Image Processing Reference
In-Depth Information
Table 6.8 Measured and estimated runoff amounts from the SCS Model (Chen 1996 )
Measured
runoff (ft 3 )
Estimated
runoff (ft 3 )
Date
Precip. (in.)
Error (%)
Basin 1
5/21/92
0.32
21,081
20,501
−2.8
4/24/93
0.46
47,574
45,958
3.4
Basin 2
5/21-22/93
0.51
175,478
168,447
4.0
6/17/93
0.34
58,988
48,621
17.6
Basin 3
5/08/93
0.97
298,174
370,230
24.2
Basin 4
5/21/92
0.32
17.705
14,631
−17.4
4/01/93
0.50
61,628
54,947
−4.1
5/05/93
0.56
76,830
72,217
−6.0
5/06-07/93
0.86
145,866
184,371
26.0
5/08/93
0.85
213,671
172,787
−25.4
Basin 5
3/21/95
0.63
146,406
61,266
−58.2
3/23/95
0.99
215,290
326,322
51.6
4/08/95
0.77
136,607
143,693
5.2
5/25/95
1.02
328,555
355,778
8.0
is compared to estimated runoff in cubic feet per storm event. Under-estimates are
represented by a minus sign, and over-estimates by a plus sign. Seven of the errors
are less than 10% with five between 17% and 26%, still within the practical working
range according to collaborating practitioners. Estimates for mid-valley basins 1, 2,
and 4 performed best. Basins 3 and 5 are foothill sites with granular soils and
considerable open space.
Remote sensing applied to estimating/predicting urban storm runoff is of great
scientific and practical planning value. Yet, it is virtually unexplored at this point in
time due to rare coincidence of empirical rainfall and runoff data at specified urban
drainage basins. While this study dealt only with water runoff quantity, similar
remote sensing opportunities are pursued for water quality.
6.6
Temporal Application of the V-I-S Model
The V-I-S model has been applied to several change detection studies (Ward et al.
2000 ; Madhaven et al. 2001 ; Hung 2003 ; Kaya et al. 2004 ). This section highlights
two examples, one in Turkey and one in Utah.
6.6.1
SPOT-X Data: Pre- and Post-earthquake Analysis
Kaya et al. ( 2004 ) employed SPOT-X to record earthquake-induced land cover
change in northwest Turkey in consequence of the Izmit earthquake of August 1999.
The trend and relative magnitude of land cover change were displayed using the
 
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