Order classification of river watershed divides based on processing digital elevation models

The principles and the algorithm of order classification of river watershed divides are outlined. It is shown that a formal application of any available order classification procedures for river watershed divides is not theoretically grounded as well as being impractical, because the physical mechanisms for formation of watershed divide network are different from those operating in the river network. We have formulated the basic principle of determining the watershed divides order on the basis of a serial sequence of sections constituting the travel path of an arbitrary water drop from the watershed divide to the outlet section of the basin. It is suggested that the order N should be assigned to the section of the watershed divide belonging to the full divide line of the N-order basin only if the travel path from it to the N-order stream is “full” in the topological sense, i.e. includes sections of all orders, from 1 to N. Also, we present a variant of determining the order on the basis of so-called higher-order triplets, incomplete sequences of sections of three neighboring orders along the travel path, with the higher of them determining the watershed divide order. The use of triplets is a subjective procedure of generalization that eliminates the influence of recent random erosional incisions on the forms of stable high-order watersheds. We outline the variants of the technique for identifying the network of watershed divides and calculating their orders, based on processing the digital elevation models (DEM) through the use of standard GIS ArcMap tools. Results are obtained in the form of a correlated classification of river and watershed networks which are rationally interpreted and hold promise for investigating the structure, functioning and evolution of river systems. The study revealed the existence of formation “cores” of river systems, i.e. regions within which the system reaches a higher stream order and which are bounded by watersheds of the same order.     

Measures of the Vertical Size of River Systems as Indicators of Their Formation Conditions: Case Study of Mountains of Crimea and Caucasian Black Sea Coast

Water Resources - The main measure of a river system is commonly accepted to be its catchment area, which determines its main function, i.e., collecting precipitation. However, the river basin also...     

Potential of river network modeling based on GIS technologies and digital elevation model

The development of GIS technologies and the availability of a wide range of geodatasets provide great potential for modeling physiographic objects, in particular, river systems. The adequate automatic method of river network digitizing was developed and tested using the digital elevation model based on applying the Complex Energy Index (CEI); the results are presented. The index form includes the independent parameterization of main geomorphologic and climatic factors of the first-order stream generation. The method testing proved that it is efficient and the results of its use can be reliably interpreted. The software was developed on the basis of ArcGIS tools. It implements the full algorithm of the automatic digitizing of river network using the digital elevation model. It also allows advancing studies on this issue, and could be used for solving applied problems.     

The Forms of Linear Structure of Overland Flow in Medium-Height Mountain Regions: Case Study of the Sikhote Alin

Water Resources - Large subsurface streams on steep slopes have stable positions with distinct catchment areas (drainage basins), linear shapes, and lengths of tens and hundreds meters. They form a...