EUROWATERNET QUANTITY (EWN-Q) 2 nd Review – 2004 Update

1. EUROWATERNET QUANTITY (EWN-Q) 2nd Review – 2004 Update Budapest 11-12 Nov 2004

2. In this presentation… EUROWATERNET QUANTITY brief description Number of stations in the network and status after the 2nd update (2004) How the data have been used

3. EUROWATERNET QUANTITY: Provides comparable an reliable information on quantitative aspects of freshwater resources, It is based on existing national monitoring networks in EEA member countries, it makes no additional demands for new data gathering.

4. EUROWATERNET QUANTITY overcomes: The lack of a water quantity network updated on a timely basis in Europe (see EEA Technical Report 99) The lack of a database for high- and low-flows updated on a timely basis in Europe.

5. EWN-Q has been designed for: providing data on precipitation (mean and maxima) and river discharges (mean, maxima and Q95); obtaining the areal precipitation and internal flow and sum of outflows temporal and spatial aggregations according the EEA´s water reporting strategy, i.e. annual and national.

6. EWN-Q stations and determinands

7. Precipitation measured at selected RGSs which are representative according to the topography representative according to the data length and quality eligible for mean areal precipitation

8. RGS Statistics RGS Statistics No of selected stations for pilot study (to be updated) No of stations provided for pilot study

9. River discharges at BGS measured at non-altered catchments representative according to the data length and quality eligible for annual internal flow

10. River discharges at FGS measured on the mouth or boundaries representative according to the data length and quality eligible for actual outflow

11. Statistics for gauging stations

12. Problems encountered 1) Dataset only for precipitation or discharges 2) Dataset for stations but no time-series associated 3) Time-series only for the mean value, lacking info on maxima. 4) Different datasets for different updates => which stations are the representative? 5) Minor common problems, such as errors in coordinates, change of names/ids, data units (mm instead of m3/s).

13. Use of data 1) Spatial aggregation for areal precipitation 2) Spatial aggregation for areal inflow 3) Sum of outflows 4) Floods (P and Q maxima) 5) Low-flows (Q95, P-percentiles)

14. Process for annual aggregation 1) Stations used for spatial aggregation checked 2) Time-series for these stations checked 3) For each year, do values exist for all stations? Otherwise, apply rules for data filling 4) Interpolation 5) Statistics derived from this process: accept/reject the value obtained.

15. Ex 1: Mean precipitation in 1997

16. Ex 2: Inflow in 1997

17. Results for 1997

18. Timeseries Ex: Q in HU

19. Timeseries Ex: P in LV

20. Data for flood indicators Pmax Countries with data: FI, LV, AT, HU, ES. The time-series length is as for P. Data allow the ratio Pmax/P (value and date) and frequency distribution for maxima

21. Most frequent month=7

22. Data for flood indicators Qmax Countries with data: FI, LV, AT, HU, ES. The time-series length is as for P. Data allow the ratio Pmax/P (value and date) and frequency distribution for maxima