| Variable | Symbol | Description |
| Basin area | A |
|
| Basin perimeter | P |
|
| Total number of streams | Nu |
|
| Total stream length | Lu |
|
| Basin length | Lb |
|
| Mean stream length | Ls | Total stream length/Total number of stream segments [18] |
| Average length of first order stream | L1 | Total length of first order stream/Number of first order streams [29] |
| Ratio between average lengths of first to second order streams | R12 | Average length of first order streams/Average length of second order streams [29] |
| Bifurcation ratio | Rb | Ratio of number of stream segments of one order to the number of the next higher order [20] |
| Stream frequency | Fs | Total number of streams/Basin area [17] ) |
| First order stream frequency | Fs1 | Number of first order streams/Basin area [29] |
| Ratio of first order stream number to perimeter | RP1 | Number of first order streams/Perimeter |
| Drainage density | Dd | Total stream length/Basin area [17] [37] |
| Maintenance coefficient | Mc | 1/Drainage density [20] |
| Circularity ratio | C | (4π × basin area)/Perimeter2 [39] |
| Elongation ratio | Re |
|
| Form factor | Ff | Basin area/Basin length2 [17] |
| Relief ratio | Rr | Basin relief/Basin length [20] |
| Relative relief | Rl | Basin relief/(Perimeter × 100) [38] |
| Hypsometric Integral | HI | (Elev mean – Elev min)/(Elev max – Elev min) [18] |
| Ruggedness number | Rn | Basin relief × Drainage density [29] |
[20]