Abstract:
The state of Punjab has a dominant agrarian economy and is considered India's bread basket. However, it is now
under the problem of falling agro-economy primarily because of pervasive depletion of groundwater levels and
deteriorating groundwater quality in south-west Punjab, but increasing salinity is a major concern. The irrigation
requirements of crops are fulfilled by groundwater and canal water but the introduction of canal irrigation has led
to waterlogging and subsequent salinization rendering large fertile-land areas becoming unproductive mainly in
the south-western part of Punjab. There was an apprehension that excessive withdrawal of groundwater might
have caused a reversal of natural groundwater flow pattern that might have caused ingress of saline water into
fresh groundwater region of central Punjab. To address the apprehension related to the rise in groundwater salinity and its subsequent ingression in the fresh-water zone and suggest suitable management solutions, a study
was undertaken to analyse the data related to salinity, isotopes, land-use and land cover (LULC) along with field
and laboratory experimental results. The depth-wise isotope analysis shows that there is a large variation in isotopic signatures of shallow and intermediate aquifers and it decreases with the depth of aquifers (150–250 m). It appears that very deep groundwater (>250 m) is relatively isolated and does not show a large variation or
mixing effect. Tritium analysis shows that dynamic groundwater is actively recharged through canal, river,
and/or rain. The presence of modern groundwater at deeper depth indicates a good interconnection between
shallow and deep groundwater. Interpretations of the results show that the canal is the main source of groundwater recharge in south-west Punjab and the evaporation process is responsible for increasing the salinity hazard. In the central parts of Punjab, groundwater and rain are the main sources of groundwater recharge, while
rain is the main source of groundwater recharge in the Kandi area. In the south-west Punjab, some primary salinity has formed as a result of mineral dissolution which has further increased due to evaporative enrichment
