and results in low yields* 2 This is also caused hy over-irrigation.
Like the practice of submerging crops, over-irrigation is a consequence of the uncertainty of water supply. Low water rates and the existing system of distributing irrigation water are also factors making for the indiscriminate use of water. 3 Waterlogging has been observed in all the major irrigation works
The above description indicates that both the inadequate length Of canals and seepage of water from them lead to uncertainty of water supply under a system of canal irrigation. 5 Control of water has two aspects
1 Most irrigation water contains about -g- to 3 tons of salt per acre-foot.
(An acre-foot of water is the amount of water that will stand a foot deep on an acre of land assuming that there is no percolation.) In the absence of proper drainage the water-table rises and the subsequent evaporation of saline water results in large quantities of salt being deposited in the root zone. This injures the rice crop, Carter,L.M.
A World Geography of Irrigation, Oliver and Boyle, Edinburgh, 1970, P 48.
2 Report of the Irrigation Commission. 1972. Vol. I, op.cit., p 109.
3 Hoon,R.C. 'Interaction between Irrigation and Drainage,' in Symposium on Irrigation and Drainage, op.cit.. pp 70-78| for the impact of low water rates on over-irrigation see, Anon, 'Interaction between Irrigation and Drainage, ibld.g p 17*
4 Evaluation of Ma.ior Irrigation Pro.iects. op.cit., p 14* No regular statistics is maintained regarding the waterlogged areas in India and the rate of their increase. Generally speaking, the problem is more acute in the Indo-Gangetic plains which have bad slopes.
5 In Peninsular India, except for isolated areas in the Deccan canal area, water-logging is not a serious problem of good drainage,
Ahuja,P.R. & Rao,P.S. 'Importance of Investigation in Planning Anti- Waterlogging Scheme,' Central Board of Irrigation and Power,
Symposium on Inter-relationship between Irrigation and Drainage, Publication No*72, New Delhi, 1972, pp 32-33*
(l) control over the total volume of water that is required for a crop in a given season and (2) the ability to apply this amount in varying quantities according to the water requirement of the crop at different stages in the growth cycle. While the system of canal irrigation possess, on the whole, some degree of controllability of the first type, in the sense that the supply of water is more certain than under rain-fed
conditions, there is no means of exercising control of the second type.'*' For this purpose we need highly developed procedures and equipment for measuring water supply such as meters, division boxes for dividing water into streams, weirs, control gates, etc. In effect, it means the replacement of the supply of water on an area basis by that on a
volumetric basis. We come full circle here because irrigation on an area basis was adopted, following the recommendations of the First Irrigation Commission, on account of the difficulty of supplying water on a volumetric basis* The chief argument advanced by the Commission, a propos the fixation of water rates on a volumetric basis, was the prohibition cost of installing water meters on a large number of small farms. 2 Ansari, in a reconsideration of the Commission's arguments,
1 This is not to suggest that water is released from canal outlets without regard for the duration of crop* In the Tungabhadra Project, paddy is sown in April and is harvested in mid-January.
The crop receives water for three and a half months, the dis
tribution of water during this period being 15 waterings at
a depth of 3 inches per watering, Evaluation of Major Irrigation Projects, op.cit*. p 90? Report of the Irrigation Commission. 1972, op.cit.. pp 187-189*
2 For a summary of the Commission's objections to volumetric charging see Ansari,N. Economics of Irrigation Rates - A Study in Punjab and TJttar Pradesh. Asia Publishing House, London, 1968, pp 110-111.
While admitting th&t the chief obstacle is the cost of installing
devices for the measurement of water on farms, observes that sufficient experimentation has not been done in this field.^ Perhaps this was due to the preoccupation with the fixation of water rates on a volu
metric basis rather than the measurement of water supply per se* It is to be hoped that with the increasing recognition of the need for controlled irrigation in the cultivation of HYV, the latter aspect of irrigation will receive more attention* Volumetric control, and
indeed, volumetric charging is operative in the case of state tube-wells*
Both types of control of water supply are required to grow HYV rice successfully* The first type can be achieved by the irrigation authorities undertaking the construction of channels themselves and not leaving it to individual cultivators and by state governments passing and enforcing legislation regarding the acquisition of lands for the
3
construction of canals* To the extent that uncertainty of water supply is due to loss of water through seepage, the lining of canals and
channels will lead to assured water supply on the farms* If the un
certainty of water supply is due to loss of water through seepage,
1 AnsarijN. Economics of Irrigation Rates - A Study in Punjab and Uttar Pradesh, op.cit*, pp 110-111*
2 Government of India, Programme Evaluation Organisation, Study of the Problems of Minor Irrigation* Publication No. 4-0, New Delhi, 1961, pp 149-151.
3 The alternative here would be to reduce the size of the cultural command area as suggested by the authors of the Report on Measures to Accelerate Utilisation of Irrigation Water* op.cit** pp 2-3*
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