SWMM 5.2.2 Code for Drainage Mat Layer (for green roofs)

 

Variable Name	Type	Description
thickness	double	the layer thickness (ft)
voidFrac	double	the void volume / total volume
roughness	double	Mannings n for green roof drainage mats
alpha	double	slope/roughness term in Manning equation

This code defines a struct called TDrainMatLayer, which represents a Drainage Mat Layer commonly used in green roofs. The struct contains several variables:

• thickness: a double that represents the thickness of the layer, in feet.
• voidFrac: a double that represents the void volume of the layer over the total volume of the layer.
• roughness: a double that represents the Mannings n, a roughness coefficient used in the calculation of flow through open channels, for green roof drainage mats.
• alpha: a double that represents the slope/roughness term in the Manning equation, used to estimate the resistance to flow in open channels.

The struct is used to store information about the Drainage Mat Layer, which can then be used in various calculations and simulations related to green roofs. This struct is usually used along with other layers and other parameters to evaluate the water management of green roofs.

// Drainage Mat Layer (for green roofs)

typedef struct

{

    double    thickness;          // layer thickness (ft)

    double    voidFrac;           // void volume / total volume

    double    roughness;          // Mannings n for green roof drainage mats

    double    alpha;              // slope/roughness term in Manning equation

}  TDrainMatLayer;