Loading...
HomeMy WebLinkAboutWPO201300001 Assessment - Environmental 2013-01-07 EROSION AND SEDIMENT CONTROL NARRATIVE Introduction The purpose of this Erosion and Sediment Control Plan is to control sediment and stormwater related water quality problems caused by land disturbance of new construction. These plans are in compliance with the Virginia Erosion and Sediment Control Handbook, third edition, 1992, by the Virginia Department of Conservation and Recreation. Project Description The Britts Mountain project proposes the installation of a monopole tower, an open compound surrounded by retaining wall at the rear, and the operation of antennas and associated equipment in a raw land lease area. The project is located in Charlottesville, VA on a residential parcel where an easement will be created and centered along the existing gravel access drive. The access easement will be located off of Britts Mountain Hollow on the east side of the property. Grading of the site and related activities will be performed to install the tower site and gravel access road with minimal disturbance as possible with erosion and sediment control measures to protect downstream facilities. The Virginia Erosion and Sediment Control Handbook was followed as much as practical on this site. Silt fence and temporary diversion dikes will be used for erosion control. The parcel is roughly 4.5 acres of which approximately 0.40 acres will be disturbed for site construction. An erosion and sediment control plan is included on sheet C-2A through C-2B of the plan set for Britts Mountain and the details are included on sheet C-2C. All other related material is attached in this narrative. Existing Site Conditions The existing site consists of densely wooded area around the existing residence and throughout the rest of the parcel. The access drive crosses an existing railroad and leads up to the residence. The project site will be located to the rear of the existing residence. Drainage does not appear to be an issue of concern at this site since there is a significant drop in elevation from the rear to the front of parcel. According to USGS topography mapping, the nearest body of water this area drains to is a tributary of Moores Creek which ultimately drains into the Charlottesville Reservoir. Area slopes range from 14 to 50%. Adjacent Property The site is bordered by several residential properties and the railroad right of way to the north of the site. The nearest major highway is Route 29 — Monacan Trail Road which is north of the property and railroad right of way. Off-site Areas No off-site land disturbance is anticipated for this project. A designated staging and stockpiling area is located at the northeastern corner of the property. Soils A geotechnical investigation of the site has not yet been performed; however, a brief survey of the soils was obtained via online web soil survey. The soils at this site are categorized as mainly Chester very stony loam soil. The hydrologic soil groups are identified as type B which have a moderate infiltration rate and consist of moderately or well drained soils. Critical Erosion Areas Critical erosion areas include drainage areas where slope length exceeds 300 feet for the range of slopes indicated. Albemarle County GIS indicates most of the site is in within the critical slope area. However, after development, the site area and access road will not be at critical slope. The maximum grade within the site construction limits is 33%. Erosion and Sediment Control Measures Unless otherwise indicated, all vegetative and structural erosion and sediment control practices shall be constructed and maintained according to minimum standards and specifications of the VESCH handbook. Structural Practices 1. Temporary Construction Entrance—3.02 Temporary construction entrances shall be installed as shown on plans. During muddy conditions, drivers of construction vehicles will be required to wash their wheels before entering the highway. Runoff from this device will be directed towards silt fencing and inlet protection devices. 2. Silt Fence—3.05 Silt fence will be installed as shown on plans. Caution should be used during the construction of a silt fence to prevent failure from undercutting, overtopping, or collapsing, and to ensure that flow bypass areas and overflow outlets are stable. Silt fence shall be used throughout the majority of the site to prevent sediment from entering the ditches. 3. Culvert Inlet Protection—3.08 Culvert inlet protection will be installed as shown on plans to prevent sediment from entering, accumulating in and being transferred by a culvert and associated drainage system prior to permanent stabilization of disturbed area. 4. Temporary Diversion Dike—3.09 Temporary diversion dikes will be installed upstream of the construction activities to direct undisturbed upland flow from draining onto the project site. 5. Outlet Protection—3.18 Outlet protection will be installed as shown on the plans to prevent scour at stormwater outlets, to protect the outlet structure, and to minimize the potential for downstream erosion by reducing the velocity and energy of concentrated stormwater flows. Vegetative Practices 1. Topsoiling—3.30 Topsoil will be used to help provide a suitable growth medium for vegetation. 2. Temporary Seeding—3.31 & Permanent Seeding—3.32 All disturbed areas which will be left dormant for extended periods of time shall be seeded with fast germinating temporary vegetation following grading. Selection of the seed mixture will depend on the time of year it is applied. Permanent seeding will be used to help reduce erosion and decrease sediment yield from rainfall, water and wind by reducing the velocity and volume of overland flow. Plant materials selected for permanent seeding should suit the climate, soils and topography of the site. 3. Soil Stabilization Matting—3.36 Soil stabilization mats will be installed (Treatment 2) alongside of the access road where the slopes are steep and tie into existing grade. Management Strategies 1. Construction shall be sequenced so that grading operations can begin and end as quickly as possible. 2. Install sediment control measures as a first step in grading and seed and mulch these areas following installation. 3. Clearly mark all areas which are not to be disturbed with flags, signs, etc. 4. Complete site clearing and prepare for construction. 5. Place temporary seeding to be utilized until final grading takes place. 6. Construct gravel access road, gravel parking area and gravel compound. 7. Complete final grading of site. 8. Place permanent seeding. 9. After site is stabilized, remove all temporary erosion and sediment control practices and install permanent vegetation on the disturbed area. Permanent Stabilization All areas disturbed by construction shall be stabilized with temporary and permanent seeding following final grading. This practice will help reduce erosion and decrease sediment yield from rainfall, water, and wind by reducing velocity and volume of overland flow. Steeper slopes such as those along the roadway that are to tie into existing grade will be stabilized with erosion control soil stabilization stone mat. Stormwater Management An overall drainage area was determined by studying the topographic map which is approximately 48.65 acres. The drainage area encompassed by the site development area within this catchment includes 2.46 acres and an upstream area of 6.93 acres. The total disturbed area is 0.40 acres. The compound site is 0.03 acres and the additional gravel required for the access drive is 0.10 acres which increases the impervious area of the subcatchment by a total of 0.13 acres. The site area is approximately 0.40 acres. In relation to the contributing drainage area of 48.65 acres, the increase in flow is negligible since the runoff curve number, CN remains the same for post development conditions. Furthermore, the development area is less than 1% of the contributing drainage area. Thus, the outfall of the development is adequate. Maintenance All erosion and sediment control measures shall be checked daily and after each significant rainfall. The following items shall be checked in particular. I. Silt fence shall be checked daily for undermining or deterioration of the fabric. Sediment shall be removed when the level of sediment deposition reaches halfway to the top of the barrier to reduce pressure on the fence and allow enough space for accumulation from future rainfalls. 2. The temporary construction entrance may require periodic topdressing to prevent mud or sediment from leaving the site. All objectionable materials spilled, washed or tracked on to public roadways shall be removed. 3. Reseed and mulch areas where temporary seeding seedling emergence is poor or where erosion occurs, as soon as possible. Do not mow the areas where temporary seeding is present, and protect from traffic as much as possible. 4. Permanent seeding shall be inspected for failure and repairs shall be made within the same planting season, if possible. Re-evaluate planting materials, quantities of lime, and fertilizer if inadequate coverage is produced. 5. Culvert inlet protection shall be inspected after each rain and repairs made as needed. Aggregate shall be replaced or cleaned when inspection reveals that clogged voids are causing ponding problems which interfere with on-site construction. Sediment shall be removed and the impoundment restored to its original dimensions when sediment has accumulated to one-half the design depth. 6. The temporary diversion dike shall be inspected after every storm and repairs made to the dike, flow channel and outlet as necessary. Once every two weeks, whether a storm event has occurred or not, the measure shall be inspected and repairs made if needed. Damages caused by construction traffic or other activity must be repaired before the end of each working day. _ ., ,,,5 ,, i - Weer -.,....1•...../(PJ‘...._, / b' 7 , . ' ••v' • ‘-',.. .-. to ,' i -• i— .- % ,... -..-... ha • ' tk ,..•", ^ ,•!'",''''‘,7 \ : it. ' : ,, ' , \ 11A117 -\ L::-.‘,,;;;1"1.-.^.1 ..i..,,, to c....„ ,.,.,,, 1., • -‘,,,44• „ , \ P f \ ,' k•\N.:;: - 1-, ,II.. - '411_1 m,,,..4.6.60.,ito \ :it, - ' \t\' ."" t ,k - . •:..,..',.-,_ vw,...., ..-' - ,ji. N..\\\. '•i•• /- 9.. ' 1 a•AO `'''',."47(^ As\ ').\ ,...-.., .'''\'.$,....,-"7.I:17:• .. /,'*lb,!". ,\. ... ,a't rk • ... , t\,,,J,,.„. * A ,i 7_1- , , -n..\.!-..... t.), it. •,ii, -,...:,. ., , . . .•.....„, ..-, „-,,.. ,. ,,, ,,, . it".°4. •(..51.""-.*:\- -' , "%.-.,,,c''',:,^,--,,,- ^f '__.,!,F''''',"^".. '...:' i In-*' * 4 . :,.--,,,, r . i . 4..,,,.. ,.s.,,%.,... . '14)`,,,.. ,,,,. ,',„ ',,,4't ,,*%.?-7.70 'cr.,' (< F.:Z.\ ..);-,./.:11,-,/';,,,,,, (:.,...,4-1,.i t ,-4., t,;,.1.4,.. ■ , ..4 \%';'' . ..,..,,,? 0,, ,i...\ --). 7,(.'4 ,\•. ,-77/,'.,,t..,,,,eN f,T..v \ti .... ,.. r.,...,..>.,._ , ,.., ,,,..> ,, , , ...... . . „„. „ ... -,. .,,,_ , ,.. , t ,/, c ..-;,,,..- i 4 4 „,x,;'''. t! .;sk......,.._ \\ .• \•,„!,„ . *14 - '.f!, 4','',) ' •---.....‘ ,7.y' -3/-‘\ .\,,--:--''.". -., ..1 r. s ... '‘,-....-,-,- • - ---, , .., _ ., A \--_— ), _-:1:.. . sx,- :,, ...4. . j , ..„-.... - . 1 7-- --\- `'''. ' `" — t .•!,_,'-''A ;..4 U- • 4'2 ,i(l ' .::."\ \ '1_,/ i/ ';'-'/,'*--- - - 4.:(---—,‘-:•. w ..,„; • \ ..., .. ..). ‘.. •--y.., I .•••••••,,1,.••`.. .s. • ' 0,,i' \ -:v ,--./ •7?' --\-4,;Li •s^, ---\,,/ 7 ' -- ' r ."'-\ * '*:^:r ‘,141,,,f ' ..4'''',--.H.,•t4;4' l':'- '‘},'\,(' \t24';''' ' , - ,s„ ,. , It . .•,,Aill . , ‘,.. y,ks, , t, • ..-.,...... „ N 1 ..„...e. I„, \ . )1 4..-1-;-.4.. 'k -....,-, 01. i,.,..A.--. ., • , , ....,./ „„,,--7,..- 0,..\ - )4i., . 1• ,„......„ss i., , /A,......,„,-, i‘... 7 4 Est j '‘,!c-,./-, ., L.....:,..,\ -,... ,- , ,....„.,-- „ 5 . , v■, ibiet9,0. .r. ., - --,42r., "'N \ . :-•- „.,...—• - ,...,.•'• ., • - . . I. •. I , ..., ,v 1 , t?,, % 4 . •-•7'•,....., ',... \ 4.„'„ .,(...-....../#1.Z.,ci \o„, \+,,,,t \ 4 72 ...// 1 -\\ . V A , \--4:— z \,,; f ,) ,,jj - f•----' ji., ,,,,... 0;.„ .., ; •. C.-- •§',j i• ct"-■.\, ''. - . ,\\■%.' , - ,,) "..1 i• • _,...‘,..% , ....„\\,.,:. ( C. . _, ' . 4, • \ •/1 \ ,,•) , ) ''• . --Th f - • - 4 'Z'y,,,:,..__,*,... ,i < ,:._ ...........„.„,„..... ,..... , ,.. ,,( ii.„. ,, ,, „ ..„ ....-„, ,„„,v- -.., • r -: .;„ •-.,',4.:,,,.. a.-.. 1 i 1 (-,)),' ' C - A \ '- At.47.4'\!,./-7.„L' i,tic \-4:::,L-41`,3-.. ('N„ ..\1 *'" ' .,1) V 1 ----\,,\.., v A,....-.. .;- \ \ z .-:-- / ",--,\.-----"'-/ : . ) H ple/ i `),/":"II % "(I )g ,,ir'' C':--:'?.... 44.-."4; ' „IF" ' ' '",.s. ...***‘*' I Oh• I .," '\ *".._'••° ( •„.., -: „._:. 1.--:)\-\„,,..-,,,,....,.. N3 v1 ,,i, .,,, -- )) , - ‘ ,- , . .... N.../,711. \ \\\`‘..---- ...°."1: '-''I''',‘!('', f.,,,r.4.- *,.? `,.!,'.,:, '14 ,...., , kl s, '-- .:0';'';'+' rf , / i.. , \-\ i!,,/ ,' ,•^".,„p, _--...„' 2 I II,',.\, ri / , ',,,'",',,1,.. ,„/,'"Jr , ,. , P(.....,,,? .. ' \ s .••4.) • .•° I i '.1,-'',-,,---."'\:.:.„..* ..„' 4,.,% • ,I \., ,\' I.,'', -, ff.- • ' ,,..",:lk\,,t•-,•1"-.,.:";.;,,__ i •.. , ....:,,:,,- ; ,,,,, :„:c,..„, ti...--.77..-•:' '.,.,(.1‘.:4;-;14„, 2' il \ (f) -j k ''') '`.' - I ',--1—:.N. l' ' ..?) \. -.......,., it ,—,...--W!,‘.s.':\'' .-sii- t.': , ..‘ '''' . ,,,,,:.; ;.,s•-•"•,-..„,r.,,. I ,„./.,...c.'-...:.--,;..!,...".., v...--„. r....,„.„hi. H 'Q• ( :.'..,,,3 <-1,f;,. 11 02- ,; , ;,\ < -/4 'A 71' .4''' ( .V\ ''''''' .\\Tt. L )1>k ',\‘* ■ .*--, ' *^,I( 'Ilf,..",,,; ((r **,. N';',:',',.-7.:S ' \A ,,, ,,,..; A.,1 , IT( Nor if* , ' ,,,V,(,`!., ■ !it,' ‘‘its. '''' * ' -*. ,., ...,\ , ;,„..„, :. ,..,, r„„„„.., ,.,,,,, .....,..,s,, ...s., a .. . ..,„..,. „ _ :\,... .... , ,... ,,) „,, ....„. 17, , ( ,,,,, ),;., .„--„, .,,c,,,, ,,. ..\ -,.., ,....., -,,,‘., ,‘....,.. .N.,.i„, „..„.....- , ,, „, co r•- •••1 •'.' . Yr#0„ -'4,4, '',N,,, 0.„.,' ,■'''' ''',;., ' :,",'...\'. --Kt 1/..)... •"---- 7t.' (1, \-\.,-”' A I&`1‘,,,, cr (it ' ?.7..7.'N, ,',F,, - c-'s '''• 'i •-- '13 , ( % w" );I .:1* .1/4 -‘-',...• , ' '•``.-. N,\ VC„, '‘':'...„;'). V.%' , .,,,!:`..,‘'‘.,'; i'A‘N 1"------V. '' .. ' ° i •- - 1 ... 1r .„.,.... , ,,,,, .,„,,,.;,, ,.‘1/4, ,. k,, ,,,,,,I .), , , 0,.,,,, ,„ ., -.:---_,), ‘-',,, " 13, '''. g •' (. .1/ `-,.. 4 C . ',` ii,..,,..,:.,'0 ' •4P( '1\'' I c'e-1-'k'MAI .' -5 ' E 2 u) -2.,,,,,, -.,.. ,.. ..1,,ij ,r, ,\ .6.flr_..,,. ,,,- r. -,),-,,......,- Op-,.., I"., •.,.,- ,',4-,,..' :2,--i':".: 1 ' t, `,, (1 ,-. . ".' e. 1:.) ) c%-141 •-. —) ..f\ .. ,s.,,s0 ' ...1 .....*:1;., ) ,,,„ ' s''\:'''''..44,..:•4-"-'''''''N''.c. -\ ''‘'44ii:ii$,•+‘ . ly, : ;,'4,- ..•; • - • ' \ ' ''') 't ' cf 51 + \\''44'-\\'',\,\,% ',! t',4,, , H -10 \ '''•\•','• ,‹"3'- --,-.;\ - / )1'•:":;\ "\ .. , ,A'."- % ,•: '-\". :-.70/- -. ... .<7 ) ) • , -,—, .. ---..._ .•,.:,-,,i-. , II & CI ,_ f „,k1 ,. I ; ..'N, *''' \ !I • . 6. ‘., -„-- ' --,, .,,,-.„_,,, ' Ifl,'., ""•\ ---- L..). , il i 1,:i ".-,,,,;„;,- , s'"--...„,.._ , W \"\ ••.)A :E- V) i : ) ''') 19>,,...)'D f 4---,--1.* 2- '17 / ---. '-'="" ) N.....,.‘,,,,4,---•• :,..,,,'.• .. ) ., ., .... 4 8 .707)/7....-..,,,,;,-.:;- . _.....\--y.;A::;. -----). f, ---„, ',,,,,v,,,,:-.: 'ver., ,, , Q. ,&:',. • .yl,'--s---...--, ,:`,", 1 ' :1--_,... , \s\‘. . t --,-, ,r\ . .. , ....,. ..„.. 4,3 3 E m :4 ,c,,, ,,, proilikki o a i I, ,2. ]1j i�, d C� d1S C7(// 3'(C.:5- '44 s . Co co 4196` �X1.0 8 O8 w �' b9 k� ,r) \,\, \\ 8 `` ;195�! ' 11.04L------�}'PPL--...4...z l o`r's \\\\\\\\\X6 11-1£L 1}9£f `8bl \\\\\L:i 716 ft I.i 4.0Z i V) os _ -708 ft N.,.., s 9G Y, �•r ,y,„______„ l 692`ft°`-�- . 2 \\...\\:"....' ...''''''''''' /// X89 e9 ii. ?.\ i`� N� }1 Ob9 J18b9 ' . 899 sr,a A }1 Z9 O yy', -,,,Ni "�'O \ 899 b s ,,s�''���,",w' ZC)rs s s er ,6,,caLS `S' �y a Y` o ``��'VVmss �'� "' a 1 0 Of O _ .N. ` O ti 47, N '-b ■fie„ C S�� 11b09�1 s ti M, ,,i.2 Ni9dk 28 y� "h�ti� /MA- ........\ 4\ 714., ..... \ \\ ((5f: it r� }•0bg / a Ti CO , MSRMaps: Print Page 1 of 1 Send To Printer Back To MSR Maps Change to 11x17 Print Size Show Grid Lines Change to Landscape ■t GS8 km W of Charlottesville,Virginia, United States34#M(*<;■1 - !/)1 r'1 '. _- `'rr :J f, rfrf _ r r-_ *` _``1,+! _9. \\,',....7....../-_____,,fii,i, 1,,.. ....,xze r...........- ."..z. f...,,,r,..,-. i........_ ,....„...jo lb otoilit.....„„, %.,,\-.% ).:... "?' IF:5->l, ;,..,__..--"°,;://,'-F.--.Cf,:elY 11C-'''..----'__.-.,'"/ or'412.`- .-- ',,, 1 je't ir- ,, -___„......„ ......-7 ........:4,,,,,,,,,, ,/,...,,__..- . ......,,,,7,-..„..).,---. .........„. ....,...-- I i -..-.--4/4 {� Jr•-'rte t ,fir;!'� ` r l 1,..._...-•:;,--• '''__ `y1 - fir,{. - -/r /7"-7_,....e:-..--, r ��` f X . 1 f' ..f-fir'' ,, ,,i ," ,. I 1 F.. / ,,,,I-N_ ,." 1 .,-.;".-:,- /if 1 y 1 t :::::.,..,, ,,,.,...,...... / 1 )) .,,;( / ,,,,e {{fi+ _,,,. '` � I}r' -r� r�i-f J i t � -r � � • J ` J -. y ' . r te '•rI _ �"—.�''�,a V.. 1(1 I,,,—...r— „".... 7 `�r _ i � .`�.�--t r`.1 r r- ,rt - o ff Sri - � � 'r!ti_�. X 1 f-`*'1. t,' ..._.yr j t r^ ",, rri' /`�r�'� r 1 -,.. ."--_,..:‘,.+/-/-‘m„ - ' "'� e�r r t re i. fir.- _ f =--`w(i,0,111 ... _„,-----s__........Vfr—"'N\1\_ ----"-:=61 �•tom y� ,� I�}J l'�1�-`-.- , T ' �rf _' :2-.., r y 5.� -,! r% --ti r'' k r / ( e1 . 1 ,/1r c '`'` V �ti ff/ NyL., 4 f rJX'�_r' �r)- r </t. / j ' X1 f ti (..`/ i "`:-� �f7 r er ' { r-- � (R)11 02 7°'''.... Nd ....Al . 11; ,,,--;..,/,/,, ! ......../4--,-------77 1( Q.,__,, I'' ,..->,, y 3 4„II -....--_-___:____.-------r--_,__---- ( 1 I,,, ‘... — P rtwi ,...--°"..7 7,./e• i ' i eroti ) ) r- r„,:,,,,„ ,____ , L,.,\ .,,:. i ( i'. Y.- 1"14-r. / ' / i;F 1 -r--„,/ 7 J f r �,,. , t r { d / r .... .•I; ----7-11'Nii,(:--:1'.-.::-----k--7 43 I j 4 1,..--" ....-."7/ 4. ..I ..-:,/, / ,/,/.1 /„________..- •-� Lk - `'.‘'1.'. I i l 1 •Ill�I ti ii Il ii-C T. /. �;',,:.),,./,.... -.:/.. ....,.;.---.5.-- !r,`�rJf `� J '� r+�4 1 f 1f, ti t 'ti. , 1 ' i I = .,. - r 11 C.....___.. - •• ,..'I i' ,'�.1, .'•,k..,• ,.. __ _ ......1.,.. ' '' � i I I � , .r FJ' �r i i' Ii (i'l "`, I l 1,. 0 11'S ''�_ 'ti w. ~J ! f r f�f :`�r._=_. -__,.....--7 m I 100r 200 300 yds 100 100' 300' Lp djh#frxuhvI#ri#Mkh#✓K1V1#k7hrajIfddNxuyhI L 4'5 3 4 3 41,lfurvriw4 'rusruiwh'gi#frerms of Use Privacy Statement http://msrmaps.com/Printlmage.aspx?T=2&S=11&Z=17&X=1784&Y=10522&W=3&D=O... 1/3/2013 Soil Map—Albemarle County,Virginia (Britts Mountain-Charlottesville,VA) to < M en n n m n 713500 713600 713700 713800 713900 714000 38°0'35" / 38°0'34" <°o °o o o ,, 4-o � o v a o i M, g O w — ' _, O ' • L — O Q f w fe X ; P'' O .. N M ' 'Alli"'"*. ''''0 x ~ ° €° It et O Y e k *r 2 m ,as tf F O O O O O 38°0'6" N - N 38°0'5" 4 713500 713600 713700 713800 713900 71400D ° °' Map Scale:1.4.290 if printed on Asize(8.5"x 11")sheet. a v En N Meters A0 40 80 160 240 /,\V 0 150 300 600 900 Feet USDA Natural Resources Web Soil Survey 1/3/2013 aW Conservation Service National Cooperative Soil Survey Page 1 of 3 co co O O O C 0 a O C N N ac° y_ c E f0 a) L m l0 N O N co a) 7 Cr' W •O a) >p CO N-o N d fo C T O (a U N a) O _c -o co U co co CO t� CO Y E N a co o N a) `° C N a) ca O co E W C 0 ca= w O ` O Ul -0 O Z a) a (0 N m C (n @ co a) a) N o E a a) a) m X O U a7 a3 U N T M 0 E O t- ..co cc N E a)To a) N y Z Z t O U E y Q 3 y ° y ° N 0 7 Z < > N N L O` >_ a) O a.)'g a) E E C)—' 0 >,C) r 3 y (a N Q CU v m .c (U N C c m o `m Q a Q 7o m ° E 3 m i m ° ° �o " o co-° Q a>i O C T > Y O C 3 N 7 3 0 _-' T LL O C O O 3 a) m O E _ a7 N N N — N O N _c Z N 1] �@ O N a) O cc a N a) N CO a co O E T.0 E E ti C a>) a ° aa)) C.)) (U v -0 aE) C a`) a 0 VN) E Q 0 T 9 Y a) N _ 2 a) -a > 3 --E N @ E a N O fa a) .y Q O O N O a) m ° a Z m 00) .t a C) N a) N N @ N "'V 'OD N N E c -C Y > ... f0 O C) a) c T a) a) N a)a) i as 2:E O: T 7 — Z ° c O C m N N V 16 a O m 0 c a.0 To N C, E a) a) (0 2 d o O C O (i/) Z a @ _c N 7 N N C ca C E •' y CO U U a a) (n a) p 'a a) N a a) E co N U N a) a) o o cn > — Z °-) a) o m E 2 E- w E a ° a E CO O H ,s co u) 0 1- ° E o T a) Q 7 C_ > N 2) > .� a) o C 0 u) >co 70 O O N 0 (u u) 0 r a -c C) a °co N 0 - aa) — m N a c N Q S a c m ° ° o o 0 r Z co I o a O1 2 co N w T 2 a N = N N V CI) C a° 7 O a Y O O cc m m cf m U)co m w C m a) N E. V > 6 c U = O U 7) O D 2 . J N N Q LL m t w J CL o Q O Q C y m m a u) o N a N m v a) L N C V � m a -0 o m O O O W O O a) y ( °` m m .- n (� T m a n p - a m a n 8 a > m d o v d LL o E O co : o a Q u) y Z Q ° 2 LL 3 ° T N >) w m r N U m Y C 2 N Y m U — N 3 N` O C O `O m O m m N N N C 0 m O la m o C 'O O d y =N Q I '5 m co U U (7 C7 J J 2 a a d m Cl) Cl 1) Cl) I Cl) C) U O C m a N o c To m Ce ° o -- — ae) J ® X • X © . 1 QC © OO > t III O ,ca 14 m A d N — .O fn N .c'.- en 7 C N O z U 44 ft Soil Map—Albemarle County,Virginia Britts Mountain-Charlottesville,VA Map Unit Legend Albemarle County,Virginia(VA003) Map Unit Symbol Map Unit Name Acres in AOi Percent of AOI 15D Chester very stony loam, 15 to 25 percent 2.6 4.3% slopes 15E Chester very stony loam,25 to 45 percent 51.7 84.8% slopes 38D Hayesville very stony loam, 15 to 25 percent 5.8 9.5% slopes 70D Porters very stony loam, 15 to 25 percent 0.8 1.4% slopes Totals for Area of Interest 60.9 100.0% USDA Natural Resources Web Soil Survey 1/3/2013 Conservation Service National Cooperative Soil Survey Page 3 of 3 Hydrologic Soil Group—Albemarle County,Virginia Britts Mountain-Charlottesville,VA Hydrologic Soil Group Hydrologic Soil Group-Summary by Map Unit—Albemarle County,Virginia(VA003) Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 15D Chester very stony loam, 15 to 25 B 2.6 4.3% percent slopes 15E Chester very stony loam,25 to 45 B 51.7 84.8% percent slopes 38D Hayesville very stony loam, 15 to 25 C 5.8 9.5% percent slopes 70D Porters very stony loam, 15 to 25 B 0.8 1.4% percent slopes Totals for Area of Interest 60.9 100.0% Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D)and three dual classes(ND, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential)when thoroughly wet. These consist mainly of deep,well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture.These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential)when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (ND, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. USDA Natural Resources Web Soil Survey 1/3/2013 Conservation Service National Cooperative Soil Survey Page 3 of 4 AASHTO Group Classification(Surface)-Albemarle County,Virginia Britts Mountain-Charlottesville,VA AASHTO Group Classification (Surface) AASHTO Group Classification(Surface)—Summary by Map Unit—Albemarle County,Virginia(VA003) Map unit symbol Map unit name Rating Acres in AO1 Percent of AO1 15D Chester very stony loam,15 to 25 A-4 2.6 4.3% percent slopes 15E Chester very stony loam,25 to 45 A-4 51.7 84.8% percent slopes 38D Hayesville very stony loam,15 to 25 A-4 5.8 9.5% percent slopes 70D Porters very stony loam, 15 to 25 A-4 0.8 1.4% percent slopes Totals for Area of Interest 60.9 100.0% Description AASHTO group classification is a system that classifies soils specifically for geotechnical engineering purposes that are related to highway and airfield construction. It is based on particle-size distribution and Atterberg limits, such as liquid limit and plasticity index. This classification system is covered in AASHTO Standard No. M 145-82. The classification is based on that portion of the soil that is smaller than 3 inches in diameter. The AASHTO classification system has two general classifications: (i) granular materials having 35 percent or less, by weight, particles smaller than 0.074 mm in diameter and (ii)silt-clay materials having more than 35 percent, by weight, particles smaller than 0.074 mm in diameter. These two divisions are further subdivided into seven main group classifications, plus eight subgroups, for a total of fifteen for mineral soils. Another class for organic soils is used. For each soil horizon in the database one or more AASHTO Group Classifications may be listed. One is marked as the representative or most commonly occurring. The representative classification is shown here for the surface layer of the soil. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Lower Layer Options: Surface Layer USDA Natural Resources Web Soil Survey 1/3/2013 Conservation Service National Cooperative Soil Survey Page 3 of 3 K Factor,Whole Soil—Albemarle County,Virginia Britts Mountain-Charlottesville,VA K Factor, Whole Soil K Factor,Whole Soil—Summary by Map Unit—Albemarle County,Virginia(VA003) Map unit symbol Map unit name Rating Acres in AOI Percent of AOt 15D Chester very stony loam,15 to 25 .24 2.6 4.3% percent slopes 15E Chester very stony loam,25 to 45 .24 51.7 84.8% percent slopes 38D Hayesville very stony loam, 15 to 25 .20 5.8 9.5% percent slopes 70D Porters very stony loam, 15 to 25 .17 0.8 1.4% percent slopes Totals for Area of Interest 60.9 100.0% Description Erosion factor K indicates the susceptibility of a soil to sheet and rill erosion by water.Factor K is one of six factors used in the Universal Soil Loss Equation(USLE) and the Revised Universal Soil Loss Equation (RUSLE)to predict the average annual rate of soil loss by sheet and rill erosion in tons per acre per year. The estimates are based primarily on percentage of silt, sand, and organic matter and on soil structure and saturated hydraulic conductivity(Ksat).Values of K range from 0.02 to 0.69. Other factors being equal,the higher the value, the more susceptible the soil is to sheet and rill erosion by water. "Erosion factor Kw(whole soil)" indicates the erodibility of the whole soil. The estimates are modified by the presence of rock fragments. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff- None Specified Tie-break Rule: Higher Layer Options: Surface Layer USDA Natural Resources Web Soil Survey 1/3/2013 Conservation Service National Cooperative Soil Survey Page 3 of 3 CLARK• NEXSEN 0 D 0 S Architecture& Engineering O ARCHITECTURAL. LL MECHANICAL ❑ CIVIL ❑ ELECTRICAL Li STRUCTURAL DATE 2 41 I 3 ?tv. —5-15 COMPUI'D BY __eel 15R t 7) MaLKI1. .tKi COMM.NO. 3030, 0-7 j CHECKED BY PROJECT V,1211'1 iNICalhll? SHEET NO. I OF SHEETS £Checxa.1C r�"t .D{' ttt.aPoe Acra (E' 1Tr_ I)'/+ayt4{:S rC �� �- dR = 1.4(0 AC sty / fif /-415 3S _ S3Ac + 2.10 A,C. = AC r ` 4-efAS "fit, f✓E 271 't:Lt'.P17 Aciou} ) Std: 51/t,.IOFMf_NT- Art- _ `-t ,CAS AC 2 .27 c Ts tT- T a1�AaE • {� 25,2"l r s WrnP � = x.35 AC fzU h1 o F pF or►Pa( GtLA,I/ L. pfX-r- 1 m w?•i cr,1.L >- a. 1-`Z)A C AcA r (hyy.,r. SA al E" f .IS c A 1OO ...- oS (H r4-460,r-, (cm- w66.11P5 , Cale-d-) CD _ q e.rs' _ x,21 e Flo) , , (z)= 3.8,3 crs ( ,) 8.55er 4 t nC-rerMZ C;.214 r D 3c{ C ts 2∎S-TIA2t3 D Aec-A t� st�T TIC 0,7 AC S L{3��' Sl+vw IuGQ{A5� t1�w e£tr4-114T) Xtc-n t otAS rSv4:2 0 Al2,cA (7,1�� �e = 02 AC 5F = 5 ot\! L^'"?; 51L1 1--tNct;` (2C:`.,19)CC . { �� 0.Lt0 ta,C _ i(n01 c0 t'4'(w°t)i"t) Y4,4,CA2c WinTR-55 Current Data Description --- Identification Data --- User: CCY Date: 2/11/2013 Project: Britts Mountain Units: English SubTitle: Areal Units: Acres State: Virginia County: Albemarle Filename: H:\PJ\3036\073\Civil\E&S\BrittsMtn.w55 Sub-Area Data --- Name Description Reach Area(ac) RCN Tc OVERALLpre Subcatchment Outlet 48.65 60 .232 OVERALLprs Subcatchment Outlet 48.65 60 0.232 DA-up Upstream Drainage Outlet 6.93 60 0.200 DA-sitepre Outlet 2.46 70 0.100 DA-sitepos Outlet 2.46 71 0.100 Total area: 109.15 (ac) --- Storm Data -- Rainfall Depth by Rainfall Return Period 2-Yr 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr 1-Yr (in) (in) (in) (in) (in) (in) (in) 3.5 4.5 5.2 6.2 6.7 7.5 2.8 Storm Data Source: Pittsylvania County, VA (NRCS) Rainfall Distribution Type: Type II Dimensionless Unit Hydrograph: <standard> WinTR-55, Version 1.00.09 Page 1 2/11/2013 3:42:35 PM • CCY Britts Mountain Albemarle County, Virginia Storm Data Rainfall Depth by Rainfall Return Period 2-Yr 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr 1-Yr (in) (in) (in) (in) (in) (in) (in) 3.5 4.5 5.2 6.2 6.7 7.5 2.8 Storm Data Source: Pittsylvania County, VA (NRCS) Rainfall Distribution Type: Type II Dimensionless Unit Hydrograph: <standard> WinTR-55, Version 1.00.09 Page 1 2/11/2013 3:42:35 PM CCY Britts Mountain Albemarle County, Virginia Watershed Peak Table Sub-Area Peak Flow by Rainfall Return Period or Reach ANALYSIS: 10-Yr Identifier (cfs) (cfs) SUBAREAS OVERALLpre 25.27 82.83 OVERALLpos 25.27 82.83 DA-up 3.86 12.41 DA-sitepre 3.59 8.21 DA-sitepos 3.83 8.55 REACHES OUTLET 58.66 189.75 WinTR-55, Version 1.00.09 Page 1 2/11/2013 3:42:35 PM CCY Britts Mountain Albemarle County, Virginia Hydrograph Peak/Peak Time Table Sub-Area Peak Flow and Peak Time (hr) by Rainfall Return Period or Reach ANALYSIS: 10-Yr Identifier (cfs) (cfs) (hr) (hr) SUBAREAS OVERALLpre 25.27 82.83 12.07 12.06 OVERALLpos 25.27 82.83 12.07 12.06 DA-up 3.86 12.41 12.06 12.04 DA-sitepre 3.59 8.21 11.95 11.94 DA-sitepos 3.83 8.55 11.94 11.94 REACHES OUTLET 58.66 189.75 WinTR-55, Version 1.00.09 Page 1 2/11/2013 3:42:35 PM CCY Britts Mountain Albemarle County, Virginia Sub-Area Summary Table Sub-Area Drainage Time of Curve Receiving Sub-Area Identifier Area Concentration Number Reach Description (ac) (hr) OVERALLpre 48.65 0.232 60 Outlet Subcatchment OVERALLprs 48.65 0.232 60 Outlet Subcatchment DA-up 6.93 0.200 60 Outlet Upstream Drainage DA-sitepre 2.46 0.100 70 Outlet DA-sitepos 2.46 0.100 71 Outlet Total Area: 109.15 (ac) WinTR-55, Version 1.00.09 Page 1 2/11/2013 3:42:35 PM CCY Britts Mountain Albemarle County, Virginia Sub-Area Time of Concentration Details Sub-Area Flow Mannings's End Wetted Travel Identifier/ Length Slope n Area Perimeter Velocity Time (ft) (ft/ft) (sq ft) (ft) (ft/sec) (hr) OVERALLpre SHEET 100 0.5000 0.800 0.164 SHALLOW 1030 0.5430 0.050 0.024 SHALLOW 1400 0.3000 0.050 0.044 Time of Concentration .232 OVERALLpos User-provided 0.232 Time of Concentration 0.232 DA-up User-provided 0.200 Time of Concentration 0.200 DA-sitepre User-provided 0.100 Time of Concentration 0.100 DA-sitepos User-provided 0.100 Time of Concentration 0.100 WinTR-55, Version 1.00.09 Page 1 2/11/2013 3:42:35 PM CCY Britts Mountain Albemarle County, Virginia Sub-Area Land Use and Curve Number Details Sub-Area Hydrologic Sub-Area Curve Identifier Land Use Soil Area Number Group (ac) OVERALLprePaved parking lots, roofs, driveways B .48 98 Woods (fair) B 48.17 60 Total Area / Weighted Curve Number 48.65 60 OVERALLposPaved parking lots, roofs, driveways B .61 98 Woods (fair) B 48.04 60 Total Area / Weighted Curve Number 48.65 60 DA-up Paved parking lots, roofs, driveways B .001 98 Woods (fair) B 6.93 60 Total Area / Weighted Curve Number 6.93 60 DA-siteprePaved parking lots, roofs, driveways B .35 98 Woods - grass combination (fair) B 2.11 65 Total Area / Weighted Curve Number 2.46 70 DA-siteposPaved parking lots, roofs, driveways B .48 98 Woods - grass combination (fair) B 1.98 65 Total Area / Weighted Curve Number 2.46 71 WinTR-55, Version 1.00.09 Page 1 2/11/2013 3:42:35 PM