HomeMy WebLinkAboutSP201500003 Review Comments Special Use Permit 2015-02-27*—&A
County of Albemarle
Department of Community Development
Memorandum
To: Claudette Grant, Planning
From: Glenn Brooks, Engineering
Date: 27 Feb 2015
Subject: North Point amendment (SP201500003, amending SP200700003)
The special use permit application and floodplain development permit for amending the middle entrance
crossing of Flat Branch at the proposed North Point development has been reviewed. There is not enough
information provided to make a full review of the floodplain impacts and changes to the special use permit.
The following comments and requests for information are provided for Planning and the applicant;
1. Please provide a comparison of the approved arch span and the proposed amendment using box
culverts. Show the differences to the stream and to the floodplain, as well as the hydraulic models.
2. Please provide the HEC -RAS analysis on disc. The computer files are needed for adequate review.
3. The HEC -RAS model appears to be independently generated. The FEMA model must be used.
Please obtain the FEMA model for Flat Branch, and update the existing model with the surveyed
cross - sections to establish the base flood. Use the existing model to generate the proposed model.
4. Please provide data to demonstrate compliance with 18- 30.3.13B and 18- 30.3.14. Specify the
floodplain rise, how obstruction or fill is minimized and protected against erosion or pollution.
5. Much of the grading activity shown on the plans is not for the crossing. Please clarify that this fill area
is not part of this permit.
6. The plans show only one floodplain line beyond the fill area, implying there is no change. This is not
usually the case in front of a culvert constriction. Please show lines before and after the proposal, so
the changes to the floodplain are clear.
7. Condition #1 should be revised to reflect new ordinance requirements. 18- 30.3.13 requires a
Conditional Letter of Map Revision prior to construction. A Letter of Map Amendment or Revision is
required after construction. It is recommended that plan and plat approvals be conditioned on both
these FEMA approvals.
8. Please show appropriate transition between the stream channel and the box culverts, clarifying the
length of stream necessary to be disturbed. This will be for comparison with the arch.
9. Conditions 2, 3, 4, and 9 are unnecessary, as these are required by ordinance. As an example, in
condition #9, the county no longer has a Natural Resources Manager position, and in addition to
mitigation and erosion control plans, a VSMP /SWPPP may be required.
10. Please provide a copy of the wetland and stream disturbance documentation submitted to the state.
The difference in stream impacts at this crossing is pertinent to the review, as it appear the prior
approval emphasized minimizing impacts to the stream in the use of the arch.
file: El_sp_GEB_NorthPoint_ amendment middle_crossing.doc