Climate-proof River Water Balance

According to Water Framework Directive 2000/60 (WFD) and following national legislation, River Basin Authorities (RBA, hereafter also ”Authority”) evaluate and periodically update river water balances; the client currently has their own balance model, to be updated periodically and used for withdrawal permissions surveys.

Updating model with climate change scenarios from climate impact indicators shows effects of withdrawals on the river in the years to come and supports the client in defining measures to counteract such effects, to add to the survey of each new withdrawal request.

Added value of this approach is in using state of art Climate Change scenarios and coupling them with an existing operative tool through use of indicators, to improve its usefulness for the Client.

Read Full Technical Report here!

River in the Emilia Romagne region

Case Study Description
Data Description
Reference information

Water-management issue to be addressed

According to Water Framework Directive 2000/60  (WFD) and following national legislation, River Basin Authorities (RBA) are entitled to evaluate and periodically update water balances along river network¹.

ADBRR has working prototype of main  rivers water balance scheme that integrates Flow Duration Curves (FDC), withdrawals permissions database, Minimum Environmental flow rules,  in order to assess feasibility and sustainability of actual and future withdrawals.

Such a scheme can be upgraded with information on water availability and demand variation in climate change scenarios.

Decision support to client

The Authority releases mandatory surveys for every withdrawal request, with particular regard to Minimum Environmental Flow (MEF) to prescribe and compatibility with River Water Balance (RWB). Given that many withdrawals remain active for decades, once allowed, use of climate change indicators allows sounder decisions on withdrawals permissions to be taken. During examination of one or more withdrawal requests, the Authority checks the proposed indicators (all coming as output of entire and coherent river water balance) both for subcatchment involved by requests and all downstream ones (in actual and C.C. scenarios):

  1. Water availability
  2. Days of no withdrawal
  3. Withdrawals sustainability

If climate change scenarios indicate potential environmental (indicator 1 or 2) or socioeconomic (indicator 3) issues, the Authority will insert in the survey appropriate warnings, indications and technical recommendations to make the applicant aware of inconveniences and opportunities, thus reducing chances of future complains and conflicts, such as:

  •  The withdrawals permission may be revised (in quantity or duration) before the natural expiry date to cope with changed water balance condition (i.e. in case of reduced availability), the needs of environmental protection or fair redistribution of resources between different applicants (in accordance with the priority recognized to different uses by law)
  •  Opportunity to equip the derivation with storage devices, if C.C. scenarios highlight a resource shift between summer and winter periods, as good practice both for reducing expected impact of the derivation and increasing availability of the resource to the end user.

Temporal and spatial Scale

Hydrology of the river is expressed as FDC whose variation in C. C. condition is derived from SWICCA indicators (River flow-daily) easy to adapt to Client time scale needs (seasonal) to take into account interannual resource variability according to WFD guidelines (European Commission guidance documents)².

Spatial resolution (0.5 deg) of the indicator is enough to describe variation at subcatchment level (see Figure 1), availability of  hydrological ECV at  5 km resolution could improve their usability.

Expected variation in water demand is also to be extracted at subcatchment level, at present to be derive from socioeconomic indicators (as GDP ECFIN at 0.1 deg resolution).

Knowledge Brokering

First meeting with Client was held the 3rd of December 2015 to introduce the SWICCA case, identify indicators and data/tools available, and set the mode of work for the coming year.

Following meetings in mid-January and late February have been devoted to details on existing water balance scheme and actual water demand information. As workflow proceeded smoothly phone and mail contacts with Client followed as preferred way of communication in the subsequent months, during which first two indicators on environmental impact (water availability and Days of no withdrawal) have been setup. Withdrawals impact indicator has been defined in the last meeting of November 11thtogether with following conclusions and remarks:

  • Due to national legislation (particularly decrees on how to develop river water balance) Third indicator (withdrawals sustainability) has been identified in the residual available water volume at the end of each subcatchment after all withdrawals/discharges take place in actual an C.C. scenario.
  • Reliability of projections in C.C. conditions of water demand variation still is an open question for the Client that need to understand which indicators can be reasonably linked to water demand variation and to identify the wisest choice among available hydrologic and RCP’s models and particularly ensembles Vs. single models. Simplified hypothesis on use of ensemble is described as follows.

Due to high number of possible combinations for both model input/forcing and hydrological models, discussions with the Client were to:

  • Choose the hydrological model that better suited local data
  • present results of indicators in probabilistic way coming from results of all remaining model – forcing combinations
  • assume only human consumption variation related to Population SSP3 Trend scenario

The last assumption is particularly tricky and after discussion and support from scientific side, is based on a recent document from nearby River Basin Authority of Po river that shows different envisaged patterns of withdrawal changes:

  • no relevant changes expected for industrial and energy sector;
  • for human consumption increasing in the middle period, with stabilization decreasing in the long period due to increasing efficiency;
  • for agriculture, it’s difficult to make forecasts due to predictable increase in temperatures and evapotranspiration on one side, but unpredictable market request that could have a much larger effect on water withdrawals.

In the last months of 2016 to early in 2017, the transition to new organization of river District Authorities was completed and competencies inside Emilia Romagna Region (Client) bureaus were reassigned; contacts with new officer in charge for this case study have been carried on, upgrading brokering and targets of case study.

During the meeting in January 2017 with the Client, a better definition of third indicator has been shared, using WEI+ indicator, to be calculated for Savio River Case Study in every season. This indicator, following indications of Po River District Authority, should be customized with Client data-needs and coupled with ecological state of river in order to evaluate the feasibility of new withdrawals.

Following skype meetings and conference calls focused on definition of indicator and sharing of first results of Case Study.

Climate Impact Indicators

Pan-European Indicators

For river water balance Case study, following SWICCA indicators have been used:

  • River flow – ECV (0.5 deg grid, daily time series)
  • GDP ECFIN scenarios
Local indicators

Water balance results at present sub catchment closure based on actual FDC and demand patterns. For every sub catchment, a detailed balance output is available with  available resource compared to environmental flow needs and existing allowed withdrawals.

Pan-European data to local scale

Read Full Technical Report here!


Step 1: Identification of station of interest at local scale along river network Extraction of upstream catchment area A1.

Step 2: Identification of closer gauging station or pixel along river network for which Pan-EU indicator is available, Extraction of upstream catchment area A2.

Step 3: Extraction, for Pan EU station/pixel, of percentiles P2 of interest of Flow Duration Curves in Climate Change scenarios extraction of water demand  variation W2  indicators average on area A2 or as closer as possible spatial unit.

Step 4: Downscaling of percentile to local stations  P1 using catchment area ratio,   P1= P2/A2*A1, Actual water balance is seasonal (separate FDC for 2 periods in the year) so adaptation of available pan-EU annual FDC would be needed (i.e extraction of seasonal FDC from C.C.  Flow time series, procedure to be defined in detail).

Step 5: Estimating water demand variation W1 upstream of selected local stations starting from closer EU available one W2 with reasonable criteria (area, population density, geographical proximity).

Step 6: Using modified FDC and water demand in existing water balance scheme, aggregation level of resulting balance is upstream sub catchment for every local station of interest, to derive following indicators:

  • FDC-Environmental indicator: putting in evidence stations  (sub catchment) for which expected  resource will significatively reduce and Environmental flow days will be heavily reduced.
  • Withdrawals impact indicator: sub catchments  with higher and lower expected withdrawals sustainability in C.C. conditions.

(envisaged indicator output  is in the form of sub catchment polygon maps with assigned average ranked values of Indicator from low to high ).

Lessons learnt

When considering the entire workflow, the main successful factors in the suggested implementation of indicators are the flexibility of implementing climate change information (by downscaling information from SWICCA indicators to the existing subcatchments) inside an existing water balance scheme, currently used and updated by the Client, clearly a saving time option for both the Client and the Purveyor, as long as the online SWICCA demonstrator interface that is quite easy to use and to take data from for the area of interest.

Main Limiting factor is the necessity to identify the most reasonable subset of combinations and scenarios of C.C. to be implemented in the final indicators and to be used by the Client; it hasn’t been easy to choose between high number of available hydrologic and RCP’s combinations for practical purposes of the Client, nor to translate socioeconomic indicators to water demand variations.

Also, Seasonal flow duration curves, although in principle quite usable for the case study, have not been used and have been recalculated from daily time series due to the necessity to have devoted curves for exactly the two seasons of interest for the Client in its specific territory.

Going deeper in the step by step workflow successful and limiting factors could summarized in:

Step 1: Identification of station of interest at local scale- no limiting factor, ready to be used with limited time

Step 2: Identification of closer gauging stations - no limiting factor, quite easy even with 0.5 deg resolution indicators due to the subcatchment spatial resolution of final indicator.

Step 3: Extraction, for Pan EU station/pixel, of percentiles of interest of FDC and extraction of water demand variation/ Step 4: Downscaling of percentile to local stations P1 using catchment area ratio - successful factor is mainly the easiness to adapt current hydrological information (FDC) in C.C. scenarios using SWICCA indicators.

Step 5: Estimating water demand variation W1 upstream of selected local stations starting from closer EU available one W2 with reasonable criteria - again it’s quite immediate to adapt information for indicators such as Population SSP indicator to the area of interest, but moving from Socioeconomic indicators to water demand variation need a lot of assumptions to be supported before being usable by the Client.

Step 6: Using modified FDC and water demand in existing water balance scheme – final indicators - main successful factor has been the availability of an existing water balance scheme to adapt and to be used to extract indicators of interest for the Client. Main limiting factor has been the wide range of possible combination and scenarios of C.C. to be reasonably reduced both for implementation purposes and for communication of added value to the Client, we explored the use of a web mapping service available as prototype at also to make decision from different scenarios easier to handle, as long as presenting results from all different possible combinations in probabilistic form

Importance and Relevance of Adaptation

Expected effects of the proposed climate service for Clients are envisaged in

  • Sounder analysis when allowing new withdrawals, that can stay active for decades, thus facing climate change scenarios, releasing climate change compliant permissions arguably leads to mid-long term benefits in terms of reduced conflict for water resource chance.
  • Avoiding local on demand detailed studies on climate change effects; effort and skill for adapting pan-European information, once available, to local scale being anyway more affordable, thus releasing internal resources for another institutional task.
  • Having established indicators on climate change by qualified research centers gives to final decision adequate robustness to be defended in case of objections.

Water balance related analysis in climate change scenarios were not carried out on (at spatial and temporal level comparable to the actual Water balance scheme) before. Expected indicators lead to the actual water balance scheme and decision to be taken on it being more compliant with EU guidelines2, and development of water balance, towards full implementation of WFD that explicitly considers climate change effects on water management tools.

Pros and Cons or Cost-Benefit analysis of climate adaptation

Without climate adaptation indicators decision taken with (up to date) information on water resource availability and demand have a relatively short-term validity and arguably need frequent updates to monitor compatibility between resource and demand. On the other side, the envisaged indicators can be used for identifying water deficit areas (for MEF and subsequently river quality state) under climate change scenarios, or whether climate change will exacerbate or limit current water deficits, planning restrictive measures on withdrawals in advance.

It is well known, particularly in Emilia Romagna Region, that all measures to reach the good ecological state on surface water bodies according to the WFD implies social and economic costs³ although no detailed evaluation is available at present in that territory with reference to C.C. adaptation measures on withdrawals and environment

Policy aspects 

Studies on climate change effects on river basins resources are available at regional and WFD basin districts level, (see for example PO River basin authority recent update of River Basin Management Plan RBPM4), often with support of numerical hydrological models and simulated discharge time series in climate change scenarios. Major RBA guidelines on implementation of WFDexplicitly consider water balance evaluations as mandatory for every new withdrawal permission. Despite such a level of focus on climate change impact on the balance between environmental needs, water demand and resource availability, at present policy on withdrawals permissions mainly rely on MEF definition and updated large scale water balance schemes (updated once every few years), as tools for decision making on withdrawals compatibility and effects on river long term status.

Client policy on withdrawals permissions relies on similar criteria. Recent updates from Emilia Romagna Region contribution to 2nd RBMPs (2016-2021) implementation have introduced new values of MEF and proposed large scale update of water balances with relatively up to date aggregated withdrawals estimation 7.

Recent local directive, at regional level, apart from simple MEF application, brings some simplified criteria to judge new withdrawals compatibility, basing primarily on derivation length, maximum derivable flow and environmental state of the river, aimed at Regional Environmental Protection Agency (that release the permission to the final user) as a simple tool for withdrawal judgment. Nonetheless Agency needs a mandatory survey by the RBA on compatibility with the river water balance before releasing ore denying permission.

National legislation (DM 28/07/2004) in application of the WFD brings detailed guidelines on how to develop river water balance from RBA’s (both for actual and future conditions, although referring to local masterplans to define such future conditions, and for annual an inter-annual time frames), but practical application of such a detailed approach in the decision process of withdrawals survey is lacking in the territory managed by the Client.

Use of envisaged indicators, derived from a balance scheme that is fully compliant with national guidelines, overcomes these limitations adding a new set of instruments, compliant with national legislation, to fully evaluate effects of new withdrawals in the mandatory survey in both actual and future conditions, without the need of running complex models, keeping an adequate spatial and temporal resolution.


Paolo Mazzoli – GECOsistema srl
GECOsistema – Geographic Environmental Consulting


[1] G. Cassani, M. Franchini, G. Galeati, P. Mazzoli: The Water balance: A methodology for evaluating the compatibility between surface water resources and environmental and anthropic requirements; 2009, L’ACQUA, vol.2, pp. 45-57.

[2] European Commision, Guidance document on the application of water balances for supporting the implementation of the WFD- Technical Report - 2015 – 090,

[3] ARPA-Emilia Romagna- valutazione dei costi economico-sociali per il raggiungimento dell’obiettivo di stato buono dei corpi idrici ai fini dell’applicazione delle esenzioni -

[4] PO River Basin Authority, Piano di gestione del distretto idrografico- aggiornamento al 2015- technical report – Dec. 2015 

[5] PO River Basin Authority, Valutazione del rischi ambientale connesso alle derivazioni idriche in relazione agli obiettivi di qualità ambientale definiti dal piano di gestione del Distretti idrografico Padano- Technical guideline Dec. 2015 .

[6] Emilia Romagna Regional Agency for Environment (ARPA)- Individuazione Del Deflusso Minimo Vitale Di Riferimento – Dec 2015.

[7] Emilia Romagna Regional Agency for Environment (ARPA)- Quadro Conoscitivo Bilanci Idrici – Dec 2015.

[8] Emilia Romagna Region - DIRETTIVA CONCERNENTE I CRITERI DI VALUTAZIONE DELLE DERIVAZIONI DI ACQUA PUBBLICA [Directive on evaluation criteria for public water withdrawal], approved by regional assembly on July 25th 2016.


Relevant EU Policy


Purveyor: Paolo Mazzoli – GECOsistema srl

GECOsistema – Geographic Environmental Consulting

Value added by Copernicus Climate Change Service: 

Regione Emilia Climate proof

Client: Autorità dei Bacini Regionali Romagnoli (Italy)

Emilia Romagna River Basin Authority
Via Miller, 25 - 47121 Forlì ( Italy)
c.p.p.  Gabriele Cassani


One of the four main basins governed by ADBRR, spatial discretization in homogeneous sub catchments for water balance calculation

One of the four main basins governed by ADBRR, spatial discretization in homogeneous sub catchments for water balance calculation.

Figure 2. Schematic representation of Flow duration curve (Cassani et. Al ., 2009 ) , upper figure showing how upstream flow duration curve and allowed amount of derived volume V, lower figure showing consequent reduce flow duration curve downstream.

Schematic representation of Flow duration curve (Cassani et. Al ., 2009 ) , upper figure showing how upstream flow duration curve and allowed amount of derived volume V, lower figure showing consequent reduce flow duration curve downstream.