Chapter 10, Problem 10.5.3P

Since your team is doing such an outstanding job for your client, they requested a preliminary evaluation to estimate flow under the highway considering the implementation of a masterplan for the entire watershed that drains to the roadway. Your team developed the unit hydrograph below for a 1 hour storm duration. Calculate the watershed response to the hyetograph provided and provide the total peak flow (cfs). Table 1. Effective Precipitation Time [hr] P [in.] 1 0.5 2 2.5 Table 2. Unit Hydrograph Time [hr] QUH [cfs] 0 0 1 400 2 1600 3 800 4 0

1.20. A small community of 1500 people has a dry-weather wastewater flow of 650 m³/d and a wet-weather flow ranging up to 6000 m³/d. What is the probable cause of this wide fluctuation?

Problem 1 The storage, elevation and outflow data of a reservoir are given below in Table 1. When the spillway crest is at elevation 300.2 m, the following flood given in Table 2 was expected into the reservoir. If the reservoir surface is at elevation 300.00 m at the commencement of the inflow, route the flood to determine the (a) the outflow hydrograph (b) the reservoir elevation vs time curve Table 1 Elevation, m Storage (S) 106 m3 Outflow discharge (Q) m³/s 299.5 4.8 300.2 5.5 300.7 19 301.2 6.6 50 301.7 7.2 94 302.2 7.9 144 302.7 8.8 200 Table 2 Time, h Flood discharge, m3/s 13 3 25 6 65 75 12 66 15 54 18 40 col i

Ans. A coffer dam is designed for a 25 year flood and constructed. If it takes 5 years to complete the construction of main dam, what is the risk that the coffer dam may fail before the end of the construction period ? What return period in the design of coffer dam would have reduced the risk to 10% ?

Question-4b A canal irrigates a portion of a culturable command area to grow sugarcane and wheat. The average discharges required to grow sugarcane and wheat are, respectively, 0.40 and 0.50 cumes. The time factor is 0.5. Find the required design capacity of the canal.

A bankrupt chemical firm has been taken over by new management. On the property, they found a 20,000 m3 brine (i.e., salt) pond containing 25,000 mg/L of salt. The new owners propose to flush the pond into their discharge pipe leading to the Pacific Ocean, which has a salt concentration of about 35,000 mg/L (or 3.5% salt). You have been hired by the company to calculate the flow rate (in m3/s) of freshwater (0 mg/L salt) that must they use to reduce the salt concentration in the pond to 500 mg/L within 3 months (90 days). To increase your billable hours, then calculate the total volume of water that was used (in m3) and the mass of salt (in kg) that was exported to the Pacific Ocean. You may assume the pond volume remains the same during the flushing process, the pond is completely mixed, and the salt is a conservative substance.

(e) A River in the Thunder Bay area experienced peak floods of 2600 ft³/s and 3000 ft³/s respectively for the return period of 15 and 30 years. The flood peak data on this river normally follows the normal probability distribution. You, as a novice engineer, are asked by your supervisory engineer to estimate the peak flow on this river for the return period of 70 years.

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]

Water resources engineering In A coffer dam is designed for a 25 year flood and constructed If it takes 5 years to complete the construction of the main dam, what is the risk that the coffer dam may fail before the end of the construction period? What return period in the design of coffer dam would have reduced the risk to 10%?