0501_AsheCo_MSWLF_031213OnSiteSWMeeting_DIN18717_20130327

North Carolina Department of Environment and Natural Resources
Division of Waste Management
Pat McCrory Dexter R. Matthews John E. Skvarla, III
Governor Director Secretary

2090 US Highway 70, Swannanoa, North Carolina 28778
Phone [phone] \ FAX [phone] \ Internet http://wastenotnc.org
An Equal Opportunity / Affirmative Action Employer – Printed on Dual Purpose Recycled Paper

March 27, 2013

Mr. Scott Hurley
Director Environmental Services
PO Box 1327
West Jefferson, North Carolina 28694

Subject: Summary of March 12th On-site Meeting- Stormwater Management
Ashe County MSW Landfill
Ashe County, Permit #05-01, Document ID No. 18717

Mr. Hurley:

I am writing to summarize the discussions from our March 12, 2013 meeting regarding the
storm-water control issues in MSW Phase 4. The summary will outline the noted factors which
contribute to the current situation and outline countermeasures typically used in landfill cells to
control storm-water.

The primary factor appears to be the relatively large area in Phase 4 with no storm-water control
features. According to the most recently issued Permit to Operate, Phase 4 encompasses an area
of approximately 7.85 acres. Subtracting out the areas within the temporary cell and the north
end of Phase 4 where waste has been placed and the cover graded to direct storm-water away
from the cell, at least 4.0 acres of Phase 4 are left that are collecting storm-water. One (1) inch
of liquid per acre is equivalent to 27,154.3 gallons. The open area in Phase 4 is generating at
least 100,000 gallons of liquid for each inch of rainfall received at the facility.

The small volume of waste existing in Phase 4 is another factor contributing to storm water
control issues. Liquid can quickly percolate through the small waste mass to the sump where it
flows by gravity to the leachate lagoon. The leachate lagoon has a capacity of 500,000 gallons
with two feet of free board, according to the Engineering Plan submitted as part of the Phase 4
Permit to Construct application. The leachate lagoon can quickly reach capacity given the
significant volume of liquid being generated in Phase 4 during rain events. This is important
since your primary method of managing leachate is through recirculation. That is difficult at best
in the small amount of waste in the phase. The Section assisted Ashe county in their management
of the leachate by allowing recirculation in Phase 2. The benefit was minimal since the phase
was already saturated by the time this change was implemented.

Other contributing factors discussed include the side-slope drainage from Phase 2 and the
inability to continue hauling leachate to the West Jefferson Wastewater Treatment Plant
(WWTP). The benches added to the northern side-slopes of Phase 2 directed storm-water from
Mr. Scott Hurley
Meeting Summary
March 27, 2013
Page 2 of 3
those slopes into Phase 4. The West Jefferson WWTP refused to accept any more leachate from
the facility. Ashe County was able to find another WWTP willing to accept the leachate. The
high precipitation totals are a factor.

There are several storm-water management features successfully utilized at facilities throughout
the State. These include, but are not limited to, flexible membrane rain covers and storm-water
diversion berms with rain flaps.

A rain cover is a thin sheet that is usually placed over the disposal area, on the protective cover,
to keep rain from entering the leachate collection system (LCS). Similar to the flexible
membrane liner, the rain cover is installed in large panels that are then seamed in the field.
Ballast, generally tires or sandbags, are placed at specific intervals to hold the rain cover in
place. Any storm-water that is collected on the rain cover may then be pumped off into storm-
water management features outside of the disposal area. With this system, waste filling
generally begins in the high side (elevation) of the disposal unit with the rain cover being pulled
back so that liquids percolating through waste are captured in the LCS. Using this system,
storm-water falling in unused disposal areas cannot enter the LCS and is managed separately.

Similar to the rain cover, storm-water diversion berms with rain flaps can be installed. The
berms are small dams constructed perpendicular to the fall line in the bottom of the disposal unit.
Construction of the berms involves welding a flap of liner material to the flexible membrane
liner on the bottom of the disposal unit. The flap is then laid on top of a berm, generally
constructed with the same material as the protective cover, just down-stream of the weld. The
LCS is installed on either side of the berm with a sleeve in place adjacent to the berm so the
system can be connected once the flaps and berms are removed. In this manner, the diversion
berms create zones within the disposal unit that are hydraulically disconnected. With this
system, waste filling generally begins in the low side of the disposal unit and progresses upward
towards the berms. Once filling activities near the berms, they are removed and the LCS lines
connected. Using this system, storm-water falling in the unused disposal zones cannot enter the
LCS and is managed separately.

There are other options available. The two systems outlined above have been utilized to
successfully manage storm-water throughout the state. Ashe County, if they haven’t already,
must plan for installation of storm-water control features. If they aren’t part of the approved plan,
they must be submitted to the Section for review and a permit modification prior to
implementation. Given the critical nature of these designs, it is crucial for you work with your
consultant engineer in planning and implementing these strategies.

There is erosion evident in the protective cover. The area in Phase 4 where the plastic sheets
were installed have significant loss of protective cover. It is probable the protective cover has
been removed in some locations all the way down to the flexible membrane liner. These areas
must be repaired prior to placement of waste in order to ensure the integrity of the liner system.
It is crucial for you to work with your consultant engineer in planning and implementing the
protective cover repair work as well as having competent quality assurance oversight to ensure
the underlying components are not compromised.

The county has incurred significant cost, more than the cost of the management methods, to
purchase a truck for hauling leachate to the wastewater treatment plan. However, given the
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Meeting Summary
March 27, 2013
Page 3 of 3
amount of leachate generated for every inch of rainfall, the control of the liquids is not occurring
rapid enough. The county should contract for additional trucks to remove leachate so that more
leachate is being removed than is being generated.

If you should have any questions regarding the contents of the letter please contact me at (828)
296-4703, or by email at [e-mail] .

Sincerely,
Allen Gaither
Environmental Engineer

Cc: Dr. Patricia Mitchell – Ashe County Manager
Mr. Charles Gerstell – SWS/MRO
Mr. John Murray – SWS/MRO