This case study consists of two types of aquifer recharge: open pond infiltration and deep well injection. These aquifer recharge systems are located in the dune area North of The Hague (Den Haag in Figure 1) and they are operated by Dunea, the water company that supplies water to The Hague and nearby cities and communities. The Meuse river is the source for the drinking water produced by Dunea and a typical multi-barrier treatment approach ensures that the drinking water meets the high Dutch quality standards. Dunea’s multi-barrier consists of three main treatment steps: pre-treatment (coagulation) of surface water, infiltration in and recovery from the dune aquifer system (Managed Aquifer Recharge, MAR), and a post-treatment including dosing of activated carbon. The drinking water is, in this way, distributed chlorine-free to the costumers. These MAR systems started around 1950 with 36 infiltration ponds that were supplemented with 22 injection wells in 1980, as an answer to an increase in the demand, providing nowadays around 48 m3/year.
MAR profile:
Attribute |
SCHEVENINGEN |
Waalsdorp |
|
---|---|---|---|
General information |
Country |
Netherlands |
Netherlands |
City |
Den Haag |
Den Haag |
|
Site name |
Scheveningen |
Waalsdorp |
|
Operator name |
DUNEA |
DUNEA |
|
Type of MAR |
Dune infiltration |
Aquifer transfer and recovery |
|
Year commenced |
1954 |
1990 |
|
Current status |
Full operation |
full operational |
|
Map coordinates |
52.108686/ 4.272546 |
52.097; 4.312 |
|
Operational scale (Mm3/a) |
46 |
1 |
|
Objective |
Drinking water production |
Drinking water production |
|
Capture zone |
Influent source |
River water |
river water |
Pre-treatment |
Source water treatment before recharge |
Coagulation micro strainer rapid sand filtration
|
coagulation micro strainer rapid sand filtration flotation activated carbon |
Recharge |
No of recharge facilities |
36 |
22 |
Hydraulic loading rate (m3/m2 d) |
5 |
|
|
Recharged volume (Mm3/a) |
45 |
1.8 |
|
Sub-surface |
Residence time (d) |
Min 28 days | Max 70 days | Mean 48 days
|
Min 100 | Max 200 | Mean 112 |
Aquifer properties |
Range of hydraulic conductivity representative of the target aquifer (m/s) 1×10-4 – 1×10-5
|
Range of hydraulic conductivity representative of the target aquifer (m/s) 1×10-2 | 1×10-3 | 1×10-4 | 1×10-5 | 1×10-6 |
|
Lithology of target aquifer: porous |
Lithology of target aquifer: porous |
||
Thickness of unsaturated zone (m) 5 - 7
|
Thickness of unsaturated zone (m) 0 |
||
Thickness of target aquifer (m) 55 |
Thickness of target aquifer (m) 45 |
||
Recovery |
Distance of recovery wells from point of recharge (m) |
65 |
110 |
Recovered volume (m3/a) |
46 |
1.8
|
|
Recovered infiltrate (%) |
80-100 |
80-100 |
|
No of recovery facilities |
12 km drains, 1200 phreatic wells |
24 wells |
|
Post-treatment |
Water treatment after recovery |
Softening | activated carbon | aeration | rapid and slow sand filtration | |
Softening | activated carbon | aeration | rapid and slow sand filtration |
|
End-use |
domestic (drinking water) |
domestic (drinking water)
|