Sheet1Q. No. 1 a) Solution- index loss for A = 0.6 in/hr = 0.3
in/half-hr- index loss for B = 0.2 in/hr = 0.1 in/half-hrTime
(hr)Accumulative rainfall depth (in.)Rainfall depth(in.) index loss
(in.) AExcess rainfall (in.)A index loss (in.)BExcess Rainfall
(in.)B0.00.00.0-0.0-0.00.50.40.40.30.10.10.31.00.90.50.30.20.10.41.51.61.10.30.80.11.02.02.31.20.30.90.11.12.52.61.40.31.10.11.3b)
SolutionTo compute half hour unit hydrograph for basin B from 2 hr
unit hydrograph using s-hydrograph method.Time(hr)Sub-basin B 2-hr
UH(cfs/in)2nd 2-hr UH(cfs/in)3rd 2-hrUH(cfs/in)4th
2-hrUH(cfs/in)5th 2-hrUH(cfs/in)SHydrograph (Col 1)Lagged by 0.5 hr
(Col 2)Col 1-Col
2(Co1-Col2)*2/0.50.000000.540400401601.0170170401305201.53203201701506002.045004503201305202.5540405804501305203.0480170650580702803.5390320710650602404.03104500760710502004.523054040810760502005.018048017083081020805.513039032084083010406.090310450085084010406.5602305404087085020807.040180480170870870007.530130390320870870008.020903104500870870008.50602305404087087000c)
SolutionTime(hr)Sub-basin B2-hr UH(cfs/in)Excess Rainfall(B)Due to
1st stormDue to 2nd stormDue to 3rd stormDue to 4th stormDue to 5th
stormDirect Runoff(cfs)Base Flow for B(cfs)Stream
Runoff(cfs)000000.5400.3121201211700.45116670671.53201.0966840204020424501.11351281704447704772.55401.316218032018752901090134801442164503522211383013833.53901171925404954161760017604310931564805945851908019084.523069124390528702181301813518054923104296241509015095.51303972230341507118901189690275218025340391509156.5601836130198299681068174012249014323450305037.53091660991693530353820612406611724102418.500830447816001609020335210501059.50223961061100262602610.50000Total
rainfall =4.1inch14268Intensity =1.64in/hrArea of basin B =8700Acre
=13.59Squarea miles
Time(hr)Subbasin A 0.5-hrUH(cfs/in)Excess Rainfall(A)Due to 1st
stormDue to 2nd stormDue to 3rd stormDue to 4th stormDue to 5th
stormDirect Runoff(cfs)Base Flow for B(cfs)Stream
Runoff(cfs)00010100.5200.12210121700.2741110211.51900.819141649105923100.931385618143101532.54001.140621526322339103493450458024817177621106313.54204290320279209940109504360368436036034111811011914.5310317233640544012841012945250256228837849512481012585.516016502483244621100101110690932200279396916109266.5505181282253417171072772021072144275503105137.50044081176301103118000164599160101708.5000018557310839000222210329.50000101010000101010.5001010Rainfall
total =3.1in9610Rainfall intensity = 1.24in/hrArea of basin A =
7750Acre = 12.11Square miles
