hydrology past question analysis 2014-2025

Question 1 — Introduction to Hydrology & Precipitation

Part (a)

Topic	Freq	Years Asked
★★★ What is hydrology? Scope & applications	9	2019S, 2018F, 2018S, 2017F, 2016F, 2015F, 2014F, 2013S, 2012F
★★ Hydrological cycle with neat sketch	8	2019S, 2017F, 2016S, 2016F, 2015S, 2014S, 2013F, 2012F
★ Engineering uses/applications of hydrology	5	2019F, 2018S, 2015S, 2014S, 2013S
Water balance equation	3	2016S, 2015F, 2013F
Impact of hydrology in water resources projects	2	2017F, 2019F

Part (b)

Topic	Freq	Years Asked
★★★ Estimate missing rainfall data (Normal Ratio Method)	7	2019F, 2016S, 2016F, 2015S, 2014S, 2013S, 2012F
★★ Calculate optimum number of rain gauges	6	2016S, 2016F, 2015S, 2014S, 2013S, 2012F
★ Evaporation calculation from reservoir water balance	4	2019F, 2018F, 2015S, 2013S
Factors affecting evaporation & transpiration	3	2019F, 2016F, 2014F
Describe PET and AET	2	2019F, 2016S
Withdrawal rate from reservoir calculation	2	2019F, 2015F

Question 2 — Precipitation Analysis

Part (a)

Topic	Freq	Years Asked
★★★ Methods of computing average rainfall over catchment	8	2019F, 2018S, 2017F, 2016F, 2015S, 2014S, 2013S, 2012F
★★ Thiessen polygon method — calculate average precipitation	7	2018S, 2017F, 2016S, 2016F, 2015F, 2014S, 2013S
★ Orographic/precipitation phenomena in Nepal/Himalayas	4	2018F, 2017F, 2014F, 2013F
Types of rain gauges / recording rain gauges	3	2019F, 2014S, 2013S
Isohyetal method for mean precipitation	2	2016F, 2014S

Part (b)

Topic	Freq	Years Asked
★★★ Double mass curve — test consistency of rainfall data	11	2019S, 2019F, 2018F, 2017F, 2016S, 2016F, 2015S, 2014S, 2013S, 2013F, 2012F
★ Working of weighing bucket rain gauge	3	2017F, 2014F, 2013F
Explain recording type rain gauges	2	2019F, 2013S
Plot hyetograph from rain gauge data	2	2019F, 2017F

Question 3 — Runoff, Infiltration & φ-Index

Part (a)

Topic	Freq	Years Asked
★★★ Calculate φ-index from storm rainfall & runoff data	12	2019F, 2019S, 2018S, 2017F, 2016S, 2016F, 2015S, 2015F, 2014F, 2014S, 2013S, 2012F
★★ Estimate runoff from storm with φ-index given	5	2017F, 2016F, 2014F, 2013F, 2012F
★ Factors affecting evapotranspiration	4	2016F, 2015S, 2014S, 2013S
Define PET and AET	3	2019F, 2016S, 2015F
Calculate runoff coefficient	2	2016F, 2015F

Part (b)

Topic	Freq	Years Asked
★★ Catchment & meteorological factors affecting runoff	5	2019S, 2017S, 2016F, 2015S, 2012F
★ Penman's equation for evapotranspiration	4	2017F, 2016S, 2015F, 2012F
Explain initial losses in hydrological cycle	2	2019S, 2016F
Significance of calculating PET and AET	2	2014S, 2013S

Question 4 — Stream Gauging & Discharge Measurement

Part (a)

Topic	Freq	Years Asked
★★★ Define stream gauging / site selection for gauging station	7	2019F, 2018S, 2016S, 2015F, 2014S, 2013S, 2012F
★★ Rating curve — significance & uses	6	2019S, 2019F, 2016S, 2015S, 2015F, 2013F
★ Salt dilution (tracer) method vs current meter	4	2016S, 2016F, 2014S, 2013S
Float gauging & bubble gauge for stage measurement	2	2019F, 2015F
Different methods of stream gauging	2	2017S, 2012F

Part (b)

Topic	Freq	Years Asked
★★★ Current meter discharge — area velocity method (V = aN + b) [MOST REPEATED]	15	2019S, 2019F, 2018F, 2018S, 2017F, 2017S, 2016S, 2016F, 2015S, 2015F, 2014F, 2014S, 2013S, 2013F, 2012F
★ Slope-area method for discharge estimation	3	2019F, 2017F, 2012F
Mid-section method of computing discharge	2	2016S, 2015F
How is average velocity over vertical determined	1	2016S

Question 5 — Unit Hydrograph Theory

Part (a)

Topic	Freq	Years Asked
★★★ What is unit hydrograph? Uses, assumptions & limitations	10	2019F, 2018S, 2017S, 2016S, 2015S, 2015F, 2014S, 2013S, 2013F, 2012F
★★ Derive unit hydrograph from storm hydrograph	5	2016S, 2016F, 2014S, 2013S, 2012F
★ S-curve method — derive n-hr UH from m-hr UH	4	2017F, 2016S, 2015F, 2013S
Plot unit hydrograph from given ordinates	2	2019F, 2015F
Estimate peak flow from unit hydrograph peak	1	2018F

Part (b)

Topic	Freq	Years Asked
★★★ Apply UH — two successive storms / flood hydrograph	11	2019F, 2019S, 2018S, 2017F, 2016S, 2015S, 2015F, 2014S, 2013S, 2013F, 2012F
★★ Superposition method — derive longer duration UH	5	2018S, 2017F, 2016F, 2014F, 2012F
★ 4-hr DRH for rainfall with φ-index	3	2017S, 2016F, 2013F
Estimate peak flow & time from compound storm	2	2019F, 2015F

Question 6 — Flood Frequency & Estimation

Part (a)

Topic	Freq	Years Asked
★★★ Gumbel's method — calculate T-year flood	14	2019S, 2019F, 2018F, 2018S, 2017F, 2017S, 2016S, 2016F, 2015S, 2015F, 2014S, 2013S, 2013F, 2012F
★★ Confidence limits for design flood (80%, 90%)	4	2019F, 2017F, 2016F, 2012F
★ Empirical methods — Modified Dicken's, WECS/DHM	6	2019F, 2018S, 2017F, 2016F, 2015S, 2014S
Return period & reliability calculation	3	2019F, 2019S, 2015F
Define return period, frequency, risk	2	2017S, 2013F

Part (b)

Topic	Freq	Years Asked
★★ WECS/DHM method for ungauged rivers in Nepal	5	2019F, 2018S, 2017F, 2016F, 2013S
★ Frequency & probability concepts in flood studies	3	2017F, 2016F, 2014F
Log-Pearson Type III distribution	2	2018F, 2016S
Why recharging groundwater is required	1	2012F

Question 7 — Short Notes (Any Two, 2×5 = 10 Marks)

Topic	Freq	Years Asked
★★★ WECS/DHM method for flood estimation	8	2019F, 2018S, 2017F, 2016F, 2015S, 2014S, 2013S, 2012F
★★★ Base flow separation methods/process	7	2019S, 2018S, 2017F, 2016S, 2016F, 2015F, 2014S
★★ Types of aquifers / aquifer characteristics	5	2017S, 2015S, 2014S, 2013S, 2012F
★★ Infiltration indices (φ-index, W-index)	4	2016S, 2016F, 2014S, 2013S
★★ Rating curve development and uses	4	2019S, 2016S, 2015F, 2013F
★ Potential & actual evapotranspiration (PET/AET)	4	2019F, 2017S, 2015F, 2014F
★ Risk, frequency & return period	3	2019S, 2017F, 2016F
★ Pump test in groundwater	3	2017S, 2015S, 2012F
Slope-area method for discharge	3	2017S, 2014S, 2012F
MIP (Medium Irrigation Project) method	3	2019F, 2016F, 2014F
Double mass curve technique	2	2016F, 2015S
IDF (Intensity-Duration-Frequency) curve	2	2018F, 2017F
Hydrologic cycle components	2	2016S, 2014S
Recording charts of rain gauges	2	2016S, 2014S
Dilution techniques for discharge	2	2016S, 2015F
Single & double ring infiltrometers	1	2019S
Float gauge for stage measurement	1	2015F

Ultra High-Priority Topics (10+ Times)

Topic	Frequency
Q1b: Calculate optimum number of rain gauges & estimate missing rainfall	7 each
Q2b: Double mass curve for consistency check	11
Q3a: Calculate φ-index from rainfall-runoff data	12
Q4b: Current meter discharge calculation using V = aN + b [MOST REPEATED]	15
Q5a: Unit hydrograph theory — definition, uses, assumptions, limitations	10
Q5b: Apply UH to successive storms / derive flood hydrograph	11
Q6a: Gumbel's extreme value method for flood estimation	14