Hydrological information systems Svein Taksdal Head of section, Section for Hydroinformatics Hydrology department Norwegian Water Resources and Energy Directorate The importance of well designed and well working computer systems for hydrological services

2 Why invest in specialized computer system for hydrology? ■ One defined place to store hydrological data ■ Avoid local copies of data ■ Secure long-time storing ■ Professional systems can handle large amount of data ■ Enables safe back-up routines ■ Easy to extract data for different use – e.g.: ■ Hourly data for latest days for flood warning ■ Daily mean of 50 years for statistical use

3 Key characteristics - in general for professional software ■ Based on well documented source code that is possible to maintain and further develop ■ Easy to adapt to local requirements and needs ■ Well designed data model implemented in an industry-standard database tool ■ Possible to integrate with external systems e.g. simulation models, publication tools, data dissemination routines, GIS, etc ■ Easy to use – (or easy enough to use…)

4 Special needs for hydrological systems(1) - not necessarily covered by more general systems, e.g. meteorological systems ■ Flexible storing: ■ Flexible handling of different parameters and measuring units (easy for user to add new data types) ■ Handling of different time steps of the observations (e.g. day, 12 hours, 6 hours, 3 hours, 1 hour, 30 minutes, 15 minutes and 1 minute) ■ Support of non- fixed time steps

5 Special needs for hydrological systems(2) ■ Data input: ■ File input Flexible and well documented file formats Ability to include metadata in import-files (unit, parameter, data source, gauging principle) ■ Support for automated input of data from data loggers and data acquisition systems ■ Manual input: Tool for digitalizing paper charts (limnigramme ) User interface for manual registration Hydro- logical data- base Automatic processing Automatic data transmission

6 Special needs for hydrological systems(3) ■ Rating curves: ■ Software tool for calculation of the rating curve equation ■ Recalculation of discharge in case of rating curve revisions ■ Handling of rating curves based on multiple segments ■ Different rating curves for different time periods

7 ■ Hydrological analysis: ■ Flood frequency analysis ■ Low flow (drought) analysis ■ Volume (summation) calculations of various types ■ Flow duration curves (e.g. for hydropower planning) Special needs for hydrological systems(4)

8 Special needs for hydrological systems(5) ■ Quality control program: ■ Interactive graphical corrections ■ Comparison of different stations ■ Plausibility check ■ Other relevant auxiliary information

9 The importance of hydrological information system for flood forecasting ■ Streamlined and automated routines for data retrieval and data import ■ Data base and data structure support high level of service availability ■ Historical data and real time data available in same system ■ compare current situation with older events ■ Storing of forecasts in the HIS opens for easy comparison of forecasts vs. observations ■ Evaluate the goodness of the prognosis

10 New IT-tools → new working routines? ■ Traditional work routines: ■ Every office/work group handle data separately ■ Local data collection ■ Local data storing (often in spreadsheets) Flood prognosis office Statistics and analysis group Regional office Local IT- system/files Products Data collection Hydrometric station

11 Streamline the routines! ■ Shared routines ■ Phase out duplicated work flow Shared database Shared tools (analysis, models, presentation etc.) Hydrometric station Data collection Flood prognosis office Statistics and analysis group Regional office Quality control

12 Two possible roads to follow: 2. Buy a commercial HIS +Fast in production +Tested software +Less costly (but not cheap) +Available support -General system Not fine tuned for local needs -Priced pr user (usually) -Dependent of supplier Desired new functionality might not be approbated by the supplier 1. Local development +Complete control with source code +Adapt to all local needs +Easy to add new modules and functionality +Scale with no extra cost -Long time development -Hard to keep up with new IT-technology -Costly (in man-labour)

13 Conclusion ■ Well designed software is essential to ■ produce hydrological data of high quality ■ reduce need of manpower ■ secure long term storing of data ■ make data available to all users and systems – including the flood forecasting routines ■ publish data to the public

14 Thanks for your attention! and don’t forget to have fun in the water too…..