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

Section 40 Disposition versions

2020-12-31

40. Chicago rainfall is defined in equations 3-9 and 3-10:

Equation 3-9:

Equation 3-10:

where:

	iav	=	Rain intensity before the peak (mm/h);
	iap	=	Rain intensity after the peak (mm/h);
	tav	=	Time before the peak (min);
	tap	=	Time after the peak (min);
	r	=	Symmetry factor corresponding to the values indicated in Table 3.15;
	A,B,C	=	Regression coefficients of the intensity-duration-frequency curve defined in equation 3-11.

Equation 3-11: i = A/(B + t)c

where:

	i	=	Rain intensity (mm/h);
	t	=	Duration of the rain (min).

Table 3.15 Symmetry factor

Place	Symmetry factor (r)
Montréal	0.45
Lennoxville	0.37
Val d’Or	0.38
Québec	0.38
La Pocatière	0.42
Normandin	0.32
Bagotville	0.42
Other	0.40

O.C. 871-2020, s. 40.

Not in force

In force: 2020-12-31

40. Chicago rainfall is defined in equations 3-9 and 3-10:

Equation 3-9:

Equation 3-10:

where:

	iav	=	Rain intensity before the peak (mm/h);
	iap	=	Rain intensity after the peak (mm/h);
	tav	=	Time before the peak (min);
	tap	=	Time after the peak (min);
	r	=	Symmetry factor corresponding to the values indicated in Table 3.15;
	A,B,C	=	Regression coefficients of the intensity-duration-frequency curve defined in equation 3-11.

Equation 3-11: i = A/(B + t)c

where:

	i	=	Rain intensity (mm/h);
	t	=	Duration of the rain (min).

Table 3.15 Symmetry factor

Place	Symmetry factor (r)
Montréal	0.45
Lennoxville	0.37
Val d’Or	0.38
Québec	0.38
La Pocatière	0.42
Normandin	0.32
Bagotville	0.42
Other	0.40

O.C. 871-2020, s. 40.