Drinking Water Protected Areas: Luxembourg Experiences 22nd Working Group C Plenary Meeting Brussels 21/03/2012 Tom SCHAUL Administration de la gestion de l’eau Grand-Duché Luxembourg

0. Overview Transposition of EU Groundwater Directive Luxembourg - Legal Act - Delineation of Groundwater Bodies - Status Drinking Water Protected Areas (DWPA), Luxembourg - Groundwater as Drinkwater resource - Drinking Water Protection Zones: - History - Methodologies - Actual re-delineation - Challenges 3. Discussions relative to Guidance Document No16

1. GWD-Luxembourg: Legal Act Règlement grand-ducal du 08 juillet 2010 relatif à la protection des eaux souterraines Quality standards Threshold values 3

1.GWD-Luxembourg: Delineation of Groundwater Bodies - based on 10 Hard Rock (sediment deposits) aquifers responding to WFD criterias - delineation according to geological criterias and hydrogeological understandings  homogeneous geological units 31 monitoring stations 4

1.GWD-Luxembourg: Delineation of Groundwater Bodies Transboundary GWB with France, Germany, Belgium (Rhine river basin) 5

1.GWD-Luxembourg: Status 2 out 5 GWB in poor chemical status: (1) nitrates (2) pesticides Most common Pesticides: + Metolachlore ESA A Desethyl-Atrazine (58%) B Atrazine (53 %) C Dichlorbenzamide (49 %) D Bentazone (28%) E N,N-Dimethylsulfamide (4 %) F Desisopropyl-atrazine (3 %) 20 40 60 80 200 400 600 Pesticide concentration [ng/l] 6

2.DWPA: Groundwater as Drinkingwater Luxembourg 2/3 of drinking water from groundwater (78 000m3/day) 336 Abstraction points: 75% springs / 25% drillings +/- 1% with treatement due to human made pollution Muschelkalk Luxemburger Sandstein Bundsandstein Mittlerer Lias Dogger Devonschiefer 7

2.DWPA: Groundwater as Drinkingwater resource, LU Sediment deposits / fissured aquifers Main aquifer: Luxembourg Sandstone ( > 80% of ressources)  partially rapid flow / high vulnerability 8

2. DWPA: Identification and Delineation Luxembourg Protection zones ( zones de protection-ZPS): (1) Identified in River Management Basin Plan (19 out of monitoring stations in ZPS) - No binding legal act (2) Re-delineation according to - National Water Law of 2008: - creation of binding legal acts - at latest by end 2015 - 2012: binding legal act defining measures in all ZPS - Risk approach / vulnerability mapping 9

2.DWPA: Identification and Delineation Luxembourg Protection zones (ZPS): - part of a groundwater body « Safeguard zones » according to art.7 WFD Second interpretation of Guidance Document 16 with focused protection measures (in accordance with DW obligations) + focused monitoring 10

2.DWPA: Identification and Delineation Luxembourg According to guidance document No16: DWPA: - whole groundwater bodies - cover: (1) Safeguard zones: (2) Zones of potential abstraction LU: Zones of potential abstraction Possible delineation according to water law Actually no zones identified Delineation not always useful 11

2. DWPA: Identification and Delineation Luxembourg Delineation of zones of potential abstraction not useful: Example: Confined aquifer of Luxembourg Sandstone: DW exploitation sites for emergency cases 12

2. DWPA: Identification and Delineation Luxembourg Example: Confined aquifer of Luxembourg Sandstone: Results of numerical modelisation study No additional abstraction possible Over-exploitation and hence poor quantitative status Delimitation of «  safeguard zones » But: no delimitation of zones of potential abstraction  DWPA = GWB ? Map representing numerical simulation of GW-drawdown due to additional abstraction 13

2. Actual Re-Delineation of « Zones de protection » Consideration of hydrogeological properties: Fissured aquifers with preferential infiltrations and flows Risk based approach Vulnerability mapping 14

2. Actual Re-Delineation of » Zones de protection » Harmonized methodology of delineation based on a national guideline: Vulnerability approach Stepwise: Catchment characteristics (quality, hydraulics,…) => Mapping + field investigations Orientated on German Guideline DVGW W101 and international guidelines in fissured/karstic aquifers (eg Cost620, Switzerland) 15

2. Actual Re-Delineation of » Zones de protection » Example: Spring catchement with high risk ( high vulnerability) ZIII: Wider protection zone (catchment area) ZII: Closer protection zone ( 50 days travel time) ZII-V1: Closer protection zone with higher vulnerability (preferential flows, infiltrations) ZI: Immediate protection zone (20 meters upgradient to catchment ) 16

2. Actual Re-Delineation of » Zones de protection » Example: Abstraction boreholes in a confined aquifer (low vulnerability)  good protection no closer protection zone wider protection zone delineation: - according to abstraction regime (limited to 4 month/year) - consideration of increasing future abstraction rate - numerical modelling  Additional monitoring wells Wider protection Zone (+/-2km) Abstraction boreholes Additional monitoring wells 17

2. Actual Re-Delineation of » Zones de protection » Risk categories according to table 1 GD- N016 Delimitation of protection zones LU Monitoring and measures Type 1: Low Risk, General Protection Zones - Wider Pz - Specific monitoring possible (additionnal stations, frequences) - Measures related to type of zone Type 2: Moderate Risk Precautionary Protection - Wider PZ - Closer PZ - Specific monitoring possible(additionnal stations, frequences) Type 3: High Risk Specific Protection - High vulnerability PZ 18

2. Actual Re-Delineation of » Zones de protection » Example: Abstraction spring catchments (Lux. Sandstone) Challenging situations: Rapid transit times (up to 60m/ hour) No preferential infiltration Depth groundwater table at depth of 30-60m Identification of high risk zone ( ZII-V1)  difficult Very large extension of zone II ( 50 days transit times) 19

3. Discussions relative to Guidance Document No16 Delineation of zones of potential abstraction not always useful «DWPAs are whole groundwater bodies » ? Further guidances in relation to risk based approach. More experience exchanges eg. with case studies spring catchment and specific hydrogeological settings (eg fissured aquifers). Harmonized methodology in transboundary GWB.   20

Thank you! 21