[R] processing data of hierarchical river network

[tlange at gwdg.de]

Hi,

I have some hydrochemical data from observation stations of a river
network. The data set provides information about the river hierarchy, i.e.
the order of the rivers (main river is 1st order, contributing is 2nd
order, and contributing to 2nd is 3rd order... etc).

Now I would like to use the hierarchical information to:
a) plot a dendrogram of the observation stations
b) perform some simple statistics on the different branches

What packages are needed to conduct that investigation?
How the hierarchical information should be formated to be easily processed
with R?

Thank you,
Torsten