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WE322 Takehome

This document provides instructions and questions for a third year diploma assessment in water engineering. It includes 5 questions assessing hydrology concepts. Question 1 has two parts asking students to compute a hydrograph from rainfall and calculate excess water storage. Question 2 has two parts about factors influencing surface runoff and calculating hydraulic conductivity. Question 3 has three parts involving Horton's infiltration equation and reservoir inflows and outflows. Question 4 has two parts about culvert design life and well testing. Question 5 has three parts involving a flow duration curve, power station demand, and unit hydrograph assumptions. Students are instructed to show their working clearly and answer all questions.

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Desly Kalong
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25 views5 pages

WE322 Takehome

This document provides instructions and questions for a third year diploma assessment in water engineering. It includes 5 questions assessing hydrology concepts. Question 1 has two parts asking students to compute a hydrograph from rainfall and calculate excess water storage. Question 2 has two parts about factors influencing surface runoff and calculating hydraulic conductivity. Question 3 has three parts involving Horton's infiltration equation and reservoir inflows and outflows. Question 4 has two parts about culvert design life and well testing. Question 5 has three parts involving a flow duration curve, power station demand, and unit hydrograph assumptions. Students are instructed to show their working clearly and answer all questions.

Uploaded by

Desly Kalong
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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NATURAL RESOURCES DEVELOPMENT COLLEGE

THIRD YEAR TAKEHOME ASSESSMENT

DIPLOMA IN WATER ENGINEERING


COURSE: WE322 ADVANCED HYDROLOGY

INSTRUCTIONS TO CANDIDATES:
i. Ensure that your student number is clearly written on each answer SCRIPT
ii. Show your working clearly
iii. Answer ALL questions

Total number of marks…100marks


QUESTION ONE
A river catchment has a 2 hour unit hydrograph with the ordinates 0, 3, 11, 35, 55, 66, 63, 40, 22,
9 and 2m3/s. Assume that the base flow at time t=0hr is 50m3/s and linearly increase to 74m3/s at
time t=24hours.
a) Compute the hydrograph resulting from two successive 2 hour period of effective rain of 2.0 cm
and 3.0 cm respectively. (15marks)
b) To prevent downstream flooding, the maximum flow to be released from the catchment is set at
273m3/s. Calculate the space required to store the excess water for this event in cumecs. (5marks)

QUESTION TWO

a) Discuss the factors influencing surface runoff, sketches allow one to gain more marks.
(10marks)

b) A well of 700 cm radius in a confined aquifer was pumped at a steady rate of 40L/s from a fully
penetrating well. When the well water level remained constant at 85.5m above datum, the
observation well (borehole) constructed at a distance of 10m recorded a water level of 86.5m. The
well thickness is estimated at 20000mm. Determine the hydraulic conductivity and transmissivity
around the well in m/day and m2/day respectively.
(10marks)
QUESTION THREE
a) Suppose that the parameters for Hortons equation are fo=3.5mm/hr, fc=0.6mm/hr and k=4.1/hr.
Determine the infiltration rates 0min, 10min, 20min, 1hr, 1.5hr and 2hr and cumulative infiltration
after 2 hours. Assume continuously ponded conditions. (10marks)

b) A reservoir has the following inflows and outflows (in cubic meters) in one hydrological year.
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Inflow 20 28 40 18 15 10 10 8 6 4 6 9
Outflow 60 90 112 40 25 18 5 4 2 2 11 5
If the storage at the beginning of January is 800 m3, determine the storage at the end of December.
(5marks)
c) Distinguish in detail the difference between groundwater recharge and discharge.
(5marks)

QUESTION FOUR

a) A culvert has an expected life span of 8 years. If the acceptable risk of at least one event
exceeding the culvert capacity during the design life is 12.5%, what design return period should
be used? What is the probability that a culvert designed for an event of this this return period will
not have its capacity exceeded for 60 years? (10marks)

b) With regards to wells, discuss the importance of slug testing and well testing. Aid of
diagrammatic representation is essential. (10marks)
QUESTION FIVE

Flow data for a proposed hydropower station is tabulated below.

Mean daily discharge Frequency of occurrence


(m3) (days)
>50 21
50-40 132
40-30 176
30-20 191
20-10 285
<10 290

a) Draw the flow duration curve for this site. (10marks)


b) If at least 20 cumecs of flow is needed to generate a minimum power demand how many
days in a year will the power station fail to meet the demand? Show working clearly on graph.
(5marks)
c) Discuss the assumptions considered during the formulation of a unit hydrograph.
(5marks)
ALL THE BEST!!!!!

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