WATER & SOIL MGMT
WATER & SOIL MGMT AGSM 335
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This 73 page Class Notes was uploaded by Freeda Batz on Wednesday October 21, 2015. The Class Notes belongs to AGSM 335 at Texas A&M University taught by Staff in Fall. Since its upload, it has received 44 views. For similar materials see /class/225899/agsm-335-texas-a-m-university in Agriculture Education at Texas A&M University.
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Date Created: 10/21/15
MANAGEMENT OF SUBSURFACE DRAINAGE SYSTEMS AGSM 335 FfS oi Jb qH g NUMBER QWE REQUEREMNT SUHTAILE UTLET SUITALE OUTLET 339 DRAINAGE OF AGRICULTURAL LAND PERCENT OF COUNTY AS DRAINED LAND Dahor heademMdramedagnw uraHmd S mm u s Depa hverdm comm Eursaum Denis 191a semiowmuwe am WW5 spend Repo m5 Dramazem gncuhura magma 5w 5 Wm WM mum Uses ROLLS OF DRAIN TUBING ummer TMdvamed Iann FIGURE 13 Rum Ilrvrlwplncul nl 1mm gum 4m dnnnml and undmmul Lmd ILhum 1mm Mummy and Run Wtff 39 745 5551 marmm 0 A g 7 4 14mm mg i 475p panMei Spacing amp Depth 4 5mm recnmmemlallnn r sila39ilower 8 clos er A current theory says that shallower amp cluser placement may reduce nitrate losses from drained elds quotEff V v 1 i FROM HANDOUT MATERIALS mm H mm mm mm m M W nmm FROM HANDOUT MATERIALS M qSLS2 43200 ere Qr relief drain discharge cfs C drainage coef cient inhour 39 drain len9th1100 feat drain lengthI feet S draIn spaclng 300 feet 5 drain spacing feet q drainage coefficient 0008 inhr w E Suppose q drainage coefficient 12 inchday L drain length 1300 feet S drain spacing 250 feet Q 43200 Q 0069 cfs a r 43200 q S L S2 43200 Q 05024 250 13002502 43200 Q017 cfs FROM HANDOUT MATERIALS FROM HANDOUT MATERIALS Wm xxxg JV 39Ii 7 a Wig i FROM HANDOUT MATERIALS DRAINAGE COEFFICIENT DC Amount of Water to be Removed inlday HHHHHHH Darcy s Law applied to subsurface drainage vz K Kdy dx dx d qxyvyK y dx q DC xj qX Dc x Ky and IfZD Ifxdx KW DC 52 7 bid 8K 2 m alxo 7 01 50 4K 51Ebhd2 lfcl 2dmm1 STEADY STATE ELLIPSE EQUATION 4 K DC ERE d9 a is the effectivetile depth See EXAMPLES S1 2amm2 DC S Zdeerz FROMm my s A DC q 024 inlday K 48 inlday S 2 demm2 4 48 Z s quotW 273 3 S 202 feet OR 200 feet mum u In mm u y m n Wu m mm m Spacing 8x Dapih NOW WHAT HAPPENS IF depth to barrier a approaches in nity S1 2amm2 DC S approaches in nity MUST INCLUDE THE CONCEPT OF EFFECTIVE DEPTH m m V m mwr mum m kwhuuwm ihmmmmyvtummy vz mm H mm nn H n m r n m pnwvg huwccn S 3 4K E2 61Ler m2 4 48 Z W 2 403 3 S 446 feet u m gun m r limm TILE SPACING EXAMPLE Trial S S calculated TILE SPACING EXAMPLE Trial S S calculated 24 red line 23 blue line Elilb mun w llrlm lhcmvm 1mm TILE SPACING EXAMPLE Trial S d S calculated 24 red line 23 blue line 215 nal Iwuu m Mmme In mu w mm t39vv m um mm m it 4i n n mm HunJH m at mm TILE SPACING EXAMPLE Impervious layer is 40 feet belowthe le line le line is 8 feet below the soil surface Desired water free depth is 5 feet Hydraulic Conductivity is 48 inday Drainage Coef cient is 024 inday TILE SPACIN EFFECTIVE DEPTH NRCS has developed FIGURES that include the concept of effective tile depth THIS MEANS NO TRIAL AND ERROR THESE are shown in FIGURES 429 in the NRCS HANDO TILE SPACING EXAMPLE 1 Take qK or DCK with same units qK 024 inday I48 inday 0005 Take ma with same units ma 340 0075 USE FIGURE 429 TILE SPACING EXAMPLE REMEMBER WHEN USING THE NRCS FIGURES DO NOT USE TRIAL AND ERROR TILE SPACING EXAMPLE Take qK or DCK with same units qK 024 inday I48 inday 0005 Take ma with same units ma 340 0075 USE FIGURE 429 Sa 80 and S 0 40 320 VERSUS 332 feet by trial and error TILE SPACING EXAMPLE Suppose a in nity LARGE NRCS method Take qK or DCK with same units qK 024 inday I48 inday 0005 Figure 430 with m 3 ft FIND S 380 ft Drain Grades and Velocities Where local conditions require the use of drains on steep slopes which result in velocities greater than those shown in the following table special measures should be used to protect the line Drain Grades and Velocities Where siltation is not a problem the full recommended MINIMUM grades are as ows MINIMUM VELOCITY 14 ftsec Drain Diameter in Drain Grade 4in 5in Bin 007 005 Drain Grades and Velocities MAXIMUM VELOCI TIES SOIL TEXTURE Sand amp Sandy Loam Silt amp Silt Loam Silty Clay Loam Clay amp Clay Loam Coarse Sand or Gravel VELOCITY ftsec rm H a Na scha39 THE NRCS METHOD IS THE MOST 4 90MHONLV USED METHOD FOR ESTIMATING RUNDFF 1 mawquvuwha quon a mu um um I mtn Mlh u quotmm quotunai at m w IETIE APPROXIMATE P31me or moment RAIIFALL mm cores RLNBFF NRCS CURVE NUMBER 2 The Curve Number is between 0 and 100 which is related to the amount of runoff generated from a watershed 3 Larger ON values are associated with greater runoff volumes NRCS CURVE NUMBER Determine the total volume of runoff generated by a storm event P 0ZS2 P 0 8S WHERE Q is the runoff volume inches P is the precipitation inches 8 is the precipitation surface storage before onset of runoff inches NRCS CURVE NUMBER 4T39Eunction of antecedent moisture conditions surface cover land management and soil type For multiple land us and soil types use a weighted averae see Example 52 in the text Weight by area within a watershed NRCS CURVE NUMBER Surface storage is estimated by the curve number 1000 CN WHERE ON is the NRCS Curve Number S 10 SUMMARY 1Given rainfall duration return period and location determnne depth of precipitation P 2 Determine weighted value of the CURVE NUMBER Adjust of ANTECEDENT SOIL MOISTURE as necessary 4 Calculate S and Q The 028 Factor The precipitation must exceed 028 l before runoff occurs 025 Initial abstraction II that includes 39 Surface d ssi s I Vegetation interception 39 Evaporation 39 In ltration S Potential maximum retention atter surface runoff begins quotmen Rnnnn wrms mm or rtnT hens pmdicxrd by Em 5 5 1nd 5 4 NRCS CURVE NUMBER Determine the total volume of mnoff generated by a storm event WHERE Q is the runoff volume inches P is the pre tation inches 8 is the preclpltation surface star before onset of runoff inches Hydrologlc Soll Groups HSG i hydrologic soil groups gt ABCD I A sand loamy sand or sandy loam 39 B silt loam or loam 39 C sandy clay loam I D clay loam silty clay loam sandy clay silty clay or clay based on surface soil texture when choosing a group must consider compaction by heavy equipment exposure of subsoil etc HYDROLOGIC SOIL FINAL INFILTRATION GROUP A B C D Mm scs mdmwlr Sm Gmups mm mm w my mlmrm m m m lnwmlrunuffpummmlInclududup magma liulc n5 05 51 and aquot and deep pcrmuhlc ion 53w Q39w Moderately low rmml39fpulvmml Mostly sandyand Ms an a sum lcsulccp than A lmmbmc Nr rJg mmvmunn o 0470 15 noquot polcnlul Hiin lay veil mm high H 041m okcnhal and some 5mm mils mm nnpunll hll wmmmum HSGs based on Saturated Hydraulic Conductivity Km A soil high in ltration rates Km 030 i Jhr B soil moderate in ltration rates 015 inlhr lt Km lt 030 inJhr HSGs based on Saturated Hydraulic Conductivity Km c soil slow in llrulion rates 00 hr lt Km lt 015 inJhr D soil very slow in ltration rates K 39 Ih See Appendix D HANDOUT NOTES for a list of the most common soils in each state with HSG type A B c or D Curve Numbers CN and Anltecedent Moisture Conditions other hydraulic conductivity 0N SRO SURFACE RUNOFF values are provided in Soil potential of area surveys which are available on a county basis 39 Table 53 very limited TEXT OTHER references for more extensive listing CN39s developed for land use I land treatment combine one mu 39 L x A A a Rm mm Numbquot rrm mu 5393 Hydra11g Sml hpr RandCum Nu mbm CA9 u E D Hydmlngl39 Sail ampl quotquot W 77 quot5 939 quot Land Usr and demlngiz Cnndilinn B c Rm my 72 u M 91 Pillow 77 35 91 i l 57 7a Ra 39 Raw mp 391 x mil gum as 75 52 as mglziml and mired good n2 7 7 RI Four 72 3 88 Small 3min Good 67 78 85 W a 7 3quot Contoured good 65 75 82 a m 75 as 31 CIlllumrd and animal good Eu 7 m an COMO er Bud WWEd K md 52 71 73 hlcaduu39 rovlinultnu gnu nu Wang 10 5x 71 73 Small grain amm Poor 65 76 EA 6 quotJ 5 J as 75 33 um 39 u 7 so xxlxvgmu mnhinalion mummy as as m 17 0 quotme 3quot mud 5 04 50 72 3 n Meadow mnunuous grass no 1vang 30 58 7 mu 5 rm 77 as hand so 5 7n 77 Pam 79 M melczuh 59 14 a2 36 P00quot bu Good 39 31 74 n Jrul pzuul mu 5m suwn Wandsgrass combinalion omhard 35 56 70 saw 0 war a humid Tabla 51 Curve Numbers fm Antacsdent Soil Moisture 00nd an ll scs 1984 Hydvologlc Soil Group A a c D Land Usa Description Commercial row hauses and townhouses 80 85 90 55 al ow poo condition 77 36 91 94 Cultivated with conventiunal tillage 72 81 83 L51 Cultivated With consenlatinn tillage 62 71 7B 81 Lawns your condition 58 74 82 BS Lawns quad condition 39 61 74 BO Pastuve 0 fange poor canditian 68 79 86 89 Pasture or Iange 39 61 74 so Mea ow 30 71 78 Pavement and r0 on 100 100 100 Woods or farest thin stand poor cover 45 65 17 as Woods at fams t good cover 25 55 70 77 aimstea s 59 74 82 86 Residential 14 acre lot pool condition 73 83 33 51 Resldentlal 14 acre lat good can itlon 61 75 83 87 ReSIde tlal 12 ac a lot poor band In 67 80 86 89 HeSIdentlal 12 acre lot good condltlon 53 70 BO 85 l arm I E lot pom canditi 63 77 84 87 Residential 2 acle lot good conditlon 47 65 77 81 q 5 E g E 5 MINIALL 0th 7 hbll 52 Adlllxunlnli lo munquot BIN numhor CNI for any M will Illluwdull so mam common nognm39r momma mun mm 530quot m Futonquot mquot m numbv mmc u 39 011W Numb1 to AMC I I AM quotI 39 V AMC Ha I AM III w 1 l pulsar u lt1 4 quot 39 quot Condlxlurl II In II AVERAGE 41421 ANTECEDENT MOISTURE commons ASM 42CNH I 10 0058CNH CN 23 OCNH N z 1 10O13CNH Curve Numbers for lmpervious Surfaces lmpervious areas lmpervious areas gt CN 98 to 100 expressed as of total area directly connected gt ow directly to a drainage system gutters sewers etc Curve Numbers CN and Antecedent Moisture Conditions CN develop from experimental plots lots of measured rainfall I runoff data throughoutthe us CN39a correlated wI land use Good for higher in ltration rates Not so good for lower in ltration rates Area Weighted Curve Number Mixed land uses and HSG39s Calculate an areaweighted CN Get a single GM for the entire re 39 Cquot 2 CNi I 2 Ai cui ON for the part of catchment having area Ai Example Problem Watershed with Land Use And HSGs Listed encian P 40 in 39 A watershed that has 35 cultivated with a D soil group quotin Row Crop 30 meadow with a B soil group 35 thin forest with a 0 soil group Required 39 Calculate Hie surface runoff excess 35quot w quot39 39quot P R rainfall 39 39 Example Problem First nd the curve numbers Use HSG 39u D as B 30 c 35 Gulliveted Meadow Thin Forest Table 53 text reference is important Example Problem Example PrOblem TT Trd clculte the S term S ekcond calculate a weighted CN S1000ICN 10 1000 I 7610 Weights based on area S 31 6 In 0N 03591 03053 03507 ONE 762 76 Example Problem Example Problem Fiflh calculate surface runoff Q Fall arm check to see if P gt 02 0 P 023m I P 083 03928 3391 6 03963 39 39 Q 40 02316 I 40 08316 Q 174 in For a rainfall event 40 In on the given watershed with average soil moisture conditions P gt o2s ox mmmnm Pnclplh cn ls formed tom water vapor As alr cools 9 capacity to hold water doom Saan 100 nla vo humidlty Saturn at 70 F v0 82 F 4am MMMth W SE NW FIGURE The relationship botwun water conhnt ofair at catwalk and alr temperature W h Am Occli cffcct 9 mom uncaturahd Ilr can a utnnhd dew point Lbs waterlb alv DegeesF Cooli beyond 100 5 Inhalation 9 attenuation Waist droplet on cold glass I dew on gnu Precipitation Oocure when three oondltione are met 1 Atrneephere ie eaturahd 2 Small pariiolee are preeent Duct Precipitation The movement and collielon of air rnaeeee lead to ahnoepheric inetahillty The reault is often precipitation Ocean ealt 3Dropeareblgenoughtoreaoh ie eurface Have to overcome updra a Precipitation Frontal Systems Allnoephere hecornee eaturalnd when the air mace is cooled by lifting alrncel alwayc Air rnaee lifting cauaed by Frontal eyehrne warm front Icold front Orooraphic effect induced by mounteine Ralnehadow produoea deeerta Convection eurnnier thunderstorms I Lquot Cold honta High intenei lehortdurah39on I narrow aware cal in the spring and Warrn fronts Gentle rainfall I long term Iwideapread Typical in the winter Omaraphic preclpilalion Increaeing rainfall with increaeing elevation scammednu nunmm nun nunkmmmumun minimkth 7 V WARM 33w FROM OLD Hch Noun svsvm WW Fm W emuuplanqu Hllhlmwmmmnlmlm Iquot 54w Kitmm lwmamwuahm ruem W mm mm 1 m5 N L oNvEcnvE PnEcwunmN Moisture Sources and Moment Eubm mhd UsGulfoflhxloo Wuhan USPudlic0 un Ouilrihulian from nominal wwdion is umquot Precipitation Data Necessary for mod land use plan Munlclpal I Indatrial I au cunurlll forestry I flood prcvontlon I rocrutlon Duh collection by Shh and PederI agenda Much ofthe duh I now onllna VII the Internet thMtIon mords nport amount Yurlyl monthin Gully I hourly Rainfall Units of measurement 9 depth in I mm I etc Can getvolume easily by multiplying by area Accuracy of measurement 001 in Misleading since no two rain gages will ever record the same amount of rain even if they are aide by side Rainfall Measurement standard rain gages are point samples only Generally a high degree ofvariatlon in any rainfall Rain gages are usually cylindrical with circular top Therefore leastsubjeetsd to edge e bct errors Rainfall Measurement standard rain gages are point samples only Mounted verlioally Haigntof 2 In about 6 ft 21 obelruolion rule lftop ofobject is so ftabwe gage Place gage 60 it away Eliminates ohslructiona that may affect rainfall capture Rainfall Measurement Two types cfrain gages Nonrecording Low cost I maintenance es Accuracy I 01 in Rainfall Monument No typoo of roin moo Rocordlng PM 039quot Popor and oloctrcnlc data collocllon Somo typo of dolologgor roqulrod Eloclrcnlc only Rocordlng roln moo Wolglilng buckot typo Good for largo rainfall ovonlo Can39t accuraton moocuro wolgh omlll rainfall ovonh Tipping buckot typo Good for unoll rolnloll ovonlc Gori39t hoop up during hoovy rolnfoll ovonlo Each Up 001 Wolglilng Buckot Rain Gogo chart Ench omoll grid 005 Precipitation Terms WW A plot of rainfdl EM VI Hm lmhyeh Colman doomhnt ruinde Slumr in 0mm of mutant elevation IW Map Map wih camI ofcomhnt rainfall Description of Precipitation MW Howlnrdltnlne Whm ofdepthpar have WMquot Description of Precipitation ReMPe od quuenc Hawaiian anew aabnnofa I nansmalls Mica3 Mdth mmum Wlnunlb MW of ine Fminlenaltyanddan on you can dam WNW depth Description of Precipitation Description of Precipitation 1 For any given return period intensity RATE decreaeea as duration increases Shortstorrns generaliy have higher Intensities 2 For any given duration intensity increaeee as the return period increaeee Severe events are Ieae frequent 3 Higher Inteneity storms generally have larger raindrops Impact the energy releaaed when the drop hit the ground Thia is one of the forces which cauaea eroeion Measurement of Precipitation Gauguin Average Whetvve went Precipitation Over en Area 139 w Infell nt vol a x 2 quotquot quot quotm 9 Arithmetic mean method Rainfall intenelty 9 Inlnr or rnrnlhr mmquot P 39W quot W Rainfall distribution Ieohyetal method Over Time 8 Over Space Aquot a m m Wm Whetweheve PMZIEWiXPJIEWi Point meeeuremente ate few location P 39 W39Pih on Muet extrapolate over the entire w 39 WNW MW weterehed i I number ofmee cucu39a ng AWN Calculating Average Pmipiu on o r quot39 Ar Precipitation Over an Area Arithmetic mean method Thieeeen polygon mom Aeeurnee uniform rainfall distribution Very eeidem eeeure Euleet tnuee but leuteoourete Assumes Ilneer variation between 919 Uee when gages are not uniformly distributed Can use wee ouhide ofwehrehed Calculating Average Precipitation Over an Area laohyetal mound Llnea ofmhnt depth Theoretically the not accurate Moat time oonaulnlng method Canuaegageaoutaldeo he watenhed Meeaured Rainfall at Six Rainfall Gagea p 1m Waterehed boundary P 39339 P2 216quot P 182 Is 210quot O P 150quot Arithmetic Mean Method Thieeeen Polygon Method These enclosed area are known as Pm swim um All gages given equal weight Weight 1 Pm 1022151eo21a220 181 P 191m I39hieeeen Polygons The area within each polygon la cloeer to the rein gage encloeed than any other raln gage The ralnfall rneaeured in the polygon ia aaeumed to he repreaenlative of the rainfall in the entire polygon Thieeeen Polygon Method Flret Draw atralght daehed Ilnee between each rainfall gage Second Draw eolld perpendicular hleectcre to theee llnee eo that waterehed area aeeoclated with each gage le encloeed by bleector llnee Thieeeen Polygon Method Third Determine the area of each polygon The rain gage weight is the area ofthe polygon it is located in Fourth Calculate the average rainfall using vg2wixpi2wi step 1 Daehed Linea Between Each Raln Gage Watershed boundary step 2 Draw the Perpendicular Blaectcr Llnea Waterehed boundary a Y 0 Slap 3 Delamine lho Area ofEach Polygon Wattshad boundaty I A5150 ll u A A136 ac Slap i4 Calculaln the Average Rainfall Izwixli112wi quotfsox102r1sox215r1aox1aor mammom arm 31 I smsonwmmm Pquot zoo in CHANNEL FLOW AND EROSION CONTROL CHANNEL FLOW AND EROSION CONTROL Tmpezmdal moss sedmn W mm w my I Kulmudu m Mum w m Munmm M m n 147 I u u v w quot 39 39 rm CHANNEL FLOW AND EROSION CONTROL HYDRA ULIC RADIUS AREAUVP CHANNEL FLOW AND EROSION CONTROL was CHANNEL FLOW AND EROSION CONTROL M39annin39s Equation for Open Channel Flow 1 K 39 vMIHP IW equation 82 and q I WARE l a as From HANDO UTS z I 2 5mm ma umle V4 0 WWW r V r l l l I l l I J A g s 4 2 n 2 a 5 a l lance m mm Hrm in W ms m quotEmu vlmv ilhlvyhmluum gmxvllmrlIlmmul mum Rm Manning39s quotquotV Formua calculates a average velocity Manning s Formula calculates an average velocity v Cn Rms 2 equation 82 CHANNEL FLOW AND EROSION CONTROL Manning39 Hahn Manning s Cod cionl n From TEXT Mm mmm mm W M WM MNquot my 39739 mm W39 N hm l hmul if mu WWMW wwmm m M w nlMlvllurw mm um um m m mm W Mm K MW mum nun ow u mquot W quotWbmm munth mmme m m w w mwawrmm m mnnm howmmmm m z W m m m mmmmnm an aw MM 39 quot2 m cmm h mpmmm m m m WMWH mm a mem mm m m vhvmmmmwm m mm wquot W W Tm Munalum 00 non mm mm W 11L m SCI smxmm mm rmm mu 1me 11 hm wummmgm mm mm mm k39vmmw m 113 23 wwwmm wwmm mmm mm Fstm mmw rom ANDOUTS CHANNEL FLOW AND EROSION CONTROL nmm l hmuwhym m thqu m ummquot um I m m m 1 mm WW m n n mum rumm n m mu m mmnn m mmhqn Mumlg mm mummm m h I mm mm n u mummy my 1 r m m My mum y m l n m m CHANNEL FLOW AND EROSION CONTROL CHANNEL FLOW AND EROSION CONTROL Inning s Weim I D dfreebwd nmm Imm HM WWW mummm m mmmum va x I m my um my I mmmmm m m CHANNEL FLOW AND EROSION CONTROL WE 6amp3 me CHANNEL FLOW AND EROSION CONTROL ngwwgw CHANNEL FLOW AND EROSION CONTROL CHANNEL FLOW AND EROSION CONTROL mm M um xlmmmmn n m 1mde JRmm wwm 1 m wmw mm mm humumanmns wl m Iuy gunman Mmmh Mumnxuuu huun Mm um Mummy x mquot m WWW unmme Hummim Hum x mmAM hummm MmmAJh mu 1 V mmxmmm u W mumm Umm m numm mnmywhm mum x mummm nm quw Jygwu w my Mvale mm From TEXT mun l39uxmu vh u Mumquot mm M ummmngu mm w WW lmmmny 7 u M mung Mme 7 Fm M WW TEXT 7 mm l mu mm c CHANNEL FLOW AND EROSION CONTROL WWW 14 CHANNEL FLOW AND EROSION CONTROL Manninu39u Cod ciunt I From TEXT CHANNEL FLOW AND EROSION CONTROL mun thvmnx uyu mmu mum mmwmum n um Hum VAmm m M Hm Ivrvuuh Wm y 1 um pan 7 mm mum W I y m U CHANNEL FLOW AND EROSION CONTROL HunMuning39seoemgientarm wer From TEXT MW mmmm H WWHMM mm mm mmw whmgmm n m u mm MMmmnwwu my I m H wwhw UHMMWH w muWWL nmm l mummmmwmWP m umm nun k mmhqn g hmm Humlmlmmhghlva m n m W Hwer my v mmnn mm My mum Wmquot M mum mu WV m y m Hm m r mmum at Law i y w r w mlmww min rm 14 gt mm x M quot 39 rm g u y Wm CHANNEL FLOW AND EROSION CONTROL CHANNEL FLOW AND EROSION CONTROL table 74 Guide to Selecdon of Vegan Retarde Class Awmg Length Ly SW Candiliom in Watz39mmy Waterway Vtgvlatwn in inches Fair Gm ms lhan2 E E 2 6 Fm D D eIommoursn c c 3 A IX 24 More than 30 Source US Soil Conservation Service 1954 a mu m Nnmu uph fur u mm aw elocuy in mlyvlnkhl gum waxtnay vmh nllrdanw ag a Sum Canal and mm 198 CHANNEL FLOW AND EROSION CONTROL Film Ind mu m Wamagraph m mechalmel cp l in z K plxmd M mum wim mudunudan u Samquot cm and Gwen was From HANDOUTS 20 CHANNEL FLOW AND EROSION CONTROL 21 CHANNEL FLOW AND EROSION CONTROL 22 comm nmome s V as hr645 XERWMIN AER39K IJ 3963P m Aa m Wa W ag 39 IGURE 66 Twiull USLE mum mosh plul mun Pullman Washingwn Il homgmph hy39 Ellmx ilkWm WWEWW Wamwmm aamc uww mm m V mum lnmhh llmnmupm t nu kmnlnllmld kan lmmm InIh 1 twin mi lnu runm g lnmmll39uuluwdlI mm u I I 1 l u n 7 g u u m 1 L39 7 I u 14 mm x 7 n um I h l I 1 2 u n H H 139 u 1 1m 3 u H u u uh 1 M D le Iquot n m H L3 a u 1 l m m my H m n 1 2 7 z rnlu y 39lt n 2 u m ll Imvu I I 1 w h w n In Lu u yu w u h 2 n M A HIWm H m 7 7
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