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Home My WebLink About20000659 Ver 2_Email_20161219Higgins, Karen From: Higgins, Karen Sent: Monday, December 19, 2016 1:07 PM To: 'Chris Wu' Cc: Trevor Crawford; James Zieglmeier; Bromby, Craig A; Nimmer, Kim; Burdette, Jennifer a Subject: RE: 3M Chris - Thanks for sending this updated info. Jennifer and I do not have any further questions at this time. Please include this sequencing with your mine application and your 401 WQC application. Thanks- Karen hanks- Karen Karen Higgins 401 & Buffer Permitting Branch Supervisor Division of Water Resources Department of Environmental Quality 919 807-6360 office k Ir uJ.:_Ih_i.c iu�sC ncdenr.gov 512 N. Salisbury Street, Suite 942-E, Raleigh, NC 27604 1617 Mail Service Center, Raleigh, NC 27699-1617 x EFn7 itorrcspomlen to amY from this aYYYress is subio t to the Nodh Carolina Public ReconYs Law amY rr7abe �Yisclose� Y to thi Y padies, From: Chris Wu [mailto:cwu@ectinc.com] Sent: Thursday, December 15, 2016 12:57 PM To: Higgins, Karen <karen.higgins@ncdenr.gov>; Burdette, Jennifer a <Jennifer.Burdette@ncdenr.gov> Cc: Trevor Crawford <tccrawford@mmm.com>; James Zieglmeier <jazieglmeier@mmm.com> Subject: RE: 3M Karen, Jennifer — as we discussed earlier today, 3M has slightly modified its approach to severing the streams. Please review to make sure this approach is consistent with our conversation. Under Phase 1 expansion, an additional stripping area will be added, which is referred to as "Stripping Area V (see attached figure). This area is located in between 2 of the streams, outside the buffers, and outside the contributing drainage area to these streams. An additional temporary sediment basin will be added as a BMP to control runoff during stripping activities. This stripping area will allow 3M to extend the existing quarry northward between these streams and create a low -point in the topography which can be utilized, in conjunction with permanent/temporary stormwater diversions, to intercept surface water which would normally flow through these streams to Jordan Lake. Phase 2 expansion will require these streams to be immediately diverted to the existing quarry, away from Jordan Lake. In order to do that, temporary water pumping measures will be implemented until earthen diversion channels can be constructed. There are 3 intermittent streams that will be diverted to "Stripping Area V. The individual streams and respective measure(s) to divert surface water runoff to the existing quarry are listed below: Stream SA3: 3M will place a temporary diesel powered pump outside of the 50' buffer at the point of severance and pump the stream until it's dry. 3M intends to schedule this work during a dry period to minimize the amount of water that will need to be pumped. Once the stream has dried up 3M will manually excavate a hole at the point of severance and insert the pump into the hole as a precautionary measure. Once this hole is created, a 4' tall embankment with 2:1 side slopes will be constructed within the streambed and pumping measures will be implemented immediately. This embankment will create a temporary surface water reservoir capable of storing 0.33 ac -ft. This stream is intermittent and the pump will be operated based on water levels within the temporary reservoir. While pumping occurs, a stormwater diversion will be constructed to intercept this stream flow and divert the water "stripping Area V. The diversion will be approximately 600 feet long and it is anticipated to take about 3-4 weeks to construct (pumping would need to occur for this construction duration). The diversion is designed to pass the 100yr- 24hr storm with 12" minimum of freeboard. Additional Data: Contributing Drainage Area: 6.9 ac 25yr-24hr peak flow rate: 15.83 cfs 25yr-24hr runoff volume: 1.66 ac -ft Temporary Pump Flow Rate: 5,000 gpm (11.14 cfs) — please note that pump rate is a maximum flow rate and will likely never be reached. All water will be pumped into Stripping Area E where the majority of water will infiltrate into subsurface fractures or collect at the bottom of the Jordan watershed portion of the quarry. Anticipated pumping duration: 3-4 weeks Stream SA4- Pumping will occur immediately out of the existing ACOE jurisdictional pond located at the headwaters of this stream using a temporary diesel powered pump. Similar to SA3, 3M will pump the stream dry, manually excavate a hole at the point of severance and insert the pump prior to construction of a stormwater diversion will be constructed to intercept this stream flow and divert the water to the quarry. This specific stormwater diversion will be a portion of the diversion needed for stream SA3 (SA3 and SA4 will share one diversion). Stream SA4 is closer to "Stripping Area E", and it is anticipated to take 1-2 weeks to construct this portion of the diversion. Pumping would need to occur for 1-2 weeks on an intermittent basis. The pump will operate based upon water levels within the existing pond. Additional Data: Contributing Drainage Area: 8.02 ac 25yr-24hr peak flow rate: 25.65 cfs 25yr-24hr runoff volume: 1.93 ac -ft Temporary Pump Flow Rate: 5,000 gpm (11.14 cfs) — please note that pump rate is a maximum flow rate and will likely never be reached. All water will be pumped into Stripping Area E where the majority of water will infiltrate into subsurface fractures or collect at the bottom of the Jordan watershed portion of the quarry. Anticipated pumping duration: 1-2 weeks Stream SBI: Minimum pumping is anticipated at this location because "stripping area V will be nearby, and the stream often dries up throughout the year. However, similar to SA3 and SA4, 3M will manually excavate a hole at the point of severance and insert pump as a precautionary measure prior to construction within the buffer/streambed areas. An 150 foot long stormvxaterdiversion will be constructed immediately which will be capable ofpassing the 100yr-24hrstorm with 12" minimum of freeboard. This diversion should take approximately I week to construct. Please let us know if you have any questions. Thanks, Chris Christopher Wu Water Resource Project Manager EDvin3DDleDta| Consulting &TechD0|ogy, Inc.* T208Falls ofNeuse Road, Suite 1021Raleigh, NC 27615 919.861.8888(Dffioe)1919.423]045(CeU) *Operating within North Carolina as "Environmental Consulting & Technology of North Carolina, PLLC."