr 2014
Reviewer: Glenn Brooks
A. Stormwater Management and Mitigation Plan (WP0201400036)
1. Revise the calculations to use a 24hr storm for the 2 and 10 year intervals.
2. Verify and show the drainage area to the basin.
3. Provide a seal and signature on all plans and computations.
4. Provide 4 copes for approval.
File: El swm GEBChestnutGrove.doc