Development cycle; RoR layout with headrace canal

Phases of the hydropower development cycle

1. Reconnaissance: Desk study and site visit to identify and rank the sites; rough cost and energy.
2. Pre-feasibility: Survey, hydrology and geology at a moderate level; compare alternative layouts; select the best.
3. Feasibility: Detailed investigation, design optimisation, cost (±10-15%), economic and financial analysis, IEE/EIA.
4. Detailed design and tendering: Final drawings, specification, tender documents, contract.
5. Construction and commissioning: Build and test the plant.
6. Operation and maintenance: Run, maintain and monitor.

Layout of RoR plant with headrace canal

Plan
 River~~~~~  Weir             Canal
 ~~~~~~~~~~~|Intake=Desander===========\
 ~~~~~~~~~~~                            \ Forebay
                                          \ Penstock
                                            PH -> Tailrace
                                               -> River
Section along waterway
 weir  intake desander    canal (slope 1:1000)  forebay
 __|~~~|__ __ ___________________________________|
                                               \ penstock
                                                  \__PH

Main components: diversion weir with undersluice, intake with trash rack, gravel trap, settling basin (desander), headrace canal with cross-drainage works, forebay with spillway and trash rack, penstock, powerhouse, tailrace and switchyard. The canal is laid along the contour at a small slope so that most of the gross head is kept for the penstock.