Conjunctive Use of Ground Water & Surface Water, A Case Study of Nepal

Abstract

Major problem of the developing country is to maintain the food deficit for the people who are suffering for their survival. It is challenge to cope with the increasing population and decreasing the agricultural land. For high level production, it is requirement of government for making policy for the best agricultural technology with proper management of all vital factors e.g. Modern seeds, Pesticides, Herbicides, Proper Management of Irrigation, and Sound Institution. In our case, we have taken Narayani Irrigation System for studies with implementing the Conjunctive Use of Surface and Ground Water. There is vast changing in climate and it is major issue worldly affecting the natural environment and monsoon. So, the available surface water is also affected day by day gradually. At present, project is facing with the deficit of water for existing cropping pattern in culturable command area. The command area is potential for the good source of groundwater. So, we have studied the data of project and calculated the fulfillment of water demand by the use of deep tubewell to maintain smoothly the water demand for the cropping pattern that is liked by most farmers. We have calculated the Cost Benefit Ratio and External Rate of Return to compare the beneficial situation after the selection of conjunctive use in project area. There are 15 Blocks in which only 12 Blocks are under operation. So, we have taken 1-12 Blocks to study the conjunctive use. For continuous process of maintaining the irrigation system, it is important to maintain the ground water recharge. Ground water Recharge Shallow aquifer and permeable alluvium has been recharging directly from the source of rainfall and infiltration from river. Infiltration rate is decreasing toward the southern from the study area. Seepage from lake and pond, water from the irrigational return, and precipitation are the main source of recharging the aquifer. In rainy season, aquifer became fully recharged and any additional creates the flooding of the area. So, site is very proper to be recharged to store the extra surface water. Thus, the management technique using conjunctive use is suitable to fulfill the demand of irrigation water to the farmers.