Skip to main content
ARS Home » Pacific West Area » Tucson, Arizona » SWRC » Research » Publications at this Location » Publication #102690
Title: INFLUENCES OF MAP SCALE ON DRAINAGE NETWORK REPRESENTATION 1263

Author
item MILLER, S - UNIV. OF ARIZ.
item GUERTIN, D - UNIV. OF ARIZ.
item Levick, Lainie

Submitted to: Hydrology and Water Resources in Arizona and the Southwest
Publication Type: Proceedings
Publication Acceptance Date: 3/1/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: Stream channels are the foundation upon which much hydrologic and geologic research is based. Stream channels transport water and sediment through and out of a watershed. As such, in order to understand the processes that control runoff, flooding, and the amount of water that sinks into the soil, it is important that we have a strong understanding of where the channels are located, how long they are, and other characteristics. This paper presents research describing how using different sources of information regarding the stream channels can affect research. Four different map sources were used, two of which are very commonly used. It was found that the commonly available data do not accurately represent stream channels in the Walnut Gulch Experimental Watershed and various reasons for why the maps produce different results are discussed.

Technical Abstract: In hydrologic and geomorphic research, the stream channel network is the basis for modeling and interpreting surface processes. Although the automated extraction of channels from a digital elevation model is becoming more widely applied, the standard method for delineating streams has been to capture them from aerial photographs and topographic maps. Much of the original research in basin geomorphology and scaling issues in hydrology was based on network data derived from commonly available maps. A serious flaw is inherent in this approach, however; the number of streams, basin order, and resulting network complexity is primarily a function of the scale of the base maps. Hydrologic detail is lost when small-scale maps or photographs serve as the basis for interpretation. This paper presents the results of a study using multiple maps at a variety of scales (1:12,000, two sets at 1:24,000, and 1:62,500) on the Walnut Gulch Experimental Watershed in southeastern Arizona. Significant differences in stream order, network complexity, channel length, and runoff efficiency were found as a function of scale. These differences have potentially significant implications for current research issues on the watershed, including hydrologic modeling efforts incorporating routing, watershed analyses, and multi-scale watershed modeling.