The law of basin areas indicated that the mean basin area of successive ordered streams formed a linear relationship when graphed. Studies of other natural branching networks have revealed patterns similar to the stream order model. For example, the bifurcation ratio of three has also been discovered in the rooting systems of plants, the branching structure of woody plants, and the veination in leaves and the human circulatory system. In addition to the mathematical relationships found in stream ordering, various aspects of drainage network forms were also found to be quantifiable. One such relationship was drainage density .
Drainage density is a measure of the length of stream channel per unit area of drainage basin.
The measurement of drainage density provides a hydrologist or geomorphologist with a useful numerical measure of landscape dissection and runoff potential. On a highly permeable landscape, with small potential for runoff, drainage densities are sometimes less than 1 kilometer per square kilometer. On highly dissected surfaces densities of over 500 kilometers per square kilometer are often reported. Closer investigations of the processes responsible for drainage density variation have discovered that a number of factors collectively influence stream density. These factors include climate, topography, soil infiltration capacity, vegetation, and geology.