Potenzialabschätzung von technischen Wasserspeicheroptionen, Bewässerungsansätzen und ihrer Umsetzbarkeit

Irrigation is one of the most effective measures to avoid or reduce yield losses caused by droughts. When water resources are limited, the main challenge relates to the issue of increasing water availability for crop production without causing or exacerbating conflicts of interest with other water-consuming sectors. Considering the already observed change of rainfall patterns in Germany, water storage reservoirs could be part of the solution to agricultural producers. Such reservoirs can be filled in autumn or winter months either with surface water run-off in case of persistent or heavy precipitations, or with abstractions from surface waters when water levels and discharges are high. The stored water can then be used for irrigation in case of spring or summer droughts, thus improving water availability and increasing the reliability of water provision for agricultural producers as well as reducing the conflicts of interest regarding groundwater extractions. This working paper presents the results of a comprehensive literature review carried out in order to identify research needs in the field of agricultural water management and to provide orientation for the research project LAWAMAD – Agricultural Water Management in Germany. In the first step the available technical water storage options and the criteria which are of importance when deciding on their implementation are reviewed. Subsequently, the feasibility of these options for German agriculture is being discussed and the four most suitable ones – water storage basin, rainwater retention basin, infiltration facility and dams are identified. The choice of a technical water storage option and the decision about its size and volume depends among other things with the already available or envisioned irrigation infrastructure and farm strategies to optimize irrigation. Respectively, we discuss the existent irrigation methods, their advantages and disadvantages, as well as chances and risks of irrigation from the agronomic and the economic efficiency perspectives. In the final step of our literature review we provide an overview of the current state of scientific discussion on the barriers to investments in irrigation and water storage infrastructure from three theoretical perspectives.