Netherlands Hydrological Instrument
Unifying Dutch hydrological expertise for national policy analysis
The large hydrological institutes of the Netherlands, Deltares, Alterra, the national Environmental Assessment Agency (PBL) and the Ministry of Transport, Public Works and Water Management (V&W) have joined forces to build a new national hydrological modeling instrument. The Netherlands Hydrological Instrument (NHI) will be used by ministries, institutes and other organisations involved in national water policy issues, such as drought management, manure policy and climate variability.
The basis of the NHI is a state-of-the-art coupling of the groundwater (MODFLOW), the unsaturated zone (metaSWAP) and the surface water (MOZART-DM) models. The resolution of the groundwater model is 250 by 250 meters and groundwater flow is computed on daily basis. Below one of the results of the model is displayed.
Figure 1 Simulated average groundwater levels for a period of 30 years.
A flow in about 8500 surface water units (see figure 2) is computed with a time step of ten days.
Figure 2 Schematised Dutch surface water units and their waterlevels, used in NHI model.
The data for the instrument are derived from several national databases, including the subsoil, groundwater abstractions, topsoil, land use, drainage, water distribution, water management and meteorological data. In addition the database on vegetation development, vegetation-atmosphere and groundwater-surface water interactions is updated.
The NHI is envisaged as a permanent national modeling framework that will ensure continuity of modeling in time and space. As such, it will become a standard support for the national policy making. An additional ambition of the NHI is to become a modeling framework also for the regional water management (i.e. provinces, water boards, water supply companies). For that purpose, necessary up- and downscaling procedures need to be developed and a compatibility of the NHI and regional models achieved.
The development of this new hydrological modeling instrument is a quality boost for national water management, primarily due to a unique cooperation of all major research institutes and policy makers. The first version of the NHI is already operational; the modeling instrument is used for development of countrywide climate change scenarios and in coming months it will also be used for a regional drought management.
For more information regarding the NHI you are referred to the contact page.