Page 317 - ToroProductCatalogue2016

Precipitation and Infiltration Rates
Precipitation Rates
To avoid run-off and water wastage, select sprinklers so that the precipitation rate is less than or equal to the infiltration rate of the soil. The type of soil, condition of both soil and ground cover, and slope affect the infiltration rate. The table below shows some indicative average rates. Always confirm the infiltration rate with on-site tests. Where system precipitation rates are higher than the infiltration rate, it may be possible to avoid run-off by repeating the irrigation cycle for shorter periods
of time.
Company policy is one of constant improvement and therefore changes in specif Toro Australia Pty Ltd, 53 Howards Road, Beverley, South Australia, 5009. Phone
Table 1: Indicative Maximum Precipitation Rates – mm/hour
Soil Texture
0-5% slope
5-8% slope
8-12% slope
12+ % slope
Cover
Bare
Cover
Bare
Cover
Bare
Cover
Bare
Coarse sandy soils
50
50
50
38
38
25
25
12
Coarse sandy soils over compact subsoils
44
38
31
25
25
19
19
10
Light sandy loams uniform
44
25
31
20
25
15
19
10
Light sandy loams over compact subsoils
31
19
25
12
19
10
12
7
Uniform silt soils
25
12
20
10
15
7
10
5
Silt soils over compact subsoil
15
7
12
6
10
4
7
2.5
Heavy clay or clay loam
5
4
4
2.5
3
2
2.5
1.5
The maximum precipitation rates values listed in this table are suggested by the US Department of Agriculture. The values are indicative averages only and may vary with respect to actual soil and ground cover condition.
Slope, Angle and Ratio Precipitation Rates
%
Angle
Ratio
Slope Factor
%
Angle
Ratio
Slope Factor
0
10
20
30 33
40 50
60
67 70
80
90 100
0°
5° 43' 11° 19'
16° 42' 18° 16'
21° 48' 26° 34'
30° 58'
33° 50' 35° 0'
38° 40' 42° 0' 45° 0'
~~~~~~~~~ ~
10:1 5:1
3:1
2:1
1.5:1
1:1
1
1.054
1.12
1.20
1.41
ications may be made without notice and without incurring liability. Please refer to www.toro.com.au 1300 130 898, fax (08) 8243 2488. A.B.N. 47 001 310 443
317
0.5:1 63° 27' 200 62° 15' 190 60° 57' 180 59° 32' 170 58° 0' 160 56° 19' 150
54° 28' 140 52° 26' 130 50° 42' 120
47° 44' 110
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