Groundwater quantitative status in Denmark Hans Jørgen Henriksen Climate change and adaptive water management in EU and beyond. Vingsted March 9, 2009 Session 1 – EU Water Framework and Groundwater Directives in a changing climate

List of content WFD and groundwater directive Policy recommendations for groundwater exploitation: groundwater levels, water quality and aquatic habitats Translating qualitative policy recommendations into quantitative criteria in the Danish NOVA 2003 assessment Results of 2003 assessment Discussion – adaptive and integrated water management? Conclusion

WFD and Groundwater Directive Objectives: –Good status of surface waters (ecological and chemical) and groundwaters (chemical and quantitative) –All aquatic bodies are concerned: rivers and streams, lakes, groundwaters, coastal zone, wetlands… –The good status of 2015 has to be reached – going in the right direction isn’t sufficient –If not possible to reach goals in 2015 => Delays to 2021 or 2027 Reframing to less strict objectives (in both cases justified technical and economical)

Winter precipitation and groundwater level South Jutland: Zealand: Groundwater level (m) Winter precipitation mm Winter precip. 3-year average value

Groundwater quality and groundwater abstraction

Requirements for groundwater discharge to aquatic environment Max reduction of low flows Depending on ecological Objectives of river reach: A : max 5 % B1: max 10 % B2: max 15 % B3: max 25 % CE: max 50 %

Four quantitative sustainable yield indicators (NOVA 2003 assessment) Ensemble approach (Jakeman and Letcher, 2003, Henriksen et al. 2008):

Assessment of sustainable yield and scale

Precautionary principle: Indicator 1 : 35% Nickel > 10 μg/l > 20 μg/l Others:Chlorite,sulphatehardness Sub area Area Exploitation rate

River reaches and environmental flow

Selected indicators and climate Climate variation and indicator 1-3

Results for different areas

Result of assessment for Denmark (2003) Sustainable yield Current abstraction Subareas Exploitation rate (%)

Discussion More information: Henriksen et al., 2008: Scientific recommendations: Validate the quantitative criteria, based on monitoring data!

Ex post validation of quantitative criteria (max. reduction of min. flow incl. waste water discharge) < 10 km 2 10 – 50 km 2 > 50 km 2 Max. 5 % Rødlersbæk: -90,6 % Herredsbæk: ? Max. 10 % Svinninge å: -30,3 % Elverdams å: -5,6 % Mern å: 4,3 % Højbro å: 4,4 % Harrested å: 6,3 % Lille å : 6,5 % Krogbæk: 9,0 % Græse å: 10,2 % Vivede m.å: 14,2 % Kalvemode å: 17,6 % Max. 15 % Åmose å: -11,8 % Flads å: - 2,1 % Seerdrup å: 3,5 % Tude å: 3,6 % Tryggev.å: 10,1 % Havelse å: 14,6 % Bjerge å: 14,8 %

Ensemble resource indicators and modelling can be used as tools for adaptive water management Policy recommendations:

Adaptive water management: use higher learning levels Doing things better (reducing water consumption: Improving irrigation efficiency) How to do better things (adjusting land use & crops; Improving water quality and Aquatic habitat conditions) Social learning Water users and farmers starting to see things differently. Improved spatial perception and understanding of the aquifer, and the importance of groundwater, as part of the whole system (supplying wetlands etc.) Adaptive management can be defined as a systematic process for improving management policies and practices by learning from the outcomes of implemented management strategies (

What is required if water resources should be managed by adaptive water management (in learning processes)? NeWater Guidebook: Lessons Learned from 7 case studies

Conclusions Total available water resource is in balance with abstraction on the national level, but the nationwide resource and exploitation is unevenly distributed, and is fluctuating in time => –Over-exploitation around Copenhagen, Århus and Odense and for intensive irrigated areas in western Jutland due to regional variations in available resource & water uses –Extreme droughts and climate variation is important for exploitable resource, and for the state of the groundwater dependent ecosystems. Minimum flow reduction most critical barrier for groundwater exploitation The four ensemble indicators should be further validated based on monitoring data. Linked to the scale they have been applied. Approved more generic indicators could be scaled for 50 km 2 (max. 5, 10 and 15 % reduction), where 15 stations on Sjælland documents good ecological status with abstraction in these ranges. Further development, tests, validation and documentation is needed Adaptive management is recommended as a way to allow higher order learning (double & triple loop) from groundwater systems, and in order to increase buffering capacity and adaptive capacity of the whole system. This is also an advantage in order to plan for adaptation for climate change

What we don’t want from the future: A duck stuck in a boat on a river… Foto: HarmoniRiB, CEH (UK)