The effects of using traditional methods as opposed to automated methods were not fully evaluated for flat areas. In order to evaluate if the use of automated methods still proves viable in areas of low slope, a more thorough investigation using several study areas of the same shape and area, but different slopes, would have to be implemented.
Automated methods, requiring the use of a computer to extract hydrologic parameters, produce very consistent results for hydrologic parameters. Paper map-based methods of parameter extraction tend to vary more than do automated methods, especially for large areas.
As with traditional paper map-based methods, on-screen digitization from raster graphic maps is a highly subjective process. However, measurements for the large study area closely resemble results derived from automated processes using DEMs, more so than results derived using paper maps. This result implies that differences are most likely attributed to errors associated with physically measuring parameters with a map wheel and a planimeter, rather than the subjective nature of the application.
As paper map-based methods are more tedious than automated methods (with the exception of the TIN), and more time consuming, moving to automated methods would accelerate the design process. Parameters extracted using WMS, CRWR-PrePro, different resolution DEMs, and on-screen digitization from raster graphic maps do not vary significantly from one another, and any error associated