{"title":"长期干旱对缺水地区沿海含水层的影响:以勒布纳(突尼斯东北部邦角)为例","authors":"Mohamed Neji , Sameh Chargui , Fethi Lachaal , Claude Hammecker , Olivier Grunberger","doi":"10.1016/j.gsd.2025.101462","DOIUrl":null,"url":null,"abstract":"<div><div>The coastal aquifer of Lebna (Northeast Tunisia) is a vital water resource supporting agricultural and industrial activities. The aquifer has historically benefitted from natural recharge and inputs from the Lebna dam reservoir (constructed in 1986), which has mitigated saline intrusion. A severe drought period from 2020 to 2023 significantly impacted groundwater resources and agricultural productivity, coinciding with a near depletion of the dam reservoir. This research aims to characterise this drought period (2020–2023) and assess its impact on the coastal groundwater resources and agriculture. A multidisciplinary approach was employed, combining hydrogeological monitoring (Groundwater levels and salinity from 181 wells), isotopic analysis (δ<sup>18</sup>O, δ<sup>2</sup>H), remote sensing (NDVI, Landsat), drought indices (SPI), and field surveys. Results indicate a pronounced rainfall deficit (SPI values from −0.4 to −1.2) and a 63 % reduction in irrigated agricultural land compared to 2019, based on surveys of 30 farmers. NDVI analyses showed reductions in vegetation cover and water body of 45 % and 77.78 %, respectively, during the dry season and 93.6 % and 84 % during the wet season from 2019 to 2023. Comparative analysis of groundwater level and salinity measurements from 181 wells in 2019 and 2023 highlighted a piezometric drop of 9 m below sea level (mbsl) and a significant salinity increase, with electrical conductivity reaching up to 21 mS/cm. The dam filling in 2019 raised groundwater levels, while its near-empty state between 2020 and 2023 resulted in lowered groundwater levels. Isotopic analyses of the δ<sup>18</sup>O and δ<sup>2</sup>H revealed significant groundwater recharge from the dam in 2019, as evidenced by values near the Global Meteoric Water Line (GMWL). In contrast, no recharge occurred in 2023 due to extremely low reservoir levels (12.85–10.80 m). These findings emphasise the critical need for effective drought anticipation and adaptive strategies to mitigate future extreme events.</div></div>","PeriodicalId":37879,"journal":{"name":"Groundwater for Sustainable Development","volume":"30 ","pages":"Article 101462"},"PeriodicalIF":4.9000,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"The effect of prolonged drought on a coastal aquifer in water scarcity regions: A case study of Lebna (Cap Bon, Northeast Tunisia)\",\"authors\":\"Mohamed Neji , Sameh Chargui , Fethi Lachaal , Claude Hammecker , Olivier Grunberger\",\"doi\":\"10.1016/j.gsd.2025.101462\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>The coastal aquifer of Lebna (Northeast Tunisia) is a vital water resource supporting agricultural and industrial activities. The aquifer has historically benefitted from natural recharge and inputs from the Lebna dam reservoir (constructed in 1986), which has mitigated saline intrusion. A severe drought period from 2020 to 2023 significantly impacted groundwater resources and agricultural productivity, coinciding with a near depletion of the dam reservoir. This research aims to characterise this drought period (2020–2023) and assess its impact on the coastal groundwater resources and agriculture. A multidisciplinary approach was employed, combining hydrogeological monitoring (Groundwater levels and salinity from 181 wells), isotopic analysis (δ<sup>18</sup>O, δ<sup>2</sup>H), remote sensing (NDVI, Landsat), drought indices (SPI), and field surveys. Results indicate a pronounced rainfall deficit (SPI values from −0.4 to −1.2) and a 63 % reduction in irrigated agricultural land compared to 2019, based on surveys of 30 farmers. NDVI analyses showed reductions in vegetation cover and water body of 45 % and 77.78 %, respectively, during the dry season and 93.6 % and 84 % during the wet season from 2019 to 2023. Comparative analysis of groundwater level and salinity measurements from 181 wells in 2019 and 2023 highlighted a piezometric drop of 9 m below sea level (mbsl) and a significant salinity increase, with electrical conductivity reaching up to 21 mS/cm. The dam filling in 2019 raised groundwater levels, while its near-empty state between 2020 and 2023 resulted in lowered groundwater levels. Isotopic analyses of the δ<sup>18</sup>O and δ<sup>2</sup>H revealed significant groundwater recharge from the dam in 2019, as evidenced by values near the Global Meteoric Water Line (GMWL). In contrast, no recharge occurred in 2023 due to extremely low reservoir levels (12.85–10.80 m). These findings emphasise the critical need for effective drought anticipation and adaptive strategies to mitigate future extreme events.</div></div>\",\"PeriodicalId\":37879,\"journal\":{\"name\":\"Groundwater for Sustainable Development\",\"volume\":\"30 \",\"pages\":\"Article 101462\"},\"PeriodicalIF\":4.9000,\"publicationDate\":\"2025-05-19\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Groundwater for Sustainable Development\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S2352801X25000591\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"ENGINEERING, ENVIRONMENTAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Groundwater for Sustainable Development","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2352801X25000591","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, ENVIRONMENTAL","Score":null,"Total":0}
The effect of prolonged drought on a coastal aquifer in water scarcity regions: A case study of Lebna (Cap Bon, Northeast Tunisia)
The coastal aquifer of Lebna (Northeast Tunisia) is a vital water resource supporting agricultural and industrial activities. The aquifer has historically benefitted from natural recharge and inputs from the Lebna dam reservoir (constructed in 1986), which has mitigated saline intrusion. A severe drought period from 2020 to 2023 significantly impacted groundwater resources and agricultural productivity, coinciding with a near depletion of the dam reservoir. This research aims to characterise this drought period (2020–2023) and assess its impact on the coastal groundwater resources and agriculture. A multidisciplinary approach was employed, combining hydrogeological monitoring (Groundwater levels and salinity from 181 wells), isotopic analysis (δ18O, δ2H), remote sensing (NDVI, Landsat), drought indices (SPI), and field surveys. Results indicate a pronounced rainfall deficit (SPI values from −0.4 to −1.2) and a 63 % reduction in irrigated agricultural land compared to 2019, based on surveys of 30 farmers. NDVI analyses showed reductions in vegetation cover and water body of 45 % and 77.78 %, respectively, during the dry season and 93.6 % and 84 % during the wet season from 2019 to 2023. Comparative analysis of groundwater level and salinity measurements from 181 wells in 2019 and 2023 highlighted a piezometric drop of 9 m below sea level (mbsl) and a significant salinity increase, with electrical conductivity reaching up to 21 mS/cm. The dam filling in 2019 raised groundwater levels, while its near-empty state between 2020 and 2023 resulted in lowered groundwater levels. Isotopic analyses of the δ18O and δ2H revealed significant groundwater recharge from the dam in 2019, as evidenced by values near the Global Meteoric Water Line (GMWL). In contrast, no recharge occurred in 2023 due to extremely low reservoir levels (12.85–10.80 m). These findings emphasise the critical need for effective drought anticipation and adaptive strategies to mitigate future extreme events.
期刊介绍:
Groundwater for Sustainable Development is directed to different stakeholders and professionals, including government and non-governmental organizations, international funding agencies, universities, public water institutions, public health and other public/private sector professionals, and other relevant institutions. It is aimed at professionals, academics and students in the fields of disciplines such as: groundwater and its connection to surface hydrology and environment, soil sciences, engineering, ecology, microbiology, atmospheric sciences, analytical chemistry, hydro-engineering, water technology, environmental ethics, economics, public health, policy, as well as social sciences, legal disciplines, or any other area connected with water issues. The objectives of this journal are to facilitate: • The improvement of effective and sustainable management of water resources across the globe. • The improvement of human access to groundwater resources in adequate quantity and good quality. • The meeting of the increasing demand for drinking and irrigation water needed for food security to contribute to a social and economically sound human development. • The creation of a global inter- and multidisciplinary platform and forum to improve our understanding of groundwater resources and to advocate their effective and sustainable management and protection against contamination. • Interdisciplinary information exchange and to stimulate scientific research in the fields of groundwater related sciences and social and health sciences required to achieve the United Nations Millennium Development Goals for sustainable development.