GIS-BASED DIGITAL TERRAIN MODELING FOR MORPHOMETRIC ASSESSMENT OF SEASONAL STREAM BASINS IN MOUNTAINOUS REGIONS

Abstract

Seasonal streams in mountainous and foothill regions can provide an important source of runoff, particularly during snowmelt and periods of rainfall. However, their irregular flow regimes and complex terrain make the assessment of basin characteristics challenging. This study presents a mathematical approach to representing the topographic surface of a seasonal stream basin and deriving a digital terrain model from elevation reference points. The Achchiksay basin, located in the Kyzylcha area of Dehqonabad district, Kashkadarya region, Uzbekistan, was used as the case study. A calculation grid was formed from the available elevation data, and an interpolation-based procedure was applied to describe the spatial variation of the terrain. The mathematical formulation incorporates a series representation and integral transformations to obtain an expression for basin-surface modeling. A numerical experiment using the study site's experimental parameters was then carried out, resulting in a digital terrain model of the basin. The model provides a spatial representation of elevation and can support subsequent morphometric analysis and preliminary assessment of seasonal runoff catchments. The approach may be useful in terrain studies where reliable representation of basin relief is needed to inform water-resource planning. Further validation against independent elevation data and field measurements would help quantify model accuracy.