07/1841 - Response to Information Request [As Published] · 132007.1841

STORMWATER MANAGEMENT PLAN 5

4.2.2 Manning’s ‘n’

Values for the dimensionless Manning’s ‘n’ coefficient for open channel and piped flows were
ig pip

assigned according to Table 4.1 in accordance with QUDM.

Table 4.1: Study Manning’s ‘n’

 

 

 

Conduit condition Manning’s ‘n’
Grassed, Landscaped Swales 0.045
Reinforced Concrete 0.014

 

 

 

 

4.2.3 Energy Loss Coefficients

Entrance and exit loss coefficients were utilised according to Table 4.2 in general accordance
with QUDM.

Table 4.2: Pipe Energy Loss Coefficients

 

 

 

Energy Loss Loss Coefficient
Entry Loss 0.5
Exit Loss 0.2

 

 

 

 

4.2.4 Infiltration Characteristics

The Horton infiltration method was adopted for the drainage study. The values used for
maximum infiltration rate, minimum infiltration rate and decay rate of infiltration were
10mm/hr, Imm/hr, and 0.0001/sec respectively for pervious areas and 1mm/hr, 1mm/hr, and

0.000 l/sec respectively for impervious areas

 

BARLOW GREGG VOM M3048
DECEMBER 2007