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HomeMy WebLinkAboutConsultant Review - 195 BRIDLE PATH 10/21/2010 f SITE DEVELOPMENT BRIDLE PATH NORTMANDOVER, MASSACHUSETTS NORTH A'NDOVER PLA NNU; DEPARTMENT INFILTRATION SYST DRAINAGE CALCULATIONS DATE: October 21, 2010 r .t NqRT)j,�N V Pf..AWt PREPARED FOR: Robert Ercolini 195 Bridle Path North Andover, Massachusetts 01845 � � OFI�fq�Sd` r VI_ADINIIJI L.�� 1IF-jw;i-iC NOK Merrimack Engineering Services, Inc. Phone: (978)-475-3555 66 Park Street Fax: (978)-475-7448 Andover,MA 0 18 10 1 1 1 is °'r '.+."L �•y! a��Y����'� 'r F,k xtT�" � � i .F' 4 - t � y ra! t t, ' 4 `� Bridie=Path, NorthRndover,'MA;�O1118454 k 5�� - 1 y".� d+aa� z• x t� �;�,a •x+1w z ,q''� r - ` ,�`• K -3• ii s a !', g � �} iy• ,.�ql .- � �5a�y'� `G<-' sYt�' � � t ^ �� 1t `t s �v t �K N r't T•� ..v -. is- ..(� i.� < z 1 5 -•° W - •xnA `y"'� t S ioia 5 at•..s s `..;, r ;Y " r,,(E;^"k, �)f f v ivd +a+ ,! x L` tom' v� �zJp'�, •z�i,�\Nfi�''"; 4� i� x rF "'-{' t r,•� r tp� t Yll ���•xtt �y-s{ rx e i. ,}. ��� -• s ��.. :..��:.ff�•��, !a x.,. ,s ,' w �'"¢ ., r;t i��',ex fK� �,,; �(.1��,•'�. �` $ S h�,�? s� .w 3.�'y .� x s fi ��'y+y`<5 i�{.. ' �1 �c �yUk� 7� t' .�' 9 )tts 6 ty R- F) J t 3 5.�. t. ! 1• l �' 2 xr � i �� 'E Nr 7r 434R u. sy � ti .� "` 1�' �201�QtOoAi9Ie r0r � 's�t3L `�. 3 •frEy eimagery Date:Jun 1J.2(110 -' -- k » ,42'432.18 N :,71,°04'52.31`W '.A-1 17841} � .I 4 �s1�• •' SITE DEVELOPMENT BRIDLE PATH NORTH ANDOVER, MASSACHUSETTS System drainage calculations As the result of property renovation, the new impervious area on site consists of: Bluestone walk and patio on concrete base— 665 s.f, Walls around patio - 143 s.f, Total 808 s.f. 100 year,24 hours duration storm develops rainfall of 6.4 inches for Essex County [Guidelines for soil and water Conservation in urbanizing areas of Massachusetts],which generates runoff from impervious area with Curve Number CN=98 equal to 6.12 inches,or 0.51 feet.So the runoff volume from new impervious area will be Vr= 808 s.f. * 0.51' =412 c.f., which has to be accommodated on site by Storage and Infiltration System, in order not to increase post-development runoff rate. Soils within the vicinity of the project have been mapped by USDA-NRCS(formerly SCS)and consist of Sutton series soils,which are classified within the SCS Hydrological Soils Group B. Considering the using the 42"Diameter,36"Height Cisterns for roof runoff of recently built addition to the house on site, accept the same type leaching system to accommodate runoff from proposed impervious area of 808 s.f. The cisterns are based on and surrounded by 6" layer of crushed stone with void ratio y=0.4;Outside Diameter of crushed stone area=4.5' Storage volume per 1 unit(Incremental for HydroCad Model): - 6"crushed stone layer with void ratio y=0.4—(Elevations 0' -0.5')=3.0 c.f. - Cistern with water level up to the invert pipe-2.5' above the 6"stone bed=40 c.f Total storage volume per unit=3.0 c.f+40.0 c.f=43.0 c.f Accept total 4 cisterns for the new impervious area with the 2 cisterns in 2 locations. Available storage 172 c.f. Infiltration area for the system S= 7r*4.5'(D) *4.5'(D)/4 *4(Cistems)+2.5'(H)*4.5'(D) * 4(Cisterns)= 108.6 s.f. Percolation rate for the soils on site P=30 min/inch=2 in/hour=0.17 ft/60 min= 0.0028 ft/min Exfiltration flow for the system is: F=P * S=0.0028 ft/min* 108.6 s.f. =0.3 c.f./min =0.3 c.f./60 sec=0.005 cfs. (accept 0.01 cfs for HydroCad Model) Attached is the HydroCad computer model based on SCS-TR20 Runoff Method for the proposed site infiltration system,which has been designed to mitigate any increase in peak runoff rate.The calculations performed for the 100-year,24-hour duration storm event. As model shows the peak elevation inside the system is 2.565,which covers the 6" layer of crushed stone and 2.06' of the 3'-height cistern, which is 0.44' (5")below the invert. The system is adequate to store and infiltrate the runoff from the new impervious area during 24-hour duration 100-year storm event. Merrimack Engineering Services, Inc. Page 3 Printed: October 21,2010 NSA NSIS (N p ew Impervious Area) (Storage and Infiltration System for New Impervious Area) Drainage Diagram for Post-development SUbCat Reach Pon 2Un Prepared by Merrimack Engineering Services 10/22/2010 HydroCAD®7.00 s/n 000899 ©1986-2003 Applied Microcomputer Systems Post-development Type ///24-hr 100-yr Rainfall=6.40" Page 5 Prepared by Merrimack Engineering Services 10/22/2010 H droCAD®7.00 s/n 000899 © 1986-2003 A lied Microcomputer Systems Time span=0.00-24.00 hrs, dt=0.02 hrs, 1201 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment NIA: (New Impervious Area) Runoff Area=808 sf Runoff Depth=6.16" Tc=5.0 min CN=98 Runoff=0.12 cfs 0.010 of Pond NSIS: (Storage and Infiltration System for Peak Elev=2.56' Storage=144 cfOutflow=0.01 cfs 0.010 of Total Runoff Area = 0.019 ac Runoff Volume = 0.010 of Average Runoff Depth = 6.16" Type 111 24-hr 100-yr Rainfall=6.40" Post-development Page 6 Prepared by Merrimack Engineering Services 10/22/2010 H droCADO 7.00 s/n 000899 © 1986-2003 A lied Microcom uter S stems Subcatchment NIA: (New Impervious Area) Runoff = 0.12 cfs @ 12.07 hrs, Volume= 0.010 af, Depth= 6.16" Runoff by SCS TR-20 method, 6 4=SCS, Time Span= 0.00-24.00 hrs, dt= 0.02 hrs Type III 24-hr 100 yr Ra Areas CN Descri tion 808 98 New Patio and Walls within 100' Buffer Area Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec 5.0 Direct Entry, Adjust to minimum 5 minutes Subcatchment NIA: (New Impervious Area) Hydrograph p Runoff 0.13= 0.12 CfS 0.12 - Type III 24-hr 100'-yr 0.11= Rainfall=6.40" 0.1= Runoff Area=808'.sf 0.09 Runoff V0 lume=0.010'af 4 0.08 Runoff Depth=6.16" 0.07= Tc=5.0 min 0 0.06': CN=98 u- 0.05 0.04 0.03 0.02 0.01= 0 01 122, 0 - 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) Post-development Type 11124-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 7 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 10/22/2010 Pond NSIS: (Storage and Infiltration System for New Impervious Area) Inflow Area = 0.019 ac, Inflow Depth = 6.16" for 100-yr event Inflow = 0.12 cfs @ 12.07 hrs, Volume= 0.010 of Outflow = 0.01 cfs @ 11.24 hrs, Volume= 0.010 af, Atten= 92%, Lag= 0.0 min Discarded = 0.01 cfs @ 11.24 hrs, Volume= 0.010 of Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.02 hrs Peak Elev= 2,56' @ 12.96 hrs Surf.Area= 0 sf Storage= 144 cf. Plug-Flow detention time= 98.4 min calculated for 0.010 of(100% of inflow) Center-of-Mass det. time= 98.2 min ( 841.1 - 742.9 ) # Invert Avail Storage Storage Description 1 0.00' 172 cf Custom Stage Data Listed below x 4 Elevation Inc.Store Cum.Store (feet) (cubic-feet) (cubic-feet) 0.00 0 0 0.50 3 3 3.00 40 43 # Routing Invert Outlet Devices 1 Discarded 0.00' 0.01 cfs Exfiltration at all elevations Discarded OutFlow Max=0.01 cfs @ 11.24 hrs HW=0.03' (Free Discharge) t-1=Exfiltration (Exfiltration Controls 0.01 cfs) Pond NSIS: (Storage and Infiltration System for New Impervious Area) Hydrograph 0.12 cfs [B Inflow 0.13- N Ell Discarded 0.12= Inflow Area=0.019 a 0.11= Peak Elev=2.56' 0.1= Storage 144 cf 0.09 0.08 .. 0.07= o 0.06-:" u- 0.05= 0.04 0.03_: 0.02 0.01 cfs = 0.01 ' ` 0= 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) SITE DE VEL OPMMENT BRIDLE PATH NORTHANDOVER, MASSACHUSETTS Rainfall Data Map iM -, �t,��r' •�-# ,� ,.rw .i. .'3 '"'" &r-ate . n RE s �pps� M,� r �'Y1Z ME VMS '� ung y k d=` .,33# Y -4W7 '`sr�` 4r FiN - WW 1't � I � � � t1� 1 a ` � s � �� � �' f � �fix : q y ; � °� -^�� a ,� .� + t'�y"' 'l- m p z i 7 ��'�:ry= 'r�# `k- v '`z�i,'a t ,�, ✓ '� ra�,." "sY 'i '£'3 ;�1'"$�'6 i 'M.. � ' Z Merrimack Engineering Services, Inc. Page 8 Printed: October 21,2010 SITE DEVELOPMENT BRIDLE PATH NORTHANDOVER, MASSACHUSETTS Soils description: Sutton series soils The Sutton series consists of coarse-loamy,mixed,mesic Typic Dystrochrepts.These deep, moderately drained soils are on uplands.The soils formed in glacial till. Slopes range from 0 to 15 percent. Sutton soils formed in the same kind of material as well drained Chariton soils, poorly drained Leicester soils,and very poorly drained Whitman soils.They are similar to the Shituate and Woodbrige soils. Sutton soils do not have the fragipan,which the Shituate and Woodbrige soils have.They have less sand in the substratum than the Shituate soils. Typical pedon of Sutton fine sandy loam,3 to 8 percent slopes, in the town of Boxford, 600 feet west of the junction of Interstate Route 95 and Massachusetts Route 97: Ap-0 to 9 inches;very dark grayish brown(1 OYR 3/2)fine sandy loam;weak fine granular structure; friable;many fine roots; 10 percent angular gravel,5 percent angular cobblestones;strongly acid;abrupt smooth boundary. B21-9 to 22 inches;yellowish brown(I OYR 5/4)fine sandy loam; weak fine granular structure; friable; many fine,common fine roots; 10 percent angular gravel,5 percent angular cobblestones; very strong acid;clear smooth boundary. B22-22 to 26 inches;light olive brown(2.5Y 5/4)gravelly fine sandy loam; few fine faint grayish brown(2.5Y 5/2)mottles; and few fine distinct yellowish brown(10 YR 5/6)mottles; weak fine granular structure; friable; 15 percent angular gravel, 10 percent angular cobblestones; very strongly acid; clear wavy boundary. C1-26 to 31 inches; light olive brown(2.5Y 5/4)gravelly fine sandy loam;common fine and medium distinct gray (N 510)and strong brown(7.5 YR 5/6)mottles;massive; friable;25 percent angular gravel, 10 percent angular cobblestones;very strongly acid;abrupt wavy boundary. CI-31 to 60 inches; light olive gray(5Y 6/2)gravelly fine sandy loam;many fine and medium prominent light gray (N 7/0),yellowish brown(10YR 5/6),dark reddish brown(5YR 3/4),and yellowish red(5YR 5/8)mottles; massive; friable; 10 percent angular gravel, 10 percent angular cobblestones;very strongly acid. The thickness of the solum ranges from about 20 to 30 inches.The depth to mottling ranges from 16 to 24 inches. Gravel-size coarse fragments make up 5 to 25 percent of the solum. Reaction in unlimed areas is very strongly acid to medium acid. The A horizon has hue of 7.5YR or l OYR,value of 4 or 5,and chroma of 4 or 6. It is fine sandy loam,sandy loam, or loam. The B22 horizon has hue of l OYR to 5Y,value of 4 or 5, and chroma of 4 or 6 and is distinctly or prominently mottled. It is fine sandy loam or sandy loam. The C horizon has hue of 2.5Y or 5Y,value of 5 or 6,and chroma of 2 to 4. It is fine sandy loam,sandy loam,or the gravelly analogues of these textures.The consistence of C horizon ranges from friable to firm. The horizon is massive or has platy structure. Merrimack Engineering Services, Inc. Page 9 Printed: October 21,2010 Locntlon:_n5- I �� fit, ,, Owner's Name: Map/Parccl: Address: Instalter. Tel Nom'PuQI__impair Date: ( t egov , Wetlands . Zone E _Soli Synibol I I Soil I�Ihme��Sofl(3.1.5 50 -}� - b..&W p4t;r Deep-Obsematign Hole Logs Elmmdon Depth Soil H6iion Sall Tenure Sall Color' Soll Mottling. % Gravel,Stones,eta n �v'qp G S t LT 2,�Y `� �'mx 3 " Parent Ataterlal. 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