Onslow Sands Mine (2)

A NCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen H. Sullins
Governor Director
MEMO
TO: Cory Larsen
FROM: John Dorney
DATE: July 20, 2010
RE: Comments on wetland monitoring plan for Onslow Sands project, Onslow County
Dee Freeman
Secretary
Staff from the Wetlands Program Development Unit who are familiar with wetland monitoring
have reviewed the "Operation and Monitoring Plan - Onslow Sands, Inc. Bellmont Avenue" prepared by
Walton Engineering as revised on June 24, 2010. We believe that the plan needs major changes as
outlined below before approval by DWQ in order to provide assurance that wetland standards (15A NCAC
2B..0231) are met. Please contact me at 733-9646 or Rick Savage at 715-3479 if you have any
questions.
1. Additional monitoring wells - Two (2) additional wells need to be established in the wetland near
the "Pearson Family Cemetery" and on the west side of the site since it is possible that
groundwater withdrawal could result in alteration of the hydrology for these wetlands.
2. Relocated well - The well (Proposed Monitoring Well #2) is located directly downslope from
Discharge Pipe #2. This well must be relocated away from the discharge in order to be
representative. We suggest a location midway between Discharge Pipe #2 and Discharge Pipe #
1.
3. Additional discharge location for water - We suggest that an additional discharge location be
added to the plan on the west side of the site in order to provide assurance that the hydrology of
this area is not altered. A located near (but not directly upslope from) Proposed Monitoring Well #
4 would be appropriate.
4. Well monitoring - Well monitoring shall use automatic monitoring wells set to record water levels
four times a day for the first six months. The frequency can then be lowered to daily upon written
agreement of DWQ if the data demonstrate no significant effect on hydrology.
5. Reference wetlands - The applicant will need to identify the wetland types on site (using the
recently adopted NC WAM wetland types - see weblink
athttp://portal.ncdenr.org/c/document I library/get - file?uuid=d93ece45-aeb5-420c-bcd5-
07698149711 b&groupld=38364) and then propose monitoring locations (at least one for each
wetland type) near the proposed mine. DWQ will need to approve those locations in writing.
6. We suggest that the applicant propose hydrology criteria which shall be maintained compared to
the reference wetlands. The criteria should be a percentage deviation from the water level shown
in the reference wetlands and DWQ will need to approve that criterion.
Please let us know if you need additional information.
Cc: Rick Savage
Ginny Baker
File copy
401 Oversight/Express Review Permitting Unit
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
Location: 2321 Crabtree Blvd., Raleigh, North Carolina 27604
Phone: [phone] FAX: [phone]
Internet: http://h2o.enr.state.nc,us/ncwetlands/
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