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The correct choice is (a) Centimeters

To elaborate: The rate of rainfall is EXPRESSED in centimeters of water during a given period of time. One centimeter rainfall is the QUANTITY of water COLLECTED on a certain AREA due to rainfall which becomes one centimeter in height.

The CORRECT choice is (c) Mass curve

To explain: The graph of the CUMULATIVE values of water quantity against time is known as mass curve. A mass curve of the HYDROGRAPH which expresses the AREA under the hydrograph from one time to another.

The CORRECT answer is (a) Vertical depth

To EXPLAIN: All forms of precipitation are MEASURED on the BASIS of vertical depth of water which would accumulate on the level SURFACE if all the precipitation remained where it fell. The rainfall is usually measured with rain gauges.

The correct choice is (d) Topography

Explanation: The study of the shape and features of the surface of the earth is known as topology and it is a very IMPORTANT factor which is affecting the runoff and also the nature of CATCHMENT AREA DEPENDS on it.

Right option is (a) PLANIMETER

Easiest explanation: GENERALLY interval of iso-hyete is one cm. after drawing the iso-hyetes; the area between two successive iso-hyetes is MEASURED by using a Planimeter. The rest of the procedure of finding out the MEAN rainfall is SIMILAR to that described in the second method.

The correct option is (c) Sun

To elaborate: The energy input to hydrological cycle is sun. DUE to sun, water evaporates from water bodies. On cooling, the vapors FORM cloud which FALLS down in the form of RAIN, snow, hail etc which is known as precipitation.

The correct ANSWER is (b) FRANCIS turbine

Best explanation: Modern power plants use Francis turbine. Francis turbine is a WATER turbine developed by James Francis. It is an INWARD flow reaction turbine that combines radial and axial flow concepts. These are primarily used for electric production.

Right option is (d) Surge tank

Explanation: Surge tank is introduced between the dam and POWER house nearest to the power house and PREFERABLY on the high ground to reduce the height of tower to provide better regulation of water pressure in the system during variable LOAD CONDITION.

Right option is (a) 1805.56 DAY sec meter

To explain I WOULD SAY: TOTAL RAINFALL

Right ANSWER is (a) True

The explanation is: Presence of Corrosive gases like H2S and SO2 does affect the VOLTAGE drop at brush contacts in generator leading to poor commutation. SILVER contacts of relays get blackened and lead to HIGH contact resistance and failure of RELAY occurs.

Right option is (a) Draught

For explanation I would say: The hydrograph can be drawn taking DAY, month or YEAR as time axis. The hydrograph BASED on year wise data GIVES information concerning the lean or draught year. This is very essential for deciding the location and size of hydel POWER plant.

Right choice is (a) Recording gauge

Best explanation: These are rain gauges which can give a PERMANENT, automatic rainfall record in the form of a pen mounted on a clock driven chart. From the chart INTENSITY or rate of rainfall in cm per HOUR. The recording is DONE by an attached siphon.

Correct option is (a) BURIED penstock

Best explanation: Buried penstocks are USED in cold climates where FREEZING is expected. TYPES of penstocks have shorter life period. A buried penstock will not be subjected to the problem of harmonic VIBRATIONS sometimes associated with the traditional penstock.

Right choice is (a) Reservoir

The best explanation: The basic requirement of a hydroelectric power station is a reservoir where LARGE quantity of water is STORED during flood season and used during dry season. The reservoir is generally built of constructing dam ACROSS river.

Right choice is (c) 1932

To elaborate: This unit hydrograph PRINCIPLE was EXPRESSED by Sherman in 1932; he introduced the THEORY of unit hydrograph. He POINTED out that all hydrographs have same TIME resulting from rainfalls of the given duration.

The correct choice is (a) I = R/(T+C)

The explanation: The intensity of rainfall is given by,

I = R/(T+C)

Where, I = intensity in inches/hr.

T = Duration of rain storm in hours

R & C = these are constants quoted by different AUTHORITIES for different AREAS of world.

The intensity also DEPENDS on the area selected for the measurement.

Correct CHOICE is (a) Continuously recording gauge

Explanation: The INTENSITY of rainfall is expressed as an AMOUNT of precipitation in a stead period. During heavy rainstorm the intensity of rainfall varies widely from minute to minute and can be measured only with a continuously recording gauge.

Correct answer is (d) Storage Reservoirs

The best I can EXPLAIN: The capacity of the HYDRAULIC plant is done on the basis of minimum quantity available. Usually storage reservoirs are constructed for such plants in order to STORE the water during peak PERIODS of RUNOFF and supply the same during off peak periods of runoff.

Right choice is (a) Precipitation

The best explanation: The RAINFALL is ALSO known as precipitation, is a natural PROCESS of atmospheric vapor into water. Atmospheric vapor are nothing but clouds which are contamination of air and water. When the temperature GOES below dew point then precipitation takes PLACE.

Right answer is (a) Minimum quantity of water AVAILABLE

Easy explanation: As the availability of water depends on natural phenomenon of rain, the MAXIMUM capacity of hydraulic generating plant is USUALLY FIXED on the basis of minimum quantity of water available at selected site.

The CORRECT choice is (a) 60,000 DAYS

The explanation: Per DAY requirement: 500 X 10^3 liter = 500 X 10^3 m^3

Available WATER in the dam = 30000 X 10^6 m^3

No of days water supplied = 30000 X 10^6/500 X 10^3 = 60000 days.

The correct OPTION is (d) Run-off river POWER plants

To explain I WOULD say: Run-off river power plants can be with or WITHOUT pondage. A runoff river plant without pondage has no control over river flow and uses WATER as it comes. The runoff river plant with pondage may supply base load power.

Correct ANSWER is (a) 74MW

Easiest EXPLANATION: Power developed = wQHno X 10^-3 KW

= 9810 X 9639.8 X 0.86 X 0.91 X 10^-6 MW

= 74 MW.

The correct choice is (b) DRY weather flow

For explanation: Dry weather flow is a WASTE WATER flow in a sewer system during dry WEATHERS with minimum filtration process while entering the ground. Insufficient flow VELOCITIES during DWF can increase retention.

Right OPTION is (a) True

For explanation: Hydrographs of various rainfalls will be similar in shape. The ordinates are proportional to the runoff VOLUMES within a FIXED duration and similar rate and a REAL DISTRIBUTION of rainfall. However, the occurrence of identical rainfall is very rare.

Correct choice is (c) It is highly accurate

Easy explanation: The mean rainfall of the basinin THIESSON method is given by:

HA = \(\frac{h1A1 + h2A2 + h3A3 + h4A4 + h5A5+ h6A6 + h7A7 + h8A8}{A1+A2+A3+A4+A5+A6+A7+A8}\)

This method gives better result than arithmetic mean method because it is very accurate and each point on a perpendicular bisector of the line joining the two gauging stations will be equidistant from both the stations. If one moves SLIGHTLY this or that SIDE of the bisector, the position will DISTINCTLY fall in the domain of that station of which ones position is now near.

The correct answer is (d) Summer

The best explanation: During summer, the evaporation loss from free WATER surface is considerably LARGE and this evaporated water finds ROOM in the air mass. The water holding CAPACITY of air in the form of vapor is ALSO considerably large in hot weather.

The correct answer is (a) 441.45MWh

The BEST I can EXPLAIN: The power capacity of plant in KW is given as

P = mgH/1000 X n{overall}

= (5 X 106 X 1000 X 9.81 X 75 X 0.72) / (365 X 24 X 3600 X 1000)

= 83.99Kw

Energy produced in KWH = P X Load factor X (365 X 24)

= 83.99 X 0.6 X 365 X 24

= 4441451.44kwh

= 441.45 MWH.

Correct option is (a) Pumped storage PLANTS

Explanation: Pumped storage plants can be used with hydro, steam and IC engines. The generating pumping unit is at the lower end. During off peak HOURS some of the surplus electric energy generated by the base plant is utilized to pump WATER from TAIL water pond into the head water pond.

Right OPTION is (d) INFINITE

The explanation is: The number of unit hydrographs for a given basin is theoretically infinite. This is because there may be one unit hydrograph for POSSIBLE duration of RAINFALL and every possible distribution pattern of rainfall in the basin.

Right option is (a) Energy curves of flow

Easiest explanation: The maximum RATE of flow through the river is calculated by energy curves. Flood marks are also used to GET the maximum flow rate. The following curves include DICKENS FORMULA, Inglis formula and ryve’s formula.

Correct option is (b) Thiesson method

For explanation: Thiesson method is very ACCURATE compared to other methods and is generally used when the catchment area lies between 500 to 5000km square. Assume that there are stations in the GIVEN basin names=d as 1, 2, 3, 4, 5, 6, 7, and 8. It is very important to divide the total basin area in such a way that each located station in the basin represents that area in the TRUE.

Correct answer is (a) True

The explanation is: The transpiration and INTERCEPTION losses depend on the nature and EXTENT of vegetation including CROPS. Vegetation, particularly of forest, has considerable effect upon the runoff. It consumes a PROPORTION of the rainfall, causes interception losses and provides physical OBSTRUCTION for runoff.

Correct answer is (c) year to Year

The EXPLANATION is: The annual rainfall at any given station varies irregularly from year to year. The RANGE of this VARIATION marks the RELIABILITY of the rainfall and has great importance in the design of storage reservoirs.

Correct answer is (a) Based on hydrological aspect

To EXPLAIN I would say: The EVAPORATION of the water from the SURFACES of river and oceans and its precipitation on the earth is known as hydrological cycle. Based on hydrological aspect the distribution of precipitation on the earth SURFACE and BENEATH the earth is calculated.

Right choice is (a) Butterfly valve

To ELABORATE: For moderate HEADS butterfly VALVES are preferred. Gate valves are used to regulate the flow. This valve is used both as intake gate and as turbine valve. It helps INSPECTION without dewatering the penstock line.

Right option is (d) 25000 SQ KM

To explain: The unit hydrographs can be applied successfully to basin areas as large as 25000 sq km. provided distribution patterns are classified into different types and unit hydrographs are developed for each TYPE it is always PREFERABLE to divide the large basin into sub-areas, UTILIZE hydrographs for each sub area independently and combine the resulting hydrographs together.

The correct choice is (b) Sedimentation effect

Easy explanation: SEDIMENTS in the aquatic ECOSYSTEM are analogous to SOIL in the terrestrial ecosystem as they are the SOURCE of substrate nutrients, and micro- and MACRO flora and -fauna that are the basis of support to living aquatic resources.

Correct CHOICE is (B) Pump storage power PLANTS

The best I can explain: Pumped storage plants supply the peak load for the base power plants and pump all or a PORTION of their own water supply. The PLANT contains a tail water pond and a head water pond connected by a penstock.

Correct CHOICE is (d) Exposed penstock

Explanation: Exposed penstocks are less expensive and have a longer life. Their inspection and maintenance is easier. Penstocks are not covered because exposed PIPES are easily accessible. The WATER flow rate is 2, 4, and 7 m/s in LOW, medium and high head power plants respectively.

The CORRECT OPTION is (a) P.F = 2.4

Best explanation: Pondage factor = T1/T2 = (TOTAL number of hours in one day)/(Total number of hours PLANT is running)

P.F = 24/10= 2.4.