Watershed characteristics directly influence hydrological processes, impacting runoff volume, peak flow, and timing. Understanding these characteristics is crucial for effective watershed management and predicting runoff behavior.
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Source: http://ecoursesonline.iasri.res.in/mod/page/view.php?id=2172
Diagram Defining Basin Length. (Source: Zavoianu, 2011)
(Source: http://www.fgmorph.com/fg_4_8.php)
| Characteristic/Term | Formula/Description | Significance for Hydrology & Runoff |
| Drainage Basin/Watershed | Area draining to a point | Defines the area contributing to runoff. |
| Drainage Divide | Boundary between basins | Separates adjacent watersheds. |
| Concentration Point | Outlet point | Measurement location for stream flow. |
| Time of Concentration (Tc) | Time for water to reach outlet from farthest point | Determines peak flow timing. |
| Stream Order | Hierarchy of streams (Horton-Strahler) | Indicates drainage network complexity. |
| Stream Density (Ds) | Ds = Ns/A (Ns=streams, A=area) | Indicates stream frequency. |
| Basin Characteristics | | |
| Basin Area (A) | Measured by planimeter, GIS, maps | Runoff volume, peak flow magnitude. |
| Basin Length (Lb) | Longest flow path to outlet | Time of concentration, peak flow timing. Lb = 1.312 A^0.568 (small basins) |
| Basin Slope (S) | S = h/L (h=elevation, L=distance) | Runoff velocity, erosion potential, peak flow magnitude. |
| Basin Shape | | |
| Form Factor (Ff) | Ff = A/L^2 (A=area, L=length) | Basin elongation, peak flow characteristics. |
| Circularity Ratio (Rc) | Rc = 12.57 A/Pr^2 (A=area, Pr=perimeter) | Basin circularity, peak flow characteristics. |
| Elongation Ratio (Re) | Re = 1.128A^0.5/L | Basin elongation, peak flow characteristics. |
| Compactness Coefficient (Cc) | Cc = 0.2821Pr/A^0.5 | Basin compactness, peak flow characteristics. |
| Channel Order (Nw) | Nw = Rb^(W-w) (Rb=bifurcation ratio) | Drainage network complexity, runoff routing. |
| Channel Length (Lw) | Lw = L1 * RL^(w-1) (L1=1st order length, RL=length ratio) | Runoff travel time within channels, peak flow timing. |
| Channel Slope | Elevation difference / channel length | Channel flow velocity, sediment transport. |
| Drainage Density (Dd) | Dd = L/A (L=total channel length, A=area) | Drainage network efficiency, overland flow length, infiltration capacity. |
| Centroid of the Basin | Weighted center of watershed | Hydrologic modeling and analysis. |
| Surface | Land cover, soil type, roughness | Infiltration, runoff volume, flow velocity. |
| Orientation | Aspect (slope direction) | Solar radiation, evapotranspiration. |
| Altitude | Elevation | Precipitation, temperature, snowmelt. |
| Stream Density (Ds) | Ds = Ns/A (Ns = number of streams, A = area) | Stream frequency, drainage texture. |
Source: http://ecoursesonline.iasri.res.in/mod/page/view.php?id=409
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