SWMM 5.2.2 Code for LID Process in LID.h

 This code defines a struct named "TLidProc" which represents the LID (Low Impact Development) process, which is a generic LID design per unit of area.

The struct contains the following fields:

Field	Type	Description
ID	char*	identifying name of the LID process
lidType	int	type of LID (corresponds to an enumerator from the "LidTypes" enumeration)
surface	TSurfaceLayer	surface layer parameters
pavement	TPavementLayer	pavement layer parameters
soil	TSoilLayer	soil layer parameters
storage	TStorageLayer	storage layer parameters
drain	TDrainLayer	underdrain system parameters
drainMat	TDrainMatLayer	drainage mat layer
drainRmvl	double*	underdrain pollutant removals

The "ID" field is a string that can be used to identify the specific LID process. The "lidType" field is an integer that corresponds to one of the enumerators from the "LidTypes" enumeration. This allows the code to determine the specific type of LID process represented by this struct.

The "surface", "pavement", "soil", "storage", "drain" and "drainMat" fields are structs themselves and they contain specific parameters for the surface layer, pavement layer, soil layer, storage layer, underdrain system and drainage mat layer respectively. The "drainRmvl" field is a pointer to an array of doubles, which represent the underdrain pollutant removals.

This struct is used to store all the information about a specific LID process and can be used to design and simulate the performance of the LID unit. The struct also contains information about different layers of LID unit, like surface layer, soil layer and storage layer which helps to simulate the performance of LID unit.

// LID Process - generic LID design per unit of area typedef struct { char* ID; // identifying name int lidType; // type of LID TSurfaceLayer surface; // surface layer parameters TPavementLayer pavement; // pavement layer parameters TSoilLayer soil; // soil layer parameters TStorageLayer storage; // storage layer parameters TDrainLayer drain; // underdrain system parameters TDrainMatLayer drainMat; // drainage mat layer double* drainRmvl; // underdrain pollutant removals } TLidProc;

SWMM 5.2.2 Code for Defining LID data in LID.h

 This code defines several structs that are used to store information about different layers of a LID (Low Impact Development) unit. The structs define the properties of each layer, such as thickness, porosity, permeability, and other parameters that are specific to each layer.

The structs defined in this code are:

Struct Name	Description
TSurfaceLayer	Information about the surface layer of the LID unit, such as depression storage or berm height, roughness, slope, and alpha term in Manning equation.
TPavementLayer	Information about the pavement layer of the LID unit, such as thickness, void fraction, permeability, clogging factor, and regeneration interval.
TSoilLayer	Information about the soil layer of the LID unit, such as thickness, porosity, field capacity, wilting point, suction, saturated hydraulic conductivity.
TStorageLayer	Information about the storage layer of the LID unit, such as thickness, void fraction, saturated hydraulic conductivity, clogging factor and information about whether it is covered or not.
TDrainLayer	Information about the underdrain system of the LID unit, such as flow coefficient, head exponent, offset height, delay time, head when drain opens and closes, flow rate curve.
TDrainMatLayer	Information about the drainage mat layer of the LID unit, such as thickness, void fraction, roughness, slope/roughness term in Manning equation.

The fields of all the structs are double type except for the "covered" field which is of int type.

The code also defines a MAX_LAYERS macro which is set to 4. This macro is used as a constant throughout the code to specify the maximum number of layers that are allowed in the LID unit.

This way, the code defines the different layers of LID unit and the properties of each layer with the help of structs. This makes it easy to simulate and analyze the performance of LID unit by using these structs to store the information about different layers and their properties.

#define MAX_LAYERS 4 // LID Surface Layer typedef struct { double thickness; // depression storage or berm ht. (ft) double voidFrac; // available fraction of storage volume double roughness; // surface Mannings n double surfSlope; // land surface slope (fraction) double sideSlope; // swale side slope (run/rise) double alpha; // slope/roughness term in Manning eqn. char canOverflow; // 1 if immediate outflow of excess water } TSurfaceLayer; // LID Pavement Layer typedef struct { double thickness; // layer thickness (ft) double voidFrac; // void volume / total volume double impervFrac; // impervious area fraction double kSat; // permeability (ft/sec) double clogFactor; // clogging factor double regenDays; // clogging regeneration interval (days) double regenDegree; // degree of clogging regeneration } TPavementLayer; // LID Soil Layer typedef struct { double thickness; // layer thickness (ft) double porosity; // void volume / total volume double fieldCap; // field capacity double wiltPoint; // wilting point double suction; // suction head at wetting front (ft) double kSat; // saturated hydraulic conductivity (ft/sec) double kSlope; // slope of log(K) v. moisture content curve } TSoilLayer; // LID Storage Layer typedef struct { double thickness; // layer thickness (ft) double voidFrac; // void volume / total volume double kSat; // saturated hydraulic conductivity (ft/sec) double clogFactor; // clogging factor int covered; // TRUE if rain barrel is covered } TStorageLayer; // Underdrain System (part of Storage Layer) typedef struct { double coeff; // underdrain flow coeff. (in/hr or mm/hr) double expon; // underdrain head exponent (for in or mm) double offset; // offset height of underdrain (ft) double delay; // rain barrel drain delay time (sec) double hOpen; // head when drain opens (ft) double hClose; // head when drain closes (ft) int qCurve; // curve controlling flow rate (optional) } TDrainLayer; // 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;

SWMM 5.2.2 Code for LID Storage Layer

 

Variable Name	Type	Description
thickness	double	the layer thickness (ft)
voidFrac	double	the void volume / total volume
kSat	double	saturated hydraulic conductivity (ft/sec)
clogFactor	double	clogging factor
covered	int	Boolean flag indicating if rain barrel is covered (TRUE if it is covered)

This code defines a struct called TStorageLayer, which represents a storage layer in a Low Impact Development (LID) system. 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.
• kSat: a double that represents the saturated hydraulic conductivity, the rate at which water can flow through the soil, in feet per second.
• clogFactor: a double that represents the clogging factor, which can be used to account for the potential reduction of the saturated hydraulic conductivity due to clogging or other factors.
• covered: an integer that is a Boolean flag indicating if the rain barrel is covered. This is set to TRUE if the rain barrel is covered and FALSE otherwise.

The struct is used to store information about the LID storage layer, which can then be used in various calculations and simulations related to the LID system. The struct is usually used along with other parameters such as precipitation, infiltration, and evapotranspiration to evaluate the water management of the LID system.

// LID Storage Layer typedef struct { double thickness; // layer thickness (ft) double voidFrac; // void volume / total volume double kSat; // saturated hydraulic conductivity (ft/sec) double clogFactor; // clogging factor int covered; // TRUE if rain barrel is covered } TStorageLayer;

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;