The Application of SWAT Model and Remotely Sensed Products to Characterize the Dynamic of Streamflow and Snow in a Mountainous Watershed in the High Atlas

Abstract

Snowfall, snowpack, and snowmelt are among the processes with the greatest influence on the water cycle in mountainous watersheds. Hydrological models may be significantly biased if snow estimations are inaccurate. However, the unavailability of in situ snow data with enough spatiotemporal resolution limits the application of spatially distributed models in snow-fed watersheds. This obliges numerous modellers to reduce their attention to the snowpack and its effect on water distribution, particularly when a portion of the watershed is predominately covered by snow. This research demonstrates the added value of remotely sensed snow cover products from the Moderate Resolution Imaging Spectroradiometer (MODIS) in evaluating the performance of hydrological models to estimate seasonal snow dynamics and discharge. The Soil and Water Assessment Tool (SWAT) model was used in this work to simulate discharge and snow processes in the Oued El Abid snow-dominated watershed. The model was calibrated and validated on a daily basis, for a long period (1981–2015), using four discharge-gauging stations. A spatially varied approach (snow parameters are varied spatially) and a lumped approach (snow parameters are unique across the whole watershed) have been compared. Remote sensing data provided by MODIS enabled the evaluation of the snow processes simulated by the SWAT model. Results illustrate that SWAT model discharge simulations were satisfactory to good according to the statistical criteria. In addition, the model was able to reasonably estimate the snow-covered area when comparing it to the MODIS daily snow cover product. When allowing snow parameters to vary spatially, SWAT model results were more consistent with the observed streamflow and the MODIS snow-covered area (MODIS-SCA). This paper provides an example of how hydrological modelling using SWAT and snow coverage products by remote sensing may be used together to examine seasonal snow cover and snow dynamics in the High Atlas watershed.

Combining Hydrological Models and Remote Sensing to Characterize Snowpack Dynamics in High Mountains

“…We applied a methodology akin to that used by [10,11,34,49] for calibrating snow parameters to simulate SWE and streamflow in the study basin. However, in the absence of in situ data in the study basin, we utilized two newly developed datasets as reference data for snow parameters calibration.…”

“…Multivariate parameter estimation can lead to more realistic internal model dynamics and associated hydrological characteristics [30,31], ultimately enhancing the overall representation of catchment behaviour. Prior research has demonstrated the effectiveness of using remotely sensed data to implement and calibrate hydrological models [32][33][34]. The issue of model equifinality, where multiple parameter sets can produce equally good model performance, introduces uncertainty that can undermine the reliability of hydrological models in forecasting future water resources, especially in mountainous regions where snow processes significantly influence the hydrological cycle [19].…”

“…The selected parameters were divided into three groups comprising snow parameters, basin parameters and elevation lapse rate parameters. In earlier research endeavours [10,11,34,48] aimed at stimulating the SWE, SNOCOVMX and SNO50COV were deemed insensitive and consequently omitted. Nevertheless, in our investigation, we opted to incorporate these parameters (SNOCOVMX and SNO50COV) to assess their influence on streamflow simulation.…”

Spatial Layout of Vegetation Buffer Zones around Water Bodies to Avoid Non-Point Source Pollution in a Mining Area

“…The research area is located in Jiawang District in the northeast of the main urban area of Xuzhou City (34 1a), covering an area of 496.59 km 2 . It is located in the transitional zone between the North China Plain and the alluvial plain of the Yellow River, characterized by low hills, hillside plains, and alluvial plains.…”

“…In recent years, various pollutants stemming from agricultural cultivation, aquaculture, urban development, and other land-use practices have been introduced into water bodies as non-point source pollution through diverse surface-loading mechanisms, leading to water eutrophication [2,3]. After many years of research, the riparian vegetation buffer zone adopted in the process of material flow has been identified as a method with low cost, high efficiency, easy operation, and the most natural ecology [4].…”