Forests have a positive effect on the groundwater balance and the water quality of a region. However, forests are also major consumers of water. The quantity and quality of groundwater and surface water can be positively influenced by the increased conversion of coniferous stands.  Measurements in combination with simulations prove the influence of hardwood-dominated forest conversion on the seepage water quantity and quality of forest stands. These measures can only have a targeted effect if the hydrogeological conditions at the site are known. Water is increasingly a limiting growth factor for agricultural crops. Irrigation of agricultural crops has become increasingly important in recent years. In addition to increasing the yield, the quality of the products is ensured and the production risk of repeated dry phases during the vegetation period is countered. With climate change, the demand for irrigation water is increasing and must be ensured with various measures.