AgFE Department, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India.
School of Water Resources, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India.
J Environ Manage. 2023 Sep 15;342:118095. doi: 10.1016/j.jenvman.2023.118095. Epub 2023 May 13.
For operational flood control and estimating ecological flow regimes in deltaic branched-river systems with limited surveyed cross-sections, accurate river stage and discharge estimation using public domain Digital Elevation Model (DEM)-extracted cross-sections are challenging. To estimate the spatiotemporal variability of streamflow and river stage in a deltaic river system using a hydrodynamic model, this study demonstrates a novel copula-based framework to obtain reliable river cross-sections from SRTM (Shuttle Radar Topographic Mission) and ASTER (Advanced Spaceborne Thermal Emission and Reflection) DEMs. Firstly, the accuracy of the CSRTM and CASTER models was assessed against the surveyed river cross-sections. Thereafter, the sensitivity of the copula-based river cross-sections was evaluated by simulating river stage and discharge using MIKE11-HD in a complex deltaic branched-river system (7000 km) of Eastern India having a network of 19 distributaries. For this, three MIKE11-HD models were developed based on surveyed cross-sections and synthetic cross-sections (CSRTM and CASTER models). The results indicated that the developed Copula-SRTM (CSRTM) and Copula-ASTER (CASTER) models significantly reduce biases (NSE>0.8; IOA>0.9) in the DEM-derived cross-sections and hence, are capable of satisfactorily reproducing observed streamflow regimes and water levels using MIKE11-HD. The performance evaluation metrics and uncertainty analysis indicated that the MIKE11-HD model based on the surveyed cross-sections simulates with higher accuracies (streamflow regimes: NSE>0.81; water levels: NSE>0.70). The MIKE11-HD model based on the CSRTM and CASTER cross-sections, reasonably simulates streamflow regimes (CSRTM: NSE>0.74; CASTER: NSE>0.61) and water levels (CSRTM: NSE>0.54; CASTER: NSE>0.51). Conclusively, the proposed framework is a useful tool for the hydrologic community to derive synthetic river cross-sections from public domain DEMs, and simulate streamflow regimes and water levels under data-scarce conditions. This modelling framework can be easily replicated in other river systems of the world under varying topographic and hydro-climatic conditions.
对于具有有限测量横断面的三角洲分汊河系，进行操作洪水控制和估算生态水流状况，使用公共领域数字高程模型 (DEM) 提取横断面来准确估计河水位和流量具有挑战性。为了使用水动力模型估计三角洲河系的时空变化的水流和河水位，本研究提出了一种新颖的基于 copula 的框架，从 SRTM（Shuttle Radar Topographic Mission）和 ASTER（Advanced Spaceborne Thermal Emission and Reflection）DEM 中获得可靠的河流横断面。首先，评估 CSRTM 和 CASTER 模型相对于测量的河道横断面的精度。此后，通过在印度东部一个复杂的三角洲分汊河系（7000 公里）中使用 MIKE11-HD 模拟河水位和流量，评估基于 copula 的河道横断面的敏感性，该河系有 19 个分流。为此，根据测量的横断面和合成横断面（CSRTM 和 CASTER 模型）开发了三个 MIKE11-HD 模型。结果表明，开发的 Copula-SRTM（CSRTM）和 Copula-ASTER（CASTER）模型显著减少了 DEM 衍生横断面的偏差（NSE>0.8；IOA>0.9），因此，能够使用 MIKE11-HD 令人满意地再现观测到的水流状况和水位。性能评估指标和不确定性分析表明，基于测量横断面的 MIKE11-HD 模型模拟精度更高（水流状况：NSE>0.81；水位：NSE>0.70）。基于 CSRTM 和 CASTER 横断面的 MIKE11-HD 模型，合理地模拟了水流状况（CSRTM：NSE>0.74；CASTER：NSE>0.61）和水位（CSRTM：NSE>0.54；CASTER：NSE>0.51）。总之，该框架是水文界从公共领域 DEM 中提取合成河道横断面并在数据稀缺条件下模拟水流状况和水位的有用工具。该建模框架可以在世界上其他具有不同地形和水文气候条件的河系中轻松复制。
