ScienceDirect Developments to improve hydraulic ...

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INTERNATIONAL CONFERENCE ON WATER RESOURCES, COASTAL AND OCEAN ENGINEERING (ICWRCOE 2015)

Developments to improve hydraulic competence of spillways Harinarayan Tiwaria,* , Nayan Sharmaa a

Department of Water Resources Development & Management, Indian Institute of Technology Roorkee, India, 247667

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Dams whose collapse could cause loss of life or huge assets damage are considered to survive a probable maximum flood (PMF), but the PMF in various locations has been amplified at regular intervals, resulting in spillways that no longer convene the proposed norms. Spillway rehabilitation is required for lots of dams in India; in order to get better hydraulic competence. Catastrophe in Uttarakhand (June 2013) necessitates the research aspect of spillway rehabilitation. Increasing specific flow form hydraulic structures is one of the thought of spillway rehabilitation. Labyrinth weir may be used for amplifying specific flows of existing spillway. Sediment trapping behind Labyrinth weir might be one of the disadvantages for river with high sediment flow. The Piano Key Weir (PKW), ramped type Labyrinth weir is a hydraulically attractive alternative to linear overflow weirs, increasing the unit discharge for similar heads and spillway widths. This advantage allows operating dam reservoirs on an increased level and provides thereby an enhanced retention volume. It is a result of the non-linear nature of PKW being folded back and forth to make repeated cycles or keys. This type of weir is particularly suitable for sites where topographic conditions limit the extent of its width. Together with its high discharge capacity for low heads, this geometry makes these weirs interesting in spillway rehabilitation. This paper investigates the recent developments to improve hydraulic competence of spillways. Head reduction over crest can improve efficiency as well as reduce submergence. This study shows that for increasing discharge, head reduction with respect to conventional rectangular weir is reducing but reduction was found above seventy percent for all the experiments  © 2015 The Authors. Published by Elsevier B.V.  Peer-review under responsibility of organizing committee of ICWRCOE 2015.  Keywords: Dam; Spillway; Labyrinth weir; Piano Key Weir; Specific Flow

* Corresponding author. Tel.: +91-7669298985. E-mail address: [email protected]

   