Environmental Engineering Reference
In-Depth Information
A two-way layout analysis of variance was also conducted on scrubbed loads.
The results are shown in Table
3
. For all water quality constituents, land use was
judged to have affected the scrubbed loads. The effects of regional characteristics
(city) were likely to be small on SS and TP.
To investigate the relationship between traffic volume and runoff load, the
mean traffic volume was monitored at the road sections. In the survey, the num-
bers of pedestrians, automobiles and commercial vehicles, such as trucks and
buses, per hour were counted. The results are shown in Fig.
5
. In residential dis-
tricts the traffic volume was small, except in Osaka. In commercial districts, the
number of pedestrians was relatively large. In industrial districts, traffic volume
especially that of commercial vehicles, was larger than in residential and com-
mercial districts. The traffic volume in industrial districts was 100 times larger
than in residential districts. However, the difference in runoff load between the
Table 3
Results of the analysis of variance (Scrubbed load)
Source of variation
BOD
COD
SS
TN
TP
Land use
**
**
**
**
**
City
**
**
**
Land use × city
*5% Significance.
**1% Significance.
1200
Truck, bus
Auto
Pedestrian
1000
800
600
400
200
0
Chiba
Yokohama
Osaka
Kobe
Fig. 5
Traffic volume at the sites surveyed
