Groundwater Management in Urban Area
N.Dörfliger
of Water, Environment & Ecotechnologies division
Changsha, May 2014
ASEM Seminar on Sustainable Management of Water resources in the context of urbanization
> 2 Water, Environment & Ecotechnologies division
> Outline • Urban water cycle framework
– Role of the groundwater and of reclaimed water
– Urbanization and water supply in the world and with a focus in Asia
– Groundwater abstraction for water supply in India and in China
• Groundwater management
– In terms of quantity with contribution of groundwater modeling to face water demand
– In terms of early warning system for flooding
– In terms of groundwater protection and vulnerability
– In terms of reclaimed water
• Conclusions and Perspectives
Urban water cycle - facts Groundwater management Conclusions - Perspectives
> 3 Water, Environment & Ecotechnologies division
Urban water cycle - facts Groundwater management Conclusions - Perspectives
Storm water
Water supply
Wastewater
Groundwater River Reservoir/Lake Alternative source (reuse, desalinization)
Potential resource Reuse of water Reclaimed water
Sewer capacities Water treatment standards
Water quality Potential resource Flooding control and mitigation
Reduce leaking of pipes Protection scheme - vulnerability
> 4 Water, Environment & Ecotechnologies division
In 2015, > 50% of all people on earth, about 4 billions of people are expected to live in urban areas
Asia is strongly concerned for large urban centers
The increase of urban density More than one habitant of the world/two leaves in town. Acceleration of the trend Population of the 30 largest urban centers In millions More than
Evolution of worldwide population
In billions
Urbanization and Wsupply Groundwater management Conclusions - Perspectives
> 5 Water, Environment & Ecotechnologies division
Groundwater abstraction in India i.e. : Today, 89% of groundwater abstraction are for irrigation needs (70% of irrigation needs) and 9% of groundwater abstraction are for water supply, covering 80% of domestic water supplies; 251 km3/year in 2010 , Groundwater abstraction in total Groundwater abstraction in China : 20 % of groundwater = urban water supply ; overexploitation with geological hazards and environmental issues; 112km3/year in 2010 of Groundwater abstraction in total
Urbanization and Wsupply Groundwater management Conclusions - Perspectives
Source: Margat, J., and J. van der Gun. 2013. Groundwater around the World, CRC Press/Balkema
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Groundwater management issues in urban areas – variety of groundwater types
Local and shallow aquifers Groundwater basins Complex hydrogeological structures (karst, hard rock, …)
Urbanization and Wsupply Groundwater management Conclusions - Perspectives
> 7 Water, Environment & Ecotechnologies division
Groundwater management issues in urban areas - In terms of quantity with conjunctive use with surface water and alternative
water such as reclaimed water - Needs of monitoring Groundwater level through appropriated network, as well as abstraction
volumes and of modeling various demand scenarios in order to avoid overexploitation and linked problems : subsidence, quality problems.
Modified from Foster et al 1998
Urbanization and Wsupply Groundwater management Conclusions - Perspectives
> 8 Water, Environment & Ecotechnologies division
Groundwater management issues in urban areas Overexploitation due to increase of water demand => cone of depression in
groundwater of several decades of m depth Needs to set up various scenarios for remediation, and to carry out modeling
Urbanization and Wsupply Groundwater management Conclusions - Perspectives
Here example of Shanghai Illustration with similar situations in 1970’s in Bordeaux urban area in South West France
Y. Zhou et al Physics and Chemistry of the Earth 47–48 (2012) 99–113
> 9 Water, Environment & Ecotechnologies division
Groundwater management issues in urban area – Bordeaux (SW France)
Urbanization and Wsupply Groundwater management Conclusions - Perspectives
Illustration 8 : Carte des volumes prélevés par bassin versant et par usage
Consequences of an intense development In Eocene: depression of GW level in Bordeaux area In Oligocene: dewater of sectors
A threatened Gw ressource 65% of GW used for Water supply In quantity: - Eocene: renewal compromise - Oligocene: decrease of spring discharges In quality: - Eocene: possible salt water intrusion - Oligocene: increased vulnerability to
surface pollutions
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Groundwater management issues in urban areas Example of MONA model in Bordeaux area (South West France)
Urbanization and Wsupply Groundwater management Conclusions - Perspectives
- 15 layers from Plio Quaternary to Bajocian - 66953 meshes of calculation (2km x 2Km) - Pseudo 3D model (no explicit scheme for
impervious layers) - Year time step from 1972 – 2013 - 3248 capture works - 400 groundwater level time series
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Groundwater management issues in urban areas
Urbanization and Wsupply Groundwater management Conclusions - Perspectives
Simulation of scenarios and also recently concerning Climate changes MONA model = a decision support tool, running every year and update of the model
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Urbanization and Wsupply Groundwater management Conclusions - Perspectives
Groundwater management – mitigation of flooding where groundwater contributes to floods, i.e. in karst aquifers area, through determining the proof of GW contribution, and groundwater level and saturation index of soil and sub-soil within warning systems
Example Of catchment Of La fontaine de Nîmes Spring (Nîmes town – South France)
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Groundwater management – mitigation of flooding where groundwater contributes to floods, i.e. in karst aquifers area, through determining the proof of GW contribution, and groundwater level and saturation index of soil and sub-soil within warning systems
Urbanization and Wsupply Groundwater management Conclusions - Perspectives
Taking into consideration initial water saturation of soil and of aquifer within a real time warning system Valorisation of groundwater level => Reservoirs modeling Warning chart for
forecasting
Rainfall cumul (mm)
Wat
er
leve
l of
ind
ex (
gw s
atu
rati
on
) –
m a
.s.l
Level 1 vigilance
Level 2 overflow
Level 3 historical
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Groundwater management – groundwater protection scheme (protection zones) and vulnerability mapping - Example of Montpellier (South France ) and urban area
Urbanization and Wsupply Groundwater management Conclusions - Perspectives
> 15 Water, Environment & Ecotechnologies division
Groundwater management – groundwater protection scheme (protection zones) and vulnerability mapping - Example of Montpellier (South France ) and urban area
Urbanization and Wsupply Groundwater management Conclusions - Perspectives
Very high vulnerability
High vulnerability
Moderate vulnerability
Low vulnerability
A support to cross with occupation of soil, activities, in order to define risk sectors and as well protection measures such as protection perimeters of capture work => A decision tool for planning
Risk index Global vulnerability PaPRIKa method
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Groundwater management and reclaimed water – Management aquifer and soil treatment concept under a variety of environmental conditions (hard rock and granular aquifers, ephemeral streams, …)
Urbanization and Wsupply Groundwater management Conclusions - Perspectives
Influence of infiltration pond To the recharge of the aquifer Water budget, using isotopic analyses of rainfall and gw Electrical conductivity of Gw
Gajuel catchment – peri urban area of Hyderabad, India
> 17 Water, Environment & Ecotechnologies division
Groundwater management and reclaimed water – Management aquifer and soil treatment concept under a variety of environmental conditions (hard rock and granular aquifers, ephemeral streams, …)
Urbanization and Wsupply Groundwater management Conclusions - Perspectives
Importance of maintenance of ponds in order to optimize infiltration
Survey of quality impact (chemistry, microbiology)
> 18 Water, Environment & Ecotechnologies division
Groundwater management and reclaimed water – Management aquifer and soil treatment concept under a variety of environmental conditions (hard rock and granular aquifers, ephemeral streams, …)
Urbanization and Wsupply Groundwater management Conclusions - Perspectives
Optimization of waste water treatments through combined geomaterials and natural soil filter, reactive geobarriers
Optimizing treatment of wastewater using natural soil system for infiltration ponds • Mechanical filtration of organics and heavy metals • Oxidative degradation of Dissolved Organic Matter and ammonium
From pilot column to geo barriers ponds From experimental data to transport reactive modeling (MARTHE © brgm + MIN3P (Mayer et al. 2002))
Monitoring of
water level
Fixed hydraulic Head
Porous cups
Geochemical monitoring of outlet solution
Non saturated
biogeochemical
transfert reactive
model
Secondary effluent of
Waste water
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Groundwater management and reclaimed water – MAR
Urbanization and Wsupply Groundwater management Conclusions - Perspectives
Optimization of waste water treatments through combined geomaterials and natural soil filter, reactive geobarriers
Consumption of CH2O reproduced at the column outlet after 30 numerical tests
Adjustment of kinetic redox processes coefficients
Modelling artifact
Waste water
Column outlet
Ntot Column outlet
NO3- Column outlet
NO3- Waste water
NH
4+
mo
l/L
N
O3- m
ol/
L
Slight overestimation of nitrification processes: All NH4
+ transformed in NO3-
NO3- matches with Ntot
Production of N2 = denitrification with CH2O degradation and pyrite oxidation Ntot initial=3.15 x10-3 mol/L Ntot final=1.44 x10-3 mol/L
Pettenati et al. 2011 WaterReuse Barcelona
> 20 Water, Environment & Ecotechnologies division
- Groundwater = high potential resource for urban area
- Strong development with potential problems of susbidence, quality problems
- Importance of adequate managing in terms of quantity and quality, with conjuncture use of surface water and reclaimed water, of integrated management approach
- MAR – important concept through infiltration ponds to improve infiltration, or geomaterials barrier in order to strengthen purification process
Thank you for your attention !
Urbanization and Wsupply Groundwater management Conclusions - Perspectives
