Abstract


EFFECT OF DRİLLİNG WELLS ON UNDERGROUND WATERS IN AHLAT (BİTLİS) DİSTRİCT OF AGRİCULTURAL IRRİGATİON
Especially in arid and semi-arid regions, need to control underground water levels and therefore plan to irrigation systems, manage and develop appropriate strategies for sustainable agricultural production is becoming increasingly important. In order to propose more efficient irrigation techniques, need for accurate and optimal informations on the relationship between agricultural product and water use with groundwater sustainability. In this study the change of groundwater level of district Ahlat that locate in the Van lake basin has been revealed. Underground water that used for irrigation of agricultural lands in the district is taken by drilling. Each drilling is used for watering agricultural area between 100 decares and 300 decares. Measurements were made in 13 boreholes to produce geographical data that would adequately represent the area to reflect the underground water level of the research area. It was determined that underground water was extensively used for irrigating the products grown in agricultural areas of the district of Ahlat. Height difference between wells and dynamic water level changes have provided important clues fort he identification of wells fed from the same aquifer. The direction of the underground flow has appeared relation to the hydraulics slope. As a result when the maps showing the dynamic level of groundwater are examined , it is seen that underground flows flow from high sections to low sections in sub basins. As a natural consequence of this process, groundwater which is located in the higher parts moving t oto lower parts, has caused the water level to drop in the upper wells. The result of the second land study (after the irrigation season ,20 september 2017) are also consistent with these informations. The water level of the wells in the areas where elevation is less unchanged or even inreases, indicating that the groungwater flow is compensated by the hydraulic gradient compensating fort he water loss in spite of the water consumption. The level measurements of the groundwater in the aquifer which selected wells, the hydraulic gradient direction and level changes were connected were evaluated according to were made the result of the two land studies. According to which underground flow ind the sub basins were determined to be from West to the east of the study area and generally other parts from the North to the South .

Keywords
Groundwater , Ahlat District , Agricultural Irrigation, Dynamic Level , Dynamic Level Change