(SEM VI) THEORY EXAMINATION 2024-25 RIVER ENGINEERING

BCE062 – RIVER ENGINEERING

Time: 3 Hours | Max Marks: 70

SECTION A – Short Answer Questions

(2 × 7 = 14 marks | Attempt ALL)

 Write definition + 1–2 supporting points

Important Questions with Proper Explanations

1. Classification of Rivers in Alluvial Plains

Rivers in alluvial plains are classified based on their planform as:

Straight rivers                Meandering rivers               Braided rivers                  Anastomosing rivers

2. Meandering

Meandering is the winding or sinuous path of a river formed due to erosion on the outer bank and deposition on the inner bank.

3. River Restoration

River restoration is the process of improving the physical, ecological, and hydrological condition of a degraded river to bring it closer to its natural state.

4. Time Series

A time series is a set of hydrological data such as discharge, rainfall, or sediment load recorded over regular time intervals.

5. Spur

A spur is a transverse structure extending from the river bank into the river flow to deflect the current away from the bank.

6. Objectives of River Training

River training aims to:                                      Control floods

Prevent bank erosion                                       Improve navigation

Protect hydraulic structures

7. Purpose of Groynes

Groynes are used to:                                        Control river flow direction

Reduce erosion near banks                              Promote sediment deposition

SECTION B – Medium Answer Questions

(7 × 3 = 21 marks | Attempt ANY THREE)

 Write definition → explanation → diagram/examples

1. River Morphology & Rosgen Classification

River morphology deals with the study of river shape, structure, and behavior.

Rosgen Classification classifies rivers based on:

Channel slope                                                  Sinuosity

Width–depth ratio                                           Bed material

Types: A, B, C, D, E, F, and G streams.

2. Delta Formation and Control

A delta forms when sediment deposition at a river mouth exceeds removal by waves and tides.

Control methods:                                          Channel training

Dredging                                                         Diversion channels

Protective embankments

3. Reach vs Corridor | Biologs vs Rootward

Reach vs Corridor

Reach: Short river stretch with uniform characteristics

Corridor: Wider zone including river channel, floodplain, and vegetation

Biologs vs Rootward

Biologs: Living materials like plants used for erosion control

Rootward: Root-based systems used to stabilize river banks

4. Natural Channel Design – Steps                 Site inspection

Hydrological analysis                                      Sediment analysis

Channel geometry design                              Stability check

Monitoring and maintenance

5. River Training Works

River training works include:                          Guide banks

Spurs                                                              Embankments

Levees                                                             Cut-offs

These works control flow, protect banks, and stabilize river channels.

SECTION C – Conceptual Questions

(7 × 1 = 7 marks)

1. Bed Load, Suspended Load & Wash Load

Bed Load: Moves along the river bed by rolling or sliding

Suspended Load: Carried within flowing water

Wash Load: Very fine particles that do not affect bed shape

Saltation:
Bed load particles move in a hopping manner along the bed due to flow energy (draw sketch).

2. Classification of Rivers in Flood Plains

Floodplain rivers are classified as:             Meandering rivers

Braided rivers                                            Straight rivers

Explain characteristics briefly.