Common use of Flow Accumulation Algorithm Clause in Contracts

Flow Accumulation Algorithm. The second important decision to make is the flow accumulation algorithm. In the software used for this project, SagaGIS, there are eleven algorithms available. The most common algorithm, Deterministic-8, or D8, is widely available in many different software packages, is commonly used, and is fast, but is known to have limitations. All flow entering a cell can only leave the cell in one direction, which is problematic in flatter areas where flow would disperse. This often results in channel braiding. More complex flow accumulation algorithms exist, allowing for flow in multiple directions from each cell, and that handle both accumulation and dispersion of flow across a DEM, but these are often less widely available, and have large increases in processing time. The most sophisticated of these would require processing on high-end computing hardware or require a large amount of processing time in order to model flow accumulation statewide or over large areas. One of the most common of this type of algorithm is called Digital Elevation Model Networks or DEMON (▇▇▇▇▇-▇▇▇▇▇▇ & ▇▇▇▇▇▇, 1994). Final processing was performed using the DEMON algorithm. The processing for this single watershed took several days on a very high power desktop computer.