Water Resources and Hydrology MCQs 2026

Shift in rating curve after flood may result from

1. A only chlorine decay ✓
2. B only coagulation ✓
3. C scour or deposition changing channel geometry ✓
4. D only wind shift ✓

Gauging station record is essential for

1. A only brick testing ✓
2. B only motor design ✓
3. C only highway alignment ✓
4. D calibrating hydrologic models and flood frequency ✓

Weir or flume in stream gauging provides

1. A uncontrolled random flow ✓
2. B zero measurement accuracy ✓
3. C only groundwater sampling ✓
4. D controlled stage-discharge relationship ✓

Float method of stream gauging gives

1. A exact groundwater transmissivity ✓
2. B chlorine residual ✓
3. C approximate surface velocity estimate ✓
4. D concrete strength ✓

Discharge measurement by velocity-area method integrates

1. A velocity across cross-sectional area ✓
2. B only surface width ✓
3. C only wind speed ✓
4. D only air pressure ✓

Current meter measures

1. A rainfall depth ✓
2. B groundwater K in lab only ✓
3. C BOD in lab ✓
4. D flow velocity at point in stream cross-section ✓

Stage-discharge relation at gauging station is called

1. A IDF curve ✓
2. B rating curve ✓
3. C mass curve only ✓
4. D grain size curve ✓

Saltwater intrusion in coastal aquifer is worsened by

1. A heavy rainfall only ✓
2. B high canal lining ✓
3. C excessive groundwater pumping lowering fresh head ✓
4. D zero irrigation ✓

Unconfined aquifer specific yield affects

1. A only air temperature ✓
2. B only pipe surge ✓
3. C only coagulant dose ✓
4. D water released from storage per unit drawdown ✓

Steady confined aquifer discharge to well (Thiem) depends on

1. A transmissivity and drawdown logarithmically ✓
2. B only rainfall intensity ✓
3. C only wind speed ✓
4. D only BOD ✓

Cone of depression forms around

1. A rain gauge ✓
2. B pumping well in aquifer ✓
3. C Venturi meter ✓
4. D sedimentation tank ✓

Porosity is ratio of

1. A void volume to total soil volume ✓
2. B solid volume to voids ✓
3. C water depth to rainfall ✓
4. D BOD to COD ✓

Specific yield is

1. A total porosity always equal ✓
2. B storage coefficient in confined aquifer ✓
3. C volume of water drained by gravity per unit aquifer volume ✓
4. D Manning n ✓

Transmissivity T equals

1. A K/b ✓
2. B K + b only ✓
3. C b/K² ✓
4. D K × b where b is saturated aquifer thickness ✓

Hydraulic conductivity K has units of

1. A pressure only ✓
2. B velocity (m/s or cm/s) ✓
3. C dimensionless only ✓
4. D temperature K ✓

Darcy law for groundwater is

1. A Q = K i A ✓
2. B Q = CiA rational ✓
3. C Q = AV pipe ✓
4. D Q = Manning AR^(2/3) ✓

Seepage from reservoir foundation is controlled by

1. A cutoff walls, grouting and drainage blankets ✓
2. B only chlorination ✓
3. C only air pollution law ✓
4. D only trickling filter ✓

Safe yield of reservoir is

1. A maximum single day spill ✓
2. B maximum dependable yield without failure during critical period ✓
3. C zero outflow always ✓
4. D only evaporation ✓

Mass curve (ripogram) of inflow helps determine

1. A pipe friction only ✓
2. B required storage for given demand pattern ✓
3. C wind rose only ✓
4. D slump only ✓

Dead storage is provided below outlet level for

1. A recreation only ✓
2. B flood wave only ✓
3. C sediment accumulation over life ✓
4. D zero sediment ✓

Live storage in reservoir is

1. A volume between minimum drawdown and full supply level ✓
2. B sediment pool only ✓
3. C dead storage below outlets only ✓
4. D air space above dam ✓

Spillway crest elevation governs

1. A only groundwater head in well ✓
2. B only BOD in sewage ✓
3. C reservoir maximum normal pool and flood routing ✓
4. D only wind speed ✓

Attenuation in reservoir routing reduces

1. A peak outflow compared to peak inflow ✓
2. B storage capacity to zero ✓
3. C flood volume entirely ✓
4. D water level rise ✓

Level pool routing assumes

1. A steep gradient in lake always ✓
2. B uniform water surface elevation in reservoir ✓
3. C no storage change ✓
4. D only pressurized pipe flow ✓

Muskingum routing method uses

1. A storage as function of inflow and outflow weights x and K ✓
2. B only Darcy law ✓
3. C only Manning in pipes ✓
4. D only Hazen Williams ✓

Hydrologic flood routing computes

1. A only evaporation from pan ✓
2. B only pipe minor losses ✓
3. C only air density ✓
4. D outflow hydrograph from inflow and storage relationship ✓

UH ordinates sum multiplied by duration gives

1. A zero volume ✓
2. B infinite peak ✓
3. C only groundwater ✓
4. D volume of direct runoff equal to unit depth times area ✓

Synthetic unit hydrograph by Snyder uses

1. A only BOD data ✓
2. B only wind rose ✓
3. C basin lag and peak discharge factors from physiographic data ✓
4. D only concrete mix ✓

Lag time of basin is approximately

1. A canal design period ✓
2. B return period 100 years ✓
3. C time from centroid of rainfall to peak of hydrograph ✓
4. D base period of wheat ✓

Time base of unit hydrograph extends until

1. A rainfall starts only ✓
2. B direct runoff essentially returns to zero ✓
3. C only peak occurs ✓
4. D one hour only ✓

Unit hydrograph theory assumes

1. A nonlinear always ✓
2. B snowmelt only ✓
3. C linear time-invariant response for direct runoff ✓
4. D groundwater only ✓

Unit hydrograph is defined for

1. A 10 cm rainfall always ✓
2. B 1 unit depth of effective rainfall over catchment for given duration ✓
3. C zero rainfall ✓
4. D annual mean flow ✓

Blaney-Criddle method estimates ET using

1. A only groundwater head ✓
2. B temperature and daylight percentage ✓
3. C only pipe diameter ✓
4. D only concrete grade ✓

Consumptive use of crop is essentially

1. A evapotranspiration minus effective rainfall plus other adjustments ✓
2. B canal seepage only ✓
3. C sediment load ✓
4. D BOD removal ✓

Pan evaporation exceeds lake evaporation because

1. A pan is always shaded ✓
2. B pan absorbs more heat and has different aerodynamics ✓
3. C lake has higher albedo always ✓
4. D pan is underground ✓

Crop coefficient Kc relates

1. A runoff to rainfall only ✓
2. B crop ET to reference ET0 ✓
3. C BOD to population ✓
4. D Manning n to slope ✓

Reference crop evapotranspiration ET0 is

1. A ET from bare rock only ✓
2. B ocean evaporation only ✓
3. C sewer infiltration ✓
4. D ET from standardized grass surface ✓

Evapotranspiration ET combines

1. A only groundwater flow ✓
2. B only pipe surge ✓
3. C evaporation from surfaces and transpiration from plants ✓
4. D only sedimentation ✓

Antecedent moisture condition AMC changes

1. A only wind direction ✓
2. B only pipe material ✓
3. C effective curve number for same watershed ✓
4. D only dam height ✓

Direct runoff depth in SCS method when P > Ia is

1. A Q = P always ✓
2. B Q = S only ✓
3. C Q = CN ✓
4. D Q = (P − Ia)²/(P − Ia + S) ✓

Initial abstraction Ia in SCS method is often taken as

1. A 0.2S ✓
2. B 0.8S ✓
3. C zero always ✓
4. D equal to rainfall ✓

Potential maximum retention S in SCS method is

1. A S = CN only ✓
2. B S = 254 CN ✓
3. C S = Q/A ✓
4. D S = (25400/CN) − 254 mm ✓

Higher SCS curve number indicates

1. A less runoff always ✓
2. B greater runoff potential for given rainfall ✓
3. C zero infiltration capacity always ✓
4. D lower peak discharge always ✓

SCS curve number method estimates

1. A only evaporation from ocean ✓
2. B direct runoff from rainfall and watershed storage ✓
3. C only pipe friction ✓
4. D only air quality ✓

Rational method is reliable for

1. A small urban catchments under 80 hectares typically ✓
2. B large river basins only ✓
3. C groundwater aquifers only ✓
4. D ocean tides ✓

Time of concentration is

1. A base period of crop ✓
2. B time for runoff to travel from hydraulically farthest point to outlet ✓
3. C return period of storm ✓
4. D canal design life ✓

Runoff coefficient C in rational formula represents

1. A Manning n ✓
2. B Lacey silt factor ✓
3. C ratio of peak runoff rate to rainfall intensity ✓
4. D Hazen C only ✓

Rational formula for peak discharge is

1. A Q = AV only ✓
2. B Q = Manning n ✓
3. C Q = CiA ✓
4. D Q = ΔD/B ✓

Land use change to impervious surface

1. A increases infiltration always ✓
2. B reduces infiltration and increases runoff ✓
3. C has no hydrologic effect ✓
4. D eliminates evaporation completely ✓

Green-Ampt model assumes

1. A no infiltration occurs ✓
2. B fully saturated surface always from start ✓
3. C only rocky pavement ✓
4. D sharp wetting front and uniform initial moisture ✓

Horton equation models infiltration rate as

1. A linear increase forever ✓
2. B zero always ✓
3. C Manning uniform flow ✓
4. D exponential decay toward constant final rate ✓

Infiltration capacity decreases during storm because

1. A soil moisture increases reducing suction gradient ✓
2. B soil becomes drier always ✓
3. C wind stops always ✓
4. D temperature drops to zero ✓

Infiltration is process of

1. A evaporation from leaves only ✓
2. B discharge over weir ✓
3. C chlorination only ✓
4. D water entering soil surface into unsaturated zone ✓

Rational formula uses rainfall intensity from

1. A IDF curves for design duration equal to time of concentration ✓
2. B only monthly mean temperature ✓
3. C only reservoir dead storage ✓
4. D only trickling filter rate ✓

IDF curves are obtained by

1. A only soil compaction test ✓
2. B only slump test ✓
3. C frequency analysis of annual maximum rainfall series ✓
4. D only sieve analysis ✓

Higher return period storm has

1. A greater rainfall depth for same duration ✓
2. B lower intensity always ✓
3. C zero depth ✓
4. D shorter duration only ✓

Return period of 100 years means

1. A event occurs exactly every 100 years ✓
2. B average interval between exceedances of given magnitude ✓
3. C zero probability in any year ✓
4. D intensity is always zero ✓

Intensity-duration-frequency curves relate

1. A only groundwater transmissivity ✓
2. B only BOD to COD ratio ✓
3. C only canal duty ✓
4. D rainfall intensity to duration and return period ✓

Depth-area-duration curves show that rainfall depth

1. A increases with area always ✓
2. B is constant for all areas ✓
3. C generally decreases with area for same storm duration ✓
4. D equals runoff always ✓

Probable maximum precipitation (PMP) is used for

1. A drip emitter sizing only ✓
2. B brick masonry only ✓
3. C slump test ✓
4. D spillway and dam safety design ✓

Double mass curve analysis detects

1. A inconsistency in rainfall or runoff records ✓
2. B pipe friction factor ✓
3. C concrete strength ✓
4. D motor slip ✓

Isohyetal method is most accurate when

1. A no rainfall occurs ✓
2. B one gauge covers Himalaya ✓
3. C isohyets are drawn from sufficient gauge data ✓
4. D only wind data available ✓

Thiessen polygon method weights rainfall by

1. A area influence of each gauge ✓
2. B only highest reading ✓
3. C only lowest reading ✓
4. D perimeter of basin only ✓

Arithmetic mean method for areal rainfall suits

1. A single gauge only always ✓
2. B zero gauges ✓
3. C ocean areas only ✓
4. D gauge stations uniformly distributed over basin ✓

Isohyet is a line joining areas of

1. A equal rainfall depth ✓
2. B equal temperature ✓
3. C equal discharge ✓
4. D equal groundwater head ✓

Point rainfall is measured by

1. A current meter in pipe ✓
2. B rain gauge at specific location ✓
3. C Venturi in canal ✓
4. D Rebound hammer ✓

Runoff is that part of precipitation which

1. A only evaporates ✓
2. B only remains as vapour ✓
3. C flows over or through surface to stream channels ✓
4. D never reaches basin outlet ✓

Transpiration is

1. A water vapour loss through plant stomata ✓
2. B infiltration into aquifer ✓
3. C sediment transport in river ✓
4. D coagulation in treatment ✓

Evaporation from open water depends primarily on

1. A only soil colour ✓
2. B only pipe diameter ✓
3. C only BOD ✓
4. D vapour pressure deficit, wind and temperature ✓

Hydrologic cycle describes

1. A only groundwater flow ✓
2. B continuous movement of water between atmosphere, land and oceans ✓
3. C only pipe friction ✓
4. D only sewage treatment ✓