1 EUROPEAN TOPIC CENTRE ON WATER EUROWATERNET QUANTITY (EWN-Q) 2 nd Review – 2004 Update Budapest Nov 2004

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

3 EUROPEAN TOPIC CENTRE ON WATER 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 EUROPEAN TOPIC CENTRE ON WATER 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 EUROPEAN TOPIC CENTRE ON WATER 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 EUROPEAN TOPIC CENTRE ON WATER EWN-Q stations and determinands Station typeVariable monitoredDeterminands Rain gauges (RGS)PrecipitationP, Pmax (value and date) Reference gauging stations (BGS) Discharge Q, Qmax (value and date) and Q95 Flux gauging stations (FGS) Discharge

7 EUROPEAN TOPIC CENTRE ON WATER 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 EUROPEAN TOPIC CENTRE ON WATER RGS Statistics No of selected stations for pilot study (to be updated) No of stations provided for pilot study

9 EUROPEAN TOPIC CENTRE ON WATER River discharges at BGS measured at non-altered catchments representative according to the data length and quality eligible for annual internal flow

10 EUROPEAN TOPIC CENTRE ON WATER River discharges at FGS measured on the mouth or boundaries representative according to the data length and quality eligible for actual outflow

11 EUROPEAN TOPIC CENTRE ON WATER Statistics for gauging stations

12 EUROPEAN TOPIC CENTRE ON WATER 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 EUROPEAN TOPIC CENTRE ON WATER 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 EUROPEAN TOPIC CENTRE ON WATER 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 EUROPEAN TOPIC CENTRE ON WATER Ex 1: Mean precipitation in 1997

16 EUROPEAN TOPIC CENTRE ON WATER Ex 2: Inflow in 1997

17 EUROPEAN TOPIC CENTRE ON WATER Results for 1997

18 EUROPEAN TOPIC CENTRE ON WATER Timeseries Ex: Q in HU

19 EUROPEAN TOPIC CENTRE ON WATER Timeseries Ex: P in LV

20 EUROPEAN TOPIC CENTRE ON WATER 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 EUROPEAN TOPIC CENTRE ON WATER Most frequent month=7

22 EUROPEAN TOPIC CENTRE ON WATER 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

23 EUROPEAN TOPIC CENTRE ON WATER