20090662 Ver 1_Staff Comments_20090630

Lucas, Annette
From: Lucas, Annette
Sent: Tuesday, June 30, 2009 2:12 PM
To: Cranford, Chuck
Cc: Lucas, Annette
Subject: 09-0662 Evers, LLC
Attachments: 09-0662 Evers, LLC.doc
Chuck,
My comments are attached - there were a lot of technical issues associated with the proposed infiltration basin (as you
will see). I spoke with Wanda Austin about some of these comments yesterday.
Thanks,
Annette
From: Cranford, Chuck
Sent: Friday, June 26, 2009 9:40 AM
To: Wanda Austin
Cc: [e-mail]; Lucas, Annette
Subject: RE: Evers
Wanda
I have given the Evers Project a preliminary review and spoken with Annette Lucas in the Wetlands Unit who will review
the stormwater management components.
At the very earliest, we will have a response by the end of next week, which at this point looks like it will be a request for
additional information.
Just so you know, we have 60 days to review 401 Water Quality Certification Applications, which for this project
provides a deadline of August 8. We try to review projects as quickly as possible and accommodate applicant needs, but
are required to process projects in the order in which they are received.
Let me know if you have any other questions.
Regards,
Chuck
Chuck Cranford - [e-mail]
North Carolina Dept. of Environment and Natural Resources
Asheville Regional Office
Division of Water Quality - Surface Water Protection Section
2090 U.S. 70 Highway
Swannanoa, NC 28778
Tel: [phone]
Fax: [phone]
E-mail correspondence to and from this address may be subject to the
North Carolina Public Records Law and may be disclosed to third parties.
From: Wanda Austin [mailto:[e-mail]]
Sent: Wednesday, June 24, 2009 6:12 PM
To: Cranford, Chuck
Cc: [e-mail]
Subject: Re: Evers
Thank you. The contractor is needing this quickly. We have had the 404 certification and would like to be able to install
the culvert this week. What can we do to expedite this ?
From: "Cranford, Chuck" <[e-mail]>
To: "[e-mail]" <[e-mail]>
Sent: Tuesday, June 23, 2009 3:49:19 PM
Subject: Evers
Hello Wanda:
I have received the 401 package and will likely get to it within a week or so.
Chuck Cranford - [e-mail]
North Carolina Dept. of Environment and Natural Resources
Asheville Regional Office
Division of Water Quality - Surface Water Protection Section
2090 U.S. 70 Highway
Swannanoa, NC 28778
Tel: [phone]
Fax: [phone]
E-mail correspondence to and from this address may be subject to the
North Carolina Public Records Law and may be disclosed to third parties.
F mail ..re ,?,nde x to Lind from this sender is subject to the N.(- PuNic Records I v,end may be disclosed to third parties.
2
09-0662 Evers, LLC
AML Comments
June 30, 2009
Please provide a field study of the infiltration rate of the in situ soils in the
location of the proposed infiltration trench. If the infiltration rate is less than 0.52
inch/hour, then please select another device to treat the stormwater from this site.
Please provide a BMP Supplement Form for each proposed best management
practice that will be used on the site (including both worksheets, Design Summary
and Required Items Checklist), as well as all of the required items. The BMP
Supplement Forms are available on the DWQ web site at:
littp://li2o.enr.state.nc.us/sutbnip forms.htm.
2. If the soil study shows that the infiltration rate will support an infiltration trench,
then please address the following issues:
a. Per the BMP Manual, please provide a flow splitter device to bypass storm
volumes that are in excess of the treatment volume as determined from the
one-inch storm. Volume in excess of the treatment volume shall be evenly
distributed across a minimum 30 foot wide vegetated filter strip.
b. There appear to be a number of discrepancies on the Stormwater
Management Plan sheet about various aspects of the infiltration basin
design, such as the use of a 4" sand filter and filter fabric and the
dimensions of the device. Please correct these discrepancies in your
resubmittal.
c. Per the BMP Manual, infiltration trenches should be lined with a layer of
sand with a depth of four inches or greater. Also, drainage media should
be enclosed on all sides by a geotextile filter.
d. Please re-size the infiltration trench based on the actual infiltration rate of
the in-situ soil.
e. Per the BMP Manual, trench depths must be between three and eight feet.
The DWQ recommends that you consider a more shallow infiltration
trench to avoid hitting rock and for better cost-effectiveness.
f. Per the BMP Manual, the width of an infiltration trench should be less
than 25 feet.
g. Per the Required Items Checklist, please show the boundaries of the
proposed drainage easement around the infiltration basin.
h. Please specify a minimum slope of 0.5% for the underdrain pipes. Please
also specify the size and spacing for the underdrain pipe perforations.
You may wish to consult section 5.7 of the BMP manual.
Per the BMP Manual, please provide a pretreatment device to remove
sediment prior to the stormwater entering the main treatment area of the
infiltration basin.