Excess irrigation as a MAR technique is used on irrigated farmland where excess water is available and is spread over the area during dormant or non-irrigated seasons to allow for aquifer recharge. Excess irrigation has possible benefits over other traditional MAR techniques. Irrigated agricultural areas are available worldwide and already have the required infrastructure to connect these areas to water sources. It further does not compete with other land uses and gives farmland a second beneficial purpose. Effects of water- intensive agriculture (declining water tables) can be buffered through application of this method.
| Typical system capacity scale | Household – Town (≈102m3/year – ≈106 m3/year). |
| Geology | Unconfined aquifers composed of permeable sedimentary rocks. |
| Topography | Preferably flat or gentle sloped terrain but slope characteristics can be interrupted to enhance water infiltration. |
| Soils | Permeable soils able to guaranty water quality standards to the target aquifer. |
| Water source | Source of irrigation water. |
| Pre-treatment | Depending on water source quality. |
| MAR main objective | Agriculture. |
| Relative cost | Low. |
Advantages and disadvantages of the system (adapted from IGRAC, 2007):
Advantages
- No competition with other land uses.
- Relative low cost because existing irrigation infrastructure can be used.
- Broad areas may be used for aquifer recharge.
Limitations
- Can be applied only to unconfined aquifers.
- Can be applied only on croplands where excess water can be provided.
- Depends on specific site cropping cycles.
- Require growers to engage additional coordination issues beyond conventional irrigation for farming.
- Potential of soil and aquifer pollution with nutrients and salt concentration on the soil profile.
Case studies
Further information
References
- IGRAC. (2007). Artificial Recharge of Groundwater in the World.
- DEMEAU. (2014). Characterization of European managed aquifer recharge (MAR) sites – Analysis.