Q-2, r. 9.01 - Design code of a storm water management system eligible for a declaration of compliance

Section 25 Disposition versions

2020-12-31

25. The following rules apply to factor, tf, of equation 3-3:

(1)  the water flow time, tf, for a storm water management system constituted of ditches is established using equation 3-5:

Equation 3-5:

where:

	tf	=	Water flow time in the storm water management system constituted of ditches (min);
	L	=	Length of water flow into ditches between the intake and the connection point to the storm water management system (m);
	n	=	Manning’s coefficient of the ditches determined in Table 3.6 (s/m1/3)
	R	=	Hydraulic radius of the ditches established by assuming that the design flow flows into the ditch. If a number of ditch geometries are present on the route, L, the geometry showing the highest hydraulic radius value must be used (m);
	S	=	Average slope of water flow (m/m);
	60	=	Conversion coefficient for the units.

Table 3.6 Manning’s coefficients

Type of ditch		Manning’s coefficient
Unprotected ditches A) Earth
	Without vegetation	0.018
	Grassed	0.025
	Sparse bush	0.080
	Dense bush	0.120
B) Rock
	Smooth and even	0.038
	Irregular with roughness	0.043
Protected ditches
A) Concrete
	Unfinished concrete	0.015
	Finishing	0.013
B) Concrete apron
	Stone and mortar walls	0.018
	Concrete block walls	0.023
	Armour stone walls (riprap)	0.025
C) Gravel apron
	Concrete walls	0.019
	Stone and mortar walls	0.022
	Armour stone walls (riprap)	0.028
D) Brick		0.016
E) Bituminous concrete		0.015
F) Wood		0.012
Road and drainage ditches
A) Depth < 200 mm
	Grass 50 mm	0.058
	Grass from 100 to 150 mm	0.070
	Hay 300 mm	0.130
	Hay 600 mm	0.215
B) depth from 200 to 450 mm
	Grass 50 mm	0.043
	Grass from 100 to 150 mm	0.050
	Hay 300 mm	0.105
	Hay 600 mm	0.145

(2)  the water flow time, tf, for a storm water management system constituted of pipes is established using equation 3-6:

where :

	tf	=	Water flow time in the storm water management system constituted of pipes (min);
	L	=	Length of water flow into the pipe between the intake and the connection point to the storm water management system (m);
	n	=	Manning’s coefficient of the pipes determined in Table 3.7 (s/m1/3)
	D	=	Diameter of the pipe (m). If a number of pipes are present on the route, L, an average diameter must be used;
	S	=	Average slope of water flow (m/m);
	60	=	Conversion coefficient for the units.

Table 3.7 Manning’s coefficients

Type of pipe	Roughness or corrugation		Manning’s coefficient
Round concrete pipe	Smooth		0.013
Rectangular concrete pipe	Timber formwork (rough)		0.016
	Timber formwork (smooth)		0.014
	Steel formwork (smooth)		0.013
Corrugated steel pipe Annular or helical corrugations	68 over 13 mm (annular)
		Unpaved	0.024
		25% paved	0.021
		100% paved	0.012
	68 over 13 mm (helical)
		Unpaved	Variable with D
		25% paved	Variable with D
		100% paved	0.012
	76 over 25 mm (helical)		Variable with D
	150 over 25 mm		0.024
	125 over 25 mm		0.026
	75 over 25 mm		0.028
	150 over 50 mm		0.035
Corrugated steel pipe Multiplates	Variable corrugation		0.028 – 0.033
Thermoplastic pipe	Smooth inside		0.010
	Corrugated inside		0.020
Cast iron pipe	Smooth		0.013
Steel pipe	Smooth		0.011
Wood culvert	Smooth		0.016

O.C. 871-2020, s. 25.

Not in force

In force: 2020-12-31

25. The following rules apply to factor, tf, of equation 3-3:

(1)  the water flow time, tf, for a storm water management system constituted of ditches is established using equation 3-5:

Equation 3-5:

where:

	tf	=	Water flow time in the storm water management system constituted of ditches (min);
	L	=	Length of water flow into ditches between the intake and the connection point to the storm water management system (m);
	n	=	Manning’s coefficient of the ditches determined in Table 3.6 (s/m1/3)
	R	=	Hydraulic radius of the ditches established by assuming that the design flow flows into the ditch. If a number of ditch geometries are present on the route, L, the geometry showing the highest hydraulic radius value must be used (m);
	S	=	Average slope of water flow (m/m);
	60	=	Conversion coefficient for the units.

Table 3.6 Manning’s coefficients

Type of ditch		Manning’s coefficient
Unprotected ditches A) Earth
	Without vegetation	0.018
	Grassed	0.025
	Sparse bush	0.080
	Dense bush	0.120
B) Rock
	Smooth and even	0.038
	Irregular with roughness	0.043
Protected ditches
A) Concrete
	Unfinished concrete	0.015
	Finishing	0.013
B) Concrete apron
	Stone and mortar walls	0.018
	Concrete block walls	0.023
	Armour stone walls (riprap)	0.025
C) Gravel apron
	Concrete walls	0.019
	Stone and mortar walls	0.022
	Armour stone walls (riprap)	0.028
D) Brick		0.016
E) Bituminous concrete		0.015
F) Wood		0.012
Road and drainage ditches
A) Depth < 200 mm
	Grass 50 mm	0.058
	Grass from 100 to 150 mm	0.070
	Hay 300 mm	0.130
	Hay 600 mm	0.215
B) depth from 200 to 450 mm
	Grass 50 mm	0.043
	Grass from 100 to 150 mm	0.050
	Hay 300 mm	0.105
	Hay 600 mm	0.145

(2)  the water flow time, tf, for a storm water management system constituted of pipes is established using equation 3-6:

where :

	tf	=	Water flow time in the storm water management system constituted of pipes (min);
	L	=	Length of water flow into the pipe between the intake and the connection point to the storm water management system (m);
	n	=	Manning’s coefficient of the pipes determined in Table 3.7 (s/m1/3)
	D	=	Diameter of the pipe (m). If a number of pipes are present on the route, L, an average diameter must be used;
	S	=	Average slope of water flow (m/m);
	60	=	Conversion coefficient for the units.

Table 3.7 Manning’s coefficients

Type of pipe	Roughness or corrugation		Manning’s coefficient
Round concrete pipe	Smooth		0.013
Rectangular concrete pipe	Timber formwork (rough)		0.016
	Timber formwork (smooth)		0.014
	Steel formwork (smooth)		0.013
Corrugated steel pipe Annular or helical corrugations	68 over 13 mm (annular)
		Unpaved	0.024
		25% paved	0.021
		100% paved	0.012
	68 over 13 mm (helical)
		Unpaved	Variable with D
		25% paved	Variable with D
		100% paved	0.012
	76 over 25 mm (helical)		Variable with D
	150 over 25 mm		0.024
	125 over 25 mm		0.026
	75 over 25 mm		0.028
	150 over 50 mm		0.035
Corrugated steel pipe Multiplates	Variable corrugation		0.028 – 0.033
Thermoplastic pipe	Smooth inside		0.010
	Corrugated inside		0.020
Cast iron pipe	Smooth		0.013
Steel pipe	Smooth		0.011
Wood culvert	Smooth		0.016

O.C. 871-2020, s. 25.