1. A Water Balance guidance, what for? Further reflections
Quantitative aspects must be addressed in WFD implementation to achieve environmental objectives (GES x SW/GQS x GW/no deterioration).
WB are key tools for MS where quantitative management is at stake or may be in the future if preventive action is not taken.
WB are to be developed when carrying out art.5 analysis. WB outcome should inform on significance of water abstractions for environmental objectives and gap to be closed with measures.
For WB MS need to rely on critical information required under the WFD: inventory of abstractions and hydrological monitoring. Data collection should be framed for easy inclusion in WBs.

2. WB should be built in a stepwise/tiered approach; a preliminary analysis to inform on WB focus, to be further elaborated in time/spatial scale, uses to be included, etc... to the level of detailed required for the purpose 
E-flows should be explicitly considered when building water balances.
WB should be used to test effectiveness of the measures to be included in PoMs, in particular the need to review of existing permits, water efficiency measures, development of reuse, etc.
WB are critical to enable comparison of the different options when applying for an exemption under art 4(7) justified by quantitative needs (dams, water transfers…).
WB can provide useful information for climate-proofing of the measures.
WB can be used as basis for emergency plans in case of water shortages and conflicting water uses