The use of regional groundwater flow characteristics for optimized screening of MAR potential and application conditions

Abstract

Managed Aquifer Recharge (MAR) interventions are usually designed for local water availability. However, regional hydrogeological conditions can be of major influence on the suitability and performance, depending on MAR type and size. Therefore, to facilitate site selection and suitable MAR scheme design and conditions, it is important to incorporate aspects of the groundwater flow systems for which MAR is considered thus reducing risks of the operation and avoiding failures. For this purpose, the regional groundwater flow theory was introduced to the MAR concept in this research. The aim is the understanding of hydrogeological behaviour on a broader basin scale, taking into account processes affecting the local conditions but might originate far from the local study site. Considering the natural characteristics of the system, e.g. groundwater flow directions, intensity and surface water-groundwater interaction, will allow design for optimal operation for the intended goal of MAR such as providing the highest recovery efficiency for ASR facilities. Besides hydrogeological factors, on a regional scale, the extent of MAR to contribute to ensuring sustainable water availability will depend on temporal and spatial distributions of often a variety of water sources and demands in both quantity and quality. This will also influence for example whether many smaller MAR systems are preferred over a few large-scale MAR systems. Based on theoretical considerations and numerical simulations, the suitability of different MAR types depends strongly on the local characteristics of the regional groundwater flow system. 1) Spreading methods, which are based on the infiltration of water by gravity, cannot be realised at a discharge area. 2) At a recharge area, the water can be injected quite easily without any excess energy investment. 3) Local flow systems with shorter characteristic residence time are the targets for short-term socioeconomic use. However, longer residence times are required for treated water due to the natural decay of components by bio-physico-chemical processes and filtering. This is especially important in a regional context, where all water demands (highlighting the environmental needs) should be considered and MAR is applied for environmental benefits. Overall, regional groundwater flow system characteristics in evaluating MAR potential and scheme selection will allow the more efficient site and MAR type selection as well as optimize MAR performance.

Full text

The use of regional groundwater flow characteristics for optimized
screening of MAR potential and application conditions
Ádám Tóth1, Marijke Huysmans2, Niels Hartog3,4, Catalin Stefan5, Judit Mádl-Szőnyi1
1 József & Erzsébet Tóth Endowed Hydrogeology Chair, Department of Geology, ELTE Eötvös Loránd
University, Budapest, Hungary
2 Department of Hydrology and Hydraulic Engineering, Vrije Universiteit Brussel, Brussels, Belgium
3 KWR Water Research Institute, Nieuwegein, the Netherlands
4 Department of Earth Sciences, University of Utrecht, the Netherlands
5 INOWAS Research Group, Faculty of Environmental Sciences, Technical University of Dresden,
Germany
Managed Aquifer Recharge (MAR) interventions are usually designed for local water
availability. However, regional hydrogeological conditions can be of major influence on
the suitability and performance, depending on MAR type and size. Therefore, to
facilitate site selection and suitable MAR scheme design and conditions, it is important
to incorporate aspects of the groundwater flow systems for which MAR is considered
thus reducing risks of the operation and avoiding failures. For this purpose, the regional
groundwater flow theory was introduced to the MAR concept in this research. The aim
is the understanding of hydrogeological behaviour on a broader basin scale, taking into
account processes affecting the local conditions but might originate far from the local
study site. Considering the natural characteristics of the system, e.g. groundwater flow
directions, intensity and surface water–groundwater interaction, will allow design for
optimal operation for the intended goal of MAR such as providing the highest recovery
efficiency for ASR facilities.
Besides hydrogeological factors, on a regional scale, the extent of MAR to contribute
to ensuring sustainable water availability will depend on temporal and spatial
distributions of often a variety of water sources and demands in both quantity and
quality. This will also influence for example whether many smaller MAR systems are
preferred over a few large-scale MAR systems. Based on theoretical considerations
and numerical simulations, the suitability of different MAR types depends strongly on
the local characteristics of the regional groundwater flow system. 1) Spreading
methods, which are based on the infiltration of water by gravity, cannot be realised at
a discharge area. 2) At a recharge area, the water can be injected quite easily without
any excess energy investment. 3) Local flow systems with shorter characteristic
residence time are the targets for short-term socio-economic use. However, longer
residence times are required for treated water due to the natural decay of components
by bio-physico-chemical processes and filtering. This is especially important in a
regional context, where all water demands (highlighting the environmental needs)
should be considered and MAR is applied for environmental benefits.
Overall, regional groundwater flow system characteristics in evaluating MAR potential
and scheme selection will allow the more efficient site and MAR type selection as well
as optimize MAR performance.