| Records |
| Author |
Van Putte, N. |
| Title |
Improving groundwater dynamics : a key factor for successful tidal marsh restoration |
Type |
Doctoral thesis |
Year  |
2023 |
Publication |
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Abbreviated Journal |
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| Volume |
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Issue |
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Pages |
166 p. |
| Keywords |
Doctoral thesis; Sustainable Energy, Air and Water Technology (DuEL); Ecosphere |
| Abstract |
Tidal marshes take up and release certain elements from and to the river water. Hence, they act as a filter, improving the estuarine water quality. This filtering function depends on the interaction between the marsh soil and water that infiltrates into the marsh platform at high tide and seeps out of the creek banks at low tide. In the past centuries, many tidal marshes disappeared due to large scale land reclamations, together with their associated ecosystem services. Nowadays, tidal marshes are increasingly restored on formerly embanked agricultural areas to regain these ecosystem services. Here, we studied the effect of historical agricultural land use on the contribution of restored tidal marshes to water quality improvement, and we investigated several solutions to stimulate the water quality improving function in newly restored tidal marshes. In restored tidal marshes, the soil is often compacted due to the historical agricultural land use, leading to a reduced organic matter content and micro- and macroporosity. In this compacted soil, groundwater flow is hindered, leading to a more waterlogged soil and reduced groundwater dynamics in the restored marsh as compared to a natural marsh. The depth of groundwater drainage and the groundwater flow velocity have important implications for the processes that contribute to water quality improvement, e.g. removal of nitrogen, phosphorus retention and silica cycling. Where groundwater drains deeper, i.e. in the vicinity of tidal creeks and in a more porous soil, these processes are promoted. We suggest that, in newly restored tidal marshes, the soil porosity can be increased by amending the soil (e.g. with organic matter), and the distance to the nearest tidal creek can be reduced by creek excavation. Numerical modelling showed that the largest gain in groundwater dynamics and seepage was attained when both measures were applied together. The effect of organic soil amendments on groundwater dynamics and nutrient cycling was further explored in a large scale in situ mesocosm experiment. Where the soil was amended, groundwater drained deeper and nitrogen removal increased. For new tidal marsh restoration projects, we advise to conduct an explorative soil study. When the soil is heavily compacted, design measures, such as creek initiation and organic soil amendments can be applied to jumpstart the contribution to water quality improvement of newly restored tidal marshes. |
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Wos |
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Additional Links |
UA library record |
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Open Access |
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Approved |
Most recent IF: NA |
| Call Number |
UA @ admin @ c:irua:196965 |
Serial |
8884 |
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| Author |
Van Putte, N.; Meire, P.; Seuntjens, P.; Joris, I.; Verreydt, G.; Hambsch, L.; Temmerman, S. |
| Title |
Solving hindered groundwater dynamics in restored tidal marshes by creek excavation and soil amendments : a model study |
Type |
A1 Journal article |
| Year |
2022 |
Publication |
Ecological engineering: the journal of ecotechnology |
Abbreviated Journal |
Ecol Eng |
| Volume |
178 |
Issue |
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Pages |
106583-15 |
| Keywords |
A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL); Ecosphere |
| Abstract |
Groundwater fluxes in tidal marshes largely control key ecosystem functions and services, such as vegetation growth, soil carbon sequestration, and nutrient cycling. In tidal marshes restored on formerly embanked agricultural land, groundwater fluxes are often limited as compared to nearby natural marshes, as a result of historical agricultural soil compaction. To improve the functioning of restored tidal marshes, knowledge is needed on how much certain design options can optimize soil-groundwater interactions in future restoration projects. Based on measured data on soil properties and tidally induced groundwater dynamics, we calibrated and evaluated a 2D vertical model of a creek-marsh cross-section, accounting for both saturated and unsaturated groundwater flow and solute transport in a variably saturated groundwater flow model. We found that model simulations of common restoration practices such as soil amendments (increasing the depth of porous soil on top of the compact layer) and creek excavation (increasing the creek density) increase the soil aeration depth and time, the drainage depth and the solute flux, and decrease the residence time of solutes in the porewater. Our simulations indicate that increasing the depth to the compact layer from 20 cm to 40 cm, or increasing the creek density from 1 creek to 2 creeks along a 50 m marsh transect (while maintaining the total creek cross-sectional area), in both cases more than doubles the volume of water processed by the marsh soil. We discuss that this may stimulate nutrient cycling. As such, our study demonstrates that groundwater modelling can support the design of marsh restoration measures aiming to optimize groundwater fluxes and related ecosystem services. |
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Thesis |
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Place of Publication |
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Wos |
000795478200005 |
Publication Date |
2022-03-05 |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0925-8574 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.8 |
Times cited |
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Open Access |
OpenAccess |
| Notes |
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Approved |
Most recent IF: 3.8 |
| Call Number |
UA @ admin @ c:irua:186605 |
Serial |
7210 |
| Permanent link to this record |
