Watershed shown in the Figure 2-1 has three sub-catchment areas. Some properties of these sub-catchment areas are given in Table 2-1.(a) Using the given IDF curves and the Rational method, calculate the 50-years design peak flow (incfs) at the catchment outlet.(b) A levee is to be designed to protect the area near to the catchment outlet using the estimated peak-flow. If the design life of the levee is 15 years, calculate the probability (%) of failure of the leveeduring its design life period.Area 1A1A2Area 2C1C2Table 2-1: Sub-catchment propertiestit2Catchment propertyArea 1Area 2Area 3Catchment area ( km²)10520Area 3АзRunoff coefficient0.250.750.5C3Time of concentration (minutes)302030t3Catchment outletFigure 2-1: WatershedIDF curves for storms in vicinity of example site99876.42+21t05 10 15 203040 5060708090 100 110 120 130Time (min)Intensity of rainfall (in./hr)

Answered: Image /qna-images/answer/31beb0e7-7f2d-439f-b48b-c40c39578553.jpg

Answered: (a) Using the given IDF curves and the…

(a) Using the given IDF curves and the Rational method, calculate the 50-years design peak flow (in cfs) at the catchment outlet.

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

See similar textbooks

Similar questions

Consider a watershed with a drainage area of 10 square miles and a mainstream length of 7.5 miles. The main channel extends from the watershed outlet to the point opposite the centre of gravity of the watershed over a distance of 3.5 miles. Given a time of concentration (Ct) of 1.5 hours and a dimensionless slope of the watershed (Cp) of 0.5, determine the standard synthetic unit hydrograph for this basin. What is the duration? Using Snyder’s method, calculate the 45-minute unit hydrograph parameter
10-min unit hydrograph for a catchment is given in Table 1 below. Table 1: 10-min Unit Hydrograph Time (min) 05 10 15 20 25 30 35 40 45 50 1.75 1.95 2.0 1.8 1.25 0.6 Flow (m³/s) 0 0.5 1.0 1.4 0 a. What is the area of the catchment? b. Construct a storm hydrograph resulting from the 40-min rainfall event. The rainfall excess depths are provided in Table 2. Determine the peak discharge resulting from this 40-min rainfall event. Table 2: Rainfall Excess Depths Rainfall Excess (mm) Time (min) 0-20 4 20-40 6
Question 2 Route the inflow hydrograph through a reservoir as indicated in Table 2. The crest height of the spillway is 50 ft and storage capacity at this level is 116 ft3/s-day. The reservoir routing curves graph is given in Figure 1. Perform calculation until the outflow value is equal to zero. Based on the obtained result, plot the inflow and outflow hydrographs. Table 2 0.4 1.6 2 2.4 2.8 Time (day) 0 Flow (ft³/s) 0 0.8 120 1.2 229 56 380 268 155 50 Figure 1 25/atO (ft/s.day)-primary x-axis 700 800 900 1000 54.0 53.5 53.0 52.5 52.0 51.5 Elevation vs Storage (curve a) Elevation vs 25/De-O (curve b) Elevation vs Outflow (curve c) 51.0 50.5 50.08 49.5 110 230 0 Water Surface Elevation (tt) 400 W 500 130 100 600 150 200 190 170 210 Storage (ft³/s.day) - secondary x-axis 300 400 500 Outflow (ft³/s.day) - tertiary x-axis 600 250 1100 700
Annual flood data of the river Kaveri covering the period from 1952 to 1983 yielded a discharge of 29,600 m/sec and a standard deviation of 14,860 m/sec. For a proposed bridge on this river near this site, it is decided to have an acceptable risk of 10% in its expected life of 50 years. What will be the design flood discharge (m3/sec) using Gumbel's method? [Take n = 50 years, Yn = 0.538, Sn = 1.1193]
A catchment area is presented in the Figure 1. Six rainfall gauges A, B, C, D, E and F are spread over this watershed and nearby. The inter isohyets areas I, II, II, IV and V are given as 20, 50, 70, 90, and 10 km? respectively. All the rainfall and isohyets are given in cm. Estimate the mean precipitation over this catchment area using arithmetic mean and isohyetal methods.
Q2) Annual rainfall and runoff values of a catchment for a period of 10 years are given below. Analyze the data to (a) develop a non-linear correlation equation to estimate annual runoff volume for a given annual rainfall value, (b) Estimate r values for the equation, (c) Estimate the runoff depth when the rainfall depth is (i) 350 mm (ii) 600 mm. 2010 2011 2017 2018 2019 Year Annual 2012 2013 2014 2015 2016 Rainfall 361 408 217 324 510 488 275 392 296 420 (mm) Annual Runoff (mm) 145 160 90 130 205 195 110 157 120 165
Hydrology 1. List the factors affecting the seasonal and annual runoff (Yield) of a catchment. Describe briefly the interactions of factors listed by you. 2. With the help of typical hydrographs describe the salient features of (i) Perennial,(ii) intermittent, and (iii) ephemeral steams. 3. Explain briefly:(a) Water year(b) Natural (Virgin) flow.
A wastewater treatment plant discharges of effluent into a stream. Just upstream from the discharge point, the stream has an ultimate BOD of 5 mg/L.Assuming a cross-sectional area for the stream equal to 100 m2, what ultimate BOD (in mg/L) would you expect to find at a point of 15,000 m downstream? Wastewater Flow: 1 m3/secBOD (ultimate): 40 mg/LRiver Flow: 10 m3/secDeoxygeneation constant kd: 0.22 day-1
The 1-hour unit (25mm) hydrograph for an ungauged watershed is estimated by a watershed modeler to be as follows: a linear increase in discharge to be 4 m³/s at 1 hour; and then, b) a further increase a) to 10 m³/s at 2 hours; and then, c) a linear decrease to 4 m³/s at 3 hours; and then d) followed by a linear decrease to zero at 4 hours. Determine the values of. 1). two hour unit hydrograph 2). four hour unit hydrograph.
From the basin map of a given watershed, the following quantities are measured: L = 150km, L. = 75km, and drainage area = 3500 km2. From the unit hydrograph derived for the watershed, the following are determined: tR = 12h, tpR = 34h, and peak discharge = 157.5 m/s-cm. Determine the coefficients C; and C, for the synthetic unit hydrograph of the watershed. Compute the six – hour synthetic unit hydrograph of a watershed having a drainage area of 25O0km2 with L = 100km and L. = 50km. This watershed is a sub – drainage area of the watershed in the first problem.
Example 8. Develop a 30-minute SCS triangular unit hydrograph for a watershed of area 550 ha and time of concentration of 50 minutes.
A 1 : 100 scale model of river is to be tested in a laboratory. The highest flood in river is 1000 m^3 /s. The corresponding discharge to be maintained in the model is ______ m^3 /s. (round off to 2 decimal places)