HomeMy WebLinkAboutWPO201100059 Review Comments Erosion Control Plan 2011-09-29ALg�,��
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COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road
Charlottesville, Virginia 22902 -4596
Phone (434) 296 -5832 Fax (434) 972 -4126
Project: Stoneiield Town Center ESC Plan; WPO- 2011 -00059
Plan preparer: Mr. Herb White, PE; W & W Associates
Owner or rep.: Albemarle Place EAAP LLC
Date received: 11 August 2011
Date of Comment: 29 September 2011
Engineer: Phil Custer
The ESC plan for Stoneiield Town Center (WPO- 2011 - 00059), received on 11 August 2011, has been
reviewed. The plans can be approved after the following comments have been addressed:
1. Similar to the comments made on previous ESC plans for Stoneiield (WPO- 2011 -00037 and
WPO- 2011 - 00055), this ESC plan must be a standalone application. However, this plan cannot
help but rely on the sediment basin constructed with the mass grading plan (WPO- 2009 - 00074)
until the site is almost entirely stabilized. Because there is a nine month timeline for all ESC
plans, the mass grading plan will need to be taken to the Board of Supervisors for an extension of
the grading permit to allow earth disturbing activities to continue (outside of reasonable building
work areas). The nine month expiration will occur on January 26`h, 2012. To schedule a hearing
on this extension, please file a request to the clerk of the Board of Supervisors by November 23ra
2011. If the Board does not grant this extension to all of or portions of this plan, all plans relying
on it may be invalidated and a stop work order for all related construction will be issued until an
amendment is approved that meets state regulations.
2. The ESC plan for this project will need to be at least three sheets:
-a sheet showing what the site will look like with proper protections on the day a grading permit is
issued (Route 29 and Hydraulic Rd improvements, Swanson Rd., Stoneiield Blvd., and Regal
Cinema work areas completed)
-a sheet showing what the site will look like on the day before the sediment basin will be filled in
(including the size and location of the soil stockpile); on this sheet, please include a note stating
that the sediment basin shall not be removed until permission is given by the county E & S
inspector
-a sheet showing the necessary protection measures /construction area to construct the areas not
stabilized in the previous sheet.
The basin cannot be removed until the majority of the site (everything but the basin and stockpile)
is stabilized with grass, roof, building pad, or gravel.
3. The site is graded/will be graded in such a way that runoff would likely end up in the Route 29
ROW (at the east end of Main Street). This plan must address this concern. It seems that the 6ft
diversion ditch, SCC1 on WPO- 2009 - 00074, could be extended to structure 79 and kept on the
plan (illustrated phase 2 as referred to in the previous comment) as surrounding infrastructure and
buildings are completed.
4. Sediment -laden water must not enter the permanent stormsewer system and detention facilities.
Inlet protection is more often than not an inadequate measure because the inlets are constructed
well after initial land disturbance. Even after installation, storm inlets are often bypassed because
their rim elevation is higher than the subbase and gravel around them until the final stage of
construction. Please make it clear throughout the plan that construction runoff is not to enter the
permanent drainage system.
Engineering review is especially concerned with the two sump conditions in the south eastern
parking lot and the grate inlets along Bond Street. A sediment trap inlet protection will likely be a
solution on structure 82. The diversion, SCCI, shown on the mass grading plan (WPO -2009-
00074) can be extended to structure 79. The grate inlets on Bond Street can be sealed until the
county inspector has confirmed the drainage area is stabilized.
The hotel construction area has a similar construction issue as the western parking lot for the
cinema plan had. To keep sediment -laden runoff out of the permanent drainage system and
Stonefield Blvd. ROW, please keep the temporary pipe system approved in the WPO- 2009 -00074
active and direct this construction area to this system with diversions on the east and north ends of
the hotel construction area. These diversions and temporary pipe system can be removed (or
abandoned) once the county ESC inspector has determined that the hotel area is stabilized. A
more advanced inlet protection on structures 110 and 112 will be needed since these inlets are in
sump. Perhaps a sediment trap inlet protection, similar to sediment trap culvert inlet protection,
could be designed at these structures. The grading for such a measure would need to be shown
and designed as a sediment trap.
5. Please show the updated grading with the Route 29 and Hydraulic Road improvements on the
phase it is expected to be completed. The county is most concerned with how the Route 29 turn
lane and Main Street entrance from Route 29 affects the eastern diversion shown on WPO -2009-
00074. Please also see comment 3.
6. Please show the soil stockpile on each phase of the plan. Please also refer to comment 2.
7. Please place a construction entrance on Swanson Drive at Hydraulic Road and include it in the
limits of disturbance. It seems unreasonable that traffic flow to the theater can be maintained
through this entrance considering the significant construction traffic. Other construction entrances
on Main Street east of Stonefield Blvd., into the hotel parking lot from Stonefield Blvd., and First
Street west of Stonefield Blvd. are recommended.
8. Please show a diversion/fill diversion at the top of the slope south of the southern Sperry Marine
boundary line.
9. Please show silt fence on the southern limits of disturbance of the hotel site.
10. The construction of Second/Third Street will either need its own sediment trap or basin north of
the intersection with Stonefield Blvd. or a ditch from the construction area to the sediment basin
approved WPO- 2009 - 00074. Please note that the use of this facility will be conditioned on Board
approval as explained in comment 1. Engineering staff will likely note that a new sediment trap or
basin for this construction area for this road (and the Haven) is a practical solution.
It is also recommended that the construction of this road be removed from this plan and included
in the Haven ESC plan which was recently submitted because the Haven will likely need an
independent sediment basin north of this intersection as well.
11. Please update the construction sequence as necessary to account for changes to the plan required
by the above comments.
12. Please include the amount of total land disturbance shown on this plan.
13. If a temporary construction trailers are necessary, they will likely need to be shown on an approved
ESC Plan.
14. Please provide a completed Bond Estimate Request Form to the county engineer to receive an ESC
bond.
File: El_ecp_PBC _ wpo- 2011 -00059 Stonefield Town Center.doc