Waterlogging blues of SW Punjab
By Sushil Kumar Mittal

AROUND the turn of the century, canals were constructed to divert water from various rivers in the Indus basin. This changed the agricultural complex and made the state not only surplus in foodgrains but also the largest contributor to the Central pool (60-70 per cent wheat and 40-50 per cent rice). The development of irrigation had, however, mixed blessings. As in other doabs of the Indus, waterlogging followed surface irrigation in cis-Sutlej doab too.

By 1965, the central part (fresh groundwater area) of Punjab was in the grip of waterlogging. This was suitably tackled by the state government by way of constructing drains and large scale groundwater abstraction (through private tubewells) to meet the demand of paddy crop which was introduced as a second major crop in the state. However, the groundwater continued to build up in south western (SW) Punjab where native groundwater is of poor quality.

Ever increasing rise in water table in SW Punjab brought about 63,000 hectares of land under waterlogging by 1978. The problem attained serious proportions during the period 1980-88 when about 2,00,000 hectares was severally affected by waterlogging. The crop yield of the cotton slumped down to 40 per cent. Though only temporarily, the situation was brought under some control due to poor rainfall cycle and the efforts of the state government by way of providing improved surface drainage, vertical drainage (private shallow tubewells). Even during the lean period, there was no significant change in the sum total of waterlogged areas (01.5 m) and critical areas (1.5-3 m) indicating only the fringe benefits of the various schemes.

During the year 1997-98, the menace of waterlogging again surfaced over an area of about 1,70,000 hectares which was mostly in the newly carved district of Muktsar. The magnitude of the problem was only marginally less as compared to the eighties. The estimated loss of cotton was about Rs 1200-1400 crore. As in the past, the state government again pressed its machinery into action.

Water & Power Consultancy Services India Ltd. (WAPCOS) during 1989 predicted that by the year 2000 and 2010, there will be about 5,21,000 and 7,02,000 hectares of area under critical waterlogging. Apart from traditionally waterlogged areas of the districts of Ferozepore, Faridkot, Muktsar and Mansa, the district of Bhatinda will also fall prey to the menace. Immediate preventive measures for the critical areas is the need of the hour. Past experience has shown that vertical drainage has proved most to be the effective tool in controlling the menace of waterlogging.

Prior to the introduction of surface water irrigation (1895) in SW Punjab, the depth of the water table varied from 20 to 50 metres. Prior to 1970, the water level observations are rather sparse. In general, there has been continuous rise at the rate of about 0.5 m/yr (average 1895-1963) in SW Punjab against periodical rise/fall in NE part of Sirhind canal system in a span of 20 years.

With Green Revolution (1965-66), there was steady increase in the cropping intensity (1960-61 — 126 per cent; 95-96 —185 per cent). Paddy was introduced as a second major crop in the state. The groundwater resources in the central zone of the state became over-exploited. There has been steady decline in the water table varying from 0.05 to 0.5 m depending upon hydrogeological conditions and the rainfall during that period indicating over-exploitation of the resource.

From 1982 onwards, the problem of waterlogging has attained serious proportions though there have been variations in the areal extent with the shifting of water table contours from NE to SW. During the period from 1980-82, many parts of the then district of Faridkot (including Mukatsar) were in the grip of waterlogging threatening the buildings and agricultural production in the state. There was shift from cotton to paddy in the waterlogged areas. Amongst other measures, vertical drainage through farmers private tubewells proved to be effective. Thereafter, from 1992 to 1995, the situation was under control largely being a dry cycle and increase in number of shallow tubewells in district Faridkot from 33,000 (1978-79) to over 1,00,000 (1996-97). It is noteworthy to mention that even during the lean period, there was no significant change in the sum total of the actually waterlogged and the potential area for waterlogging (critical area). It is a sensitive situation. During the 1997 episode, because of the heavy monsoon rainfall, it was only the potential area for waterlogging that was added to the kitty of waterlogged area causing havoc. The situation since 1982 has been critical and reduction in the area has been only a border-line case of waterlogging. Monsoon is the key factor in spread of waterlogging conditions.

The area is the cotton belt of the state and produces about 22 per cent of the cotton in the country. Cotton is the main Kharif crop and wheat is the Rabi crop. Waterlogging conditions have not only severally affected the crop yield of cotton but also forced the farmers to shift to paddy (25 per cent in district Muktsar alone during 1998-99). During 1983-84, the average yield of the cotton drastically came down to 40 per cent (compared to 72-73) in district Ferozepore and 47 per cent in district Faridkot (including district Mukatsar). It touched as all time low during 1997-98 to the tune of 32 per cent, 41 per cent and 57 per cent in district Faridkot, Mukatsar and Ferozepore, respectively.

The native groundwater in SW Punjab is saline. However, as a result of continuous seepage from surface irrigation system and subsequent rise in water table, there was marked improvement in the quality of groundwater at shallow depths. As a result, the fresh water floats over the saline water. However, there are frequent variations in the chemical quality depending upon the thickness and extent of impermeable (clay) layers. To avoid up coning of the saline water, 3/4 filter points joined together to a single pumping unit should be preferred.

Rainfall, seepage from surface irrigation system and surface bodies are mainly responsible for waterlogging. From 1948-97, wet rainfall cycle has been experienced. Similarly, widespread network of Sirhind canal system, Sirhind; Rajasthan and Ferozepore feeders, Bikaner and eastern canals are significantly contributing to the waterlogging. On an average, 33 per cent of the water let in at head goes into the sub soil. The duty allowance of water has also steadily increased with the construction of Bhakra canal system and Harike barrage. The water allowance in the command area of eastern canal is the highest in the state (5.5 cs/1000 acre) at the outlet head. In other parts, it is about 3.05 cs/1000 acre.

Remedial measures to be adopted must be area specific depending upon topographical, hydrological set up.

Tubewell drainage (vertical drainage) has been by far the most effective tool in meeting the challenge. In order to exploit the fresh water at shallow depth, multiple filter points joined together are most successful in lowering the water table. Groundwater should be preferably used in rotation with canal water. Additional requirement of water for the paddy crop should be met with from groundwater itself. According to a study, the shift from cotton to paddy implies 52 per cent reduction in the area by the same quantity of water. As an incentive, the Punjab government is already in the process of releasing 2000 energy connections for tubewells in the waterlogged area.

Effectiveness of the direct irrigation tubewells in lowering the water table have its own limitations vis. availability of the canal water for conjunctive use and up coning of the saline water. Alternatively, a battery of tubewells along major canals/distributaries in the area and groundwater mixed in a proper ratio. This will avoid any after- effects of the use of mixed water like salinisation. The Punjab government have already initiated a programme of installing 500 tubewells along right bank of Sirhind feeder. Conceptually, it is a serious effort but the distance of the tubewells from the canal (about 250 feet) is in itself a question mark on the effectiveness of the proposal. By way of reference, it may be added that similar schemes were implemented in Rechna doab and tubewells were installed at a distance of 600 feet from the canal.