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HomeMy WebLinkAbout20061820 Ver 2_Modification Request_20091019INDEPENDENT ENVIRONMENTAL ENGINEERS, SCIENTISTS 1 AND CONSULTANTS O LP Q Malcolm Pirnie, Inc. 701 Town Center Drive, Suite 600 Newport News, VA 23606 T: 757.873.8700 F: 757.873.8723 www.pirnie.com pAI October 15, 2009 Cyndi Karoly NC DENR-DWQ Wetlands and Stormwater Branch 401 Oversight/Express Permitting Unit 1650 Mail Service Center Raleigh, North Carolina 27699-1650 PIR&INIE? OCT 1 s 2009 DENR - MTER O JAIM WETLANDS AND STORMYI IM BRANCH Re: City of Jacksonville Land Treatment System Upgrade and Expansion Request to Modify Section 401 Water Quality Certification 20061820 Dear Ms. Karoly: The City of Jacksonville (City) requests the North Carolina Division of Water Quality to modify the above-referenced permit to allow authorization for the construction of nine additional stabilized access trails as part of the City of Jacksonville's Land Treatment System (LTS) Upgrade and Expansion Project. The construction of 15 stabilized access trails were permitted originally, however, subsequent investigations of field conditions have indicated that one trail (impact 1) will no longer be needed as a previously-constructed path can be used for access to this area. In addition, another trail (Impact 20) has been constructed with no impact to wetlands as the trail was constructed within an existing access road. The field investigations have also indicated the need for nine additional trails which will be required to provide City staff access to the proposed spray irrigation fields. Eight of the newly proposed trails will be completely contained within previously permitted wetland crossings (Impacts 39, 42, 43, 44, 56, and 65), while one trail is proposed within a new impact area (Impact 75). The crossings within the eight existing impact areas have already been permanently converted as permitted and aligning the new trails within these crossings has eliminated the need for additional clearing of wetlands. The City requests that the permitted impact categories for these eight areas be revised from permanent conversions to a combination of permanent conversion and fill impacts. The City also requests that the permit be modified to include Impact 75 as a new fill impact. Compensation for these additional permanent conversion/fill impacts is discussed below. As-Built vs. Permitted Impact Comparison As-built measurements of nine completed access trails were obtained August 27, 2009 to verify the area of impact of the trails. As shown on Figure SK-1 (Attached), three separate widths and one length measurement were taken along both the approach and departure sections of the trail which were used Solutions for Life'" is Cyndi Karoly NC DENR-DWQ October 15, 2009 Page 2 of 4 to calculate the area of these sections. Three width measurements were also obtained within the culvert section, one of which was the maximum width including the culvert pipes, to average the total width of this section. The average width multiplied by its length provided the area of impact for each section. The calculated areas of the approach, departure and culvert sections were combined to determine the total area of impact for each trail constructed to date. The permitted and as-built impact areas of the nine completed access trails are listed in Table 1 (Enclosed). The area of impact for each of these trails has decreased from the permitted impacts as a result of reductions in impact widths or a combination of reductions in impact lengths and widths. The decreases in impact areas range from 3 to 65% while the average decrease in permitted vs. as-built impact areas is 39%. As-Built vs. Remaining Permitted Access Trails The average widths of the as-built impact areas were multiplied by the proposed lengths of the remaining permitted access trails to estimate the anticipated impact area of the remaining four trails. This is an appropriate estimate of the impact from the remaining trails as they will be constructed using the same methods and standards as those already completed. The estimated impact area for each of the four remaining trails will be reduced from the permitted impact area (Table 1). The decrease in impact area for the four trails is estimated to range from 31 to 52% below that which was originally permitted. The reduction in impacts results from decreases in impact widths or a combination of reductions in impact lengths and widths. Proposed Impacts As mentioned above, nine additional stabilized access trails are needed and are proposed at Impacts 39, 42, 43, 44, 56, 65, and 75. Eight of the nine new trails will be constructed adjacent to above ground piping and would constitute a filling of wetlands. Two trails will be constructed within Impact 39 as shown in Figure SK-2 (Attached). Impacts within this area have been reduced from the permitted total as a review of existing field conditions indicated that the center of this impact area is stable enough to provide City access without the need for installing a stabilized access trail within this portion. Two separate trails are also proposed within Impact 42 (Figure SK-3) and a review of field conditions has indicated that a stabilized access trail is.not needed within the central portion of this impact area. The proposed impacts within Impacts 43 and 44 have been reduced from the permitted totals resulting from a reduction in both the length and width of the impact areas (Figures SK-4 and SK-5). One stabilized access trail is proposed within Impact 56, which will be constructed at the permitted length, but the impact width has been reduced (Figure SK-6). One stabilized access trail is also proposed in Impact 65 (Figure SK-7). The proposed stabilized access trail in this Impact is longer than the permitted length; however, the impact width has been reduced. The proposed trail within the new impact area (Impact 75) will be constructed to provide access from an existing LTS access road to the proposed spray is 11* Cyndi Karoly NC DENR-DWQ October 15, 2009 Page 3 of 4 irrigation field shown on the bottom of Figure SK-6. This area has been delineated and jurisdictional wetlands exist on site. The anticipated area of fill for each impact has been calculated using the mean widths of the completed access trails mentioned above and the revised impact lengths in Table 1. Based on the impact estimates calculated from as-builts to date, the combined area of fill from the nine additional access trails is 21,272 square feet. A small strip of land (approximately 5 feet wide for the entire length of the wetland), within the eight impact areas where stabilized access trails are to be constructed adjacent to above ground piping, will remain as permanent conversion to allow for maintenance of the installed piping. The remaining area within each of these eight impacts will not be maintained and will be allowed to naturally revegetate. An approximately 33,070 square foot (0.76 acre) decrease in permanent conversion area project-wide will result from changes proposed with this request for modification. The majority of the decrease results from changes in impact type in areas from permanent conversion to fill. However, approximately 12,930 square feet will be allowed to naturally revegetate and should now be considered a temporary impact. Even with the additional stabilized access trails, a net decrease in fill/excavation impacts is anticipated. There will be an approximately 2,546 square foot decrease in impacts resulting from a decrease in the width of the filling activities within the areas of the stabilized access trails. In total, if the permit is modified as requested, the project's combined permanent conversion impacts will change from 5.54 acres to 4.78 acres and fill/excavation impacts will change from 25.56 acres to 25.50 acres. Mitigation The City has previously compensated for impacts associated with the project by preserving 728 acres of land in a conservation easement held by Sturgeon City of Jacksonville Incorporated. In addition, the City has made payment to the North Carolina Ecosystem Enhancement Program (NC EEP) in the amount determined by the NC EEP, sufficient to perform the restoration of 25.6 acres of non-riparian wetlands in the White Oak River Basin, Cataloging Unit 03030001. No additional compensation associated with this request is proposed, because permanent conversion and fill/excavation impact totals are anticipated to not exceed the originally permitted amounts. However, if as-built surveys show additional wetlands were impacted, the City will evaluate mitigation alternatives such as the Hofmann Forest Mitigation Bank and NC EEP. Please contact me or Bob Belcher at 757-873-8700 if you have any questions or comments. 0 Very truly yours, MALCOLM PIRNIE, INC. Travis Comer Project Environmental Scientist trc 0707-111 Enclosures C. Brad Shaver, USACE Greg Meshaw, City of Jacksonville Bob Belcher, Malcolm Pirnie, Inc. Bill Hixon, Malcolm Pirnie, Inc. Jim Pimblett, Malcolm Pirnie, Inc. 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F D _ a 3 V N ? ? v m a » lD O A 0 00 0 J 0 N t 0 0 0 pi 0 N O 0 "' 0 T 'A m x jp d a G Z D A ? F 00 N r N f + l /i N H W N W F + ? -. A ? -+ N f+ F + f + N N f + d O A N O O O J I O n O W O V O N O A O 1 N -+ l W p w W l w 0 V a 0 pi v ? O p N p 0 ? ? T» O V 0 I n D W m N C 3 3 D a O n V A m A G m v D z v Cz sC m -I z v_ D f'1 -i IMPACT AREA I S P u r z I CITY OF JACKSONVILLE, NORTH CAROLINA IRRIGATION SYSTEM MALCOLM PIRNIE, INC. DEPARTMENT OF PUBLIC SERVICES UPGRADE AND EXPANSION TYPICAL STABLIZED OCTOBER 2009 CONTRACT 2 ACCESS TRAIL SK-1 SCALE: NOT TO SCALE + + + + + + + + j[ _J f • a + + + } + + /? + + + + f + + + +++++ e .1'87.2 x IJ + + +4+ r 89.0 x ++++++ + + x ' +++++ ,?a +++ ++ 8.5 + + + + + 4 ,,a t + 88 8 ++? + + ++ 90.8 ?.8+ 0) 89.8 ++ ++ x ? f .rc x + +/ ++++ ++ k / + + + 88. L + + + +/+ + + + + x lx 72 x ++ + + ++ ++ N 377,00 + ++++++++++}q8.#5 + + + + + + + + + + .. + + + + ,. +++T+; + :::':; y W PROVIDE 200 ?LF? s?^ a: ::...... ..... OF STABILIZED & + + ..::...:..... ACS IL j + ::::::.:•:::::::•:::::::::::. 87.6 + y r.GJ; t •''l''•j x ............ . v ...................... i .... :r::: :. .::::: Zqr:: :.. . a :::::::?; `• . ::ri .. ° f: ..8g :•: ::0: `.y.:. " .............................. ' :. ... :.:• .•:. ..: :• . .: f :.: .•.:.........•.?. . :.::............... 872 :,: :' x 4 / .... ..................... + + e.." / + } ...... r.; ......... Q ? . w ........... 5 ; ++ x 87.7 x -- N=376748.4 878 E=2426907.9 x PROVIDE 250 LF OF STABILIZED ACCESS TRAIL / 89.7 x 75 0 75 1 SCALE: 1"f50' 87.9 REF: IRRIGATION SYSTEM PLAN 18, 19 CITY OF JACKSONVILLE, NORTH CAROLINA IRRIGATION SYSTEM MALCOLM PIRNIE, INC. DEPARTMENT OF PUBLIC SERVICES ADDITIONAL STABLIZED UPGRADE AND EXPANSION OCTOBER 2009 CONTRACT 2 ACCESS TRAIL SK-2 imi SCALE: 1" = 150' LJ p ,. .... .. N=374786.7 E=2427055.3 7 7 E-242 8?..4mm + + + + + # + E +I + + + + t l / + + + + + E i + +, 9 ' tw E y"""_ IMPACT 421/') PROVIDE 130 LF/ X85.3' -OF STABILIZED ... M x .y ACCESS TRAIL :'': :. f :. .r. •. y y :;..:..•. .. ............. y **+ ... ............::...:: 4.71 'N=374154.6 .... 1 f. LE=2427165.9 y ++ '*# PROVIDE 180 LF+,++++++ **+** +*+ OF STABILIZED '" ..: *+++++*+++ +t ACCESS TRAIL + +++ ++•.. *****+*+*+++}+ + ---- __.,. .. _ + + + + +++++ * 31169 184.8 86.8 tl +Z+ ++++ 3'fI 87.2 ++ ++ X v n I X *Ir :'::' ++** +++ +++ ROAQWAY I r ( j *+ 75 0 75 150 +** SCALE: 1" =150' 85.1 +++++REF: IRRIGATION SYSTEM PLAN 22 CITY OF JACKSONVILLE, NORTH CAROLINA IRRIGATION SYSTEM MALCOLM PIRNIE, INC. DEPARTMENT OF PUBUC SERVICES ADDITIONAL STABILIZED UPGRADE AND EXPANSION OCTOBER 2009 CONTRACT 2 ACCESS TRAIL SK-3 SCALE: 1 = 150 * + + + '+ + + + + t ; + + + t _JL 41 t t +•4j ZF .. t9 n .. "'4 ++ + ?+ + t N E Fr 4 ++ +j + rn S + ? + + 464 ". + !; + J Y? + + t N + + + ++++} ++ 0 t+ .1 •+ + t t t t t t+ + +?+ + - ++ + a 4 r ?„ 0? +/ + + , + +; + + + N :.. } + t } + +i +i + r' r- ---'f` t t }++ t f f t :.. t.......... ................. ;: +++ +++?++ ++5+++++/ + + + y,t + + ..,4 + + + ::::: + +?rt? + + *+ + N d :.. .•.:•: .•:.:•..... .. + + } i +4 O .:::: :'. .:: } + f RO D 450 L OF STABILIZED :.:.: ACCESS TRAIL '. :. IMPACT 43 i i .0 m IN •4 7 j''Y S ? a J\r "'" - . r . .: :. :.......... Y"jr ..• ... 111 fJ L j + } + r + # + + + ............ ........... + + + ... 74 Z 2 .. Y ..?.. x 69.3 - N=3 3Tf?F: 9 E 429120. 21029 70.1 x + + + + + },nom} 141 v /n •• e :':.•..::'. :: W 70.9 x U (. p 0 I.::...''' ( F .......... ......... 1 :::.:.. :':'::'.....: ::. t. s N ? .... ............ ... W I :•J.::• •:: .•: :........ :::: .:•..: •.. ........, CITY OF JACKSONVILLE, NORTH CAROLINA DEPARTMENT OF PUBLIC SERVICES UPGRADE AND EXPANSION CONTRACT 2 : 75 0 75 150 SCALE: 1" =150' REF: IRRIGATION SYSTEM PLAN 22, 25 IRRIGATION SYSTEM MALCOLM PIRNIE, INC. ADDITIONAL STABILIZED OCTOBER 2009 ACCESS TRAIL SK-4 SCALE: 1" = 150' .' .... + ..... .. 1 ?.. r } .. s :. ?.......: s ?......... ........ x t s / r r r f 4 z 1 1 p N ... j ?. ?`! Z? .,? .....,.......r j N=372753.8 E=2425486.6 ' I i p t t+t + t t+ t t+ • U o i'J ,?/6,1 t+++ + +`++ ++? +_.+ ++ / t + + ' + + + + +f k d! + + + + + + + t t t t t t ft t t. t t t t t+ t + * + + + + + + + -+ + + + + + + + + + + + + k + + } + + + + + + + + + + + + + + + + + + + +,"4-'* + + + + + + + + + + ' + + + + + + + + + + 3 ?' + + + + + + + +{ + + + + + ' + + t + '+ + +... s + + t + _ ++t+ t+++++ ?t,w t? + + + + + + + + I P C 44 "" "" + + + + +6?f+ + + + + + + + + + ? + + + + + + + + + + ,*W+ PROVIDE 140 LF: + + •+ + + + + +**+tt+++++41++ + + ++ OF STABILIZED .: ! + + + + •,'+ + ,; + + --ACCESS TRAIL N=3724Tw4.6 1 ::.:,: X147 µ t- E=2421,46:1 ?.::.:..::: C? 2 ....... ..... : ....... ..... . ?=3723.08:4 ;Y .::.... ::: 1 ::::::':::::::' E2424902. ...:: a s tyo `t 1•:::. . 1 ,' ,. w N=3720714 ........: 4 4 ., ?. :. .. . yY z M :::: ::fM:.:_ T 37187 E =24238 .8 ...:::......... Y1 ::: -•.: ::........E- w. ::::::::::'::::: 4 d:: .............. f.... ........... : 4 .. ... . 75 0 75 ::::::::: <,:::. ?• s 150 N=37 E=2424 81.9 ! 1 SCALE: 1" =150 ::.'- :::::=:-:• 1 \ REF: IRRIGATION SYSTEM PLAN 24 CITY OF JACKSONVILLE, NORTH CAROLINA IRRIGATION SYSTEM MALCOLM PIRNIE, INC. DEPARTMENT OF PUBLIC SERVICES ADDITIONAL STABILIZED UPGRADE AND EXPANSION OCTOBER 2009 CONTRACT 2 ACCESS TRAIL SK-5 SCALE: 1 = 150 ......':' ......... t t :. 5 Yf iY':• .......... •Z••.I::::::. 4 {. .. ....... . .. ... 4.1.. .{ •• YN N OE F N v F ?F ?Y t t /+ t t+ tt+t/t++ x t t /+ + + .............. ?,. ... ............ + + + t ( ..... 1. ..................... .'. ................... ...:`a? .. + t t t .. d: : ':... .... a, ? :::............... . t t '':"w .. L'. f ...... .... f Iw z t e ?y t 4'v% . 1? ...... . . ..... . ... •::.' ?.. •.3... . : . r ?. X : 1 wn??.. :• y? ;' ^3 ;•' ''j•' ' \• ••F.e .1 . r :: .':.; ........ i. r ::: f PROVIDE 86 LF .. OF STABILIZED .....,. ::.::... '? ..... ... 4 N=370387.9 ::., ...... ,.::'. ' ACCESS TRAIL ......... E=2428916.8 ?. ':...t .....:::.:::::.::.:: . 'IMPACT 75 r .............. .0....... N . .'. :. / E .. ? .::::::::: .............. .'.:': N=370419.1 PROVIDE 168 LF :: E=2428682.3 ?.n OF STABILIZED : ..? y _. ACCESS TRAIL . f IMPACT 56. . ° 9 E=242894.2" ... ... ti° . 1 ,~ 4 x 67.3 .: .`°': .... 1 l N=- 6 , .41 E 5 9.0? . #•.. ... j tjf t T I `y ...... ...j....F! 31318 +j 1 + + .._, / + 13?5.3r E=2 2 7 619 -- 75 0 75 150 F, 60- "f SCALE: 1" =150' N 41-,0 REF: IRRIGATION SYSTEM PLAN 29 CITY OF JACKSONVILLE, NORTH CAROLINA IRRIGATION SYSTEM MALCOLM PIRNIE, INC. DEPARTMENT OF PUBLIC SERVICES ADDITIONAL STABILIZED OCTOBER 2009 UPGRADE AND EXPANSION ACCESS TRAIL CONTRACT 2 SCALE: 1 " = 150' SK-6 3 . . .......... ...................... ..................... r ..................... i } l : • W .. / .D J M r O 0 0 °N=363651;4 ' E=2423418 9 N 63561 7 } x ( . E=223458.E 5 ;5 63.8 . . N_=363898.6 ::•::, ::: E=2423586.8 . ? . 67.5 . , r :;<:: ::: ....... ........ :::::::::::.. : 6 ..................? ..:........,, ................... ............... N=363503.8 ..........::: :..::::::::: ?:w.:....r. ::: E. y .. r ?. 117........................ A. ?k i .4 x IQQ563377.6 60.2 x E=2423564.1-7::? N- ?2.6r IMPACT 65`,, E= 086-:4 .... ;;; r... f,l.. c. 60.8 6.4...... 4.... ••. .... 04 i 1? .. : ?:: • ':::.' •: 911, ?? •': •.C•:: •:. ?. J? p,,., w / pL PL ........ :....: .. ...... ,• .......... .. ...: :. J ?• '. ;a? ..... t 4 ;. . L . ... ..... ...... . .........: ; ;. ;. .......... f PANEL 20 / EL.52.68 53.8 ,.? PROVIDE 80 LF OF STABILIZED ACCESS TRAIL 75 0 75 150 SCALE: 1" =150' REF: IRRIGATION SYSTEM PLAN 35 :ITY OF JACKSONVILLE, NORTH CAROLINA IRRIGATION SYSTEM MALCOLM PIRNIE, INC. DEPARTMENT OF PUBLIC SERVICES ADDITIONAL STABILIZED OCTOBER 2009 UPGRADE AND EXPANSION ACCESS TRAIL CONTRACT 2 SCALE: 1" = 150' SK-7