Water Resources Systems - short answer questions from AMIE exams (Winter 2018)

Answer the following questions

Enlist the parameters that constitute the water quality and their tests.

Physical parameters
  • Turbidity
  • Temperature
  • Colour
  • Taste and odour
  • Solids
  • Electrical conductivity (EC)
Chemical parameters
  • pH
  • Acidity
  • Alkalinity
  • Chloride
  • Chlorine residual
  • Sulfate
  • Nitrogen
  • Fluoride
  • Iron and manganese
  • Copper and zinc
  • Hardness
  • Dissolved oxygen
  • Biochemical oxygen demand (BOD)
  • Chemical oxygen demand (COD)
  • Toxic inorganic substances
  • Toxic organic substances
  • Radioactive substances
Biological parameters
  • Bacteria
  • Algae
  • Viruses
  • Protozoa

Name the instruments that a typical hydrometeorological station should contain.

The common instruments of measure are anemometer, wind vane, pressure sensor, thermometer, hygrometer, and rain gauge.

What are the meaning of the terms "correlation", and "spurious correlation"?

A correlation is a measure of the direction and the size of two or more variables in a data set. This means that when looking at statistical models, if one variable changes or moves in a specific direction, then another variable does, too. When behaviours like this appear between variables in studies, statisticians assume a correlation, or link, between the samples. 
A spurious correlation in statistics represents a connection between two variables that seems to be a causal relationship but really is not. A causal relationship describes a cause-and-effect relationship between two variables, where one variable does something that directly affects the other. 

What is the probability that a 7-year return period event will occur at least once in N years?

Probability of flood at least once in next N years
= 1 – no flood in next N years
= 1 – qN
where, q is the probability of not occurring an event.

Define a time series.

A time series is a sequence of data points that occur in successive order over some period of time.

What is the utility of a time series analysis?

In particular, a time series allows one to see what factors influence certain variables from period to period. Time series analysis can be useful to see how a variable changes over time.

Name the four different periods of time that must be considered in any economic analysis, and arrange them in decreasing order of magnitude.

The term economic cycle refers to the fluctuations of the economy between periods of expansion (growth) and contraction (recession). An economic cycle is the overall state of the economy as it goes through four stages in a cyclical pattern. The four stages of the cycle are expansion, peak, contraction, and trough.

  • Expansion: During expansion, the economy experiences relatively rapid growth, interest rates tend to be low, production increases, and inflationary pressures build.
  • Peak: The peak of a cycle is reached when growth hits its maximum rate. Peak growth typically creates some imbalances in the economy that need to be corrected.
  • Contraction: A correction occurs through a period of contraction when growth slows, employment falls, and prices stagnate.
  • Trough: The trough of the cycle is reached when the economy hits a low point and growth begins to recover.

What are the basic steps of economic analysis? 

  1. Explain the strategic context
  2. Establish the need for expenditure
  3. Define the objectives and constraints
  4. Identify and describe the options
  5. Identify and quantify the monetary costs and benefits of options
  6. Appraise risks & adjust for optimism bias
  7. Weigh up non-monetary cost and benefits
  8. Calculate net present values (NPVs) and assess uncertainties
  9. Assess affordability and record arrangements for funding, management, procurement, marketing, benefits realization, monitoring and ex post evaluation
  10. Assess the balance of advantage between the options and present the results and conclusions

What arc the purpose of water resources planning?

Water Resources Management objectives can include promoting conditions for environmentally sustainable, economically efficient and equitably allocated use of water resources. They also include to increase the benefits and reduce the risk related to existing hydraulic infrastructure.

Obtain an expression to define the water power potential of a river.

The power output of a dam is calculated using the potential energy of the water and can be found using the following hydropower formula:

P = η ρ g h Q


P is the power output, measured in Watts
η is the efficiency of the turbine
ρ is the density of water, taken as 998 kg/m³ (you can change it in advanced mode)
g is the acceleration of gravity, equal to 9.81 m/s² (you can change it in advanced mode)
h is the head, or the usable fall height, expressed in units of length (meters or feet)
Q is the discharge (also called the flow rate), calculated as Q = Av.
A is the cross-sectional area of the channel
v is the flow velocity

Classify water uses with examples.

Water can be used for direct and indirect purposes. Direct purposes include bathing, drinking, and cooking, while examples of indirect purposes are the use of water in processing wood to make paper and in producing steel for automobiles. The bulk of the world’s water use is for agriculture, industry, and electricity. 

The most common water uses include:
  • Drinking and Household Needs
  • Recreation
  • Industry and Commerce
  • Agriculture
  • Electricity/Energy

What is the main function of a reservoir?

A reservoir constructed and equipped to provide storage and release of water for two or more purposes such as irrigation, flood control, power generation, navigation, pollution abatement, domestic and industrial water supply, fish culture, recreation, etc.
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