HomeMy WebLinkAboutWPO201000043 Review Comments Erosion Control Plan 2010-07-30Philip Custer
From: Philip Custer
Sent: Friday, July 30, 2010 5:24 PM
To: 'Gloeckner Engineering'
Cc: Summer Frederick
Subject: Engineering Review of Saint Annes Belfield (SDP- 2010 -00047 and WPO- 2010 - 00043)
Attachments: ESC Notes.pdf; 27 July 1999 Mark Graham Letter.pdf
Good afternoon Kurt,
I have reviewed the recent revision to the minor site plan (SDP- 2010 - 00047) and the first submittal of the Erosion and
Sediment Control Plan for (WPO- 2010 - 00043), received on 16 July 2010. All technical comments on the site plan have
been addressed. The Erosion and Sediment control plan can be approved with a few minor revisions. Please submit two
copies of the Erosion and Sediment Control Plan with the following corrections:
- Please include the County's General Construction Notes for ESC Plans. I have attached a pdf to this email with the 22
ESC notes that must be included within the plan.
- Please provide DC symbols within the limits of disturbance.
- Please provide a CE symbol in the existing paved area to the left of the building with a note stating that the existing
paved area is to be used as a construction entrance.
No additional ESC submittal review fee will be required.
After reviewing the previous Stormwater Management plans submitted to the county, I'm not convinced that the
additional increase of impervious area with the new preschool construction is accounted for. The Bioretention BMP
(practice football facility) at the downstream side of the site was approved in 1999 by the county with only a 35%
removal rate for the existing drainage area to it at the time of construction. Please refer to Mark Grahams Letter, dated
27 July 1999, which I have also attached as a pdf to this email. It should be noted that this is the only facility that this
current application drains to and I suspect it is undersized.
In previous conversations, you mentioned that the improvements currently being installed (cistern, biofilter, and porous
paving) is providing additional removal to offset the preschool impervious area increase. While we generally discourage
the offsetting of removal credits across watersheds (subwatersheds in this case), I am open to reviewing any further
analysis you wish to provide to show overall site treatment. However, this would be time consuming for both of us and
considering the current construction timeline of the preschool and my current workload, I'm offering to provide
conditional site plan approval if the owner agrees to construct a 200sf biofilter (meeting all current VSMH standards
with a 1ft ponding depth) off the paved ditch behind the dumpster in the parking lot below the preschool. At this point,
we will bond the construction of this facility at $10,000 within the ESC bond. A plan for this facility must be submitted to
this office if the analysis of the existing pollutant removal of the site facilities are not satisfactory. (The analysis of the
cistern and porous paving should be performed using the draft design guidance provided by the state BMP
clearinghouse.) This issue must be resolved before the ESC bond is requested for final release. If the applicant is
amenable to this agreement, please confirm it with a reply to this email.
The ESC bond, including the SWM portion, has been computed to be $22,200. To post the ESC bond, please contact
Ana Kilmer at 296 -5832 x3246 after reviewing the guidelines online.
Summer has informed me that all of her comments have been addressed regarding the site plan as well. For site plan
approval, please provide her with 4 copies of the site plan. Again, I'll need 2 copies of the ESC plan with the minor
revisions mentioned in the email above.
Once the site plan has been signed and the WPO bond has been posted, you may schedule a pre- construction meeting
with the Erosion and Sediment Control Inspector by contacting Kenny Thacker at 296 -5832 x3390.
Please contact me if you have any questions.
Thanks,
Phil
296 -5832 x3072