Urban stormwater capture curve using three-parameter mixed exponential probability density function and NRCS runoff...

Area of Science:

• Environmental Engineering
• Hydrology
• Urban Planning

Background:

• Current urban non-point-source management system designs often simplify rainfall depth distributions using a 1-parameter exponential probability density function.
• This simplification can lead to less accurate stormwater analysis and system design, particularly in complex urban environments.

Purpose of the Study:

• To propose a more accurate mathematical expression for rainfall depth probability distribution.
• To enhance the rainfall-runoff calculation procedure for deriving more representative stormwater-capture curves.
• To improve the design of urban drainage systems by accounting for complex land-use characteristics.

Main Methods:

• A novel probability density function for rainfall depths is suggested, moving beyond the traditional 1-parameter exponential model.
• The U.S. Natural Resources Conservation Service (NRCS) runoff curve number method is integrated to model the nonlinear rainfall-runoff relationship.
• Stormwater-capture curves were developed using rainfall data from Busan, Korea.

Main Results:

• The proposed methodology provides a more accurate representation of rainfall depth probability distribution.
• The revised rainfall-runoff calculation procedure yields more verifiable and representative stormwater-capture curves.
• The developed curves are better suited for urban drainage areas with complex land-use characteristics.

Conclusions:

• The suggested methodology offers a superior approach to designing urban non-point-source management systems compared to existing methods.
• Accurate rainfall modeling and consideration of nonlinear runoff processes are crucial for effective stormwater management.
• This study provides a more robust framework for developing stormwater-capture curves in diverse urban settings.