Integrated analysis of the water cycle

Integrated assessment of the water cycle at the research sites

BINGO evaluated the state of water resources (surface and groundwater, quantity and quality) at all the six research sites and their sub-sites. This evaluation included a consistent characterization of the catchments and surface, groundwater, and estuarine water bodies, including land use and anthropogenic water abstractions, requiring measured data, results from previous research, literature and local knowledge.

In order to analyse the impact of future weather extremes and global change on water resources, hydrological, hydraulic and water quality models were employed. Some of the 20 models are operational and already calibrated and validated to the current climate for the sites of Wupper River (Germany), Bergen (Norway) and Veluwe (Netherlands). For other cases, models were set-up and calibrated/validated (e.g. Tagus River, Portugal). For a consistent evaluation of water resources, all models were first driven with downscaled present climate reanalysis data for current and past conditions (1985-2014). At a second step, high-resolution climate input data for the time period 2014-2025 (and until 2100) was used at research sites where average evolution, and drought and flood occurrences were evaluated.

The above activities resulted in valuable outcomes including

• improved forecasts of surface and groundwater water quantity and quality,
• integrated water quantity/quality modeling, and
• improved understanding of the dominant processes that translate meteorological extremes into hydrologic extremes.

The model performances at each site were evaluated and compared, providing insight into the shortcomings and benefits of model applications and allowed a step-by-step adjustment of the models in order to become innovative and reliable tools for local end users.

Field Investigations at the research sites

In order to improve floods and droughts representation, BINGO also focused on specific modules of the models. To improve process descriptions, it was necessary to investigate the relevant processes at the field sites. Due to the variety of dominant hydrological processes, different process algorithms were considered, such as:

• Actual and potential evapotranspiration processes were further investigated at the Dutch and Cypriot in order to analyse effects of droughts on groundwater recharge and dynamics, runoff generation and vegetation patterns;
• At the German site, a sensor network of gauges and soil moisture sensors was implemented;
• At the Portuguese Tagus estuary continuous water level monitoring provided new data for model calibration;
• The Spanish partners implemented sensors in their sewer network.

All field data were used to improve the process understanding, which drive the climatic impacts on the water balance.

Future land use scenarios at the research sites

Not only climate variability influences water resources; anthropogenic activities such as water abstractions and land use changes play a major role in this respect, as their impacts can increase or decrease hydrological extremes.

BINGO developed future land and water use scenarios at the research sites, based on socio-economic factors from the EU-FP6 project SCENES. These scenarios were based on socio-economic developments taking place in the recent past and possible future settings. Two contrasting SCENES scenarios have been chosen in order to provide a wide but still realistic range of possible futures:

• Economy First: High water use increases, strong population increases, land use intensification; and
• Sustainability Eventually: Low water use and population increases, land use diversification.

Scenario data was collected in a combined top-down (SCENES) and bottom-up (local knowledge) approach and then pre-processed as input for the hydro models. The impacts strongly varied between the research sites and new knowledge and understanding of the local water cycles were established.

Water cycle at the research sites in different climate & land use

The final step consists in merging the results from the integrated assessment of the water cycle, from field work, and from the future land use scenarios, allowing an overview of the water conditions under a combination of different possible scenarios, both of climate change (including extremes) and land use. The results of this task directly linked the occurrence of different climate (extremes) and land/water use patterns with water conditions, both in terms of quantity and quality, for local water resources managers.

What was achieved?

• Descriptions of the sites and the hydrological systems,
• 20 hydro models and modelling of last 30 years and the future 85 years,
• Improved our forecasts of the impacts of climate change on floods and droughts including learning of the local processes which drive these extremes.

These integrative results helped us to pave the work for our risk management process.

MUST READ publications

• Characterization of the catchments and the water systems
• Future Land and Water Use Scenarios
• Calibrated water resources models for past conditions
• Model results for water and land use scenarios at the six research sites completed and analysed (26,7 MB)
• Improved model applications/descriptions based on field data
• Optimized water resources models as a support to management strategies
• Guidelines for the Application of hydro models
• Special report on RCP scenarios: Impacts of long-term climate change effects on typical water problems in Europe