Storage Units in InfoSWMM and SWMM5

Storage Units are drainage system nodes that provide storage volume. Physically they could represent storage facilities as small as a catchbasin or as large as a lake. The volumetric properties of a storage unit are described by a function or table of surface area versus height.

The principal input parameters for storage units include:

• Invert elevation
• Maximum water depth
• Initial water depth
• Depth-surface area data
• External inflow data.
• Infiltration Parameters (optional)

Computed output consists of

• Water depth
• Hydraulic head
• External inflow rate
• Overflow rate
• Concentration of each water quality constituent.

Diagram:

Excerpt from the EPA manual Storm Water Management Model Reference Manual Volume II – Hydraulics (PDF)