--- title: "Intake components and site factors" subject: "Water Supply Engineering" chapter: 5 key: "semester_5/water_supply_engineering:intake-components-site-factors" source: https://www.bctengineer.com/q/semester_5/water_supply_engineering/intake-components-site-factors site: BCT Engineering --- # Intake components and site factors Water Supply Engineering · Chapter 5: Intakes - Asked in: 2072 Kartik, 8 marks - Video: [Types of Intake Structure - Water Supply and Distribution of Water - Environmental Engineering 1](https://www.youtube.com/watch?v=RrtbXAqmyIo) — Ekeeda - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_5/water_supply_engineering/intake-components-site-factors - Whole chapter: https://www.bctengineer.com/md/semester_5/water_supply_engineering/chapter-5 ## Question What are the components of an intake? Enlist and discuss the factors governing the site selection for an intake. ## Short answer Intake components include the intake port with bell-mouth entry, coarse and fine screens, intake well or tower housing gates and valves, conveying pipe to the plant, sump or pump well for pumped schemes, access footbridge, and protection works like pitching and scour pipe. Site selection factors are water quantity and quality, stable bank and bed, adequate depth, flood safety, sound foundation, navigation clearance, distance and elevation to plant, accessibility, and freedom from ice and heavy silt. ## Answer #### Components of an intake 1. **Intake opening / port** with a bell-mouth entry, placed at one or more levels. 2. **Coarse screen (trash rack)** with bars 20 to 50 mm apart to stop large floating objects, and a **fine screen** (6 to 12 mm mesh) to stop small debris. 3. **Intake well / tower / chamber** that houses the gates and valves and lets water settle. 4. **Sluice gates / valves** to regulate or cut off flow. 5. **Conveying (intake) pipe or conduit** from the well to the pump house or main. 6. **Sump or pump well** (for pumped schemes) and a **foot bridge** for access. 7. **Protection works**: pitching, groynes, wing walls, embankment, guard rails, and a **flushing / scour pipe** for removing silt. #### Factors governing the site selection 1. **Water quantity**: the source must give the design flow even in the driest season; the minimum flow must exceed the demand. 2. **Water quality**: the site should be upstream of towns, sewage and industrial discharges, and away from tributaries that bring silt or pollution. 3. **Stable bank and bed**: choose a stable, non-eroding reach, preferably on the concave (outer) side of a bend where the water is deep and the current scours silt away. 4. **Depth of water**: enough depth at all stages so the intake port stays submerged at low water. 5. **Flood level**: the structure must stand above the highest flood level (HFL) or be safe against it, and the site should be free from flood and drift damage. 6. **Foundation**: sound strata for the foundation of the intake tower and pipes. 7. **Navigation**: the site must not obstruct navigation and should not be in a navigation channel. 8. **Distance and elevation**: close to the treatment plant and consumers (shorter pipeline, lower cost); for gravity schemes, enough head. 9. **Accessibility**: access for construction, inspection and maintenance in all seasons, and nearness to power for pumping. 10. **Future expansion** and **ownership of land/legal rights** at the site. 11. **Ice and silt**: the site should not be affected by ice formation or heavy sedimentation. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What bar spacing has the coarse screen? A. 20 to 50 mm B. 1 to 2 mm C. 100 to 200 mm D. 6 to 12 mm Answer: A. Fine screen is 6 to 12 mm mesh. (Key point: Trash rack) 2. What does the conveying pipe do? A. Screens debris B. Stores silt C. Carries water from well to pump house or main D. Measures flow Answer: C. It links intake well to the next unit. (Key point: Conveying) 3. Source quantity requirement? A. Any B. Flood exceeds demand C. Minimum flow exceeds demand D. Average exceeds demand Answer: C. Must supply in driest season. (Key point: Water quantity) 4. Why close to the plant? A. Larger floods B. Navigation C. Shorter pipeline, lower cost D. More silt Answer: C. Distance affects cost and head. 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