Techno-Market Survey on Adaptation of Irrigation Canals for Navigation ( Transportation)

1. Introduction

Transport infrastructure is one of the key elements in the growth of any economy. India has a vast network of irrigation canals. There exists possibility of exploiting these man-made waterways for providing transport capacity – which is being dealt with in this Techno-Market Survey. The Scope of Work outlined by TIFAC, is given in Annexure 1.1.

2. Approach and Methodology

The data collection for the study has been done by extensive interviews and field work with related institutions and experts, reference to research work, expert reports and other relevant literature.

The report evolves cut-off criteria in terms of irrigation canal parameters for determining the navigability or otherwise of canals based o various (i) Technical considerations like suitability of cross sections, side slopes, canal lining, discharges, velocity of flow, cross-drainage structures etc., and the likely impact of forces generated by ships’ motion, and (ii) cost and economics (Chapters 3 – 6).

Conclusions on navigability have been drawn on a number of major canals in India. Indira Nahar and Narmada Canal have been taken-up for more detailed study (Chapter 7).

3. Irrigation Canal: Design Principles in India

A quick review of broad irrigation design principles in India can help gauge the technical inputs required for adaptation for navigation.

The basic inputs to design of an irrigation canal system are agricultural characteristics and demand pattern of water in the command area. Usually the canal alignment follows the ridge line in the command area for ease of flow using gravity on either side.

An irrigation system consists of a hierarchical network of canals, starting with head-works, main canal, branch canals, major and minor distributaries. The water losses in an irrigation system largely accrue from seepage (which is much higher in unlined canals) and evaporation.

The general design steps followed for design of an irrigation canal system in India are:

a. Determine the water demand patter of the command area, and availability of water.

b. Determine the alignment.

c. Based on required discharges and the alignment, determine the cross sectional parameters, bed slope(s) and velocity of flow at various places using continuity equation and fluid flow equations.

d. Factors like characteristics of canal lining and corresponding rugosity coefficient are used along with the above equations to arrive at critical velocity, coefficient.

The final design is an iterative process (Chapter 3).                                                                                                 Back