Assessment of environmental flow requirements using a coupled surface water-groundwater model and a flow health tool: A case study of Son river in the Ganga basin
Assessment of environmental flow requirements using a coupled surface water-groundwater model and a flow health tool: A case study of Son river in the Ganga basin
复制标题
DOI：
10.1016/j.ecolind.2020.107110
复制
发表时间：
2020-11
影响因子：
6.9
通讯作者：
Naveen Joseph;Naveen Joseph;Pooja P. Preetha;B. Narasimhan
中科院分区：
文献类型：
--
作者：
Naveen Joseph;Naveen Joseph;Pooja P. Preetha;B. Narasimhan
人口迅速增长、工业化和不可持续的消费导致水量和水质恶化，从而影响河流的健康。确保河流健康的重要组成部分之一是环境流量。然而，在大多数水管理评估中，环境流量被忽视或没有得到适当考虑。本研究的目的是更好地量化和评估环境流量要求并制定管理实践以确保河流的生态健康。土壤和水评估工具（SWAT）与有限元地下水模型相结合，用于水文建模。使用基于流量健康工具的“流量健康评分”(FHS) 指数来评估环境流量状况。该模型针对三种条件进行了模拟：分别针对上儿子和下儿子的原始条件、管理条件和修改条件。原始条件假设没有水力干预，而管理条件则纳入了现有的管理实践，修改后的条件对应于本研究中为确保环境流动而修改的管理实践。这种方法已在恒河盆地的 Son 河中得到验证。建模的水流与观测到的流量数据一致（R2= 0.78–0.85）。此外，SWAT-FEM 耦合模型比 SWAT 模型更好地估计了低流量，从而证明了在此类环境流量评估中考虑地表水与地下水相互作用的重要性。流量健康评估表明，水库和灌溉引水严重影响了上山地区的高流量（高流量和月最高流量指数小于0.2）和下山地区的低流量（低流量指数小于0.2）。模型模拟采用修改后的管理实践，将上儿子的流量健康评分 (FHS) 从 0.4 提高到 0.6，将下儿子的流量健康分数从 0.4 提高到 0.7。这项研究表明，耦合的 SWAT-FEM 模型与水流健康工具一起，可以有效地用于评估河内水流要求并设计替代管理计划以满足河内水流要求。
Rapidly increasing population, industrialisation, and unsustainable consumption have resulted in deterioration of water quantity and quality, thus affecting the health of the river. One of the essential components for ensuring river health is environmental flow. Nevertheless, the environmental flow is neglected or not appropriately accounted in most of the water management assessments. The objective of this study was to better quantify and assess the environmental flow requirements and developing management practices for ensuring the ecological health of the river. Soil and Water Assessment Tool (SWAT) coupled with a finite element groundwater model, was used for hydrological modelling. The environmental flow regime was evaluated using an index 'Flow Health Score' (FHS), based on a Flow Health Tool. The model was simulated for three conditions – Virgin condition, Managed condition, and Modified condition for Upper and Lower Son separately. Virgin condition assumed no hydraulic interventions, while managed condition incorporated the existing management practices, and modified condition corresponded to the management practices modified in this study for ensuring environmental flow. This approach was demonstrated for the Son River in the Ganga basin. The modelled streamflow agreed with the observed discharge data (R2= 0.78–0.85). Further, SWAT-FEM coupled model better estimated the low flows than the SWAT model, thus demonstrating the importance of accounting for surface water – groundwater interaction in such environmental flow assessments. Flow health assessment indicated that reservoirs and irrigation diversions have severely affected the high flows in the Upper Son (high flow and highest monthly flow index less than 0.2), and low flows in the Lower Son (low flow index less than 0.2). The model simulation with the modified management practices increased the Flow Health Score (FHS) from 0.4 to 0.6 in Upper Son, and 0.4 to 0.7 in Lower Son. This study showed that coupled SWAT-FEM model, along with the flow health tool, could be effectively used for assessing the in-stream flow requirements and for designing alternative management plans to meet the in-stream flow requirements.