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Meets the applicable criteria for a S,,,all Area Exemption, the proposed drainage control measures should be effective in
<br />controlling runolT and sedimentation, and construction of full-scale d,ai„agc and aedi,,,r,„ T co„T,ol sT, uctures is neither
<br />needed nor justified.
<br />13 -Left Outbv Utility Borehole (MR15-L9i) — Givc„ the li,,,;ted disturbance areas, the location Ot the road and pad
<br />Oil a lOw-Ly a;dchill_ ,,,d the ve,y temporary nature Of the planned disturbance, the 13LT Outby Utility Borehole
<br />pad_ and associated road will have minimal impact relative to runoff au,d sediment CouL,buLo The I;,nited amount
<br />of drainage from upgradient areas will be iiae,Ccpted a„d ,otuted around the borehole pad by a Small upgradient
<br />diveraio„ ditch o„ tl,r, ao„div.est and northwest sides of the pad. The existing ranch road crosses a small epl,a„e,al
<br />drainage, and the existing culvert will remain inct
<br />-place. t he ,lvert ,,,3talla'v„ t,will evaldated relative to condition
<br />and cover to carry the auiticipatud truck traffic, tl,e culvert will be replaced or extended as necessary, and adequate
<br />vier ..ill be placed to carry the anticipated loads, without crushing the ct,lvert. Lhai„ag'c fio,,, the bo,el,ole pad
<br />area will be controlled under a Small-Arca txemptio,,, will, gavel surfacing On the pad and road to control runoff
<br />an,d aedi,,,r,nt acid pl.,ce,,,eot of rigid sediment filter material On the northeast side Ot the pad area. The upg,adir,„t
<br />diversion ditches will drain through rock Sediment bashes to the u„diatt„bed adjacent la„ds, aad pad cut/till areas
<br />will be stabilized wvith temporary revegetat,o„ seeding. As a very limited disturbance area (approximately 1.0 acres
<br />for the pad a„ d road. of which 2.4 acres is road) the disturbance areas meet the applicable mite,ia fo, a Small A,r,a
<br />Exemption, the proposed drainage control meast,res should be etteetive i„ co„t,oll;ag runoff and Sedimentation, and
<br />construction or 'Cull-3cale dfai„age and sedulle,lt control Structures is neither needed norjUStltlea.
<br />Field geotechnical Investigations — TC occasionally eon dari:3 field geotechnical investigations prior to, and as the
<br />basis fol -7 deai<sn au,d CouaTi LlMiO„ of engineered structures. Geotechnical investigations typically involve Shallow soil
<br />bor;n,-s (up to '0 feet) using a hollow -stem auger, andior excavation of shallow (up to 15 feet) teat pits. For both soils
<br />borings and test pits. Shrface diaturbanee ;a ,,,i„i,,,al („o more than 10 x 10 tees for boreholes, and 10 x 15 feet for
<br />teat pita) md boil. d,Slurbance and subsequent Stabilization occur within a timeframe Of less than mirday for each
<br />site (typically test pit excavation/soils boring, and backf Ili„g and leveli„g Of the resultant small area/auger-hole,
<br />occurs i„ J C0116111.101.13 aeque„ce within the course of less than two hours for each location). The geotechnical
<br />investigation activities do not involve the use Ot water and are normally conducted wide, d,y conditions o, when
<br />the ground is trozen, So the potential for related hyd,olog;e ;,,,pacts ;s negligible. All geotechnical disturbance is
<br />reseeded by broarlca3t need;„g W;TI,;„ 6-,nontlis Ot disturbance, although natural revegetation typically occurs much
<br />aoo,ter due to the limited timeframe and extent Ot the associated distUrba„ee. Occaa;o„ally pmforated PVC p;pe
<br />may be inserted in a completed borehole; and the ,r,,rta l,,de, of die hole backtilled with clean gravel, as a temporary
<br />1�;e�on,et�r ii,atall:,tio„ to measure any fluctuation in water -levels. This type of piezometer installation ;a normally
<br />very temporary (typically used less than a month) and will not ;,,,pact g,ou„dwater due to the Shallow depth and use
<br />of natural C[,tt;„ga a3 barkfll. Ally p,ezOmeter Installations are reclaimed by either pulling the PVL pipe and
<br />placing additional fill. or plugging the PVC pipe in-place t,Siu,g bagged be„ To„;r g,o,ut, die„ capping the
<br />installation with a nllhlmUtrl 1.5400t surface plug of „antral clays or cement with a Site marker.
<br />Lo:tdout Area Urainalze Modifications (MR14-254) - The drainage and aedunc„T controls for this area were
<br />approved under an SAE. as referenced i„ the Per,,,,T tr_%i, however, given the contiguradon and type and level of
<br />activities i„ d,ia ai'e.,. the e.:isting drainage and sediment controls were tound to be marginally adequate. The air
<br />conditions were reviewed and evaluated, and the follow;ng changed, as dhow„ o„ F;gu,e EX49DD-F1_ were
<br />implemented to ,,,od;ty and upgrade the s;te drainage controls in order to be effective under all reasonably
<br />anticipated conditions.
<br />The pad area on the north side of the rail spur was reduced in size by remov;„g the accumulation of eoally ,,,Ate,;Al, A„d
<br />regrading and m3eed;„g p.n-t of this area. leaving only an access road along the north side of the spur. The drainage
<br />configuration of the remaining pad Waa modified by f11;„r� u IoW a,ea and placing a berm to direct all drainage to the
<br />collection sump. The Sump capacity and function were expanded by co„st,uct;„ g a aeeo„ d au,,,p i„ dr,,;ea, ,e,novi„g
<br />acctn„ui.,ted sed;n,e„t rron, The CA;ati„g su,np, and rebuilding the rock perimeter filter. The control capacity of the raii
<br />Spur collection ditch was increased by excavating aeve,al sed„nc„ t Taps ;n the ditch and adding additional rock check
<br />da,,,s. As a very limited disturbance area (approximately 1.2 acres) the Loadout a,ea d;atu,ba„ce u,ecta the applicable c,;te,;a
<br />for a Smell AiT., Exa„ption_ the proposed drainage control measures should be effective in Co,a,ofl;„g n,notf and
<br />sedimentation. find co„atruCtio„ of fuii-acalc drmi,arc And sediment control structures is neither needed nor justified.
<br />MR 16-295 2.05-84.10 04/01/16
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