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- In-channel managed aquifer recharge: a review of current development worldwide and future potential in EuropePublication . Standen, Kathleen; Costa, Luis; Monteiro, José PauloManaged aquifer recharge (MAR) schemes often employ in-channel modifications to capture flow from ephemeral streams, and increase recharge to the underlying aquifer. This review collates data from 79 recharge dams across the world and presents a reanalysis of their properties and success factors, with the intent of assessing the potential of applying these techniques in Europe. This review also presents a narrative review of sand storage dams, and other in-channel modifications, such as natural flood management measures, which contribute to the retardation of the flow of flood water and enhance recharge. The review concludes that in-channelMARsolutions can increase water availability and improve groundwater quality to solve problems a ecting aquifers in hydraulic connection with temporary streams in Europe, based on experiences in other parts of the world. Therefore, to meet the requirements of the Water Framework Directive (WFD), in-channel MAR can be considered as a measure to mitigate groundwater problems including saline intrusion, remediating groundwater deficits, or solving aquifer water quality issues.
- Integration of managed aquifer recharge into the water supply system in the Algarve region, PortugalPublication . Standen, Kathleen; Costa, Luís; Hugman, Rui; Monteiro, José PauloThe Algarve region of Portugal is experiencing severe water scarcity with existing water supplies insufficient to meet demand, with limited resilience to drought. Managed aquifer recharge (MAR) can provide intermediate storage and bridge the gap between water availability and demand, with success depending on the water available and the aquifer capacity to accept and store the water. We present the results of a regional study quantifying both these aspects to estimate the regional potential for MAR. Our results demonstrate that MAR can comprise 10% of the total water demand of the region (24 Mm3/yr) using water that is not otherwise captured, with quality that meets the requirements of the Groundwater Directive. MAR can replace 15 Mm3/yr of surface water used in the public irrigation perimeters and 9 Mm3/yr can be used to develop and maintain a strategic groundwater resource in the aquifers of the Central Algarve. Although climate change is predicted to result in an 8–13% decrease in MAR recharge, this can be addressed by incrementally increasing MAR design capacity. MAR has similar water resource benefits to the planned major infrastructure projects (desalination and River Guadiana abstraction), with reduced environmental impacts and lower costs than almost all feasible alternatives. We conclude that MAR is an important measure to increase water supply security and drought resilience in the Algarve region.
- Decision-support groundwater modelling of managed aquifer recharge in a Coastal Aquifer in South PortugalPublication . Standen, Kathleen; Hugman, Rui; Monteiro, José PauloThe Vale do Lobo sector of the Campina de Faro aquifer system in the Algarve (Portugal) is at risk of seawater intrusion. Managed Aquifer Recharge (MAR) is being considered to avoid groundwater quality deterioration. Numerical modelling was undertaken to assess the feasibility of several proposed MAR schemes. Although some data is available, many aspects of system behaviour are not well understood or measured. We demonstrate the use of a structurally simple but parametrically complex model for decision-making in a coastal aquifer. Modelling was designed to facilitate uncertainty reduction through data assimilation where possible, whilst acknowledging that which remains unknown elsewhere. Open-source software was employed throughout, and the workflow was scripted (reproducible). The model was designed to be fast-running (rapid) and numerically stable to facilitate data assimilation and represent prediction-pertinent uncertainty (robust). Omitting physical processes and structural detail constrains the type of predictions that can be made. This was addressed by assessing the effectiveness of MAR at maintaining the fresh-seawater interface (approximated using the Ghyben-Herzberg relationship) below specified thresholds. This enabled the use of a constant-density model, rather than attempting to explicitly simulating the interaction between fresh and seawater. Although predictive uncertainty may be increased, it is outweighed by the ability to extract information from the available data. Results show that, due to the limit on water availability and the continued groundwater extraction at unsustainable rates, only limited improvements in hydraulic heads can be achieved with the proposed MAR schemes. This is an important finding for decision-makers, as it indicates that a considerable reduction in extraction in addition to MAR will be required. Our approach identified these limitations, avoiding the need for further data collection, and demonstrating the value of purposeful model design.
- Integration of managed aquifer recharge into the water supply system in the Algarve region, PortugalPublication . Standen, Kathleen; Costa, Luís; Hugman, Rui; Monteiro, José PauloThe Algarve region of Portugal is experiencing severe water scarcity with existing water supplies insufficient to meet demand, with limited resilience to drought. Managed aquifer recharge (MAR) can provide intermediate storage and bridge the gap between water availability and demand, with success depending on the water available and the aquifer capacity to accept and store the water. We present the results of a regional study quantifying both these aspects to estimate the regional potential for MAR. Our results demonstrate that MAR can comprise 10% of the total water demand of the region (24 Mm(3)/yr) using water that is not otherwise captured, with quality that meets the requirements of the Groundwater Directive. MAR can replace 15 Mm(3)/yr of surface water used in the public irrigation perimeters and 9 Mm(3)/yr can be used to develop and maintain a strategic groundwater resource in the aquifers of the Central Algarve. Although climate change is predicted to result in an 8-13% decrease in MAR recharge, this can be addressed by incrementally increasing MAR design capacity. MAR has similar water resource benefits to the planned major infrastructure projects (desalination and River Guadiana abstraction), with reduced environmental impacts and lower costs than almost all feasible alternatives. We conclude that MAR is an important measure to increase water supply security and drought resilience in the Algarve region.