Water Resources and Hydrology MCQs 2026

Synthetic unit hydrograph by Snyder uses

1. Aonly BOD data✓
2. Bonly wind rose✓
3. Cbasin lag and peak discharge factors from physiographic data✓
4. Donly concrete mix✓

UH ordinates sum multiplied by duration gives

1. Azero volume✓
2. Binfinite peak✓
3. Conly groundwater✓
4. Dvolume of direct runoff equal to unit depth times area✓

Hydrologic flood routing computes

1. Aonly evaporation from pan✓
2. Bonly pipe minor losses✓
3. Conly air density✓
4. Doutflow hydrograph from inflow and storage relationship✓

Muskingum routing method uses

1. Astorage as function of inflow and outflow weights x and K✓
2. Bonly Darcy law✓
3. Conly Manning in pipes✓
4. Donly Hazen Williams✓

Level pool routing assumes

1. Asteep gradient in lake always✓
2. Buniform water surface elevation in reservoir✓
3. Cno storage change✓
4. Donly pressurized pipe flow✓

Attenuation in reservoir routing reduces

1. Apeak outflow compared to peak inflow✓
2. Bstorage capacity to zero✓
3. Cflood volume entirely✓
4. Dwater level rise✓

Spillway crest elevation governs

1. Aonly groundwater head in well✓
2. Bonly BOD in sewage✓
3. Creservoir maximum normal pool and flood routing✓
4. Donly wind speed✓

Live storage in reservoir is

1. Avolume between minimum drawdown and full supply level✓
2. Bsediment pool only✓
3. Cdead storage below outlets only✓
4. Dair space above dam✓

Dead storage is provided below outlet level for

1. Arecreation only✓
2. Bflood wave only✓
3. Csediment accumulation over life✓
4. Dzero sediment✓

Mass curve (ripogram) of inflow helps determine

1. Apipe friction only✓
2. Brequired storage for given demand pattern✓
3. Cwind rose only✓
4. Dslump only✓

Safe yield of reservoir is

1. Amaximum single day spill✓
2. Bmaximum dependable yield without failure during critical period✓
3. Czero outflow always✓
4. Donly evaporation✓

Seepage from reservoir foundation is controlled by

1. Acutoff walls, grouting and drainage blankets✓
2. Bonly chlorination✓
3. Conly air pollution law✓
4. Donly trickling filter✓

Darcy law for groundwater is

1. AQ = K i A✓
2. BQ = CiA rational✓
3. CQ = AV pipe✓
4. DQ = Manning AR^(2/3)✓

Hydraulic conductivity K has units of

1. Apressure only✓
2. Bvelocity (m/s or cm/s)✓
3. Cdimensionless only✓
4. Dtemperature K✓

Transmissivity T equals

1. AK/b✓
2. BK + b only✓
3. Cb/K²✓
4. DK × b where b is saturated aquifer thickness✓

Specific yield is

1. Atotal porosity always equal✓
2. Bstorage coefficient in confined aquifer✓
3. Cvolume of water drained by gravity per unit aquifer volume✓
4. DManning n✓

Porosity is ratio of

1. Avoid volume to total soil volume✓
2. Bsolid volume to voids✓
3. Cwater depth to rainfall✓
4. DBOD to COD✓

Cone of depression forms around

1. Arain gauge✓
2. Bpumping well in aquifer✓
3. CVenturi meter✓
4. Dsedimentation tank✓

Steady confined aquifer discharge to well (Thiem) depends on

1. Atransmissivity and drawdown logarithmically✓
2. Bonly rainfall intensity✓
3. Conly wind speed✓
4. Donly BOD✓

Unconfined aquifer specific yield affects

1. Aonly air temperature✓
2. Bonly pipe surge✓
3. Conly coagulant dose✓
4. Dwater released from storage per unit drawdown✓

Saltwater intrusion in coastal aquifer is worsened by

1. Aheavy rainfall only✓
2. Bhigh canal lining✓
3. Cexcessive groundwater pumping lowering fresh head✓
4. Dzero irrigation✓

Stage-discharge relation at gauging station is called

1. AIDF curve✓
2. Brating curve✓
3. Cmass curve only✓
4. Dgrain size curve✓

Current meter measures

1. Arainfall depth✓
2. Bgroundwater K in lab only✓
3. CBOD in lab✓
4. Dflow velocity at point in stream cross-section✓

Discharge measurement by velocity-area method integrates

1. Avelocity across cross-sectional area✓
2. Bonly surface width✓
3. Conly wind speed✓
4. Donly air pressure✓

Float method of stream gauging gives

1. Aexact groundwater transmissivity✓
2. Bchlorine residual✓
3. Capproximate surface velocity estimate✓
4. Dconcrete strength✓

Weir or flume in stream gauging provides

1. Auncontrolled random flow✓
2. Bzero measurement accuracy✓
3. Conly groundwater sampling✓
4. Dcontrolled stage-discharge relationship✓

Gauging station record is essential for

1. Aonly brick testing✓
2. Bonly motor design✓
3. Conly highway alignment✓
4. Dcalibrating hydrologic models and flood frequency✓

Hydrologic cycle describes

1. Aonly groundwater flow✓
2. Bcontinuous movement of water between atmosphere, land and oceans✓
3. Conly pipe friction✓
4. Donly sewage treatment✓

Evaporation from open water depends primarily on

1. Aonly soil colour✓
2. Bonly pipe diameter✓
3. Conly BOD✓
4. Dvapour pressure deficit, wind and temperature✓

Transpiration is

1. Awater vapour loss through plant stomata✓
2. Binfiltration into aquifer✓
3. Csediment transport in river✓
4. Dcoagulation in treatment✓

Runoff is that part of precipitation which

1. Aonly evaporates✓
2. Bonly remains as vapour✓
3. Cflows over or through surface to stream channels✓
4. Dnever reaches basin outlet✓

Point rainfall is measured by

1. Acurrent meter in pipe✓
2. Brain gauge at specific location✓
3. CVenturi in canal✓
4. DRebound hammer✓

Isohyet is a line joining areas of

1. Aequal rainfall depth✓
2. Bequal temperature✓
3. Cequal discharge✓
4. Dequal groundwater head✓

Arithmetic mean method for areal rainfall suits

1. Asingle gauge only always✓
2. Bzero gauges✓
3. Cocean areas only✓
4. Dgauge stations uniformly distributed over basin✓

Thiessen polygon method weights rainfall by

1. Aarea influence of each gauge✓
2. Bonly highest reading✓
3. Conly lowest reading✓
4. Dperimeter of basin only✓

Isohyetal method is most accurate when

1. Ano rainfall occurs✓
2. Bone gauge covers Himalaya✓
3. Cisohyets are drawn from sufficient gauge data✓
4. Donly wind data available✓

Double mass curve analysis detects

1. Ainconsistency in rainfall or runoff records✓
2. Bpipe friction factor✓
3. Cconcrete strength✓
4. Dmotor slip✓

Probable maximum precipitation (PMP) is used for

1. Adrip emitter sizing only✓
2. Bbrick masonry only✓
3. Cslump test✓
4. Dspillway and dam safety design✓

Depth-area-duration curves show that rainfall depth

1. Aincreases with area always✓
2. Bis constant for all areas✓
3. Cgenerally decreases with area for same storm duration✓
4. Dequals runoff always✓

Intensity-duration-frequency curves relate

1. Aonly groundwater transmissivity✓
2. Bonly BOD to COD ratio✓
3. Conly canal duty✓
4. Drainfall intensity to duration and return period✓

Return period of 100 years means

1. Aevent occurs exactly every 100 years✓
2. Baverage interval between exceedances of given magnitude✓
3. Czero probability in any year✓
4. Dintensity is always zero✓

Higher return period storm has

1. Agreater rainfall depth for same duration✓
2. Blower intensity always✓
3. Czero depth✓
4. Dshorter duration only✓

IDF curves are obtained by

1. Aonly soil compaction test✓
2. Bonly slump test✓
3. Cfrequency analysis of annual maximum rainfall series✓
4. Donly sieve analysis✓

Rational formula uses rainfall intensity from

1. AIDF curves for design duration equal to time of concentration✓
2. Bonly monthly mean temperature✓
3. Conly reservoir dead storage✓
4. Donly trickling filter rate✓

Infiltration is process of

1. Aevaporation from leaves only✓
2. Bdischarge over weir✓
3. Cchlorination only✓
4. Dwater entering soil surface into unsaturated zone✓

Infiltration capacity decreases during storm because

1. Asoil moisture increases reducing suction gradient✓
2. Bsoil becomes drier always✓
3. Cwind stops always✓
4. Dtemperature drops to zero✓

Horton equation models infiltration rate as

1. Alinear increase forever✓
2. Bzero always✓
3. CManning uniform flow✓
4. Dexponential decay toward constant final rate✓

Green-Ampt model assumes

1. Ano infiltration occurs✓
2. Bfully saturated surface always from start✓
3. Conly rocky pavement✓
4. Dsharp wetting front and uniform initial moisture✓

Land use change to impervious surface

1. Aincreases infiltration always✓
2. Breduces infiltration and increases runoff✓
3. Chas no hydrologic effect✓
4. Deliminates evaporation completely✓

Rational formula for peak discharge is

1. AQ = AV only✓
2. BQ = Manning n✓
3. CQ = CiA✓
4. DQ = ΔD/B✓

Runoff coefficient C in rational formula represents

1. AManning n✓
2. BLacey silt factor✓
3. Cratio of peak runoff rate to rainfall intensity✓
4. DHazen C only✓

Time of concentration is

1. Abase period of crop✓
2. Btime for runoff to travel from hydraulically farthest point to outlet✓
3. Creturn period of storm✓
4. Dcanal design life✓

Rational method is reliable for

1. Asmall urban catchments under 80 hectares typically✓
2. Blarge river basins only✓
3. Cgroundwater aquifers only✓
4. Docean tides✓

SCS curve number method estimates

1. Aonly evaporation from ocean✓
2. Bdirect runoff from rainfall and watershed storage✓
3. Conly pipe friction✓
4. Donly air quality✓

Higher SCS curve number indicates

1. Aless runoff always✓
2. Bgreater runoff potential for given rainfall✓
3. Czero infiltration capacity always✓
4. Dlower peak discharge always✓

Potential maximum retention S in SCS method is

1. AS = CN only✓
2. BS = 254 CN✓
3. CS = Q/A✓
4. DS = (25400/CN) − 254 mm✓

Initial abstraction Ia in SCS method is often taken as

1. A0.2S✓
2. B0.8S✓
3. Czero always✓
4. Dequal to rainfall✓

Direct runoff depth in SCS method when P > Ia is

1. AQ = P always✓
2. BQ = S only✓
3. CQ = CN✓
4. DQ = (P − Ia)²/(P − Ia + S)✓

Antecedent moisture condition AMC changes

1. Aonly wind direction✓
2. Bonly pipe material✓
3. Ceffective curve number for same watershed✓
4. Donly dam height✓

Evapotranspiration ET combines

1. Aonly groundwater flow✓
2. Bonly pipe surge✓
3. Cevaporation from surfaces and transpiration from plants✓
4. Donly sedimentation✓

Reference crop evapotranspiration ET0 is

1. AET from bare rock only✓
2. Bocean evaporation only✓
3. Csewer infiltration✓
4. DET from standardized grass surface✓

Crop coefficient Kc relates

1. Arunoff to rainfall only✓
2. Bcrop ET to reference ET0✓
3. CBOD to population✓
4. DManning n to slope✓

Pan evaporation exceeds lake evaporation because

1. Apan is always shaded✓
2. Bpan absorbs more heat and has different aerodynamics✓
3. Clake has higher albedo always✓
4. Dpan is underground✓

Consumptive use of crop is essentially

1. Aevapotranspiration minus effective rainfall plus other adjustments✓
2. Bcanal seepage only✓
3. Csediment load✓
4. DBOD removal✓

Blaney-Criddle method estimates ET using

1. Aonly groundwater head✓
2. Btemperature and daylight percentage✓
3. Conly pipe diameter✓
4. Donly concrete grade✓

Unit hydrograph is defined for

1. A10 cm rainfall always✓
2. B1 unit depth of effective rainfall over catchment for given duration✓
3. Czero rainfall✓
4. Dannual mean flow✓

Unit hydrograph theory assumes

1. Anonlinear always✓
2. Bsnowmelt only✓
3. Clinear time-invariant response for direct runoff✓
4. Dgroundwater only✓

Time base of unit hydrograph extends until

1. Arainfall starts only✓
2. Bdirect runoff essentially returns to zero✓
3. Conly peak occurs✓
4. Done hour only✓

Lag time of basin is approximately

1. Acanal design period✓
2. Breturn period 100 years✓
3. Ctime from centroid of rainfall to peak of hydrograph✓
4. Dbase period of wheat✓

Shift in rating curve after flood may result from

1. Aonly chlorine decay✓
2. Bonly coagulation✓
3. Cscour or deposition changing channel geometry✓
4. Donly wind shift✓