Quantitative assessment of groundwater discharge using hydrograph separation and spring discharge in the Ouémé valley, southern Benin

IF 4.9 Q2 ENGINEERING, ENVIRONMENTAL

Groundwater for Sustainable Development Pub Date : 2025-05-12 DOI:10.1016/j.gsd.2025.101459

Bio Guidah Chabi , Huguette C. Emvoutou , Valérie D.O. Kotchoni , Abdoukarim Alassane , Iboukoun Christian Alle , Maxime Wubda , Moussa Boukari

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引用次数: 0

Abstract

Groundwater is the primary source of freshwater for drinking, agricultural water, and industrial in many nations worldwide. Understanding the interaction between groundwater and river is vital for the sustainable management of water resources. This study aims to evaluate groundwater discharge into two major rivers in coastal sedimentary basin. Water samples were collected from two rivers, rainfall, boreholes and springs, for the determination of stable isotopes. The streamflow of the two rivers is measured monthly. Springs have also been inventoried and their flow rates quantified. The isotopic signatures of the two rivers are of the same range and vary greatly from dry to rainy season (−1.32 ‰ to −3.85 ‰ for ¹⁸O and −7.56 ‰ to −21.13 ‰ for ²H), unlike that of groundwater and springs (−3.10 ‰ to −3.13 ‰ for ¹⁸O, −15.51 ‰ to −15.64 ‰ for ²H). The water level in the well is 4m above the river level in dry season, and decreases to 1.5 m in the rainy season. Groundwater discharge based on the isotopic hydrograph separation was 0–96.67 m³/s and 0.74–43.69 m³/s in Ouémé Stream and Sô River, respectively. The analysis reveals that groundwater maintains the base flow of streams in the dry season and also contributes to rivers flow in the rainy season. However, rain water is the dominant water source in rainy season. In addition, 75 springs inventoried in the valley discharge in totally more than 221 m³/h in the rivers. Hence, combining stable isotopes composition hydrometric observations and springs flow, provides an efficient method for estimating groundwater discharge rates into rivers.

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利用水文线分离法和泉水排放法对贝宁南部ousamuise河谷地下水排放进行定量评价

地下水是世界上许多国家饮用淡水、农业用水和工业用水的主要来源。了解地下水和河流之间的相互作用对水资源的可持续管理至关重要。本研究旨在评价沿海沉积盆地两条主要河流的地下水排水量。从两条河流、降雨、钻孔和泉水中采集水样，以测定稳定同位素。这两条河的流量每月测量一次。还对泉水进行了盘点，并对其流量进行了量化。两河的同位素特征范围相同，从旱季到雨季变化很大（18O为- 1.32‰~ - 3.85‰，2H为- 7.56‰~ - 21.13‰），而地下水和泉水的同位素特征不同（18O为- 3.10‰~ - 3.13‰，2H为- 15.51‰~ - 15.64‰）。井内水位旱季高于河面4m，雨季低于河面1.5 m。基于同位素线分离的地下水流量在ousamuise溪为0 ~ 96.67 m3/s，在Sô河为0.74 ~ 43.69 m3/s。分析表明，地下水在旱季维持着河流的基流，在雨季对河流的流量也有贡献。雨季以雨水为主要水源。此外，该流域共有75个清泉在江河中总流量超过221 m3/h。因此，结合稳定同位素组成、水文观测和泉水流量，提供了估算地下水排入河流速率的有效方法。

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来源期刊

Groundwater for Sustainable Development Social Sciences-Geography, Planning and Development

CiteScore

11.50

自引率

10.20%

发文量

152

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.