The stream order of main river depends upon the threshold value taken for upstream drainage area to generate the 1st order stream in any basin. If the threshold value is taken as high as more than the half of the total area of basin, the main river will become 1st order. On the other side, if threshold value of upstream drainage area is reduced, the stream order of main river goes on increasing.
so the selection of threshold value, there may be two criteria-
1) based on percentage area of total basin
2) constant value irrespective of basin area
please suggest me if there is any universal criteria.
Andrew Pel
You might be interested in my research gate publication on stream types and management implications. In that analysis, I used 1:24K and 1:100K topographic maps, where two or more contour crenellations (indentions) indicated a drainage depression to estimate the first-order stream. In some earlier work with GIS specialist, I used 5 acres or about 2 hectares to help estimate stream network, and automate stream order in the areas of Blue Ridge and Piedmont we managed. It did reasonably well, but not as good as manually analyzing the contour indicators from DEMs.
andrew
Since most of the topographic maps and DEMs in US have used 1:24,000 scale, and not LiDAR, the 1:24K has been a helpful tool in describing stream order densities in sloping terrain. However in the well vegetated coastal plain, both hydrologic boundaries, stream density and dereferencing is substantially improved with LiDAR. The famous geomorphologist Luna Leopold had a leadership position in the USGS, and he indicated that the topographic lines on contour maps were put in by cartographers using aerial photogrammetry methods. He suggested the blue lines were put in for looks, with no significant intent to be coincident with perennial streams. For me in several areas I worked in, I expanded the stream network using the contour crenulations, and used my knowledge of the stream ordering to estimate likelihood of perennial, intermittent or ephemeral channels, and estimated which streams needed stream buffers based on the estimate of their flow permanence. In the piedmont and mountains, at 1:24k scale, order 3 and larger were perennial, order 2 were intermittent, order 1 ephemeral.
John Wick
Since most of the topographic maps and DEMs in the US have used 1:24,000 scale, and not LiDAR, the 1:24K has been a helpful tool in describing stream order densities in sloping terrain. However in the well-vegetated coastal plain, both hydrologic boundaries, stream density and georeferencing is substantially improved with LiDAR. The famous geomorphologist Luna Leopold had a leadership position in the USGS, and he indicated that the topographic lines on contour maps were put in by cartographers using aerial photogrammetry methods. He suggested the blue lines were put in for looks, with no significant intent to be coincident with perennial streams. For me in several areas I worked in, I expanded the stream network using the contour crenulations, and used my knowledge of the stream order to estimate the likelihood of perennial, intermittent or ephemeral channels, and estimated which streams needed stream buffers based on the estimate of their flow permanence. In the piedmont and mountains, at 1:24k scale, order 3 and larger were perennial, order 2 were intermittent, order 1 ephemeral.