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HomeMy WebLinkAbout1982-08-04 Engineering Correspondence DEF SUB r TOWN OF NORTH ANDOVER MASSACRUSETTS OE Kfl aTh� ' Q SS/4 CHUSES E MEMORANDUM To ; B.oard of Public Works ; , Highway Department,l ��L•�� i From : Karen Pomroy , Town Planner Re : Grade Change - Rear Hill Date : October 26 , 1983 Attached is a -proposed plan for Bear Hill ;Subdivision which _ shows— th-e proposed'`grad1: rhe,nges. .on Road ` C ' and part of Road ' A ` . This item will be - on the agenda fo,r the November 7th PlanningBoard meeting . Kindly forward all' comments to my offi.ce. prior tb - that date . If you need to discuss this matter with ' me , feel free to call and we can set up" a meeting . Thank you . t S I ,tl L 1 RICHARD F . KAMINSKI AND ASSOCIATES, INC. ENGINEERS o ARCHITECTS *LAND PLANNERS •SURVEYORS j 4.51 ANDovFR STREET NORTH ANDOVER,MASS.01845 IWPHOWE 687.1483 November 4, 1983 j i Mr. Paul Hedstrom F Chairman Aso North Andover Planning Board Town Hall Main Street North Andover, MA 01845 Re. Roadway Grade Revision, Bear Hill Subdivision Dear Mr. Hedstrom Enclosed you will find a set of plans showing the proposed revisions to the approved Bear Hill subdivision plans. These revisions are: 1. Revisions of Roadway A from Sta. 28 + 50 to 44 + 50. The approved roadway grades on this section of the roadway have been lowered by an average of 4 feet. The sewer , drainage and water lines have been correspondingly lowered. The revised grades blend into the grades originally proposed a at Sta. .28 + 50 and 44 + 50. tl 2. Revisions of Roadway C from Sta. 0 + 0 to 9 + 0. The approved roadway grades on this section of the roadway have been lowered by an average of 2 feet except where it intersects with Roadway A. In this area, the road has been lowered by approximately 5 feet to conform with the revised Roadway A grades . The sewer, drainage and water lines have been correspondingly lowered. if I may be of further service to you in this matter, please do not hesitate to contact me. Sincerely yours, Richard F. Kaminski and Associates, Inc. i sepB. cashing Environmental Biologist cc: Bear Hill Development Trust JBC/j t ��]���qqII!!IMUM Ulf TOWN OF NORTH ANDOVER MASSACHUSETTS rOasT4aa,ra.ti0 •.je Ol. 1- p ^sSAckUSE� November , 3., 1983 Conservation Commission Town Hall' North Andover , MA RE : Bear. Hi11 Subdivision Dear [Members : The Planning Boa-rd ir, in receipt of a recommendation to change part of condition no . 15 in the Order .Of Conditional Approval for Bear Hill Subdivision . The recommendation is to . change the direction of drainage at Station 28 + . 0 , whereby it would not be . directed :into the retention area on lot #61 . The board does not. hake plans detailing this proposal , however we would .like your boards input on this change if it is determined to be i n your .:jurisdiction . At your request we will hold a joint meeting of both boards to discuss the matter : . i FOR THE PLANNING BOARD 5incere)`y , Eri ch Ni tzsche kp E li 1. 7 .• RE BEAR HILL SUBDIVISION DATE ; November 9 , 1983 MEMORANDUM OF AGREEMENT regarding the Wednesday , November 9 , 1983 meeting at Bear Hill Subdivision . All parties of interest were present ; representatives from the Conservation Commission , Board of Public forks , Planning Board , abutters , and the developer took part in discussion . The following is a summary of that meeting . The specific items that will be put into place by the developer to correct the current siltation/erosion problem and specific measures to prevent a future occurence are outlined below . Corrective/ Preventative measures : 1 , The culvert , damned area ( by 11/11/83) and channel ( by 11/ 21/83) on the north side of Dale Street (opposite Road A) shall be hand cleaned to remove as much sediment as possible , subject to land- owner ' s permission . The siltation fence will be removed to eliminate damning effect { 11/ 11/83} , 2 . Complete slope stabilization on and off-site ; on site specifi - cally from sta . 6+0 and 61+0 to Dale Street , inclusive of the exposed loam between sta . 5 +0 and 6+0 ( 11/16/83 ) . /"/' 3 . The binder coat shall be applied along with a tailgate berm and crushed stone along shoulder area . Any drainage or run- off shall be directed to the catch basin at sta . 0+0 and pro- posed holding pond , ( see item #4 ) ( 11/21/83 ) . 4. The excavation of a small sedimentation/holding ditch across from the Smith culvert on Dale Street shall be constructed ( 11/11/83 ) . The outlet will be raised and a stabilized berm placed around the exterior . 5 . A second temporary sedimentation/holding pond shall be exca - vated beyond sta . 60+0 to collect sediment run -off from upland slopes and minimize siltation downstream ( 11/ 16/83 ) . 0 6 . The two existing retention pond areas will function as sedi - mentation ponds during construction . The outlet has been raised to permit drainage, accumulation and the settlement of silt materials ( 11/9/83 ) . The exposed slopes shall be fully stabil - ized ( 11/ 10/83 ) . 7 . Each of the sedimentation areas will be re-seeded and stabilized to function as retention devices (end of read construction ) . 8. A siltation barrier will be placed between! sta . 4+0 and 5+0 to act as a back- up system to item ##4 and wherever else it is neccessitated (ongoing } , 9 . The siltation fences on Rand property shall be replaced and extended for a 'greater width than what presently exists 10 . The drop inlet at sta . 0+0 on Appleton Street shall be thoroughly cleaned and additional preventive erosion /sil - tation measures shall be taken to filter sediments .-f14om traveling downstream from retention pond , Additional drainage control and erosion measures are required to prevent storm water build-up to cross Appleton tt'-reet . 11 . Continuous and periodic erosion checks shall be conducted to ensure that all erosion control mechanisms are-' functioning properly . 12 . All items will be completed by the subdivision landowner . 13 . A compliance status report will be, presented at the Planning Board ' s November 21 , 1983 meeting . cc Board of Public Works Conservation Commission Designer Homes Bear H411 Development Trust ' . Engineering Research Services 20 Alfred Drive � � P.O. Box 150 North Salem, N.H. 03073 tel . (603) 893-6549 28 Oct. 1983 EROSION & SILTATION CONTROL STUDY copyright 1983, Engineering Research Services, North Salem, N. H. 03073 BEAR HILL SUBDIVISION SITE NORTH ANDOVER, MASSACHU8ET7(S) OCTOBER, 1983 i |' PREPARED FOR DESIGNER HOMES� INC" & ZAC ALEXANIAN The contents of this report are the property of / Engineering Research Services and are protected by \ 1nterna±ion Copyright Agreement" They are intended for utilization solely by the client corporationo Designer Homes, Inc" License to reprodyce, reprint, and/or otherwise disseminate this report, in toto or tptidem vv»rbisr Ks granted solely to Designer Homes, Inc. , its agent5 and assignees. Parties other than the above listed must obtain written authorization from Engineering Research Services � for purposes of cppyingv reproducing, or republication of � � this report. ! / | | | ! ! j ' � . � � ' ' � ' Engineering Research 8�rvice� 20 Alfred Drive P.O. Box 150 North Salom, N. H. 03073 tel . (603) 893-�549 28 Oct. 1983 page # 1 Designer Homes, Inc. Plaistow, N. H. IN RE" ERO8ION & SILTATION CONTROL, BEAR HILL GITEo The North Andover site known as Dear Hill presentra a trilogy of challenges in the form of soil mechanics, topography, and expediency of development. The necessity for extensive road excavation and filling precludes the traditional "cut and stebilize" approach, wherein rsmall sect1ons are developed, stabilizedv and sold prior to advancing road construction into v�rgin areas. The di.vided � ownership with present single access further complicates the situation by requir.tng several thousand feet of rpedbed to be developed at the initiation of the projeot to permit access by the second developer to the southerly half of tho* site. The sG?vere aspect of the topography neoesisitates e*xtreme cuts and fills, thereby expo50.ng vast areas of unstab1e grey and yellow clays tC) the ele0ents" The reE�ulting erosion is further compounded by tho proximity to wet1a rid m and within the Lake Co�h�ckew�ck watershed limitv�. Due to the multiplicity of �nviron men tal and economic oon�;iderationm involved in the Bear Hill site' no simple ,solution to the erosion and siltation problem appears fnrthcoming" However, a detailed on-mi.te Study ooupled with comp uteri oed modeling of runoff , droplet impact foroes, flow p a t t rn5* and velocities i rid i cate� that effic:r-acious moasures are implQmentabl(s;,. The utilization of fabric "siltation fencing" such as Sealcoat SUPRAC 5NT or FOGS '5 ffs wi1l greatly inhibit migration of clay platelete into the areao of wetlands-, and brooks. The higher material costs of the fabric in comparison to the commonly utilized hay bales is off by the ease of in�;tallation and suhSequent in areas of futureo development. Siltation fmnoing should be utilized at the toes of affected slopes and possibly in the distal limits of seasonal tributariei.:�. ' ` Engineering Research Services . 20 Alfred Drive P.O. Box 150 North Salem, N. H. 03073 tel . (603) 893-6549 28 Oct. 1983 page # 2 ` In conjunction with the siltation fencingo hydro- seeding and mulching of all involved slopes is to be undertaken prior to November second. This timeframe should Permit germination of the groundcover during the anticipated period of " Indian Summer" which generally occurs during the second and third week of November. While no appreciable increase in soil particulate cohesion nor reduction in laminar flow velocities is anticipated during the winter months, due to the minimal extent of hibernal growth expectancies, the slight development of the root systems should provide measurable reduction of "splash displacement" of soil during spring thaws" Slope areas which are not subject to future � modification (bankments which will remain in their present state of locus and grade as "front lawns" or back yards) should be subject to additional treatment in early spring. it is recommended that , such areas be limed with an agricultural-grade limestone at a dispersion rate of 9" 18 pounds per hundred square feet and hydro-seeded with an approved ground cover requiring minimal maintenance. While the "Mass. Slope Mix " has been the tradional slope seeding mixture throughout the past two decades, the grasses contained therein do present certain long-term liabilities in as much as they do require regular mowing unless one is enamoured of the rustic panorama of waving fields of grain. Whereas the slopes under discussion are sufficiently extreme so as to constitute a possible hazard to the safety of a property owner attempting to operate mechanical, equipment thereon, and whereas the long term liabilities of manufacturers, contractorso and engineers in matters of fabricationv construction, and design are currently interpreted by the courts to extend into perpetuity, it would therefore appear advisable to institute the planting of ground cover which combines maximized verdancy and soil holding characteristics with the propensity for thriving under conditions pf benign neglect. In such areas, the planting� of choice would be Crown Vetch. To ensure the sucessful propagation of this variety, the above outlined limestone application must be strictly observed. Slopes and other areas subject to subsequent alteration (unfinished road areas and sites of additional cuts or fills) should be surface-compacted by back-bladinQ wherever feasible, preferably by heavy tracked machine" ' . . .' Engineering Research Services 20 Alfred Drive P. O. Box 150 North Salem, N.H. 03073 tel . (603) 893-6549 28 Oct. 1983 page # 3 While slope mulching with hay or straw has been shown to provide a major reduction in displacement of soil particulates due to ' rain droplet impact, empirical evidence tends to indicate that laminar flow erosion continues unabated beneath the mulch material when sufficient volume of flow is present. It is thus evident that one design � � criteria must be the minimization of slope flow volume. On- site experimentation has indicated that interdiction and subsequent retention of road bed loading and runoff is the principle key to controlling the current erosion problem occuring on the lower slopes of the easterly-most section of Road A. / The construction of low earthwork berms along the easterly limits of the laterally level extensions of Road A from approximately station fifty plus zero to station fifty eight plus fifty will sufficiently reduce slope flow loading so as to ensure minimized slope-contributed particulate migration. The remaining migration generated up-slope by laminar flow should then be effectively contained within the barrier areas defined by siltation ' fencing" Temporary earthworks should be constructed of stable granular material to an elevation of one foot above existing grade to immediately effect the interdiction of road grade runoff " Prior to securing the location under discussion for the winter, steps must be taken to contain prewoipitatioh accumulation and to provide the mechanisms for settlement (and possibly the artificially induced flocculation settlement) of suspended particulates of ~ 001 mm diameter and smaller . The artificial induction of flocculation (i f deemed necessary by empirical observation during the winter) is easily and safely accomplished by the introduction of agricultural lime into the runoff while contained and relatively motionless. While this procedure would tend to increase the pH of the discharge, the slight change could be considered beneficial in light of the recent concern over excess acidity (lowered pH) in the natural rainfall . The impoundment of road accumulation (which includes runoff from upgrade slopes) necessary for both settlement and induced flocculation is readily accomplished by the construction of several impoundment, areas utilizing the road areas throughout the affected ` � ' Engineering Research Services 20 Alfred Drive P.O. Box 150 North Salem, N.H. 03073 tel . (603) 893-6549 28 Oct. 1983 page # 4 site. While the maximum anticipated rainfall could be expected to contribute some one hundred thousand gallons per hour to the area under consideration, a large portion of this volume may be safely dissipated as sheet runoff from the upper reaches of the area. The remainder, which is anticipated to contain greater siltation due to increased flow line, may be temporarily contained in earthwork retention areas constructed along the road bed 'between � station fifty plus ze"o and station fifty eight plus zero. Construction of these earthwork laterals at three hundred foot intervals, extending from the westerly upgrade to the easterly limit of horizontal continuity, constructed to an elevation of five feet above road grade, thanncxw continuing southerly along the top of the easterly slope at constant ` grade until the point of interception with the temporary interdiction berm described above should provide adequate ponding to obtain the desired minimized downslopaa erosion" Transverse siltation harriers consisting of staked hay bales and (downstream) gseotextile fencing should be placed down grade (up station) from each lateral earthworks to minimize siltation and saltation carryover" A central spillway of approximately six inches in depth and five feet in width v protected from erosion by geoteXti1e, should be incorporated into the construction of all but the last (most downgrade) lateral earthwork dike to prevent overtopping during periods of maximum influx . It is recommended that all transverse earthworks incorporate a discharge pipe of minimal diameter (three to four inches) at somewhat 1eoe than mid-elevation to permit controlled outfall to lower basins, thereby reserving the spillways for extreme conditions. The final dike should incorporate a larger outfall (four to six inch PVC pipe) at mid-elevation and this discharge piped to the nearest accessible drainage structure for distribution to the sedimentation ponds behind Lots #4 through M. The installed sedimentation ponds are subject to siltation accumulation during the period of slope stahilization. While the design intent of these ponds is to remove water borne particulates prior to dizcharge of � runoff into the municipal drainage system, thepossibiltity exists that accumulated siltation within the pond beds may create a relatively impervious clay barrier layer at the water/absorption layer interface prior to the stabilization of upstream slopesv ` thereby rendering the ponds ^ /7 / Engineering Research Services 20 Alfred Drive P.O. Box 1W0 North Salem, N. H. 03073 tel . (603) 893-6549 28 Oct" 1983 page # 5 ineffectiva" This potentiality may be averted by the simple expedient of filtration of ponding influx " The above described siltation fencing, if placed ' across the drainage piping outfall (and maintained on a regular basis) should ensure continued functioning of the sedimentation pond systems for the duration of the design intent" � � � � The final area of siltation impact to be considered � involves the Road A/Dale Street intersection area. While the gravelling of the road bed and the loaming of the contiguous slopes (currently in progress) should alleviate this condition measurably, suggested additional expedients would include the temporary modification of the drainage swale alongside Dale Street into a short-term retention / pond with transverse siltation fencing and hay bales to reduce flow-through velocities and to entrap the greater volume of water borne particles. Additional fencing along the remainder of the drainage areas and at the culvert inlet and oWal l wo6ld tend to supplement these measures. Insomuch as several of the above suggestions are currently being implemented and the remainder are consistent with the proposed time frame, it appears that the Bear Hill site may be secured for the winter in an i orderly manner consistent with the necessary protection for the contiguous wetlands and tributaries, � � � � � � ` | | 1 ' Engineering Research E3ervico*s | 20 Alfred Drive P. D. Box 1,50 North Salem, N. H. 03073 tel . (603) 893-6549 28 Oct^ 1983 # 6 pag� NOTES AND ACKNOWLEDGMENTS: Rainfall data from NOAA Runoff C.alouJ.us per TRlbot e-quations, Bed-load transport calculations by du Boys equation Intensity of bed-loading by Einstein formul,A Negev sediment at i mod� deve1oped for suspvndowW- � load model � Computur o;cideling and calculus by Z-80 based 1-1181dK system / Whi1e most data and recommendations contained j,n this | report were developed in-houoe recognition and gratitude | must he extended to Henry Van Dale, landscape i-wind erosion | / control c:onsul tan t, Phil Busby, e ' gineer & geOera1 Contractorp Bruce Clay, consulting bio1ogist, and Mike Coll1.ns and Sandy Parker 61)ecial appreciation is due James Hayden, United 8tates Goil Conservation 8ervice, for sharing his insightu, and wisdom with our staff throughout the past twelve years" D. L. Roulstonr N~ S.P, 8" Royal A, Roulstonv tec.h director re�ear�h i �^ eng neer ' | � | i , � ` ` . � � � / | i i l andover consultants 213 BAOADWAY METHUEN, MASSACHUSETTS 01844 CG �. 'n • P January 11 , 1984 North Andover Conservation Commission . T own Hall ®R North Andover MA 01845 •"�` ,�� Re : Bear Hill --- File No . 242-158 Dear Conservation Commission Members : The -purpose of this letter i:s to respond to your recently issued Order of Additional Conditions=�f-ox . the :-Bear . Hill Subdivision. This response, in an . attempt' .to 'be 'comprehensive and orderly;- will address each new condition in the sequence issued. N o . 26 - and No . 27 : Informata:onal; requiring=no response No . 28 : --_ The report ref er'enc-ed ,-i-n=this:_--tonal- -tion discusses-erosion - and- resulting :Sedimentation yin._:gen-eral-terms-,_-contains no site -Mans- and lists few spedfie -:si.te ,r--eoommendat-ions : ._.Because of this'__it. i difficult to -assess the - pre ci-s e extent -.of.--implementati.or!_:as requested = by .the Commission. However,—• the -items -which- can be eval-uat.ed -3ne�tzde: - i . Siltation fencing has been -ere cted- along- the- si.db: slopes - of Roadway A. ii . Temporary transverse earthwork- dams and -haybale -dams have ..been -placed along- Roadway- A From station 50+00 ta�tation- 58+*50:- iii : -Low earthwork berms,.--have been constructed= along easterly--.side of Roadway, A as required. iv - It is the-intention...of---the applicant--to , utilize'-.lime order• to .i.mprove removal- of--soll.-particles - in accordance-with—item. No . 16 of,-the=- 'Erosion Control- Schedule v . -Crown' -:vetch - or other -suitable cover will be utilized.--to permanently.- stabilize the - slopes . ' vi . . Fabric .si-ltation fencing. has. been uti.li2. ed..at .pipe.-.outlets . ti i Bear Hill --- Page vii . Procedures discussed in items i, ii -and iii are in need of repaie and replacement. ' Additional transverse hay-bale check dams will be constructed before February 15,' 1984 between stations 61+00 and 47+00 . A new -Construction Schedule ' and Erosion Control Plan for this portion of the project will be submitted before March 1 , 1984 in .accordance with item No.. 9 of the Erosion Control Schedule. No. 29: Soil deposition downstream from the site will be inspected on a regular. basis and cleaned as needed in accordance with item No . 15 of the Erosion Control Schedule. No . 30 : Attached are a Roadway Construction Schedule, House Construction Schedule and an Erosion Control Schedule. For some areas ( e .g. homes along Roadway C) it was -not feasible to submit a schedule at this time . No- further work will be done in these limited areas until the requested schedules' are submitted. No . 31 : No 'earth work.prohibi.ted -by_the Commission's Orders has .be en done in they. subdivision -since the Order was .issued. The'-Conservation Commission is .requested -to approve all three (3) schedules .so that -they _ may---be .imp.l:.emented. as -soon- as .possible No . 32 : : -Commencing on,.March -,1-, :_-198k. >the--, p -icant__-will-forward monthly progress- report :toThe=,=Construct"iari-_S_ehedulee _hae = been .prepared . in tabular form :.so-:-.that-.-=:each .month,=_ c.opy-::of---the'-s:chedule_s-.- - will be forwarded==-to -the-'.Commissi:ori: indi.cating__any.:-:changes.- nd..`the= monthly..status - of each phas:e=.-of- constructi-on. 1n-=add-iti0n-;- -this `monthly- report will:-include a cover-.ietter-_=whi:ch=.will :'appraise .-the -Comrui.ssi.:on-,_ of- any .matter which .requires-eld-borat-ion or 7explanation. No . 33 : The maintenance and repair of:-all_' erosiori control.. -structures will be in aocordance-.with item .Not .10 of the---original- Er.os ion ,Cont.r Plan: This includes inspection every-:other..week bnd.'..after each .rainstorm:'- _Required -repair and -maintenanc-e; • includi-rig:-.but .not:2.1imited =_ to accumulated- sediment removal., will _be-undertaken -as .-needed. I, No : 34.- The -O r rde -°of Additional Conditions`:Ili be =retarded by-:the.__ applicant -before ;-any -further work requested by -this letter---is undertaken-. Bear Hill Page 3 No . 35 ` aPP The 'licant is in agreement with the $25, 000 .00 Bond requested. . .However, in order to understand how the Bond amount is to be distributed among the various procedures required to protect wetland values, the attached schedule is submitted for the Commission's consideration. The Commission is requested to approve the attached schedule or to approve a modified version of this schedule Please inform the applicant as soon as pospible as to the Commission ' s procedure for submitting the full Bond value . Requested Action I . The Commissi.,on is requested .to.' vote to -accept and approve the responses to the additional conditions and the attached Roadway . Construction Schedule, House Construction Schedule and Erosion 'Control Schedule . II . The Co:gm7ssion is requested to vote to approve the Bond Schedule- as . sucmitted or as modified .-by the Commission. Thank;:y.ou fora-any.. cons.iderati:on--giv.en to-these requests . -_ :. Sin°ceely;__:__: .._ A-NDOVEH .-INC' wil�:idm .S.. :MacLe:od�:., ' .E. ti ::i BEAR HILL NORTH ANDOV ER CONSERVATION COKMISS ION BOND SCHEDULE $ i , 000 .00 1 Upper Pond 10, 000 .00 2 Lower ponds at $5, 000 .00 each 4, 000 feet of trenches (siltation fencing) at $1/f t 4#' 000 -00 ( estimated at 70% remaining) 4s000 .00 200, 000 ft2 of seeding at 2¢/ft 2 , 000 .00 1 , 000 .00 hay bales at $2/bale Downstream -cleaning -( estimated) 2 , 000 .00 2 , 000 .00 miscellaneous Total $25, 900 .00 $12, 500 .of the above 'Bond will be released when Roadway work and Roadway stabilization is - complete on Roadway "A" from sta. 0+0 to stab+25 and backwards -from sta. 62+0- to sta. 6+25 and when same work is complete on Roadway -- $12, 500 of;.the • above- .Bond. will __be :released when Roadway work and Roadway �tab.iliza -ion= s.: comple'.ted an-,1Roadway "A"'` from sta.:- 6 25 to sta... 6+.25 and all:`a °"Roadway.= ''C" Roadway:: work:wil-1 .:be'defined as-all, utilities ,-and' pavement to binder grade ,_.. :Roadway.-stabil.izati_oh. shall :be d.efiried as dway slopes vegetation .growing on roa . BEAR HILL EROSION CONTROL SCHEDULE l damaced along the 1• Haybale erosion checfrom stations will b0+00 to station sidelines of Road A 31+00 at 100 foot intervals to minimize erosion an prevent siltation. on- rade catch basins will be Protected with hay 2. All g bales and/or filter fabrics. 1 erosion control structures will be cleaned and 3. Al ermits. repaired as soon as the weather p The installation of ,the electrical service will be �, with the 'letter �ct 2gN 1 CC installed - in accordance fom' Riehard .Kaminski . Associates dated D : , 983 }Q0. along Roadway A' from station 0 00 to station - 32 a g be lled 5. Ut ilities for Lot. ? Dale Street will _serviceamentioned ' in the same manner as the elects-c in item #4 above. ' on Pond'. #1 - (on inlet 'riser lots -3-6 - 6. The existing roximately 1 foot which will still -: will -be .raised apP on .lots 3-b • allow -:1 foot . of_''-free board in the Pond 1 on abts°. 3-6.)- 'will.:be.r_'' 7 The e�c sting.:_out:l t .to_:Pond # ( er-fora'ted_. connected: to approx�mately._150. fee.t pipe -aroun.d._which',a .filter:_- w 13+_be constructed-;'. :.:: The---filter' -will be :constructed . in_ the�rfo3lowing-manner:- i. _T.he; xisting 'outI-pt .=ehanne..l_wilh. be=re= graded- -o.'accomodate,:,the--filter: . • The channe:l.-.wil'1'-then�be 'mulched .with hay and. lined _with -f.�ilteacedbover the= iii. . Crushed stone will. :be p . filter ,fabric. filter iv. The perforated pipe,- surrounded. by fabric will :then-:be placed on grade::in this-:channel. vere d by crushed _stone e pine will be.'.co v. Th ced--on the: end:--- 'will be -pa vi. short riser- of -.the perforated..pipe..- vi A small bafilter fabricewill be.erected-. stone and i- e to ~act- at.--the end. of the Perforated P P as---a :final-,-fjater 1-= vii� . No=: water .will be -discharged-from--Pond--# during the. construct ion-';of .this-;f ilter All=attempts will be made% to construct: -1- -2- i Hill Erosion COn 0 Schedule ' and complete said filter within a period -. of 2 days. ix. The filter will be removed when contribu- ting areas have been stabilized. X. Course gravel may be utilized where it is deemed to be more eff&ctive . an lots 3-6) will be 8. An emergency outs-et for and along the sewer easement constructed from Lot 6 an approximately an Lot J•and The willlength be constructed outlet the following 500 feet manners is A solid pipe will be placed in the embankment of Pond #1 located in the rear of Lot 6 with an inlet invert ele- vation of 1.0 feet below the elevation of the riser. outlet will The .mute of the emergency the -pr be -graded to pipetoP laced on grade) . to allow the pipe to be p All -disturbed areas will be heavily mulched -with hay--and covered with . filter fabric , laced -on the iv: Crushed. stnne will be p filter fabric. v. A perforated -pipe surrounded- :with filter fabric _will -be placed --on -.the ,-stone. ._. . 11 -be _mounded, around ..the vi. Crushed .stone. .wi pipe.. der, App1 ton--.Street will v'. The- culvert: laced :by=:.. . a 2 °inch- T at -this .time.-,:-be_-r.ep lans;-= RCR.-as . called f6r outlet ..will be`-remo.ve.d&- --The -emergency: - when _the �:riser'.- s :removed--fra.m ix;. _Course :.-gravel mays-'pe_-,substjtutbd where it. would-'be. more z e.f-fect--Ivld A detailed ->'Er`c�siori :Control..Scheduie '--out-'=fining fur.ther.�-- 9, to--station construction of Road. A from station .5 .75 royal 62- 00 .will. "be.-submitt'ed ' March racBeds =onrthat _ before: coy-further_--construction..-p portion of..::the'-road -or.:_abutting - ova.. Erosion -Control--:Schedule_'.. for -lata _21=3'7 ,64='�l 10.- An --.Appleton Street :. and -A-Z and also for= the tension of . fur.ther_._:�_ will be-� submitted--:for=approval before any work : is done in -these -areas.: il.- _as earl s- shall be -.seeded sed soil ye.x.icnep= tthieon: -_ ._ .,All expo w th_ e year (-1984y As weather­perm ,. of areas under 'canstruction inandcLoConsrucion- Roadway, -Construct-ion - Schedule . ar Hill Erosion Co' ro schedule Schedule. Seeding wall be maintained for the duration of construction. 12. 'Siltation Fencing' will be utilized in place Of diversion trenches and also used where additional protection. is warranted. This fencing will be erected as the weather permits . 1 Conditions approved with - original 'Erosion Control .. 3 Plan' , particularly items 3,4,5,6 ,7*$ and 10, will be implemented in accordance with the frequency, duration and location indicated on that plan. 14. A row of staked haybales will be placed along the 'downhill ' edge of any disturbed areas during con- struction on each building lot. Haybales will not :: be placed where there exists 50 feet or more of undisturbed vegetation on the downhill slope . 15. The occurrence of soil deposition downstream from the site .will be .i.nspected after each rain storm but no less than twice each month. Siltation. areas will be hand cleaned as necessary to remove as much sedi- ment as possible: This work is subject to obtaining land owner's permission. 16.. The ponds on lots 3-6- and. lots 7, J and --H will con- tinue to be utilized as temporary sedimentation ponds-. The--developer found :that- the original.---- sign- did no-t--._ operate effectively in removing soil'. particles ,- -there fore;=-•the..::outldts.have.-been_ raised;:_. -Tot incr.e.ase_.the,=.�, . . eff.BctiYeness,of;:_th:ese-ponds vthree-.:additional ;steps.y. - --- -. -will be -implemented:as-..needed..:.. - A) .: Pond:_#1-=-:('-ari:lots '-3 6)'° is--considerably=small-en_� existing' ' to-=Pond:# is- propor-tionaly- - -.- _- less than--the. inflow-to:-. Pond. #1_=:(determrried=_:?= by --site- observation).; - Thus,=vsilt--:laden--water -: from Pond #1 -will -be- pumped..into Pond=.#2 resulting- in -increased det.entioh--time- and increased -removal _of soil :particles. B') . Ponds #1 and- #2 :wlhl. be'.-'limed I -at: the - rate of approximately . 50-100 ppm--in- order- to- flocculate sail .particles- and Increase.-the removal -by sedimentation: Effectivene-ss _of.-__- this step. will..depend; -to.:-a large...extent:;-,on.=.-___ proper mixing -and the" :temperature...'of--the,,- water: C:) ..Prevention of the release. of -silt downstream in-the-Lake •Cochickewick-. Wa.tershed-is-a. high_ priori-ty:- Thus, when necessary as_an;=:timer-- .. genc.y 'measure ,J-:it .is `proposed-to -pump-the watert�from Pond #1 to portions of-lots----71.=.75 -_ at -elevation 295t;­ _The combination:-of ..over-.--- larid flow treatment and infiltrat.ion-=--over - C Hill Schedule Hill Erosion . .. .' etation almost 6 acres of undistarticlesg This option, should remove the soil p of caurse , ' depends on the weather and cannot be implemented before the ground thaws. lementation of steps B and C will depend on The iMP develop during construction and, of circumstances as they The most critical period course, the weather conditions. s ring, with exposed will be during late winter/enrlortunity for the vegeta- areas which have not had an PP tive cover to be established• carried out when Pond #1 Step A will be routinely referably after the water begins to reach capacity but ' p s• At all times has had the opportunity to settle for 2 day an attem t will be made to keep a minimum amount of water in Pond 1 to Prevent the release of seddawnstreamiment l will,aden wine downstream. - Release of clear Step B will be implemented if any event, be permitted. and when Step A proves unsuccessful in preventing the release of sediment downstream. -1 -711 _y , _ I o 13CA 9 ' rl ILL a � E�ULF RCA DWAY Ce)AJ5TXCk:fiD J F M A tA j J A '5 goad A j,) Ir'nc r Coat F z.) Side Scopes Sfabilizid P 3) Ufilitte..s C��tr�cl �vad d (,l-e OD -ro E Y 1) l?ough 4radir9 . 2)5'rde Slopes Sta ili zed 3.)tit i/iNn fQ1J) ¢}Binder Coat ROad. f3 6+00 �-© ¢�� CerrJ) _ d Sough �C�radinq . _ - Z)Side 51opc5 5 �Ib/I i zw - .� _=- !� Iefa S (Cot."J�'o Dale.5t1 _ f _ )(W ' ,5CHFWLF 1/ ROADWAY CM5TKI L/ �.. 13EA9 --.tIILL Road 1h+25 to 324-00 l.) Rot�gfi C-�r-ca�ii� C . Z)5ide Slopes Stab;Ii-zed 3,) Ufdir in (r-lectrlc) ` a ) Binder Co f C Road A 321-06 1-6 46-f-50 I.} Rough C-�-ding Siapes SkLbi fr zed - 3)Ufilities C�411) - - . 4.) Binder Cot d .0 -of00 -to I2-t54(em) r 1.) 1?ouyh C 1-4ding 2JSide-_Stopes Stahllt =t - ` 3.) Utilities (A C I) 4)Birder Caaf' 77 ; - S DLt� WcA artM,-- C -- Da.-tr- Mork Corn pOew-_ r- r bEAR IL Desiglier Homes ..� ()05[7 coy!S STRUCTIOkl HEDULE l984 r . X 4 All x 7 . A/ X , 55 SP — fir -of'=-�andifians = SpeciQl.'.�erm. sued- ,4 5 fleciQl Perim rt'_ 1 p1►�d for A/ =:Illeaaf�'v�- D�efet'rnlnafiori__. S — Consfructior7.: ..Sfctr-�'ed - 1�at ice of :intent-_:try t�=s�bm i Hed during,-Ov' Q.fr:- �snffi X = Work nayy f� staffed':daring this ..-month 1fa[I cMer perrnit's`l�aye been:°-: obta.fn2d.-_- - 4 Fri CAN HILL `c�es1 r2r Homes 4 COHotbt- A15TROCTIO" HEDULE a JF M A 14 J J Al D - X -FH 47 45 sRM X swv X 4,� X X SRN= = Srfe evrerv:P1'an ,rant r�r� a_rJy= ' work isgreat r�: trt :-50fl from. ..- x y p 1nJark=may gin durit' js. =rnc�t =i a!!- essarerrni.ts - - S =~- Constr�fion . .-Star---fed , HILL XIIEDULE OL6F COkk5TRUCT1()" Al a : 13 T/X I �� su 20 5 S :S;fe Pwiew.-Plcxi mush' be s�bmi�ted :JBb) _ - SRN Sete. review Flan _not' r7ecessar�l= %€ wow rsrr'� ri .:5� :==fr'or daring:this month ra Il:_offier=perrnits_. = ian Sfiar�ed O =. order,, Qf Cfiens O�rrered S _ _ Comtruc t 7"-= 71-fle 7"rt r�5f�r'_ ! = Nafiice 1r'1t -be submi Hed_-.an Aoraf4gr A da