(SEM VII) THEORY EXAMINATION 2024-25 SOIL & WATER CONSERVATION ENGINEERING

SECTION A — Very Short Answers (2 Marks Each)

a. Methods of Reducing Flood Impact

Flood embankments

Dams and reservoirs

Channel improvement

Flood forecasting

b. Vegetation Management

Use of plants and grasses to reduce runoff and soil erosion

c. Types of Soil Erosion due to Water

Sheet erosion

Rill erosion

Gully erosion

Stream bank erosion

d. Universal Soil Loss Equation (USLE)

A=R×K×L×S×C×PA = R \times K \times L \times S \times C \times PA=R×K×L×S×C×P

e. Effects of Erosion

Loss of fertile topsoil

Reduced crop yield

Sedimentation of reservoirs

Land degradation

f. Biological Methods of Soil Erosion Control

Afforestation

Strip cropping

Cover crops

Grassland development

g. Evaporation Losses

Loss of water from surface water bodies due to heat and wind

h. Aquifer

Underground layer storing groundwater

Example: Sandstone aquifer

i. Fertilizers & Pesticides

Fertilizers: Urea, DAP, NPK

Pesticides: DDT, Malathion

j. Soil Loss Estimation

Estimation of soil removed due to erosion using empirical equations

SECTION B — Descriptive Answers (10 Marks)

a. Methods of Soil Erosion Control

Mechanical methods: Contour bunding, terracing

Biological methods: Crop rotation, afforestation

Agronomic methods: Mulching, strip cropping

b. Sources of Agricultural Water Pollution

Excess fertilizers

Pesticides

Animal waste

Irrigation runoff

c. Need for Planned Utilization of Water Resources

Increasing water demand

Uneven rainfall

Prevent water scarcity

Sustainable development

d. Mechanism of Soil Erosion

Detachment of soil particles

Transportation by runoff

Deposition downstream

e. Groundwater Recharge through Wells

Rainwater directed into recharge wells

Increases groundwater table

Reduces water scarcity

SECTION C — Hydrology & Wind Erosion (10 Marks)

Hydrologic Cycle                                              Evaporation

Condensation                                                   Precipitation

Infiltration                                                        Runoff

Wind Erosion & Control

Factors:                                                           Wind velocity

Soil texture                                                      Moisture content

Control Measures:                                         Windbreaks

Shelter belts                                                    Strip cropping

SECTION D — River Engineering (10 Marks)

River Training Works                                       Embankments

Guide banks                                                    Spurs

Levees                                                             Sediment Deposition in Rivers

Deposition occurs when velocity reduces      Leads to reduced channel capacity

Causes flooding

SECTION E — Soil Erosion & Grassland (10 Marks)

Soil Erosion                                                      Removal of topsoil by water or wind

Causes:                                                            Deforestation

Overgrazing                                                      Heavy rainfall

Types:                                                              Sheet, rill, gully, wind erosion

Grassland Management                                   Controlled grazing

Reseeding                                                         Fertilization

Prevents soil erosion

SECTION F — Soil Loss & Gullies (10 Marks)

Soil Loss Estimation                                         USLE and MUSLE used

Helps in conservation planning

Modified USLE (MUSLE):                               Includes runoff volume

Gullies                                                              Deep channels formed by water erosion

Classification:                                                 Permanent

Temporary

Stages:                                                            Formation

Development                                                   Stabilization

SECTION G — Wind Erosion & Land Capability (10 Marks)

Wind Erosion                                                   Removal of soil particles by wind

Factors Affecting Wind Erosion:                  Wind speed

Soil size                                                            Vegetation cover

Land Capability Classification                          Classification of land based on suitability for agriculture

Classes I to VIII