RF DataNoYearRFDesending1196079.1100219615490319659079.14196610065.8519674765.7619683065.6719693860.6819724760.59197351.259.210197440.756.21119755055.512197642.555.413197740.155.214197855.254.915197960.65416198059.253.417198138.351.21819823350.519198338.350201985314721198628.64722198744.444.523198855.544.424198937.542.525199035.441.326199241.340.927199360.540.728199450.540.529199565.740.130199665.639.231199740.538.632199856.238.333199940.938.334200065.83835200138.637.536200239.236.83720034.235.438200454.93339200544.53140200653.43041200755.428.642201136.84.2

Sheet2Desending1009079.165.865.765.660.660.559.256.255.555.455.254.95453.451.250.550474744.544.442.541.340.940.740.540.139.238.638.338.33837.536.835.433313028.64.2

Annual RFYearJanFebMarAprMayJunJulAugSepOctNovDecTotal119870.00.00.011.6112.764.2129.7208.70.060.634.60.0622.1219880.07.90.60.034.5160.3357.4283.9103.968.60.00.01017.1319890.00.00.00.031.2238.6277.1200.646.440.90.00.0834.8419904.80.00.00.00.00.00.00.00.00.00.00.04.8519910.00.00.00.00.00.00.00.00.00.00.00.00.0619920.00.00.04.20.055.9155.3308.286.00.04.00.0613.6719930.01.316.633.466.5132.9124.8230.2116.417.625.20.0764.9819940.00.00.00.00.0226.3333.6281.2175.10.011.70.01027.9919950.00.014.82.888.0130.1283.8225.089.522.60.00.0856.61019960.00.053.272.0110.1316.9409.6322.0286.80.030.70.01601.31119970.00.026.030.2203.9138.8282.4142.799.7429.191.05.31449.11219980.00.034.913.754.1286.5368.0186.491.829.10.00.01064.51319999.50.00.00.044.1283.2213.1201.350.4222.90.05.21029.71420000.00.00.064.135.3307.7300.1181.083.9161.718.20.01152.01520010.00.00.013.9196.8149.7306.2369.1151.11.44.210.31202.71620020.03.03.56.73.5238.5252.60.0141.630.00.00.0679.41720030.07.00.00.00.00.00.00.00.00.00.00.07.01820040.00.70.052.118.8173.2302.7237.6114.158.78.62.5969.01920050.00.045.50.063.4176.60.090.80.00.00.00.0376.32020060.00.00.030.9112.3168.6256.0297.5189.593.00.013.21161.02120070.00.00.00.00.00.0387.9300.8124.640.40.00.0853.722200814.00.00.061.70.00.00.00.00.00.00.00.075.72320090.00.00.00.00.00.00.00.00.00.00.00.00.02420100.00.00.00.00.00.00.00.00.00.00.00.00.02520110.00.00.00.058.544.3268.0240.1114.70.00.00.0725.6Average1.10.87.815.949.3131.7200.3172.382.651.19.11.5723.6YearJanFebMarAprMayJunJulAugSepOctNovDecTotal119870.00.00.011.6112.764.2129.7208.70.060.634.60.0622.1219880.07.90.60.034.5160.3357.4283.9103.968.60.00.01017.1319890.00.00.00.031.2238.6277.1200.646.440.90.00.0834.8419920.00.00.04.20.055.9155.3308.286.00.04.00.0613.6519930.01.316.633.466.5132.9124.8230.2116.417.625.20.0764.9619940.00.00.00.00.0226.3333.6281.2175.10.011.70.01027.9719950.00.014.82.888.0130.1283.8225.089.522.60.00.0856.6819960.00.053.272.0110.1316.9409.6322.0286.80.030.70.01601.3919970.00.026.030.2203.9138.8282.4142.799.7429.191.05.31449.11019980.00.034.913.754.1286.5368.0186.491.829.10.00.01064.51119999.50.00.00.044.1283.2213.1201.350.4222.90.05.21029.71220000.00.00.064.135.3307.7300.1181.083.9161.718.20.01152.01320010.00.00.013.9196.8149.7306.2369.1151.11.44.210.31202.71420020.03.03.56.73.5238.5252.60.0141.630.00.00.0679.41520040.00.70.052.118.8173.2302.7237.6114.158.78.62.5969.01620050.00.045.50.063.4176.60.090.80.00.00.00.0376.31720060.00.00.030.9112.3168.6256.0297.5189.593.00.013.21161.01820070.00.00.00.00.00.0387.9300.8124.640.40.00.0853.719200814.00.00.061.70.00.00.00.00.00.00.00.075.72020110.00.00.00.058.544.3268.0240.1114.70.00.00.0725.6Average1.20.69.819.961.7164.6250.4215.4103.363.811.41.8903.9DesendingRankProbabilityReturn PeriodMonthMRF(Mean)MRF(Mean)mP=m/(1+N)T=(N+1)/mjan1.2250.41510.0813.00feb0.645215.35520.156.50mar9.755164.61530.234.33apr19.865103.27540.313.25may61.68563.8350.382.60jun164.61561.68560.462.17jul250.41519.86570.541.86aug215.35511.4180.621.63sep103.2759.75590.691.44oct63.831.825100.771.30nov11.411.175110.851.18dec1.8250.645120.921.08N=12Annual RF (MM)903.85MonthJanFebMarAprMayJunJulAugSepOctNovDecTotalMean1.180.659.7619.8761.69164.62250.42215.36103.2863.8311.411.83903.85

Annual RF

MRF(Mean)MonthMean monthly RF(mm)

CNTable 5-8 Runoff Curve Numbers- Urban Areas1Soil TypesHydrologic Soil GroupCover descriptionCurve numbers for hydrologic soil groupsCalcaric FluvisolsBCover type and Hydrologic conditionAverage % impervious area2ABCDCalcaric RegosolsACalcic CambisolsBOpen space (lawns, parks, cemeteries, etc.)3Calcic ChernozemsBPoor condition (grass cover 75%)39617480Chromic CambisolsBImpervious areas:Chromic LuvisolsBPaved parking lots, roofs, driveways, etc. (excluding right-of-way)Chromic VertisolsDStreets and roads:98989898Dystric CambisolsBPaved; curbs and storm drains (excluding right-of-way)Dystric HistosolsDPaved; open ditches (including right-of-way)Dystric NitosolsBGravel (including right-of-way)98989898Eutric CambisolsBDirt (including right-of-way)83899293Eutric FluvisolsBDesert urban areas:76858991Eutric HistosolsDNatural desert cover72828789Eutric NitosolsBUrban districts:Eutric RegosolsACommercial and business63778588Gleyic SolonchaksDIndustrialGypsic YermosolsB8589929495Haplic PhaeozemsC7281889193Haplic XerosolsBResidential districts by average plot size:Humic AndosolsB0.05 hectare or less6577859092Humic CambisolsC0.1 hectare3861758387LithosolsD0.135 hectare3057728186Luvic PhaeozemsC0.2 hectare2554708085Luvic XerosolsC0.4 hectare2051687984Mollic AndosolsB0.8 hectare1246657782Orthic AcrisolsBDeveloping urban areasOrthic LuvisolsBNewly graded areas (pervious areas only, no vegetation)77869194Orthic SolonchaksBPellic VertisolsD1 Average runoff condition, and Ia = 0.2SRendzinasD2 The average percent impervious area shown was used to develop the composite CNs. Other assumptions are as follows: impervious areas are directly connected to the drainage system, impervious areas have a CN of 98, and pervious areas are considered equivalent to open space in good hydrologic condition. If the impervious area is not connected, the SCS method has an adjustment to reduce the effect.Vertic CambisolsB3 CNs shown are equivalent to those of pasture. Composite CNs may be computed for other combinations of open space cover type.Vertic LuvisolsCVitric AndosolsBTable 5-9 Cultivated Agricultural Land1Eutric VertisolsDCover descriptionCurve numbers for Hydrologic soil groupHaplic LuvisolsBCover TypeTreatment2Hydrologic condtion3ABCDLithic LeptosolsBFallowBare soil-77869194WaterDCrop residue cover (CR)Poor76859093Humic NitosolsBGood74838890Rendzic LeptosolsBRow CropsStraight row (SR)Poor72818891Haplic NitosolsBGood67788589Eutric LeptosolsBSR + CRPoor71808790Haplic AlisolsAGood64758285Contoured (C)Poor70798488Good65758286C + CRPoor69788387FROM GIS CATCHMENT LAND USE LAND COVER AND SOIL(ARANGED)Good64748185Shape_AreaBasinSlopeLC1LC1LU_DESLC1_MASDESSOIL_TYPEMAJOR_SOILMINOR_SOILHydrology soil GroupArea Reduction(%)Hydrolic ConditionCN for Hydrologic soil groupContoured & terraced (C & T)Poor66748082Good6271788125368585.0283974.1147118966CRCLCultivationCultivated Land; Rainfed; Cereal Land Cover System; lightly stockedChromic VertisolsVertisolsChromicDHigh runoff potential79.2440390249Poor88C&T + CRPoor657379811318117.3362783.5535445CRCLCultivationCultivated Land; Rainfed; Cereal Land Cover System; lightly stockedEutric FluvisolsFluvisolsEutricBModeret Inflitration4.117412994Good84Good61707780188364.3978284.325742CRCLCultivationCultivated Land; Rainfed; Cereal Land Cover System; lightly stockedChromic LuvisolsLuvisolsChromicBModeret Inflitration0.5883952801Good84Small GrainSmall grain SRPoor657684881550138.8904564.4055845CRCBCultivationCultivated Land; Rainfed; Cereal Land Cover System; unstocked (woody pl)Orthic LuvisolsLuvisolsOrthicBModeret Inflitration4.8421804603Good84Good637583878353.6046073.466277CRCBCultivationCultivated Land; Rainfed; Cereal Land Cover System; unstocked (woody pl)Eutric CambisolsCambisolsEutricBModeret Inflitration0.0260942173Good84SR + CRPoor647583862568531.1808644.0367396364GBGrasslandGrassland; unstocked (woody plant)Chromic VertisolsVertisolsChromicDHigh runoff potential8.023340084Poor86Good60728084363764.5334443.5826336667GBGrasslandGrassland; unstocked (woody plant)Eutric FluvisolsFluvisolsEutricBModeret Inflitration1.1362939972Poor73CPoor63748285234739.3797114.157685GBGrasslandGrassland; unstocked (woody plant)Orthic LuvisolsLuvisolsOrthicBModeret Inflitration0.7332571582Poor73Good6173818478376.4441143.466277SHOShrublandShrubland; Open (20-50% woody cover)Eutric FluvisolsFluvisolsEutricBModeret Inflitration0.2448250854Poor66C + CRPoor62738184121052.9011454.6873572SHOShrublandShrubland; Open (20-50% woody cover)Chromic VertisolsVertisolsChromicDHigh runoff potential0.3781338538Poor83Good60728083213217.0977483.1286292222HSSWetlandWetland; Seasonal Swamp / MarshChromic VertisolsVertisolsChromicDHigh runoff potential0.6660278449Poor100C&TPoor6172798232013240.794592m2Good5970788132.0132407946Km2C&T + CRPoor60717881Good58697780Close-seeded SR or broadcast legumes or rotation meadowSRPoor66778589Good58728185CPoor64758385Good55697883C & TPoor63738083Good516776801 Average runoff condition, and Ia = 0.2S.2 Crop residue cover applies only if residue is on at least 5% of the surface throughout the year.3 Hydrologic condition is based on a combination of factors that affect infiltration and runoff, including (a) density and canopy of vegetative areas, (b) amount of year-round cover, (c) amount of grass or closed-seeded legumes in rotations, (d) percent of residue cover on the land surface (good > 20%), and (e) degree of roughness.Poor: Factors impair/Diminishi infiltration and tend to increase runoff.Good: Factors encourage average and better than average infiltration and tend to decrease runoff.Table 5-10 Other Agricultural Lands1Cover descriptionCurve numbers for hydrologic soil groupCover typeHydrologic conditionABCDPasture, grassland, or range-continuous forage for grazing2Poor68798689Fair49697984Good39617480Meadow-continuous grass, protected from grazing--35597279Brush-weed-grass mixture with brush the major element3Poor48677783Fair35567077Good30486573Woods-grass combination5Poor57738286Fair43657682Good32587279Woods6Poor45667783Fair36607379Good30557077Farmsbuildings, lanes, driveways, and surrounding lots--597482861 Average runoff condition, and Ia = 0.2S2 Poor: < 50% ground cover or heavily grazed with no mulchFair: 50 to 75% ground cover and not heavily grazedGood: > 75% ground cover and lightly or only occasionally grazed3 Poor: < 50% ground coverFair: 50 to 75% ground coverGood: > 75% ground cover4 Actual curve number is less than 30; use CN = 30 for runoff computations.5 CNs shown were computed for areas with 50% grass (pasture) cover. Other combinations of conditions may be computed from CNs for woods and pasture.6 Poor :Forest litter, small trees, and brush are destroyed by heavy grazing or regular burning.Fair: Woods grazed but not burned, and some forest litter covers the soil.Good: Woods protected from grazing, litter and brush adequately cover soil.Table 5-11 Arid and Semiarid RangelandsCover descriptionCurve numbers for hydrologic soil groupCover typeHydrologic condition2A3BCDMixture of grass, weeds, and low-growing brush, with brush the minor elementPoor808793Fair718189Good627485Mountain brush mixture of small trees and brushPoor667479Fair485763Good304148Small trees with grass understoryPoor758589Fair587380Good416171Brush with grass understoryPoor678085Fair516370Good354755Desert shrub brushPoor63778588Fair55728186Good496879841 Average runoff condition, and Ia = 0.2S2 Poor : < 30 % ground cover (litter, grass, and brush overstory)Fair : 30 to 70 % ground coverGood: > 70 % ground cover3 Curve numbers for Group A have been developed only for desert shrubTable 5-12 Conversion from Average Antecedent Moisture Conditions to Dry and Wet ConditionsCN For Average ConditionsCorresponding CNs ForDryWet100100100958798907896857094806391755788705185654582604078553574503170452665402260351855301550251243156305213Ethiopian Rainfall Region D1 (< 100 mm)Source:Ref. 15Ethiopian Rainfall Region A2 & B1 (mean monthly Peak > 300 mm)Table 5-13 Rainfall Groups for Antecedent Soil Moisture Conditions During Growing and Dormant SeasonsAntecedent ConditionConditions DescriptionGrowing Season Five-Day Antecedent RainfallDormant Season Five-Day Antecedent RainfallDryAn optimum Condition of catchment area soils, where soils are dry but not to the wilting point, and when satisfactory plowing or cultivation takes placeLess than 36 mmLess than 13 mmAverageThe average case for annual floods36 to 53 mm13 to 28 mmWetWhen a heavy rainfall, or light rainfall and low temperatures, have occurred during the five days previous to a given stormOver 53 mmOver 28 mm

TCCASE-1CASE-2Time of Concentration ,TC1=1/3000(L1/(S1)1/2 )0.77AVERAGE RIVER BED SLOPECHELVPDACCUMULATIVE HEIGHTTotal areaHavIavTCslopeTC02020.96000107.91583711590.0083733.1976.951988.93597732.02515643.410.030.249211441139451928.283296860.652119652.080.020.703376124549971893.833105234.4586103.650.030.263930191470011847.737200446.096161376.270.020.496661231380031837.548100210.18940794.330.010.398795557990811812.802107824.746112364.310.020.3083571235128881788.056380724.746159475.600.011.3241968172128882336954103.74452848693.073.74

D.RFDESIGN RAINFALL ANALYSIS104.3Outlier test Kn values81.31DATA QALITY TAST80.7weibull formulasample size nKn80.6AVG RFNrYearMax. RF(Xi)(mm)Descending order (X)RankY = Log(Xi)(Y-Ym)^2(Y-Ym)^3(X-Xm)^2(R/(N+1))*100102.0367548.87317073171196079.110012.000.12034416080.0417481787931.12163265312112.08871.248.873170731721961549021.950.09069076150.027311438429.31448979595122.13470.948.8731707317319659079.131.900.06006569780.0147210841715.14306122457132.17569.948.87317073174196610065.841.820.0272687270.00450295182643.428775510210142.21367.748.87317073175196747.065.751.820.02705101530.00444913272.514489795912152.2476748.87317073176196830.065.661.820.02683384670.0043956631345.428775510215162.2796648.87317073177196938.060.671.780.01673897310.0021656747112.057346938817172.30963.848.87317073178197247.060.581.780.01655389320.00212985592.514489795920182.33562.748.87317073179197351.259.291.770.01421537940.0016948756.834489795922192.3616248.873170731710197440.756.2101.750.00933984520.000902629562.184489795924202.3855848.873170731711197550.055.5111.740.00831735650.00075853912.000204081627212.4085848.873170731712197642.555.4121.740.00817511160.000739163537.035918367329222.4295848.873170731713197740.155.2131.740.00789354720.000701307272.007346938832232.44855.548.873170731714197855.254.9141.740.00747860080.000646741243.748775510234242.4675548.873170731715197960.654.0151.730.00628854060.0004986833144.343061224537252.48654.548.873170731716198059.253.4161.730.00554247730.0004126253112.663061224539262.5025448.873170731717198138.351.2171.710.00315580140.0001772819105.795918367341272.51953.648.873170731718198233.050.5181.700.00251983290.0001264904242.914489795944282.53453.448.873170731719198338.350.0191.700.00210465910.0000965545105.795918367346292.5495248.873170731720198531.047.0201.670.00036116790.0000068638309.257346938849302.56351.448.873170731721198628.647.0211.670.00036116790.0000068638399.428775510251312.57750.648.873170731722198744.444.5221.650.0000224054-0.000000106117.520204081654322.59150.648.873170731723198855.544.4231.650.0000326095-0.000000186247.807346938856332.60447.348.873170731724198937.542.5241.630.0006103129-0.0000150775122.893061224559342.6164748.873170731725199035.441.3251.620.0013796314-0.0000512442173.863061224561352.6284748.873170731726199241.340.9261.610.0017114879-0.000070804553.081632653163362.63945.848.873170731727199360.540.7271.610.0018921658-0.0000823074141.950204081666372.6545.148.873170731728199450.540.5281.610.0020828652-0.00009505873.664489795968382.6614548.873170731729199565.740.1291.600.0024949094-0.0001246184292.898775510271392.67144.648.873170731730199665.639.2301.590.003576922-0.0002139263289.485918367373402.68244.548.873170731731199740.538.6311.590.0044230661-0.00029416165.378775510276412.6924448.873170731732199856.238.3321.580.0048852645-0.000341453957.977346938878422.742.548.873170731733199940.938.3331.580.0048852645-0.000341453959.070204081680432.714248.873170731734200065.838.0341.580.0053743333-0.0003939915296.331632653183442.71935.548.873170731735200138.637.5351.570.0062508272-0.00049420499.714489795985452.72748.873170731736200239.236.8361.570.0076117986-0.000664096188.091632653188462.73648.87317073173720034.235.4371.550.0108347653-0.00112779271970.091632653190472.74448.873170731738200454.933.0381.520.0181116421-0.002437455839.870204081693482.75348.873170731739200544.531.0391.490.026157158-0.004230442916.693061224595492.7648.873170731740200653.430.0401.480.0309662103-0.005449191723.17734693889848.873170731741200755.428.6411.460.0387016729-0.007613679846.434489795910048.873170731742201136.84.2420.621.0605789742-1.0922310527138.9030612245102SUM2040.669.41.7-1.008111470.4502.768Mean Q48.648.61.7SD16.716.70.2SKEWNESS COEFICIENT0.7254-3.0743285241Max100.0mmMin4.2mmNX=Xm =X/N(X-Xm)2=n-1Y=Ym =Y/N(Y-Ym)2=(Y-Ym)3=SyCs422040.648.585714285711470.416.726225521969.41.65309344081.7-1.00810.2032591071-3.0743285241Before proceeding to the other analysis, the adequacy of rainfall data series should be checked and it should be realized. The data series could be considered and adequate if relative standard error,e +0.4 check for higher outlierCase 3If Skew ness (Cs), -0.4