JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III ENVIRONMENTAL ENGINEERING Previous Question Paper (October - 2020 - R16)

Intake works are hydraulic structures used to collect water from a surface source such as a river, lake, or reservoir and convey it to the treatment plant. Their primary function is to provide a continuous supply of water while excluding suspended matter, ice, and debris.

Types of Intake Works:

• River Intakes: Constructed along the banks of rivers to draw water directly from the flowing stream.
• Lake Intakes: Usually located at a distance from the shore to draw water from deeper, cleaner zones.
• Reservoir Intakes: Similar to lake intakes but designed to accommodate significant fluctuations in water level.
• Canal Intakes: Simple structures built on canals to draw water for irrigation or municipal supply.
• Spring Intakes: Designed to collect water from natural springs by creating a collection basin around the spring outlet.

River Intake Description:

A typical river intake consists of an intake well located near the bank, connected to the river through an intake pipe or conduit. The intake opening is protected by a coarse screen to prevent large debris, logs, or fish from entering. A gate valve is provided to control the flow, and the entire structure is often protected by a masonry or concrete pier. The intake well is usually divided into two compartments: one for the intake pipe and another for the suction pipe of the pump, separated by a fine screen to further filter the water.

Sketch Description:

Imagine a river cross-section showing the bank and the water level. A concrete intake well is built into the bank. An intake pipe extends from the well into the river, submerged below the lowest water level, with a bell-mouthed entry protected by a coarse screen. Inside the well, a fine screen separates the inlet side from the pump suction side. A pump house is located above the well, housing the pumping machinery that lifts the water to the treatment plant. The structure is reinforced to withstand the hydraulic pressure and the scouring action of the river current.

To estimate the population for 2021 and 2025, we use the Incremental Increase Method, which provides a more reliable estimate than the Arithmetic or Geometric methods by accounting for the changing rate of growth.

Calculate the average increase (x̄) and average incremental increase (ȳ):

The formula for population estimation is P_n = P₀ + n(x̄) + [n(n+1)/2]ȳ, where P₀ is the population in 2011 (225,000) and n is the number of decades.

For 2021 (n=1):

For 2025 (n=1.4):

The estimated populations for 2021 and 2025 are 268,250 and 287,230 respectively.