Assessment of water availability, drainage and irrigation problems in some selected locations of Pabna district

Abstract

The present study area Pabna sadar and Sujanagar upazilas of Pabna district which are not covered by the BWDB catchment delineation and there are no hydrological stations within this area. People of this area faces various problems like water logging, crop loss, drainage congestion, irrigation problems, scarcity of water during dry season etc. since several decades. Therefore, there is need to conduct studies on water availability, drainage and irrigation condition. The study tried to assess water availability, drainage and irrigation problems based on recent and available data in a simple as well effective method. Assessment of surface water availability has been carried out by developed a rainfallrunoff and hydrodynamic model by using MIKE 11 for the period of 2001-2009. The overall model has been developed considering historical rainfall data of 5 stations within the study area and 3 hydrological stations on Padma and Jamuna River. At the outset MIKE 11 rainfall-runoff model has been calibrated by observed and simulated ground water depth for the year 2004 and hydrodynamic model by 2004 flood satellite image. The people of the area are dependent on the ground water for their domestic and irrigation purposes. CROPWAT 8.00 has been utilized to carry out the total present irrigation water requirement of the study area. Utilizing evapotranspiration (ET0), effective rainfall, precipitation, crop coefficient and cropping pattern, the field irrigation water requirement (FIWR) for each crop was calculated. ET0 has been estimated by 30 years average weather data. On the basis of population projection by geometric progression method and per capita water demand, the domestic and municipal water requirement has been estimated. Abstraction was calculated on the basis of irrigation, domestic and municipal water requirement. Using the water-table fluctuation (WTF) method the groundwater recharge of the study area was estimated. Estimating the water-level rise and specific yield, the recharge was calculated. Most of the study area is surrounded by embankment/highway. The drainage congestion within the area is fully due to very low drainage capacity of channels/khals caused by sedimentation and anthropogenic interventions. Usable surface water is not available during monsoon as well as dry season. There is no provision of surface water so irrigation is solely depending on ground water. The total water requirement is more at Sujanagar upazila though it has less population than that of Pabna sadar. Abstraction is increasing day by day which clearly show increasing dependency on ground water. Recharge in Sujanagar is more due to Beel Gaznar and other beels. Abstraction and recharge reached almost same level in 2009 which points to is a major concern for the future.