Groundwater Vulnerability and Delineation of Protection Zones in the Discharge Area of a Karstic Aquifer—Application in Agyia’s Karst System (Crete, Greece)
This work represents a contribution to the protection techniques of karst aquifers against groundwater pollution. The paper sets out the methodology being introduced for the protection of the karstic system that gives rise to five (5) major groups of springs and supplies fourteen (14) pumping wells...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-01-01
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| Series: | Water |
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| Online Access: | https://www.mdpi.com/2073-4441/15/2/231 |
| _version_ | 1797436420986503168 |
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| author | Emmanouil Steiakakis Dionysios Vavadakis Ourania Mourkakou |
| author_facet | Emmanouil Steiakakis Dionysios Vavadakis Ourania Mourkakou |
| author_sort | Emmanouil Steiakakis |
| collection | DOAJ |
| description | This work represents a contribution to the protection techniques of karst aquifers against groundwater pollution. The paper sets out the methodology being introduced for the protection of the karstic system that gives rise to five (5) major groups of springs and supplies fourteen (14) pumping wells near Agyia Chania (Crete, Greece). Starting from a geological and hydrogeological survey of the area, the work presents a vulnerability assessment of the karstic aquifer based on the application of three index-based methods (EPIK, PRESK and DRISTPI). The protection zones for the discharge area of the aquifer were delineated through an integrated geomorphological approach and groundwater flow modeling. At first, the risk of polluting substances migration from ground surface to groundwater was considered based on the spatial distribution of vulnerability. Following this, the vulnerability was evaluated in the saturated zone, where the attenuation mechanisms of contaminants were reducing due to the raised flow velocity. The groundwater flow and contaminant transport processes was considered using the MODFLOW code. Next, the data from the vulnerability mapping and the groundwater flow simulation were merged into an integrated assessment to delimit the protection zones for the water abstraction points. The vulnerability assessment outlines zones of high vulnerability in the SE part of the area, far away from the discharge zone of the aquifer and the water abstraction points. These zones are associated with an intensive infiltration process via carbonate formations. Protection Zone I was delineated 20 m around the water abstraction points, and it should be excluded from any anthropogenic activity. Protection Zone II coves part of the very high and high vulnerability zones defined by the DRISTPI method (located upwards of the water abstraction points), as well as an area downwards of springs and wells, where the flow path lines which demonstrate the subsurface travelling time of 50 days are projected to the ground surface. Protection Zone III extends outside Zone Ι and Zone ΙΙ, up to the limits of the hydrogeological or hydrological basin, whichever is larger. It includes the entire capture zone (i.e., the surface and underground catchment area) that feeds the water abstraction points. In this manner the protection zones include the entire contributing area to water abstraction points, not just the ground surface recharge zone. |
| first_indexed | 2024-03-09T11:01:26Z |
| format | Article |
| id | doaj.art-abf876cc795b45cf9abc620a421aea07 |
| institution | Directory Open Access Journal |
| issn | 2073-4441 |
| language | English |
| last_indexed | 2024-03-09T11:01:26Z |
| publishDate | 2023-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Water |
| spelling | doaj.art-abf876cc795b45cf9abc620a421aea072023-12-01T01:14:45ZengMDPI AGWater2073-44412023-01-0115223110.3390/w15020231Groundwater Vulnerability and Delineation of Protection Zones in the Discharge Area of a Karstic Aquifer—Application in Agyia’s Karst System (Crete, Greece)Emmanouil Steiakakis0Dionysios Vavadakis1Ourania Mourkakou2School of Mineral Resources Engineering, Technical University of Crete, 73100 Chania, GreeceSchool of Mineral Resources Engineering, Technical University of Crete, 73100 Chania, GreeceSchool of Mineral Resources Engineering, Technical University of Crete, 73100 Chania, GreeceThis work represents a contribution to the protection techniques of karst aquifers against groundwater pollution. The paper sets out the methodology being introduced for the protection of the karstic system that gives rise to five (5) major groups of springs and supplies fourteen (14) pumping wells near Agyia Chania (Crete, Greece). Starting from a geological and hydrogeological survey of the area, the work presents a vulnerability assessment of the karstic aquifer based on the application of three index-based methods (EPIK, PRESK and DRISTPI). The protection zones for the discharge area of the aquifer were delineated through an integrated geomorphological approach and groundwater flow modeling. At first, the risk of polluting substances migration from ground surface to groundwater was considered based on the spatial distribution of vulnerability. Following this, the vulnerability was evaluated in the saturated zone, where the attenuation mechanisms of contaminants were reducing due to the raised flow velocity. The groundwater flow and contaminant transport processes was considered using the MODFLOW code. Next, the data from the vulnerability mapping and the groundwater flow simulation were merged into an integrated assessment to delimit the protection zones for the water abstraction points. The vulnerability assessment outlines zones of high vulnerability in the SE part of the area, far away from the discharge zone of the aquifer and the water abstraction points. These zones are associated with an intensive infiltration process via carbonate formations. Protection Zone I was delineated 20 m around the water abstraction points, and it should be excluded from any anthropogenic activity. Protection Zone II coves part of the very high and high vulnerability zones defined by the DRISTPI method (located upwards of the water abstraction points), as well as an area downwards of springs and wells, where the flow path lines which demonstrate the subsurface travelling time of 50 days are projected to the ground surface. Protection Zone III extends outside Zone Ι and Zone ΙΙ, up to the limits of the hydrogeological or hydrological basin, whichever is larger. It includes the entire capture zone (i.e., the surface and underground catchment area) that feeds the water abstraction points. In this manner the protection zones include the entire contributing area to water abstraction points, not just the ground surface recharge zone.https://www.mdpi.com/2073-4441/15/2/231karst aquifervulnerabilityindex-based methodsEPIKPRESKDRISTPI |
| spellingShingle | Emmanouil Steiakakis Dionysios Vavadakis Ourania Mourkakou Groundwater Vulnerability and Delineation of Protection Zones in the Discharge Area of a Karstic Aquifer—Application in Agyia’s Karst System (Crete, Greece) Water karst aquifer vulnerability index-based methods EPIK PRESK DRISTPI |
| title | Groundwater Vulnerability and Delineation of Protection Zones in the Discharge Area of a Karstic Aquifer—Application in Agyia’s Karst System (Crete, Greece) |
| title_full | Groundwater Vulnerability and Delineation of Protection Zones in the Discharge Area of a Karstic Aquifer—Application in Agyia’s Karst System (Crete, Greece) |
| title_fullStr | Groundwater Vulnerability and Delineation of Protection Zones in the Discharge Area of a Karstic Aquifer—Application in Agyia’s Karst System (Crete, Greece) |
| title_full_unstemmed | Groundwater Vulnerability and Delineation of Protection Zones in the Discharge Area of a Karstic Aquifer—Application in Agyia’s Karst System (Crete, Greece) |
| title_short | Groundwater Vulnerability and Delineation of Protection Zones in the Discharge Area of a Karstic Aquifer—Application in Agyia’s Karst System (Crete, Greece) |
| title_sort | groundwater vulnerability and delineation of protection zones in the discharge area of a karstic aquifer application in agyia s karst system crete greece |
| topic | karst aquifer vulnerability index-based methods EPIK PRESK DRISTPI |
| url | https://www.mdpi.com/2073-4441/15/2/231 |
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