Water Resources under Climate and Land Use Change
Water is one of the key resources for agricultural production and daily life. Water availability – influenced by climate and land use – is therefore of outstanding importance. Any environmental analysis requires information on the dynamic of water fluxes and water storages at different scales which are usually computed by simulation models. Those models must be based on a thorough understanding of processes to be able to be used for scenario quantification.
It is important not only to analyze simple input-output relationships but to consider the complex feedbacks within the plant-soil-atmosphere-hydrosphere system. Only by studying those feedbacks one is able to forecast which impact land use and climate change have on water storage, water fluxes, and water related ecosystem services. Knowledge concerning the processes and feedbacks are translated into dynamic simulation models. Nowadays, these models should consider not only vertical but also lateral processes and landscape patterns. Therefore, it is planned to adapt and apply a 3d eco-hydrological model which includes the feedbacks explained before. As any environmental modeling is faced with a number of uncertainties, they have to be quantified to be able to differentiate between signal and noise in measured data and simulation results especially if used for scenario quantification.
The work is based on the hypothesis that adapted hydrological modeling and quantification of related uncertainties are indispensable for decision making at different spatial and temporal scales. The analysis of the effects of changing landscape patterns on water related environmental services as well as on water and energy fluxes gives hints to adaptation strategies to cope with climate change effects. A comprehensive analysis of uncertainties in the chain from field data to validated model output and from climate and land use scenarios to hydrological impacts will improve decision making.
The work will be carried out in the WASCAL focal watersheds and will cover investigations from the local (point) scale up to the watershed scale. The selected watersheds will be instrumented in a way that differences between intensity of use can be determined. Local scale measurements will complete process understanding and help parameterizing the simulation models. The focus is on the effect of landscape patterns on water storage, water fluxes and related ecosystem services. The focus on small scale patterns in soils, land cover and land use etc. is innovative and challenging as most studies concentrate on larger units and consider lateral interaction in a simplified way. The results are fundamental for other WPs dealing with e.g. agriculture, SOC dynamic, and soil degradation as well as for developing adaptation strategies to cope with water scarcity.
Using the calibrated and validated eco-hydrological models, scenarios will be quantified to study possible future impact of land use and climate change on water storages and water fluxes. The results will be aggregated to a number of indicators which can be used in an integrated assessment.
This Work Package is closely interacting with other Work Packages analyzing processes in the focal areas but also with the WASCAL Competence Centre. Experimental setup, installation, analysis concept as well as model selection will be done in close cooperation with the Competence Centre to guarantee future use of instrumentation, techniques, and methods. The Work Package therefore contributes to the Capacity Building in the Competence Centre but also integrates the Graduate Studies Programme, especially the Doctoral Programme Climate Change and Water Resources, into research activities.