Streamflow Prediction in Highly Regulated, Transboundary Watersheds Using Multi‐Basin Modeling and Remote Sensing Imagery

Abstract

Despite the potential of remote sensing for monitoring reservoir operation, few studies have investigated the extent to which reservoir releases can be inferred across different spatial and temporal scales. Through evaluating 21 reservoirs in the highly regulated Greater Mekong region, remote sensing imagery was found to be useful in estimating daily storage volumes for within‐year and over‐year reservoirs (correlation coefficients [CC] ≥ 0.9, normalized root mean squared error [NRMSE] ≤ 31%), but not for run‐of‐river reservoirs (CC < 0.4, 40% ≤ NRMSE ≤ 270%). Given a large gap in the number of reservoirs between global and local databases, the proposed framework can improve representation of existing reservoirs in the global reservoir database and thus human impacts in hydrological models. Adopting an Integrated Reservoir Operation Scheme within a multi‐basin model was found to overcome the limitations of remote sensing and improve streamflow prediction at ungauged cascade reservoir systems where previous modeling approaches were unsuccessful. As a result, daily regulated streamflow was predicted competently across all types of reservoirs (median values of CC = 0.65, NRMSE = 8%, and Kling‐Gupta efficiency [KGE] = 0.55) and downstream hydrological stations (median values of CC = 0.94, NRMSE = 8%, and KGE = 0.81). The findings are valuable for helping to understand the impacts of reservoirs and dams on streamflow and for developing more useful adaptation measures to extreme events in data sparse river basins.

Evaluation of Earth Observations and In Situ Data Assimilation for Seasonal Hydrological Forecasting

“…EO fill this gap by offering consistent observations over wide spatial extents and at reasonable spatiotemporal resolution. Assimilation of in situ observations, for example, streamflow, is a common practice with justified added value but the impact of assimilating earth observations is still under scientific exploration (T. L. Du et al., 2022; Nijzink et al., 2018). The time lag between acquisition and retrieval of many EO data sets limits their use to historical studies.…”

Reservoir operation impacts on streamflow and sediment dynamics in the transboundary river basin, Vietnam

“…They included parameters related to soil water process, evaporation, runoff, sediment transport, delivery and sedimentation. Compared to previous studies using HYPE in the study areas (Arheimer et al, 2020;Du et al, 2020Du et al, , 2022, post-calibration parameters related to sediment processes are the most different, such as erodslope, erodsoil, erodmon, and sedss (Table 4). The range of post-calibration parameters related to other processes can be found in details in Du et al (2020Du et al ( , 2022).…”

“…Soil and Water Assessment Tool (SWAT) model has been frequently used for modelling streamflow and sediment concentration in various basins, including Mekong (Piman et al, 2012; Piman et al, 2013; Shrestha et al, 2016), Mississippi (Jalowska & Yuan, 2019), and Nigerian basin (Daramola et al, 2019). Meanwhile, Hydrological Predictions for the Environment (HYPE) model is well‐known for its process modelling of both streamflow and sediment concentrations at multi‐basin and continental scale (Arheimer et al, 2020; Bartosova et al, 2021; Du et al, 2022). Although SWAT can simulate both streamflow and sediment transport (Tran et al, 2022), it is often coupled with US Army Corps of Engineers' HEC‐ResSim model to model impacts of reservoir operation on changes in natural regimes of streamflow and sediment concentration (Piman et al, 2012; Piman et al, 2013).…”

“…Although SWAT can simulate both streamflow and sediment transport (Tran et al, 2022), it is often coupled with US Army Corps of Engineers' HEC‐ResSim model to model impacts of reservoir operation on changes in natural regimes of streamflow and sediment concentration (Piman et al, 2012; Piman et al, 2013). Meanwhile, HYPE can model various rule curves of reservoir operation (Du et al, 2022; Pechlivanidis & Arheimer, 2015) so that it can be directly used to assess the impacts of reservoir operation.…”

Toward Improved Parameterizations of Reservoir Operation in Ungauged Basins: A Synergistic Framework Coupling Satellite Remote Sensing, Hydrologic Modeling, and Conceptual Operation Schemes

“…In most of these cases, remote sensing is used to provide the storage variation term in the water balance equation, which does not involve the parameterizations of reservoir operation as noted earlier, making it less applicable for hydrologic simulations and forecasts in the future. Having said that, the potential of this readily available information for improving the parameter estimation of current reservoir operation schemes and enhancing the accuracy of hydrologic predictions in ungauged, regulated basins has been less investigated (Du et al., 2022).…”