HomeMy WebLinkAboutSUB201100026 Review Comments Preliminary Plat 2011-03-29OF ALBS
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County of Albemarle
Department of Community Development
Memorandum
To: Gerald Gatobu, Current Development planning and zoning review
From: Phil Custer, Current Development engineering review
Date: 29 March 2011
Subject: Glenmore Section K213 Preliminary Plat (SUB-2011-00026)
The preliminary plat for Glenmore Section K213 (SUB- 2011 - 00026), received 7 March 2011, has been
reviewed by county engineering. I can recommend approval to this preliminary plat once the following
comments are addressed.
1. Please label the road ROW with the deedbook and page number the Carroll Creek Road parcel
was recorded under. Please also provide the owner of this parcel as well. [14- 302.A.4]
2. Please show the building sites for the proposed lots. A critical slope waiver was approved with the
rezoning plan but this was for all critical slopes assumed to be disturbed when the rezoning plan
was reviewed. Where a building site can be located outside of critical slopes, it must. [ 14-
302.A.9]
3. Topography is required on this preliminary plat. The topography should be of no greater contour
interval than 4ft because that is the interval provided by the county (though the 2ft topography
provided in the road construction plans is preferable). Please show all proposed lot grading and
identify all areas of critical slopes on the plan as well. [14- 302.A.12]
4. Please show all water and sewer facilities. Water and sewer pipes should be located outside of
critical slopes where practicable. [14- 302.A.13]
5. No information has been provided regarding stormwater management. When the proposed
grading plan is included in the next submittal, please show the updated drainage area to biofilter 8
and note the amount the bioiilter will need to be upgraded. The plan will also need to identify
how much impervious area is being left untreated for the watershed to the north of these lots.
During the rezoning review, the stormwater management plan was not as detailed as the county
was accustomed to seeing. This was noted by the County Engineer, Jack Kelsey, in his
memorandum on 24 July 2007:
Storm water Detention:
The applicant has assumed a waiver for stormwater detention will be granted as part of the
final development plan review. In this case it is an acceptable concept. However, as part of the
final development plan and in accord with Code 17- 314.F.6 the applicant must demonstrate to
the satisfaction of the Program Authority that off -site improvements or other provisions for the
disposition of surface water runoff would equally or better serve the public interest and safety,
and that such method of disposition would not adversely affect downstream properties or
stream channels.
Stormwater Quality:
The applicant has proposed to address water quality by working with the water resources
manager to dedicate stream buffers as part of the final development plan review. However, in
order for dedicated stream buffers to provide any water quality benefit the runoff from
impervious surfaces must be allowed to sheet flow through the buffers and be adequately
Albemarle County Community Development
Engineering Review comments
Page 2 of 2
treated. No water quality credit is given for the concentrated release of runoff (in pipes or
ditches) into or through the buffers. Based on the conceptual grading in this application,
nearly all of the runoff from proposed streets will be collected /conveyed in ditches and culverts
and then released as concentrated flow into the existing intermittent streams. Please revise the
grading plan to be consistent with the conceptual water quality treatment proposed. Be mindful
that erosion & sediment control measures (traps or basins), that will be required for this
development, may be converted to serve as water quality facilities.
It appears as though the intermittent stream at the rear of these lots is a good candidate for a new
stream buffer. The rear of these lots should be graded to establish sheet flow and the rear property
line should not be located inside of the new buffer.
The following comments are advisory and do not need to be addressed prior to preliminary plat approval.
6. An amendment to the previously approved erosion and sediment control and stormwater
management plans will be required prior to final plat approval. The plan will need to show all new
ESC measures necessary to protect all grading in addition to the construction of all utility lines.
On one of the sheets of the ESC plan revision, the applicant will need to provide an updated
acreage for land being disturbed for the Leake Property. Total disturbance will not be allowed to
exceed 30 acres. [ZMA- 2006 - 00015, Proffer 6] The ESC plan should use sediment trap 8 as
much as is practical and know that it will likely need to be increased in size due to the increase
watershed the grading operations will trigger.
7. Please note when the final plat is submitted, it will need to show the drainage easement across the
front of the property.
8. The road bond for Carroll Creek Road has been posted on 1/21/2011. However, bonds for ACSA
will need to be posted prior to the approval of the final plat.
file: El_ppt_PBC_Glenmore Section K2B Preliminary Plat.doc