Hydropower development in Himalayan region - SWOT approach of hydraulic factors

The increase in irrigation potential through the construction of major and medium dams along with the network of canal systems for water distribution gave the food security but there was unintended fallout in the form of water logging and salinity. These two problems (water logging and salinity) have now become perpetual in nature and their aerial extent is increasing over the years with no action plan to mitigate them other than selective improvement of drainage system. The problem of water logging was first noticed in 1850 in West Yamuna Canal area and in 1884 in Nira Irrigation Project area, clearly indicating that the water logging problem is inbuilt with the irrigation projects which result because of seepage from lined/unlined carrier channels, applied irrigation & overuse of surface water, less utilization of groundwater than its annual recharge and in some cases because of the presence of sub surface lithology dominated by clay matrix. The areas under water logging was estimated by CGWB in 1999 and observed that areas in Punjab, Haryana, UP and Rajasthan covers 1.05 lac sq km and salinity in about 1.45 lac sq km (data requires updating) showing the seriousness of the problem which has converted large area non productive. Earlier estimates indicated water logging, salinity and alkalinity cover about 14,250 sq km, 30,694 sq km ad 12,780 sq km respectively under irrigation projects. The conjunctive use of surface water and groundwater (fresh or saline) is being adopted by a number of countries for achieving proper irrigation returns and solving problems of water logging. Moreover, conjunctive use is likely to be critical and a necessary option as water resource adaptation measure under the projected impact of climate change and recovering vital fertile areas for food security.