Sustainability of fresh groundwater resources in fifteen major deltas around the world
Population growth, urbanization and intensification of irrigated agriculture in the world’s deltas boost the demand for fresh water, with extensive groundwater extraction as a result. This, in turn, leads to salt water intrusion and upconing, which poses a threat to freshwater and food security. Man...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2022-01-01
|
| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/aca16c |
| _version_ | 1797747249413881856 |
|---|---|
| author | J van Engelen G H P Oude Essink M F P Bierkens |
| author_facet | J van Engelen G H P Oude Essink M F P Bierkens |
| author_sort | J van Engelen |
| collection | DOAJ |
| description | Population growth, urbanization and intensification of irrigated agriculture in the world’s deltas boost the demand for fresh water, with extensive groundwater extraction as a result. This, in turn, leads to salt water intrusion and upconing, which poses a threat to freshwater and food security. Managing fresh groundwater resources in deltas requires accurate knowledge about the current status and behaviour of their fresh groundwater resources. However, this knowledge is scarcely present, especially for groundwater at larger depths. Here, we use three-dimensional variable-density groundwater model simulations over the last 125 ka to estimate the volume of fresh groundwater resources for 15 major deltas around the world. We estimate current volumes of onshore fresh groundwater resources for individual deltas to vary between 10 ^10 m ^3 and 10 ^12 m ^3 . Offshore, the estimated volumes of fresh groundwater are generally smaller, though with a considerably higher variability. In 9 out of 15 simulated deltas, fresh groundwater volumes developed over thousands of years. Based on current groundwater extraction and recharge rates, we estimate the time until in-situ fresh groundwater resources are completely exhausted, partly leading to groundwater level decline and mostly replacement with river water or saline groundwater. This straightforward analysis shows that 4 out of 15 deltas risk complete exhaustion of fresh groundwater resources within 300 m depth in 200 years. These deltas also suffer from saline surface water which means their groundwater resources will progressively salinize. With a fourfold increase in extraction rates, seven deltas risk a complete exhaustion within 200 years. Of these seven deltas, six suffer from saline surface water. We stress that the groundwater of these six vulnerable deltas should be carefully managed, to avoid non-renewable groundwater use. The progressive exhaustion of fresh groundwater resources in these deltas will hamper their ability to withstand periods of water scarcity. |
| first_indexed | 2024-03-12T15:49:07Z |
| format | Article |
| id | doaj.art-9d292ccd8ceb40099c85d895f21fec9a |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T15:49:07Z |
| publishDate | 2022-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-9d292ccd8ceb40099c85d895f21fec9a2023-08-09T15:18:49ZengIOP PublishingEnvironmental Research Letters1748-93262022-01-01171212500110.1088/1748-9326/aca16cSustainability of fresh groundwater resources in fifteen major deltas around the worldJ van Engelen0https://orcid.org/0000-0002-7628-2548G H P Oude Essink1https://orcid.org/0000-0003-0931-6944M F P Bierkens2https://orcid.org/0000-0002-7411-6562Unit Subsurface and Groundwater Systems , Deltares, Daltonlaan 600, 3584 BK Utrecht, The NetherlandsUnit Subsurface and Groundwater Systems , Deltares, Daltonlaan 600, 3584 BK Utrecht, The Netherlands; Department of Physical Geography, Utrecht University , Princetonlaan 10, 3584 BK Utrecht, The NetherlandsUnit Subsurface and Groundwater Systems , Deltares, Daltonlaan 600, 3584 BK Utrecht, The Netherlands; Department of Physical Geography, Utrecht University , Princetonlaan 10, 3584 BK Utrecht, The NetherlandsPopulation growth, urbanization and intensification of irrigated agriculture in the world’s deltas boost the demand for fresh water, with extensive groundwater extraction as a result. This, in turn, leads to salt water intrusion and upconing, which poses a threat to freshwater and food security. Managing fresh groundwater resources in deltas requires accurate knowledge about the current status and behaviour of their fresh groundwater resources. However, this knowledge is scarcely present, especially for groundwater at larger depths. Here, we use three-dimensional variable-density groundwater model simulations over the last 125 ka to estimate the volume of fresh groundwater resources for 15 major deltas around the world. We estimate current volumes of onshore fresh groundwater resources for individual deltas to vary between 10 ^10 m ^3 and 10 ^12 m ^3 . Offshore, the estimated volumes of fresh groundwater are generally smaller, though with a considerably higher variability. In 9 out of 15 simulated deltas, fresh groundwater volumes developed over thousands of years. Based on current groundwater extraction and recharge rates, we estimate the time until in-situ fresh groundwater resources are completely exhausted, partly leading to groundwater level decline and mostly replacement with river water or saline groundwater. This straightforward analysis shows that 4 out of 15 deltas risk complete exhaustion of fresh groundwater resources within 300 m depth in 200 years. These deltas also suffer from saline surface water which means their groundwater resources will progressively salinize. With a fourfold increase in extraction rates, seven deltas risk a complete exhaustion within 200 years. Of these seven deltas, six suffer from saline surface water. We stress that the groundwater of these six vulnerable deltas should be carefully managed, to avoid non-renewable groundwater use. The progressive exhaustion of fresh groundwater resources in these deltas will hamper their ability to withstand periods of water scarcity.https://doi.org/10.1088/1748-9326/aca16cgroundwatersalinitydeltasmodel |
| spellingShingle | J van Engelen G H P Oude Essink M F P Bierkens Sustainability of fresh groundwater resources in fifteen major deltas around the world Environmental Research Letters groundwater salinity deltas model |
| title | Sustainability of fresh groundwater resources in fifteen major deltas around the world |
| title_full | Sustainability of fresh groundwater resources in fifteen major deltas around the world |
| title_fullStr | Sustainability of fresh groundwater resources in fifteen major deltas around the world |
| title_full_unstemmed | Sustainability of fresh groundwater resources in fifteen major deltas around the world |
| title_short | Sustainability of fresh groundwater resources in fifteen major deltas around the world |
| title_sort | sustainability of fresh groundwater resources in fifteen major deltas around the world |
| topic | groundwater salinity deltas model |
| url | https://doi.org/10.1088/1748-9326/aca16c |
| work_keys_str_mv | AT jvanengelen sustainabilityoffreshgroundwaterresourcesinfifteenmajordeltasaroundtheworld AT ghpoudeessink sustainabilityoffreshgroundwaterresourcesinfifteenmajordeltasaroundtheworld AT mfpbierkens sustainabilityoffreshgroundwaterresourcesinfifteenmajordeltasaroundtheworld |