Statistical dimensions of fresh water of JQ-IW and REQ-Water ESTP Water Statistics Vienna 2016 Arnulf Schönbauer THE CONTRACTOR IS ACTING UNDER A FRAMEWORK CONTRACT CONCLUDED WITH THE COMMISSION

Renewable freshwater resources JQ-IW: Table 1 REQ: Table 1

Objective brings water use in relation with natural water availability  is water use sustainable? … aims at taking stock of fresh water resources available on the national territory, and of the different flows (inflow and outflow) of which they are composed. Comparable between different countries Display national trends of development

Schematic of national water balance P precipitation Qi external inflow Eta actual evapotranspiratoin Qo total outflow from the territory R net recharge into aquifers C water consumption P-ETa = D (internal flow) P and Q are usually the only variables with a representative number of observations

Statistical Dimensions JQ–IW (Mio m3)

Statistical Dimensions REQ (Mio m3)

Methodology integration of spatio-temporal processes from incomplete, discrete data  requires extended hydrological expertise generally available from national hydrological or meteorological services Wide range of hydro-meteorological regimes, e.g.

Methodology Reference period: generally the calendar year Jan-Dec, but where snow and soil water storage is significant  hydrological year! (e.g. Nov – Oct) Long term annual averages (LTAA): average of >= 30 consecutive years

ETa and Internal Flow Actual Evapotranspiration: Total volume of evaporation from the ground, wetlands and natural water bodies and transpiration of plants. Internal Flow: Total volume of river runoff and groundwater generated, in natural conditions, exclusively by precipitation into a territory. The internal flow is equal to precipitation less actual evapotranspiration and can be calculated or measured.

Other Definitions Total Freshwater Resources: Internal flow plus actual external inflow. Groundwater available for annual abstraction: Recharge less the long term annual average rate of flow required to achieve ecological quality objectives for associated surface water. The theoretical maximum of groundwater available is the recharge.

Freshwater Resources 95% out of time Portion of the total freshwater resource that can be depended on for annual water development during 19 out of 20 consecutive years, or at least 95 per cent of the years included in longer consecutive periods. This item yields information about the average annual long-term availability of freshwater for use in human activities.

Groundwater available for annual abstraction groundwater which is not needed for ecological discharge and is also economically and technically extractable to be estimated individually for every aquifer (a “groundwater body” according to the EU WFD) precise assessments for all aquifers in a country will likely not be available, especially if there is no water shortage EU members: amount of water which can be extracted from the groundwater body without violating good quantitative status of the groundwater body, according to the WFD

Actual evapotranspiration ETa Measurement error good results only at lysimeters „grass reference evapotranspiration“ – empirical relationships for different land cover  hardly ever useful for national water balance Spatial representation: only few stations, good coverage with meteorological stations for indirect estimation (of ETp!) Time representation: some methods work with monthly data

Actual evapotranspiration ETa Modelling error depends on model From water balance equation: depending on climatic conditions, ETa might have a large relative error due to differencing large numbers with considerable error Process-based water balance models: good results

Aquifer recharge Measurement error: no direct measurements; state of groundwater system usually monitored by groundwater table observation (WFD!) Spatial representation: for larger aquifers sufficient Time representation: bi-weekly or monthly data Modelling error: estimation of recharge needs comprehensive numerical groundwater modelling for each aquifer (coupled surface water / groundwater models)

Summary on Resources Water balance figures are derived from hydrological modelling approaches Expertise from hydrological services required Use synergies with other reporting duties (EU WFD) to save efforts and to improve consistency document of the database used and the methods applied, including spatial coverage and reliability of estimates

Annual freshwater abstraction by source and by sector JQ-IW: Table 2 REQ: Table 2

Statistical Dimensions JQ -IW (Mio m3)

Statistical Dimensions JQ -IW (Mio m3)

Statistical Dimensions REQ (Mio m3)

JQ-IW: Table 3 REQ: Table 2 Water losses JQ-IW: Table 3 REQ: Table 2

Statistical Dimensions JQ –IW + REQ

Water made available for use JQ-IW: Table 3

Statistical Dimensions JQ -IW (Mio m3)

Statistical Dimensions JQ -IW (Mio m3)

Statistical Dimensions JQ -IW (Mio m3) Total water made available for use WAU= FS + FG + NfW - RW -Exp + RuW + Imp + DsW

Water use by supply category and by sector JQ-IW: Table 4 REQ: Table 3

Statistical Dimensions JQ -IW (Mio m3)

Statistical Dimensions JQ -IW (Mio m3)

Statistical Dimensions JQ -IW (Mio m3)

Statistical Dimensions REQ (Mio m3)

References Data Collection Manual for the OECD/Eurostat Joint Questionnaire on Inland Waters; (2014) version 3.1, Eurostat NACE Rev. 2, Statistical classification of economic activities in the European Community, Methodologies and Working paper, Eurostat, ISBN 978-92-79-04741-1, 2008