Head loss due to Transitions and Fittings (Local loss) for InfoSWMM and SWMM5

Head loss due to Transitions and Fittings (Local loss)

Whenever flow velocity changes direction or magnitude in a conduit (e.g., at fittings, bends, and other appurtenances) added turbulence is induced. The energy associated with that turbulence is eventually dissipated into heat that produces a minor head loss, or local (or form) loss. The local (minor) loss associated with a particular fitting can be evaluated by

                                                                                                      

where   V         =          mean velocity in the conduit (m/s, ft/s)

                K         =          loss coefficient for the particular fitting involved.

The table given below provides the loss coefficients (K) for various transitions and fittings.

 

Table 3-3: Typical Minor Loss Coefficients

Type of form loss			K
Expansion	Sudden	D1 < D2
	Gradual	D1/D2 = 0.8	0.03
		D1/D2 = 0.5	0.08
		D1/D2 = 0.2	0.13
Contraction	Sudden	D1 > D2
	Gradual	D2/D1 = 0.8	0.05
		D2/D1 = 0.5	0.065
		D2/D1 = 0.2	0.08
Pipe entrance	Square-edge		0.5
	Rounded		0.25
	Projecting		0.8
Pipe exit	Submerged pipe to still water		1.0
Tee	Flow through run		0.6
	Flow through side outlet		1.8
Orifice	(Pipe diameter  /orifice diameter)	D/d = 4	4.8
		D/d = 2	1.0
		D/d = 1.33	0.24
Venturi (long-tube)	(Pipe diameter  /throat diameter)	D/d = 3	1.1
		D/d = 2	0.5
		D/d = 1.33	0.2
Bend	90o miter bend with vanes		0.2
	90o miter bend without vanes		1.1
	45o miter bend		0.2
Type of form loss (continued)			K
Bend	45o smooth bend:      (bend radius  /pipe diameter)	r/D = 1	0.37
		r/D = 2	0.22
		r/D = 4	0.2
	90o smooth bend	r/D = 1	0.5
		r/D = 2	0.3
		r/D = 4	0.25
	Closed return bend		2.2
Sluice	Submerged port in wall		0.8
	As conduit contraction		0.5
	Without top submergence		0.2
Valve	Globe valve, fully open		10
	Angel valve, fully open		5.0
	Swing check valve, fully open		2.5
	Gate valve, fully open		0.2
	Gate valve, half open		5.6
	Butterfly valve, fully open		1.2
	Ball valve, fully open		0.1

       Source: Nicklow and Boulos (2005)

Rules and Ranges the for Hydrology Options in InfoSWMM and InfoSWMM SA

Subcatchment Hydrological (Modeling) - Data Table

This table contains all subwatershed data that is used to estimate the amount of  runoff and pollutant yielding from Subwatersheds. For more information on each of the input (data fields) in this table, Subcatchment editor may be referred.  The following table is in invert colors and shows the whole first row of the DB Table on separate rows in the image.

Field	Description
Subcatchment ID	User determined ID.  It can only be changed with the Change ID command.
Raingage ID	Specify Raingage ID used to input rainfall data to Subcatchment.
Receiving Node ID	Node ID for node receiving rainfall hydrograph from Subcatchment.
Subcatchment Area	Area of Subcatchment
Subcatchment Impervious (%)	Percentage of the Subcatchment covered by impervious surfaces.
Subcatchment Width	Characteristic width of the Subcatchment (feet or meters).
Subcatchment Slope	(%) Slope of the Subcatchment.
Subcatchment Curb Length	Total length of curbs in the Subcatchment (any length units). Used only when pollutant buildup is normalized to curb length.
Snow Pack ID	Name of snow pack parameter set (if any) assigned to the Subcatchment.
Manning's N for Imperv. Portion	Manning's N for overland flow over the impervious portion of the Subcatchment.
Manning's N for Pervious Portion	Manning's N for overland flow over the pervious portion of the Subcatchment.
Depression Stor. for Imp. Portion	Depth of depression storage on the impervious portion of the Subcatchment (inches or millimeters)
Depression Stor. for Perv. Portion	Depth of depression storage on the pervious portion of the Subcatchment (inches or millimeters).
% of Imperv. Part w/o Dep. Stor.	Percent of the impervious area with no depression storage.
Runoff Routing Destination	Choice of internal routing of runoff between pervious and impervious areas: IMPERV -    runoff from pervious area flows to impervious area. PERV -   runoff from impervious flows to pervious area. OUTLET -   runoff from both areas flows directly to outlet.
% of Runoff Routed to Destination	Percent of runoff routed between subareas.
LENGTH	Characteristic length of the Subcatchment (feet or meters).
CNTRD_DIST	Distance from centroid of Subcatchment to outlet (feet or meters).
NRCS_CN	NRCS Curve Number
DCIA_LEVEL	Directly Connected Impervious Area Level for CUHP method Level 1 assumes that all roof gutters are disconnected from driveways, gutters and Stormwater conveyance elements. Level 2 is for developments that already use Level 1 and do not have any curbs and gutters, including concrete swale gutters.  All runoff from streets and parking areas is directed as sheet flow across grass surfaces.  Intermittent curbs with frequent opening to the grass surface qualifies as Level 2.
CIA_RATIO	Fraction of the impervious area that is directly connected to the drainage system.
RPA_RATIO	Fraction of the pervious area that receives runoff from pervious area and unconnected impervious area.
TC	Time of concentration (minutes).
WQCV	Water Quality Capture Volume (watershed inches or millimeters).
WQCV_TIME	The time it takes to fully drain the brim-full WQCV
Runoff Coefficient	SDMRH only.  (Note - There is a different Runoff Coefficient reported in HYDQUA.RPT.  It is the total runoff from the Subcatchment divided by the total rainfall over the Subcatchment.  It should always be between 0 and 1.)
Storage Coefficient	Snyder UH and Clark UH.  Represents storage effects of the watershed.
Empirical Coefficient	Snyder UH only.
Conveyance Factor	Espey UH only
Infiltration Model	Use this to use a different infiltration model than the default model set in Simulation Options.
Depression Storage	Average depth of depression storage across the Subcatchment.  Can be used in NRCS methods to indicate Initial Abstraction (Ia).
Storage Coefficient	Storage Coefficient for German Runoff
Reservoir Count	Reservoir Count for German Runoff

  

Rules and Ranges the for Hydrology Options

Innovyze Hydrology Type Data Ranges and Default
Hydrology Type	Data Type	User Unit	Internal Unit	Valid Internal Range	Default Internal Values
		rain-depth
Colorado  UH		in or mm
DCIA level	enumerator			1, 2, 3	1
hydraulic length	double	ft or m	ft	>= 1	50
centroid distance	double	ft or m	ft	>= 0	0
DCIA fraction	double			0 <= & <= 1	0.2
RPA fraction	double			0 <= & <= 1	0.75
time of concentration	double	minutes	seconds	>= 1	60
captured volume	double	rain-depth	ft	>= 0	0
Drainage time	double	hours	seconds	>= 0	12
NRCS/Delmarva
Curve Number	double			40 <= & <= 100	75
hydraulic length	double	ft or m	ft	>= 1	50
time of concentration	double	minutes	seconds	>= 1	60
depression storage	double	rain-depth	ft	>= 0	0
Snyder  UH
storage coefficient	double			0.1 <= & <= 8	2
empirical coefficient	double			0.1 <= & <= 1.0	0.5
hydraulic length	double	ft or m	ft	>= 1	50
centroid distance	double	ft or m	ft	>= 0	0
depression storage	double	rain-depth	ft	>= 0	0
Clark UH
storage coefficient	double			0.1 <= & <= 10	1
time of concentration	double	minutes	seconds	>= 1	60
depression storage	double	rain-depth	ft	>= 0	0
Santa Barbara
time of concentration	double	minutes	seconds	>= 1	60
depression storage	double	rain-depth	ft	>= 0	0
Espey  UH
hydraulic length	double	ft or m	ft	>= 1	50
conveyance factor	double			0.6 <= & <= 1.3	1
depression storage	double	rain-depth	ft	>= 0	0
Modified Rational
time of concentration	double	minutes	minutes	>= 1	5
runoff coefficient	double			0 <= & <= 1	0.5
storm duration	double	factor	factor	TC:  > 0	1
		hours	hours	Dur:  >= 0
San Diego Rational
runoff coefficient	double			0 <= & <= 1	0.5
time of concentration	double	minutes	minutes	>= 1	0.75
German Runoff
Storage constant	double	minutes	minutes	> 0	5
Reservoir count	integer			> 0	1