An integrated analysis of the water cycle in the context of climate change

BINGO (Bringing INnovation to onGOing water management) is a Horizon 2020 Climate Action project that started in 2015 and ends in 2019. BINGO aims to provide practical knowledge and tools to end-users, water managers, and decision- and policy-makers to enable them to better cope with climate change. Part of the task involves performing an integrated analysis of the watercycle in the context of climate change for six research sites across Europe, located in Cyprus, Germany, the Netherlands, Norway, Portugal and Spain. All these sites are facing droughts, floods or both. To anticipate climate change effects, decision- and policy-makers require quantitative assessments of the current and future state of their regions.

The Dutch Veluwe site

The Veluwe area is a large ice-pushed moraine in the central part of the Netherlands. The elevated sandy area contains a strategic groundwater body that is important for Dutch drinking water production. As a consequence of climate change and the degradation of surface water quality, it can be anticipated that the importance of the Veluwe for drinking water production will increase. This would conflict with the growing freshwater requirements for agriculture and recreation, and with the needs of groundwater-dependant habitats and aquatic ecology in small streams.

Quantifying evaporation

The researcher group visited an innovative measurement system in the Veluwe, which is used to provide data for the BINGO project on the quantification of evaporation (i.e., evaporation from the soil surface, canopy surface and transpiration by plants); this constitutes the most significant form of water loss in the Veluwe (about 56% of the annual rainfall). Preliminary results show that the measured evaporation in heather vegetation, at 20%, seems to be much higher than the levels currently estimated by hydrological models. Such discrepancies could have significant implications for water balance studies. Twenty percent in evaporation for the Veluwe is equivalent to the entire annual drinking water abstraction in the area, i.e., 0.8-1.0 109 m3/year, which represents the annual tap water consumption of about 2 million people. Accurate numbers of evaporation are therefore indispensible for the cost-effective management of groundwater resources of the Veluwe.

Trees too

Besides the heather vegetation, a large part of the Veluwe is covered by forest. KWR will therefore perform additional measurements on tree transpiration in a controlled pot experiment with about 60 trees of 10 different species.  These measurements will be used to improve hydrological models and better represent evaporation in climate change assessments.