Deriving the Reservoir Conditions for Better Water Resource Management Using Satellite-Based Earth Observations in the Lower Mekong River Basin

Abstract

The Mekong River basin supported a large population and ecosystem with abundant water and nutrient supply. However, the impoundments in the river can substantially alter the flow downstream and its timing. Using limited observations, this study demonstrated an approach to derive dam characteristics, including storage and flow rate, from remote-sensing-based data. Global Reservoir and Lake Monitor (GRLM), River-Lake Hydrology (RLH), and ICESat-GLAS, which generated altimetry from Jason series and inundation areas from Landsat 8, were used to estimate the reservoir surface area and change in storage over time. The inflow simulated by the variable infiltration capacity (VIC) model from 2008 to 2016 and the reservoir storage change were used in the mass balance equation to calculate outflows for three dams in the basin. Estimated reservoir total storage closely resembled the observed data, with a Nash-Sutcliffe efficiency and coefficient of determination more than 0.90 and 0.95, respectively. An average decrease of 55% in outflows was estimated during the wet season and an increase of up to 94% in the dry season for the Lam Pao. The estimated decrease in outflows during the wet season was 70% and 60% for Sirindhorn and Ubol Ratana, respectively, along with a 36% increase in the dry season for Sirindhorn. Basin-wide demand for evapotranspiration, about 935 mm, implicitly matched with the annual water diversion from 1000 to 2300 million m3. From the storage–discharge rating curves, minimum storage was also evident in the monsoon season (June–July), and it reached the highest in November. This study demonstrated the utility of remote sensing products to assess the impacts of dams on flows in the Mekong River basin.

A near‐term drought assessment using hydrological and climate forecasting in the Mekong River Basin

“…The calibration period was 1984-1990, and the validation period was 1991-1997. In this study, the simulated discharge was regulated by six major dams across the MRB, and the reservoir parameters of each dam, such as its surface area and storage capacity, were obtained from the remote sensing dataset (Table 3, Ali and Sridhar, 2019). The model evaluation (Equation 2) was performed based on the Nash-Sutcliffe coefficient (NS; Nash & Sutcliffe, 1970).…”

Systems Analysis of Coupled Natural and Human Processes in the Mekong River Basin

“…As with many river basins undergoing changes in physiography, landcover, and natural and human-induced climate change, any assessment of the water cycle in this basin becomes extremely valuable when it aims to integrate human-water systems as a use-inspired scientific pursuit to understand, characterize, and quantify flows and stocks across time and space scales. Hydrology is impacted because of human-induced changes, but in modeling hydrologic conditions including droughts [2][3][4], reservoir operations [5,6], water management and tradeoff analysis in the context of hydropower generation [7][8][9], ecological flow requirements [10,11], and transboundary water governance [12,13] are also constantly assessed. The pace of change requires the integration of new methods, data, and modeling techniques to understand the flows, supply, and demand requirements with a focus on multi-sectoral water needs in a feedback framework.…”

General Assessment of the Operational Utility of National Water Model Reservoir Inflows for the Bureau of Reclamation Facilities

“…This lack of hydrological information also limits the possibility to measure reservoir inflows, largely due to high uncertainties in over-lake precipitation estimates and unmeasured streamflow from minor tributaries [9,10]. Even if some efforts have been made in using satellite data and radar data to implement reservoir inflow estimates [11][12][13][14] there is still need to invest more money into field survey data and more ground truth measurements. Knowing these limitations, the field of hydrology has begun to shift more emphasis toward large scale hydrologic modelling [15][16][17][18][19], which can take advantage of remote sensing estimates for unmeasured quantities.…”