Groundwater Body Boundaries in a Hydrogeological Model: the case of Saarland (Germany)
Thomas WALTER Landesamt für Umwelt- und Arbeitsschutz Don-Bosco-Str. 1, D-66119 Saarbrücken Germany
Identification of Groundwater Bodies in Saarland Saarland
2568 km²
1.1 million inhabitants
415 inh./km²
GWBIdentification Workshop, Berlin of Groundwater GWB Boundaries Bodies inin Saarlanda hydrogeological Model: Saarland 15./1612.2011 GWB Identification
Groundwater body deli- GWB-Delineation neation is the first and most sensitive step!
Characterisation Therefore, groundwater bodies should be hydraulically and hy- drochemically as homogene- ous as possible Monitoring
but: Groundwater bodies Measurement plans also should have a reasonable size!
GWBIdentification Workshop, Berlin of Groundwater GWB Boundaries Bodies inin Saarlanda hydrogeological Model: Saarland 15./1612.2011 Schematic Vertical Section
Structural boundary
Stratigraphic boundary
Hydraulic b.
Political boundary NW SE
- kalk
Muschel- Upper Permian kalk
Devonian Triassic sandstone Carboniferous/ Lower Permian
GWBIdentification Workshop, Berlin of Groundwater GWB Boundaries Bodies inin Saarlanda hydrogeological Model: Saarland 15./1612.2011 Groundwater Bodies
GWBIdentification Workshop, Berlin of Groundwater GWB Boundaries Bodies inin Saarlanda hydrogeological Model: Saarland 15./1612.2011 Overall Groundwater Mineralisation
LTS TSC UPV CLP DSQ 2500 2000 1500 1000 500 0
5 1 6 8 9 11 13 14 15 7 10 16 2 3 4 12 Groundwater Body
GWBIdentification Workshop, Berlin of Groundwater GWB Boundaries Bodies inin Saarlanda hydrogeological Model: Saarland 15./1612.2011 Model Conception
Complexity, Degree no. of of fidelity parameters, costs and effort Aquifer simulator
Planning model
Simplification, uncertainty, Principle model
assumptions of the Saarland model Intended accuracy Intended accuracy range
Conceptual Model
GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 Geology and Hydrogeology
GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 Exemplary Profiles
Length of section: 24 km
Length of section: 54 km GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 Main Aquifer Geometry
GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 Layer Structure and Parametrisation Permeability [m/s] Layer Stratigraphy Starting Calibrated HÜK values values Quater- 1 Flood plains, terraces q -6 -4 -4 -4 -4 nary 10 – 10 10 10 - 5 ·10 Upper Keuper ko -5 -6 -6 2 Upper 10 9·10 9 ·10 Middle Keuper km Triassic Lower Keuper ku 3 10-6 - 10-4 5 ·10-6 5 ·10-6 Upper Muschelkalk mo2 -5 -3 -5 -5 4 Middle Upper Muschelkalk mo1 10 - 10 5 ·10 5 ·10 5 Triassic Middle Muschelkalk mm 10-9 - 10-7 5 ·10-8 5 ·10-8 Lower Muschelkalk mu 6 10-6 - 10-4 10-5 10-7 - 10-6 Lower Upper Buntsandstein so Triassic Middle Buntsandstein sm 7 10-5 - 10-3 5 ·10-5 10-6 - 10-4 Kreuznach facies ro3 Permian Upper Rotliegend ro1, ro2 8 <10-5 5 ·10-6 3 ·10-7 Lower Rotliegend ru -5 -6 -7 9 Carbo- Stephanian cst <10 5 ·10 3 ·10 10 niferous Westphalian cw <10-5 5 ·10-7 8 ·10-8 11 Devonian undifferentiated d <10-5 5 ·10-7 8 ·10-8
GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 Mean Long Term Groundwater Recharge Recharge: 406,5 Mio. m³/a i.e. ca. 160 mm/year
[mm/a]
GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 Final Mesh
187.835 nodes 280.648 elements Max distance between nodes: 200 m 11 layers
GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 EXEMPLARY RESULTS GW Surface and Geology
GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 GW surface map
GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 Depth to groundwater
GWB Workshop, Berlin 15./1612.2011 GWB AND HYDROGEOLOGICAL MODEL GWB Lebach Graben
GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 Protective Cover
GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 Quantitative Status of GWB
GWR (mm) GWR (l/s/km²) GWR (m³/a) source ÖWAV- 346,0 10,96 7.556.713 Südwest
GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 Lebach Graben
GW Recharge
Main aquifer
Carboniferous, low permeability
Carboniferous, very low permeability
GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 GWB and GW Catchment
GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 Eastern Saarland
GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 Central Saarland
GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 Conflicting Interests
Quantitive status Qualitive status
hydrochemically homogeneous groundwater catchment zones bodies
Additional factors also apply (politicals borders, pressure on resource etc. …)
GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 GWB delineation is highly subjective
„natural factors“ „subjective factors“
intentions Natural conditions GWB implementer professional skills
Availability of useful data
„administrative factors“
GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 Conclusion
Regional hydrogeological models are very effective tools: - -Flow conditions within a GWB - quantification of lateral and vertical exchanges between GWBs - quantification of exchanges between ground and surface waters - improved understanding of hydraulic conditions of measuring points - definition of residence time in unsaturated zone - forecasting of effectiveness of measurements - … Hydrogeological models can help to mitigate the influence of the „subjective factor“
Availability of suitable data, elevated costs and computing limitations of modern soft- and hardware are still the main hindrances for a broader application of regional hydrogelogical models
Use of 3D Models in geology and hydrogeology is the future!
GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011 GWB Workshop, Berlin GWB Boundaries in a hydrogeological Model: Saarland 15./1612.2011