Water quality and hydrological forecasts for Sweden.

Background

The HYPE model was initially developed to support the water management work in Sweden. A first set of HYPE with high resolution for the whole of Sweden, S-HYPE, was produced in 2009 and the model is continuously improved. The current version has about 37 000 sub basins, which are further divided according to land use and soil type. Hydrological data from S-HYPE are available for downloading on vattenwebb.smhi.se.

Figure 1. This is the portal of Vattenwebb which provides data from S-HYPE.

The focus of S-HYPE was initially on discharge. Modeling of water quality, on the other hand, requires a realistic simulation of flow pathways, residence times and water flow, but this also offers opportunities for improvement of the hydrological model part.

The availability of high-resolution results also provides new opportunities for the hydrological forecasting and warning service. S-HYPE is therefore included in the new hydrological warning system HYFO. The hydrological statistics in HYFO are based on a combination of measurements and S-HYPE results and they are important for evaluation of the current hydrological situation.

Contents

This research topic focuses on improvement and development of S-HYPE, with respect to both water flow and water quality. S-HYPE will be made more useful by modeling of new substances and more accurate through improvements in the model structure, calibration and updating.

The philosophy is that the tasks should be solved with the simplest possible methodology to make the model as effective as possible. The emphasis is on development, but the accurate description of Sweden's hydrology that is collected in S-HYPE is also used for experiments and hypothesis testing for research purposes where the model can serve as a hydrological laboratory.

Research questions

  • Improvements for the warning service are done with further developed hydrological updating methods in S-HYPE.
  • A simple hydraulic formulation of the watercourses in the S-HYPE is developed for better description of residence times, river bed processes and water velocities.
  • Residence times in rivers and lakes are quantified and improved as these are important for hydro-chemical processes, but also flow times and estimates of how quickly the effect of measures can be expected.
  • The HYPE model's description of the flow paths in the soil, such as macro-pore-flow and surface runoff are evaluated and improved by including isotope data (mainly 18O).
  • The impact of regulations on flows of water and other substances is another focus area of importance for water management work.
HydroNu2014
Figure 1. The current hydrological status as described in Vattenwebb (HydroNu).