1-for the biofurcation ratio the values ranges from 3 to 5. If the value close to 3 indicate a less structural control on the basin and if the values close to 5 indicating more structural control.

2- Stream frequency: this term refer to the number of streams per unit area and caculated by the following formula Fs=Nu/A

A: basin area in sequare kilometer

Nu: total number of stream segments of all orders.

Drainge density: is the stream length per unit area in region of watershed. Calculated by thevfollowing formula Dd=Lu/A

A: the basin area

Lu: total stream length of all orders

Low value of Dd indicating wiedly spaced streams due to less ressistance rocks or those with high infiltration capacity and vice versa.

The form factor is defined as the ratio of basin area to sequare of basin length. Calculated by Ff=A/Lb2

If the values below 0.75 denot to circular watershes

If the value ranges from 0.42 to 0.2 indicate to elongate shape for the watershed

Drainage density (The slope characteristics also derived through the spatial analysis tool available in Arc GIS)

I see that there is another scientific shortcut looming, purporting the well-known “philosopher´s stone” of geomorphology and basin analysis. It is similar to the approach taken in geochemistry where a plethora of indices and ratios pretend to avoid experience and knowledge in geology and mineralogy prior to the use of endless numerical datasets.

In the current issue there will be no by-pass of geoscientific anamnesis and visual examination (mapping, sampling leading to 2- and 3-D visualization as well as follow-up laboratory analysis.

Numerical analysis encompassing hydrography such as sinuosity of channel systems, slope angle must be supported by hydrodynamic investigations (GMS tool = granulometry, morphology, situmetry) all of which is grouped under the header “geoscientific measurements, analysis, and computations”. It needs to be corroborated by measurements in structural geology and by in-door analysis of the mineralogy, petrography and chemistry as well geochronology using methods appropriate for the Quaternary and Neogene , in particular. Any stand-alone synthetic geomorphometric analysis will yield synthetic results.

To substantiate my arguments I refer to the following papers dealing with this holistic approach in basin analysis and geomorphology.

DILL, H.G., BUZATU A., BALABAN S.-I. , UFER K., GÓMEZ TAPIAS J., BÎRGĂOANU D. and CRAMER T. (2020) The “badland trilogy” of the Desierto de la Tatacoa, Upper Magdalena Valley, Colombia, a result of geodynamics and climate: With a review of badland landscapes.- Catena 194: 1-20.

DILL, H.G., BUZATU A., BALABAN S.-I. , UFER K., TECHMER A. SCHEDLINSKY, W., and FÜSSL M., (2020) The transition of very coarse-grained meandering to straight fluvial drainage systems in a tectonized foreland-basement landscape during the Holocene (SE Germany) – A joint geomorphological-geological study.- Geomorphology (in print)

Available and ready for download on the RG server.

H.G.Dill