SWMM 5 Pond Infiltration Techniques

 SWMM 5 Pond Infiltration Techniques

Storm Water Management Model (SWMM) 5 provides multiple methods for simulating pond infiltration in urban drainage systems. These methods offer flexibility in addressing various scenarios and can be adapted to specific project requirements. Below are three approaches for modeling pond infiltration in SWMM 5:

1. Pump Type 4: This classic SWMM 4 solution involves using a Pump Type 4 to simulate the relationship between pond depth and infiltration rate. While this approach has been utilized for a long time, it may not be the most efficient or intuitive method for newer users or for those who want to take advantage of SWMM 5 features.

2. Seasonal or Monthly Evap Factor Adjustment: In this approach, users can modify the SWMM 5 Evap Factor for a pond to incorporate seasonal or monthly variations in infiltration loss. By simulating infiltration loss as an increase in Pan Evaporation, this method allows for more accurate representation of temporal changes in infiltration rates and offers an alternative to using pumps.

3. SWMM 5 Outlet Structure: The latest SWMM 5 Outlet structure provides a more versatile solution for modeling pond infiltration. Users can create either a functional or tabular relationship to simulate infiltration loss as a function of pond depth. This method offers several advantages, including:

   • The ability to use multiple functions for more complex scenarios
   • A more intuitive representation of the infiltration process compared to using a pump
   • Additional features added by Lewis Rossman that enhance the flexibility and capabilities of the outlet structure

Experts such as Mike Gregory have also provided suggestions for modeling infiltration loss from ponds in the OP:ENSwmm.oprg Knowledge database. It is recommended to explore options 2 and 3, as they provide more advanced functionality and better representation of the infiltration process compared to using a Pump Type 4. By employing these techniques, users can effectively simulate pond infiltration in SWMM 5, leading to more accurate and reliable results for urban drainage system management and planning.