Numerical definition of drainage network and subcatchment areas from Digital Elevation Models (original) (raw)
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A comparison of drainage networks derived from digital elevation models at two scales
Journal of Hydrology, 1998
Automated generation of drainage networks has become increasingly popular with powerful analytical functions in geographic information systems (GIS) and with the increased availability of digital elevation models (DEMs). This paper compares drainage networks derived from DEMs at two scales, 1:250 000 (250K) and 1:24 000 (24K), using various drainage parameters common in hydrology and geomorphology. The comparison of parameters derived from the 250K DEMs with those from the 24K DEMs in 20 basins ranging from 150 to 1000 km 2 in West Virginia shows that the goodness-of-fit between parameter estimates based on the DEMs varies. Results clearly show that superior estimations are produced from the 24K DEMs. Better estimates can be obtained from the 250K DEMs for stream length and frequency parameters than for gradient parameters. However, the estimation of the mean gradient parameters based on the 250K DEMs seems to improve with increasing terrain complexity. Finally, basin size does not strongly affect the accuracy of parameter estimates based on the 250K DEMs. ᭧
Journal of Hydrology, 2001
Distributed hydrological models require a detailed definition of a watershed's internal drainage structure. The conventional approach to obtain this drainage structure is to use an eight flow direction matrix (D8) which is derived from a raster digital elevation model (DEM). However, this approach leads to a rather coarse drainage structure when monitoring or gauging stations need to be accurately located within a watershed. This is largely due to limitations of the D8 approach and the lack of information over flat areas and pits. The D8 approach alone is also unable to differentiate lakes from plain areas.
Computers & Geosciences, 2007
A digital elevation model (DEM) of a watershed can be used to acquire various parameters such as basin-wide information about overland flow direction, flow accumulation and area contributing flow to any point. The resolution and quality of a DEM are important to achieve a significant level of accuracy in derived parameters. Inadequate elevation information exacerbated by applied interpolation methods, reduce DEM accuracy, resulting in pits and flat areas and makes flow tracing a difficult task. These types of problems are more prominent in cases of residual undulating terrains. In the present paper, an attempt has been made to review and suggest an improved method for the generation of a DEM from raster contour data. Further, a criteria-based region growing method (CBRGM) is presented for the extraction of discrete drainage network (cell size: 20 Â 20 m) of the watershed. Here, the flat area removal algorithm, with a variable increment, is used to generate the DEM. This induces a gradual slope even in the case of a large contour interval (20 m) extended over larger area, as is commonly available from a topographic map at a scale of 1:50,000. Further, in order to capture topographic information in flow tracing, the CBRGM is followed. The rasterised stream network from the same topographic sheet is used as ancillary data to make the concentrated flow lines to follow the channel. The methodology has been tested over Gandheshwari subwatershed under the lower part of Chhotanagpur Plateau in Eastern India. The DEM generated using this method gives a better representation of the terrain, which shows good agreement with the terrain information delineated by using the contour and channel information available in the topographic sheet. The drainage network derived shows additional extra-concentrated flow lines, many of which match the drainage network obtained from satellite imagery (cell size: 23.5 Â 23.5 m). The algorithm thus shows superiority over other available methods for the extraction of drainage networks.
Journal of Hydrology, 1995
provides an excellent review of a number of methods for the automated delineation of valley lines and drainage networks from grid digital elevation models (DEM). She identifies two fundamental problems in using the overland flow simulation approach to delinate fully-connected and directed networks of single-cell width, and suggests ways in which these might be addressed. The problems identified are: (1) positioning of the source nodes or upstream ends of the drainage network; (2) assignment of flow directions in flat and depressional areas of the DEM. These are significant problems and methodological improvements are needed to address them. However, the methodological improvements suggested by Tribe have shortcomings which create a new set of problems as serious as those which they are intended to correct. These shortcomings are discussed in the following.
Geomorphology, 2003
Digital data on the position and characteristics of river networks and catchments are important for the analysis of pressures and impacts on water resources. GIS tools allow for the combined analysis of digital elevation data and environmental parameters in order to derive this kind of information. This article presents a new approach making use of medium-resolution digital elevation data (250-m grid cell size) and information on climate, vegetation cover, terrain morphology, soils and lithology to derive river networks and catchments over extended areas.
ISPRS International Journal of Geo-Information
This study describes a new method developed to determine the 3D positional displacements of the drainage networks extracted from Digital Elevation Models (DEMs). The proposed method establishes several stages for data preparation. The displacements are derived by means of linestring-based assessment methods, which can be applied in 2D and 3D. Also, we propose the use of several tools (maps, aggregation of results, new indices, etc.) in order to obtain a wider assessment of positional accuracy, or a time change analysis. This approach supposes a novelty in drainage network studies both in the application of line-based methods and its expansion to 3D data. The method has been tested using a sample of channels extracted from DEMs of two different dates of a zone of about 600 square kilometers using as reference linestrings those extracted from another more recent DEM which had higher spatial accuracy and higher spatial resolution. The results have demonstrated the viability of the method proposed because of the obtaining of 3D displacement vectors, which showed the general and particular behavior of the channels selected.
Drainage networks from grid digital elevation models
Water resources research, 1991
Current algorithms that deduce the drainage network from a digital elevation model (DEM) represented by a regular array of surface elevations share a fault: Unless the terrain is rugged, the derived water channels tend to flow in parallel lines along preferred directions engendered by the ...
International Journal of Innovations in Science and Technology, 2019
The rapid urbanization and the population growth, have increased the demands of fresh water to manage various tasks from domestic to industrial scales. Various man driven sectors such as agriculture, industry and water filtration plants, require fresh water to cater the need of increasing population. Therefore, the management of available fresh water reservoirs is of great importance to save water for a sustainable future “save water save life”. Digital elevation model (DEM) is efficient to extract the drainage network, basin boundaries and to evaluate the volume of fresh water available in study site. We used Arc hydro tools in Arc GIS interface for extraction of drainage network in the study site. Flow direction and accumulation were computed according to Z-value of individual pixel available in the raster grid. A total 127 streams were extracted against 127 catchments. We observed that the catchments bearing steep slopes were incised in comparison to gentle slopes which were most...
A combined algorithm for automated drainage network extraction
Water Resources Research, 1992
ABSTRACT Based on existing principles of automated drainage network extraction we have developed two methodological algorithms, the “profile scan” and “hydrological flow modeling,” and used them to extract networks from digital elevation models (DEMs). The “hydrological flow modeling” algorithm specializes in the extraction of well-connected hierarchically arranged skeletal channel networks. On the other hand, the channels extracted by the “profile scan” algorithm lack adequate connectivity, but this algorithm is suitable for the extraction of wide valley bottoms and other flat areas. A combination of the two algorithms gives a more versatile algorithm capable of yielding networks which are not only well connected but also portray the surface character of the drainage network thus generated. The good functioning of our algorithm is not inhibited by the presence of pits in the DEM. There is therefore no preprocessing of the DEM prior to drainage extraction. Rather, at the end of extraction, isolated spots are eliminated since these are the ones most probably representing artifacts.
Journal of Geographic Information System, 2013
Digital Elevation Models (DEMs) are constructed using altitude point data and various interpolation techniques. The quality and accuracy of DEMs depend on data point density and the interpolation technique used. Usually however, altitude point data especially in plain areas do not provide realistic DEMs, mainly due to errors produced as a result of the interpolation technique, resulting in imprecise topographic representation of the landscape. Such inconsistencies, which are mainly in the form of surface depressions, are especially crucial when DEMs are used as input to hydrologic modeling for impact studies, as they have a negative impact on the model's performance. This study presents a Geographical Information System (GIS) tool, named LAN (Line Attribute Network), for the improvement of DEM construction techniques and their spatial accuracy, using drainage network attributes. The developed tool does not alter the interpolation technique, but provides higher point density in areas where most DEM problems occur, such as lowland areas or places where artificial topographic features exist. Application of the LAN tool in two test sites showed that it provides considerable DEM improvement. A. GEMITZI, O. CHRISTOU 330 Figure 7. Comparison of semi variograms produced with and without the use of LAN tool, to the semi variogram with measred altitude data. u