Decline of groundwater tables in the upper Yamuna basin: causes and management strategies.

摘要

Amongst the three drainage basins in Haryana (India), the upper Yamuna and upper Ghaggar basins are experiencing groundwater table declines in good quality aquifers. Rice-wheat crop rotation widely adopted in this region is blamed for this situation. A number of groundwater regime maps were prepared to assess long-term groundwater table behaviour in these basins. The water levels during the past three decades (1974-2004) registered an annual decline varying from 30 to 60 cm. The analysis revealed that a saving of 15 cm of water in rice-wheat cropping would be able to halt the declining groundwater table. The rainfall data of Kurukshetra district for the period (1974-2004) revealed that most surface drainage surplus could be used as additional surface storage in rice fields and for groundwater recharge. Evapotranspiration calculated using the FAO CROPWAT model revealed that the evapotranspiration (ET) of the short duration crop is about 88% of the normal rice crop (transplanted on 20 June), although its duration from transplanting to maturity is almost half of the normal rice crop. Similarly, the ET of the crop transplanted one month in advance of the normal rice crop is 25-30% more. It is believed that these two aberrations aggravated the groundwater table situation more than the rice-wheat cropping itself. The review through a desk study identified a number of management strategies that could help to save 15 cmor even more water in the rice-wheat system. It is concluded that it should be possible to sustain groundwater irrigation even with rice-wheat cropping (without aberrations) at the current level in these parts of the basins.