Geoscience Reference
In-Depth Information
Table 5.1 Land use classification in Herzliya and Ra'anana residential basins
Close
Close tunnel
Open tunnel
School
Land use
characteristics
Area in
km
2
Area in
km
2
Area in
km
2
Percentages
Percentages
Percentages
Impervious area
1.62
39.2
0.73
40.9
0.27
38.3
Plant covered
0.79
19
0.37
20.7
0.16
22.7
Open area
1.09
26.4
0.41
22.9
0.16
22.4
Roads
0.64
15.4
0.28
15.5
0.12
16.6
Total
4.14
100
1.78
100
0.71
100
Herzliya industrial basin
Shore road
Impervious area
0.14
63.8
0.0002
1
Plant covered
0.02
9.6
0.0009
6
Open area
0.04
18.8
0.0007
4
Roads
0.02
7.8
0.014
89
Total
0.22
100
0.015
100
The open tunnel residential basin - This basin consists mainly of areas of high-
rise urban construction as well as low-rise construction. The percentage of built-up
area in this basin is approx. 40%.
The school residential basin - This basin consists primarily of areas of low-rise
urban construction, road areas reaching approximately 18% and built-up areas
reaching 38%.
Main highway - A station was set up in the drainage pipe next to the Herzliya
landing field, which characterizes a busy city highway.
Ra'anana industrial basin - The Ra'anana industrial basin drains an area of
approx. 100 dunams. The basin is small and is characterized by a very high
percentage of impervious areas (buildings, commercial areas, shops and roads),
reaching 70% of the total area.
Figure
5.5
shows an example of a land use analysis after processing of the aerial
photography data using ENVI guided and unguided classifications in a representative
area, a residential area (the closed tunnel) and in an industrial area of. It can be seen
that in the industrial area there are more impervious areas.
5.4.2 Storm Rain-Runoff Ratios
The runoff calculations were based on an evaluation of the runoff measurements from
field measurements carried out during the present study as well as on studies of urban
storm runoff rain ratios that were carried out previously (Goldschlager et al.
2005
;
Asaf et al.
2002
). A summary of the average values for various basins in Herzliya and
Ra'anana are shown in Table
5.2
. Overall as expected, the more the impermeable
ground cover increases, the more the runoff coefficient rises (Goldschlager et al.
2005
); Moreover, in industrial and commercial land use, the percentage of imperme-
able area rises due to the number of stores and asphalt surfaces, and there is a higher
linkage between the areas and the drainage systems. In the industrial land uses
maximum values have been observed reaching above 0.80 (Table
5.2
).
