Sprinkler irrigation method is used where soil is erodable type and high permeable. It is also known as overhead irrigation. The sprinkler method requires a large investment in installing.

Longitudinal stress is developed along walls of cylinder in shell due to internal fluid pressure on ends. The longitudinal stress is half circumferential stress.

The boards which are made by pressing mixture of saw dust, fibres of wood and glue are known as fibre boards or pressed woods or reconstructed wood.

Hydraulic depth is ratio of wetted area to top with (T). It is denoted by D
D = A/T.

A channel is said to be most economical if it gives maximum discharge under given cross-sectional area, bottom slope and roughness. The most economical section is also known as most efficient section.

The concrete pipes are provided with mortise at one end and a suitable tenon each or and mortise and tenon are tightly set by placing concrete mortar.

Infiltration galleries are used as source of water supply. These are horizontal tunnels which are constructed through water bearing strata. They are usually laid along banks of rivers, so that water can be drawn across line of flow.

Ecology deals with study of organisms in ir natural home interacting with ir surroundings. Now ecology is often defined as study of ecosystems.

The equipment torque is twisting moment which acts along to produce maximum shear stress due to combined bending and torsion.

Energy flows through ecosystem in form of carbon-carbon bonds when respiration occurs, carbon-carbon bonds are broken and carbon is combined with oxygen to form carbon dioxide.