Hydraulics & Hydrology (Civil)

Hydrology:

• Hydrologic cycle: evaporation → condensation → precipitation → runoff.
• Rainfall measurement: rain gauge.
• Runoff calculation: rational method Q = CIA.
• Hydrograph: discharge vs time.

Open Channel Flow:

• Manning's equation: V = (1/n) · R^(2/3) · S^(1/2).
• Chezy's: V = C√(RS).
• Critical depth, hydraulic jump.

Pipes vs Open Channels:

• Pipes: closed, pressurized.
• Open: free surface, gravity flow.

Irrigation:

• Methods: flow (canal), drip, sprinkler.
• Canal types: main, branch, distributary, field.
• Crop water requirement: mm/day.
• Duty & delta: Duty (D) = area irrigated per cumec; Delta (Δ) = total depth of water for full crop.
• Relation: Δ = 8.64·B/D (B = base period in days).

Dams:

• Gravity dam: resists by weight.
• Arch dam: transfers load to abutments.
• Earthen dam: soil/rock fill.
• Buttress dam: with supports.

Spillways:

• Discharge excess water.
• Types: ogee, chute, side-channel.

Hydraulic Structures:

• Weir, barrage, regulator, cross-drainage works.

Indian Major Rivers (irrigation):

• Ganga, Yamuna, Indus (Punjab).
• Cauvery (Karnataka, TN).
• Krishna, Godavari (Deccan).
• Indira Gandhi Canal (Rajasthan).

Major dams:

• Bhakra Nangal (Sutlej).
• Hirakud (Mahanadi).
• Sardar Sarovar (Narmada).
• Tehri (Bhagirathi).

RRB JE focus: open channel flow basics, irrigation types, major Indian dams.