ACCUM PLUS is a program to simulate discharge in human-dominated river systems and catchments. The algorithm considers the trap efficiency of all kind of sinks (dams, reservoirs, lakes and sedimentation areas and flood plains) as well as their year of formation. This is of crucial importance as sinks like dams change with respect of time. They appear, dissappear and change.

ACCUM PLUS is therefore well-suited for the examination of dam effects and the calibration of long-term gauging samples that can be resetted to quasi-natural conditions. 

ACCUM PLUS has been introduced to the public in 2008 by the science journal Computers & Geosciences. It has more than 700 users and can be used by everybody without any restrictions.

There are two separate versions, one for ArcGIS 9.x and another for ArcView 3.x. Software, manual and auxillary articles are available for download:

PDF-manual (ArcGIS 9.x and ArcView 3.x)
Article in Computers & Geosciences, 2008: vol.34/6
PDF-article (german) in "Angewandte Geoinformatik 2007"