Pre-modeling by Arc Hydro Tools.

This paper provides an overview of the functionality of Arc Hydro, one of the components within ArcGIS. The purpose of using GIS, specifically the Arc Hydro component, is to prepare geospatial data (e.g., preprocessing digital terrain models, identifying river networks and watershed areas, etc.) during the pre-modeling phase within HEC-HMS. Arc Hydro provides a set of standardized attributes and a toolset for implementing the data model. The Arc Hydro tools generate several datasets that collectively describe the drainage pattern of a catchment. These tools are installed as an Arc Hydro toolbar, which includes the Terrain Preprocessing menu. This menu provides functions dealing with DEM processing and is mostly used once to prepare spatial information for later use. Arc Hydro is not a hydrologic modelling software but an excellent free tool to facilitate hydrologic modelling of watersheds. It is a unique GIS program that maintains the connectivity of hydrologic features. Using the example of the Bioštica River Basin, this paper will demonstrate the pre-modeling steps utilizing Arc Hydro. Additionally, the results obtained during the pre-modeling phase serve as the foundation for the watershed delineation method, using the Point Delineation option (it allows interactive delineation of a watershed upstream of a user-specified point). In this way, the study defines the watershed area for the Hydrological Station HS Bioštica, Bioštica River. Compared to the manual subwatershed and stream network delineation approach, the Arc Hydro toolbar offers significant time savings. [ABSTRACT FROM AUTHOR]