Probabilistic Description of Streamflow and Active Length Regimes in Rivers

Area of Science:

• Hydrology
• Geomorphology
• Environmental Science

Background:

• Temporary rivers are globally prevalent yet understudied components of river networks.
• Understanding their dynamics is crucial for water resource management and ecological assessments.

Purpose of the Study:

• To develop a coupled probabilistic model for catchment discharge and active river network length dynamics.
• To classify streamflow and active length regimes in temporary rivers using analytical expressions.

Main Methods:

• Utilized a well-established hydrological model and a derived distribution approach.
• Derived analytical expressions for flow duration curves (FDC) and stream length duration curves (SLDC).
• Identified streamflow and active length regimes based on dimensionless parameters and scaling exponent 'b'.

Main Results:

• Identified two streamflow regimes (persistent, erratic) and three active length regimes (ephemeral, perennial, ephemeral de facto).
• Defined seven distinct behavioral classes based on FDC and SLDC shapes, modulated by the scaling exponent 'b'.
• Validated the analytical model using data from catchments in Italy and the USA with satisfactory performance.

Conclusions:

• Established a structural relationship between streamflow and active length regimes in temporary rivers.
• The proposed framework offers a novel tool for analyzing discharge and river network length dynamics.
• Highlights the significant role of the scaling exponent 'b' in modulating these dynamics.