Appendix I - Stormwater Management Plan

Table 4.5.2 — Table of frequency factors

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AEP (%) ARI (years) Frequency factor (F,)
63% 1 0.80
39% 2 0.85
18% 5 0.95
10% 10 1.00
5% 20 1.05
2% 50 1.415
1% 100 1.20
Table 4.5.3 - Table of Co values
Intensity Fraction impervious f;
(mm/hr)
ths 0.00 0.20 0.40 0.60 0.80 0.90 1.00
39-44 0.44 0.55 0.67 0.78 0.84 0.90
45-49 a 0.49 0.60 0.70 0.80 0.85 0.90
50-54 2 0.55 0.64 0.72 0.81 0.86 0.90
55-59 8 0.60 0.68 0.75 0.83 0.86 0.90
60-64 . 0.65 0.72 0.78 0.84 0.87 0.90
65-69 & 0.71 0.76 0.80 0.85 0.88 0.90
70-90 IX 0.74 0.78 0.82 0.86 0.88 0.90
Refer to notes over page \ aS
Uren elo pea Develop eA
Table 4.5.4 — Cio values for zero fraction impervious "!
Medium density bush, or Light cover bushland, or
Land Dense bushtand Good grass cover, or Poor grass cover, or
description High density pasture, or Low density pasture, or
Zero tillage cropping Low cover bare fallows
Intensity Soil permeability Soil permeability Soil permeability
(mmihr) "ho High | Med | Low | High | Med | Low | High | Med | Low
39-44 0.08 0.24 0.32 0.16 0.32 0.40 0.24 0.40 0.48
45-49 0.10 0.29 0.39 0.20 0.39 0.49 0.29 0.49 0.59
50-54 0.12 0.35 0.46 0.23 0.46 0.58 0.35 0.58 0.69
55-59 0.13 0.40 0.53 0.27 0.53 0.66 0.40 0.66 0.70
60-64 0.15 0.44 0.59 0.30 0.59 0.70 0.44 0.70 0.70
65-69 0.17 0.50 0.66 0.33 0.66 0.70 0.50 0.70 0.70
70-90 0.18 0.53 0.70 0.35 0.70 0.70 0.53 0.70 0.70

 

 

 

 

 

 

 

 

 

 

Refer to note over page.

Queensland Urban Drainage Manual

7

Undeveloped

Provisional edition, 2013