The weather is becoming more and more extreme as a result of climate change. We will be confronted with more flooding or drought conditions. To respond to this, RichWaterWorld has developed an innovative system which combines floodwater storage and stock storage (or retention). Thanks to this, it is possible to use the same area as a storage unit when there is a surplus and shortage of water. This model instrument has been applied to different drainage level areas (peilvakken) in the Waterrijk area in Park Lingezegen. These drainage level areas have been indicated with numbers in the figure below.
Integrated hydrological model
The MORIA model, the groundwater model of the Dutch Water Authority Rivierenland, forms the basis of the integrated hydrological model. The SWAP model (Soil-Water-Atmosphere-Plant), which feeds into the MORIA system, is used for the interaction between the water cycle and the water balance and evaporation of plants. A regional soil and hydrological system analysis was carried out in Park Lingezegen and surroundings (for more information, please see the Alterra, Wageningen UR report (in Dutch only)) in order to gain insight into the patterns and processes in the soil and water in the research area.
Thanks to the integrated version of MORIA, it was possible to calculate the effects of different weather scenarios - ranging from extremely wet to extremely dry - for the next fifteen days according to the local water balance and water levels. The current and forecast height of the water level of the Rhine was also incorporated into the model, as the Rhine influences the water levels in the Betuwe area via groundwater. The water storage capacity still available above surface level and in the soil was calculated according to the future water balance and water levels calculated thus far (see figure below). You will find a detailed description of the hydrological model and the scenario calculations carried out in this Alterra, Wageningen UR report (in Dutch only).
Validation with field data
The results from the hydrological model are validated with measurements taken in a two-hectare experimental plot. This experimental plot has been constructed near the water intake point to the reed bed that is built in predetermined water-level area 70 (peilvak 70). The water from the river Linge is fed in at this point. Meteorological observations in the experimental plot provide up-to-date information about the quantity of precipitation and also supply data that can be used to calculate the water loss through evaporation. Sensors record the groundwater levels, the surface water levels and the soil moisture content. This information is available online instantly via telemetric transmission. The hydrological model calculations are validated using this measurement data.
Advisory tool for anticipatory water management
Along with data from the hydrological model, the measurement data and results from weather scenarios are gathered in a data platform and placed in conjunction with one another. This information is then translated into an advisory tool for anticipatory water management. With this, the water authority can take into account the forecast of river discharge and developments in the weather.
If a period of heavy rainfall and high river levels is forecast, the water storage facility can be emptied in time in order to accommodate periods of peak rainfall. This in turn prevents flooding in adjacent urban areas. On the other hand, if a dry period is expected, the water storage facility can be filled and used as a reserve during water shortages. The figure below depicts how the advisory instrument operates.