--- title: "Diversion type storage plant characteristics" subject: "Hydropower Engineering" chapter: 2 key: "semester_7/hydropower_engineering:diversion-storage-plant-characteristics" source: https://www.bctengineer.com/q/semester_7/hydropower_engineering/diversion-storage-plant-characteristics site: BCT Engineering --- # Diversion type storage plant characteristics Hydropower Engineering · Chapter 2: Planning of Hydropower Projects - Asked in: 2070 Ashad, 4 marks - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_7/hydropower_engineering/diversion-storage-plant-characteristics - Whole chapter: https://www.bctengineer.com/md/semester_7/hydropower_engineering/chapter-2 ## Question Drawing a neat sketch (plan and section with all components), discuss the principal characteristics of a diversion type storage hydropower plant. ## Short answer A diversion storage plant uses a dam for seasonal storage but conveys water via a pressure tunnel to a powerhouse downstream, gaining head beyond dam height. Main components: dam, intake, tunnel, surge tank, penstock, powerhouse. It provides firm year-round power, bypasses river bends, and requires environmental flow; example Kulekhani I. ## Answer A diversion-type storage plant has a dam that creates a reservoir, but the water is taken from the reservoir by a tunnel or canal and carried to a powerhouse located away from the dam, often in another valley or far downstream. This gives extra head beyond the dam height. ```text Plan Reservoir ~~~~~~~~~~~~|Dam|--Spillway ~~~~~~~~~~~~| | Intake ---->+ | \ \== Headrace tunnel ==+ Surge tank | Penstock PH --> Tailrace --> River Section FSL ~~~~|dam Intake\______ tunnel _______(ST) \ penstock \__PH ``` #### Principal characteristics - A dam stores water for seasonal regulation, so firm power is available throughout the year. - The head is the sum of the dam head and the drop gained along the river course through the tunnel; the powerhouse is not at the dam. - Main components: dam with spillway and bottom outlet, intake with trash rack and gates, headrace tunnel, surge tank, penstock, powerhouse, tailrace and switchyard. - The tunnel runs under pressure, so the river bend between the dam and the powerhouse is bypassed. The river reach between them has reduced flow (an environmental flow is required). - It needs a high capital cost and a long construction time, but gives a large capacity and good peaking. - Example: Kulekhani I (Nepal), where the Kulekhani dam forms the Indra Sarobar reservoir and the water is carried by tunnel and penstock to a powerhouse at Dhorsing, far below. Kaligandaki A has a similar diversion layout (dam, long headrace tunnel, distant powerhouse), but with only daily pondage. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What distinguishes a diversion-type storage plant from a dam-toe storage plant? A. It has no reservoir B. Water is carried by a tunnel or canal from the reservoir to a powerhouse located away from the dam C. The powerhouse is built inside the dam body D. It uses only a weir and no dam Answer: B. The dam creates the reservoir but the water is conveyed through a tunnel or canal to a remote powerhouse. (Key point: Definition of diversion type) 2. How is the head of a diversion-type storage plant obtained? A. Only from the dam height B. From the tailrace level only C. Dam head plus the extra drop gained along the river course through the tunnel D. From the pump installed at the intake Answer: C. Diverting water through a tunnel gains extra head over the dam height. (Key point: Head) 3. Why can this type of plant give firm power throughout the year? A. The dam stores water for seasonal regulation B. The tunnel increases river flow C. The surge tank stores energy D. The tailrace returns water upstream Answer: A. Reservoir storage holds wet-season water for use in the dry season. (Key point: Seasonal regulation) 4. What environmental requirement arises in the river reach between the dam and the powerhouse? A. No requirement because flow is increased B. Fish ladder only at the powerhouse C. Environmental flow must be released because that reach has reduced flow D. The reach must be fully dried Answer: C. The tunnel bypasses the river bend, so the reach has reduced flow and an environmental release is required. (Key point: Environmental effect) ## Related in Hydropower Engineering - [Development cycle; storage plant layout](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Adev-cycle-storage-layout) — Hydropower Engineering, chapter 2 - [RoR plant layouts; storage over RoR](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Aror-layouts-storage-importance) — Hydropower Engineering, chapter 2 - [Pumped storage plant and benefit to Nepal](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Apumped-storage-benefit-nepal) — Hydropower Engineering, chapter 2 - [Pumped storage plant: power, turbine, setting, surge](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Apumped-storage-turbine-surge-numerical) — Hydropower Engineering, chapter 7 - [Powerhouse plan and sections (Francis, 10 MW)](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Apowerhouse-plan-section-francis-10mw) — Hydropower Engineering, chapter 8 - [Importance of storage plants; pumped storage layout](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Astorage-importance-pump-storage-layout) — Hydropower Engineering, chapter 2 ## Related in other subjects - [Hydropower plant components and functions](https://www.bctengineer.com/question.md?key=semester_8%2Fpower_plant_design%3Ahydropower-components-functions) — Power Plant Design, chapter 3, asked 2× - [Components and layout of diversion headworks](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Aheadworks-components-layout) — Irrigation and Drainage Engineering, chapter 5, asked 2× - [Schematic of a PROR hydropower plant](https://www.bctengineer.com/question.md?key=semester_8%2Fpower_plant_design%3Apror-schematic-components) — Power Plant Design, chapter 3, asked 2× - [Short note: Pumped storage hydropower](https://www.bctengineer.com/question.md?key=semester_7%2Fenergy_environment_and_society%3Apumped-storage-hydropower) — Energy Environment and Society, chapter 5