Solve the problem using the NRCS method for a watershed located right outside New York City, New York for a 50 year storm event. Assume the soil hydrologic group B (65%), C (25%) and D (10%). Given Am=1.29 sm. Impervious = 6.6 acres, Woods =819 acres. Overland flow: L=100 ft, s=4%, fair; Shallow Concentrated Flow: unpaved L= 2300 ft, s=2.7%, stream flow L=9000 ft, s= 3.4%, Stream is trapezoidal with a bottom width of 12 feet, top width of 20 feet for a depth of flow of 4 feet, n=0.035. Calculate the Curve Number?

The observed rainfall and discharge of a catchment is given the table. The catchment area is 0.23Km^2. Time (h) 1 2 3 4 5 6 7 8 00 9 10 11 12 13 Rainfall (mm) 0 0 2 6 10 8 2 0 0 0 0 0 0 1. Estimate the base flow. 2. Estimate the surface runoff. 3. Estimate the initial loss 4. Estimate the continuous loss using phi method. Discharge (M3/s) 20 20 20 20 30 50 40 35 25 21 20 20 20

Watershed area = 11.1 acres                 Average N concentration of inflow = 1.9 mg/L             Total Rainfall = 44.75 inches                  Average N concentration of outflow = 1.4 mg/L Total pond inflow = 330,441 ft3              Average P concentration of inflow = 0.42 mg/L Total pond outflow = 288,492 ft3           Average P concentration of outflow = 0.23 mg/L Total pond volume = 46,893 ft3 (this is the volume to the top of the riser before overflow occurs)   Answer the following questions: a) What percentage of the total rainflow flowed into the pond? b) If the pond were completely empty, how much rainfall in inches would be required to fill it to the total pond volume? Use your answer to question A to help answer this. c) What is the total Nitrogen load flowing into the pond in lbs/Acre/Year? d) How many lbs of Nitrogen did the pond remove over the year? e) What percentage of Phosphorous was removed by the pond?

Questions (3.2) Determine using the 'rational formula' with runoff co-efficient equal to 0.80, the peak storm runoff to be carried out by the underground drainage pipeline AB for the drainage basin area of 0.2 ha as shown in the given figure. Take the length of pipeline as 100 m and the level difference between A and B as 0.5 m. Assume initially a pipe diameter of 250 mm. Consider Darcy- Weisbach friction factor f = 0.015. The rainfall duration and rainfall intensity is furnished in tabular form below. Consider time of entry at end A as 2 min. Drainage basin Duration (mins) 2.0 2.5 3.0 3.5 4.0 4.5 A Pipeline Rainfall intensity (mm/hr) 122 108 97 89 82 77 Check whether the pipe size is adequate or not.

A detention basin will be built at the outlet of a 75-acre watershed. The stage-storage relationship for the planned basin is given in the table below. A weir type outlet with crest at elevation 101 ft will be used. The 25-year peak runoff rate from the watershed is 360 cfs, and this should be reduced to 180 cfs at the detention basin outlet. If themaximum storage volumeneeded forthe basin is5 acre-ft, determine the size of theoutlet weir.

If area of the catchment is 62,5 sq.mm and axial length of the catchment is 10 mm, the form factor will be:

hope your help hydraulic thanks

Q2 Q3 A small watershed consists of 2 km² of forest area (c = 0.1), 1.2 km² of cultivated area (c = 0.2) and 1 km² under grass cover (c = 0.35). A watercourse falls by 20 m in a length of 2 km. The IDF relation for the area may be taken as: I = Estimate the peak rate of runoff for a 25-year frequency. 807 0.2 -; I in cm/hr, T- yr, t in minutes. (t+12) ⁰.5 103 2-R-[IA+E]] =AS

Develop the SCS triangular unit hydrograph for a 375-acre watershed that is an industrial district. The flow length is 1275 feet, the slope is 2.75 percent, and the soil is group C. Plot the resulting hydrograph. (similar to 8.8.1)

Please help.