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Aquifers of the Scheldt basin. Testing the guidance document WATECO & IMPRESS groups Gabrielle Bouleau (ENGREF) & Arnaud Courtecuisse (AEAP). WFD objectives for aquifers. The WFD indicates in Article 4 : - PowerPoint PPT Presentation
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Aquifers of the Scheldt basin
Testing the guidance documentWATECO & IMPRESS groups
Gabrielle Bouleau (ENGREF)
& Arnaud Courtecuisse (AEAP)
WFD objectives for aquifers
• The WFD indicates in Article 4 :(ii) Member States shall protect, enhance and
restore all bodies of groundwater, ensure a balance between abstraction and recharge of groundwater, with the aim of achieving good groundwater status at the latest 15 years after the date of entry into force of this Directive,
Questions for the testing
• Do abstractions exceed the natural recharge (today and in the baseline scenario)?
• If so, what are the possible measures and their cost-effectiveness ?
Selection of the case study
• Carboniferous limestone – International Groundwater in the Scheldt basin
• over-exploited• competition between industries• national strategies to avoid a common assessment
– Different definitions of the aquifer• no comparable data
Leie
Scheldt
NORD
Chalkaquifer
Coal
Paleozoic
CarboniferousLimestone aquifer
A : holocene andpleistocene
B : eocene andoligocene
Selection of the case study
• Chalk aquifer around Lille area • National groundwater in the Scheldt basin• over-exploitation and pollution• alternative resource of the carboniferous
limestone• existing coherent data
The 3-steps approach
• Characterisation of groundwaters– 1. Definition of relevant hydrogeological units– 2. Assessment of the natural recharge of each unit– 3. Assessment of abstractions from each unit– 4. Structure of the demand – 5. Evolution of the demand
• Future demand versus natural recharge (gap assessment)
• Cost-effectiveness analysis of possible measures
The 3-steps approach
• Characterisation of groundwaters– 1. Definition of relevant hydrogeological units– 2. Assessment of the natural recharge of each unit– 3. Assessment of abstractions from each unit– 4. Structure of the demand – 5. Evolution of the demand
• Future demand versus natural recharge (gap assessment)
• Cost-effectiveness analysis of possible measures
Relevant units: assumptions
Seepage
Rainfall +reinfiltration
Naturalevapo-transpiration
rivers
abstractions
abstractions
piezometryabstraction
Rainfall +reinfiltration
abstractions
70 %
Pool model
Relevant units in Lille area
Lille Mélantois
RoubaixTourcoing
MouvauxArmentières
Béthune
Lens
La madeleineSt André
Séclin
La lys
La Deûle LaMarque
Flers enEscrébieux
DouaiPecquencourt
Aire surla Lys
Verchin
La ScarpeBassin d ’Orchies
Abstraction areas
Geographical region
Urban area of Lille
Limit ofgroundwatershed
carboniferous
Relevant units in Lille area
North ofMélantois
South ofMélantois
Bassind’Orchies
Verchin
La Lys
Abstractions
Rainfall
Pool of groundwater
River Inflow and outflow of the river
Abstractionin order toincrease theLysdischarge
Carboniferous
The 3-steps approach
• Characterisation of groundwaters– 1. Definition of relevant hydrogeological units– 2. Assessment of the natural recharge of each unit– 3. Assessment of abstractions from each unit– 4. Structure of the demand – 5. Evolution of the demand
• Future demand versus natural recharge (gap assessment)
• Cost-effectiveness analysis of possible measures
Natural recharge of each unit
Pools Natural recharge (source BRGM)North of Mélantois 19,5 Mn m3/yr = 53 400 m3/daySouth of Mélantois 22,5 Mn m3/yr = 61 600 m3/dayBasin of Orchies unknownLys at Aire sur la Lys unknownCenomanian in Verchin unknownCarboniferous limestone 50 Mn m3/yr =137 000 m3/day
Different definitions: different values
The 3-steps approach
• Characterisation of groundwaters– 1. Definition of relevant hydrogeological units– 2. Assessment of the natural recharge of each unit– 3. Assessment of abstractions from each unit– 4. Structure of the demand – 5. Evolution of the demand
• Future demand versus natural recharge (gap assessment)
• Cost-effectiveness analysis of possible measures
Abstractions from each unit
Municipality
Domestic users
Industrial users
Municipal uses
Losses
Agricultural users
Industrial users
agricultural users
Domestic individual users
Information registeredby water agencies andState offices
Information registered bypublic water services
Often underestimated
The 3-steps approach
• Characterisation of groundwaters– 1. Definition of relevant hydrogeological units– 2. Assessment of the natural recharge of each unit– 3. Assessment of abstractions from each unit– 4. Structure of the demand – 5. Evolution of the demand
• Future demand versus natural recharge (gap assessment)
• Cost-effectiveness analysis of possible measures
Structure of the demand
0
20 000
40 000
60 000
80 000
100 000
120 000
m3/dayH
ouse
hold
s
Mun
icip
aliti
es
Indu
stry
Agr
icul
ture
Leak
ages
Lille
indu
strie
lle
Oth
erm
unic
ipal
ities
Data for 2000
The 3-steps approach
• Characterisation of groundwaters– 1. Definition of relevant hydrogeological units– 2. Assessment of the natural recharge of each unit– 3. Assessment of abstractions from each unit– 4. Structure of the demand – 5. Evolution of the demand
• Future demand versus natural recharge (gap assessment)
• Cost-effectiveness analysis of possible measures
Evolution of the demand
• no change in the population and economic developments• no change in consuming behaviours• no change in distribution of abstraction
• Consequences by the year 2015:• same situation as in 2000, no measure implemented.
To be negotiated
The 3-steps approach
• Characterisation of groundwaters– 1. Definition of relevant hydrogeological units– 2. Assessment of the natural recharge of each unit– 3. Assessment of abstractions from each unit– 4. Structure of the demand – 5. Evolution of the demand
• Future demand versus natural recharge (gap assessment)
• Cost-effectiveness analysis of possible measures
Gap assessmentGroundwater pool Abstraction for
the area ofLille in m3/day
proportion rechargein m3/day
rateabstraction/recharge
Carboniferous 30 000 16% unknownNorth of Mélantois 26 000 14% 53 000 49 %South of Mélantois 64 000 34% 61 000 105 %Basin of Orchies 31 000 16% unknownLys river 38 000 20% unknownTotal 189 000 100%
Target for the testing: 70 % 10 200 m3/day needed
The 3-steps approach
• Characterisation of groundwaters– 1. Definition of relevant hydrogeological units– 2. Assessment of the natural recharge of each unit– 3. Assessment of abstractions from each unit– 4. Structure of the demand – 5. Evolution of the demand
• Future demand versus natural recharge (gap assessment)
• Cost-effectiveness analysis of possible measures
Cost-effectiveness of measures
0
20 000
40 000
60 000
80 000
100 000
120 000
m3/dayH
ouse
hold
s
Mun
icip
aliti
es
Indu
stry
Agr
icul
ture
Leak
ages
Lille
indu
strie
lle
Oth
erm
unic
ipal
ities
Reduction of losses
Communication campaign for reduction of the water demand
Communication campaign
Population Cost water-savings Alcobendas 100 000 410 600 1 650Lille area 1 000 000 10 200
m3/inhabitant Cost (E) /inhabitantAlcobendas 6 4,106Lille area 3,72 2,55
Global cost of 2 550 000 Euros for Lille Area
Less water income Less maintenance ?Higher price ?
Conclusion of the testing
• Relevant scale: • public water services + self services
• to take into account possible shifts
• Natural recharge and abstractions assessment• Strategic information
• Common monitoring needed
• Indirect effects of water savings• feedbacks on price or maintenance
