DataTamer Reach is for processing cross sections that have been surveyed to reduced level datum. Reach takes account of the time of the survey and can let you see how a cross section behaves over time. The software gets it names from its ability to group sections together in a reach. Surveys of a set of sections are defined in a reach and the software can work with the reach as an entity. In particular, Reach can compute the volume under the river bed and show how this changes over time. Thus Reach combines the spatial dimensions of the river bed with time.
There are occasions where the cross section is only partially surveyed. This happens where the main channel has changed but the berm, or higher terraces have stayed the same. Reach can extend a section by using levels collected on a previous survey. The screenshot shows a section with a complete survey done in 1973 but subsequent surveys start at 110 metre offset or at the 200 metre offset. Reach will automatically use the 1973 section to find the bed level between zero and the first point on the survey.
Reach can show how a section is changing over time. The screen shot shows the behaviour of the mean bed level. This shows the bed is eroding. The same command in DataTamer Reach can draw the RL at an offset over time, and the area under the section. The results are listed in a table, as well as in a graph, and the software can compute rates of change over a month or a year. This is useful for tracking gravel movement down a river.
The cross sections that Reach stores are usually taken from a river bed. However, the software is quite capable of working with beach profiles. Reach can compute the volume of sand in the dune and how this is changing over time.