Irrigation Water Management: Training Manual No. 6 - Scheme Irrigation Water Needs and Supply

Table of Contents

Provisional edition

a manual prepared jointly
C. Brouwer,
J.P.M. Hoevenaars
B.E. van Bosch, Consultant

International Institute for Land Reclamation and Improvement (ILRI)

N. Hatcho
M. Heibloem
FAO Land and Water
Development Division

Drawings by J. van Dijk, The International Institute for Land Reclamation and Improvement, Wageningen, The Netherlands

Photographs by B.E. van den Bosch, Consultant and FAO Photo Library.

The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying or otherwise, without the prior permission of the copyright owner. Applications for such permission, with a statement of the purpose and extent of the reproduction, should be addressed to the Director, Publications Division, Food and Agriculture Organization of the United Nations, Viale delle Terme di Caracalla, 00100 Rome, Italy.

© FAO 1992

This electronic document has been scanned using optical character recognition (OCR) software and careful manual recorrection. Even if the quality of digitalisation is high, the FAO declines all responsibility for any discrepancies that may exist between the present document and its original printed version.

Table of Contents



1.1 Relationship of this manual to foregoing training manuals
1.2 Some definitions
1.3 Summary of the manual


2.1 Introduction

2.1.1 Water sources
2.1.2 Water availability
2.1.3 Methods of tapping water from water sources

2.2 Rivers

2.2.1 Introduction
2.2.2 Tapping water from rivers
2.2.3 Availability of river flow

2.3 Reservoirs and lakes

2.3.1 Introduction
2.3.2 Water availability in lakes and reservoirs
2.3.3 Water tapping from a reservoir

2.4 Groundwater

2.4.1 Introduction
2.4.2 Groundwater availability
2.4.3 Pumping from wells


3.1 Introduction
3.2 The Approximate Method
3.3 Cropping Pattern
3.4 The Calculation Method

3.4.1 Scheme irrigation need for a simple cropping system
3.4.2 Scheme irrigation needs for a multiple cropping system
3.4.3 Determining the irrigation need for a rice-based cropping pattern

3.5 Converting from SINnet to SINop


4.1 Introduction
4.2 Command Area
4.3 Matching SINgross, and SWS

ANNEX I.1 Diagram to show the calculation of SINgross

ANNEX I.2 Diagram to show the matching of need and supply

ANNEX II Conversion table of mm/day into l/s/ha

ANNEX III.1 Data sheet 1: Determination of net scheme irrigation need for a single cropping system

ANNEX III.2 Data sheet 2: Determination of net scheme irrigation needs for a multiple cropping system

ANNEX III.3 Data sheet 3: Determination of net scheme irrigation need for rice

Suggested further reading