Table 1 Main properties of topography, meteorology, and hydrology in Lorestan province
Area (km2)
|
Meaan annual precipitation (mm)
|
Absolute maximum temperature (oc)
|
Absolute minimum temperature (0c)
|
Lowest altitude (m)
|
Highest altitude (m)
|
Average annual evapotranspiration (mm)
|
Total length of rivers (km)
|
28064
|
455.23
|
47.8
|
-31
|
239
|
4080
|
1119.4
|
10041
|
Table 2 Topographic and meteorologic characteristics of the counties in Lorestan province
Stations
|
Longitude
|
Latitude
|
Altitude (m)
|
Average precipitation in 2018 (mm)
|
Drought extent in 2018 (%)
|
Average precipitation in 2019 (mm)
|
Drought extent in 2019 (%)
|
Khorramabad
|
48.17
|
33.26
|
1155
|
105.1
|
85.9
|
105.1
|
20.8
|
Azna
|
49.25
|
33.27
|
1872
|
87.5
|
99.8
|
92.6
|
88.2
|
Aleshtar
|
48.15
|
33.49
|
1567
|
100.3
|
50
|
110.5
|
20.3
|
Aligudarz
|
49.7
|
33.4
|
1980
|
70
|
91.1
|
79.8
|
29.6
|
Borujerd
|
48.45
|
33.55
|
1629
|
96.5
|
97.5
|
111.1
|
40.9
|
Poldokhtar
|
47.71
|
33.15
|
700
|
105.2
|
99.8
|
116
|
49.6
|
Doroud
|
49.8
|
33.48
|
1450
|
134.2
|
79.2
|
125.4
|
62.1
|
Nourabad
|
48.5
|
34.8
|
1830
|
100.1
|
65.8
|
130
|
59.1
|
Kuhdasht
|
47.25
|
33.4
|
970
|
84.3
|
57.1
|
95.2
|
6.2
|
Table 3 Soil erodibility based on texture and organic matter content.
Texture
|
Organic matter content (%)
|
< 2
|
> 2
|
Clay
|
0.24
|
0.21
|
Loamy - Clay
|
0.33
|
0.28
|
Loamy
|
0.34
|
0.26
|
Sandy - Loamy
|
0.05
|
0.04
|
Sandy
|
0.03
|
0.01
|
Loamy - Clay- Sandy
|
0.2
|
0.2
|
Loamy - Sandy
|
0.14
|
0.12
|
Loamy - Sility
|
0.41
|
0.37
|
Clay - Sility
|
0.27
|
0.26
|
Loamy-Clay- Silt
|
0.35
|
0.3
|
Silty
|
0.46
|
0.37
|
Clay- Sandy
|
0.41
|
0.33
|
Table 4 List of images downloaded from the Copernicus website.
No
|
Satellite
|
Sensor
|
Path
|
Satellite images
|
Before flooding
|
After flooding
|
1
|
Sentinel-2B
|
MSI
|
T39SVS
|
2018/04/30
|
2019/04/30
|
2
|
Sentinel-2B
|
MSI
|
T38SPC
|
2018/04/30
|
2019/04/30
|
3
|
Sentinel-2B
|
MSI
|
T38SQB
|
2018/04/30
|
2019/04/30
|
4
|
Sentinel-2B
|
MSI
|
T39SQC
|
2018/04/30
|
2019/04/30
|
5
|
Sentinel-2B
|
MSI
|
T38SQD
|
2018/04/30
|
2019/04/30
|
6
|
Sentinel-2B
|
MSI
|
T39STS
|
2018/04/30
|
2019/04/30
|
7
|
Sentinel-2B
|
MSI
|
T39STT
|
2018/04/30
|
2019/04/30
|
8
|
Sentinel-2B
|
MSI
|
T39SUS
|
2018/04/30
|
2019/04/30
|
9
|
Sentinel-2B
|
MSI
|
T39SUT
|
2018/04/30
|
2019/04/30
|
Table 5 Support practices factor for different slope classes based on Wischmeier and Smith (1978).
Slope (%)
|
P
|
<3
|
0.6
|
3-6
|
0.5
|
6-9
|
0.5
|
9-12
|
0.6
|
12-15
|
0.7
|
15-20
|
0.8
|
20-25
|
0.9
|
>25
|
1
|
Table 6 Descriptive statistics for RUSLE factors
Factors
|
Min
|
Max
|
Mean
|
Standard Deviation (SD)
|
Rainfall Erosivity (R) (2017/11/01 to 2018/04/30) (MJ.mm ha-1 hr-1 yr-1)
|
40.36
|
76.45
|
58.87
|
0.22
|
Rainfall Erosivity (R) (2018/11/01 to 2019/04/30) (MJ.mm ha-1 hr-1 yr-1)
|
139.6
|
176.3
|
157.6
|
0.36
|
Soil Erodibility (K) (t ha MJ-1 mm-1)
|
0.17
|
0.49
|
0.34
|
0.008
|
Slope Length and Steepness (L)
|
0
|
0.27
|
0.13
|
0.0008
|
Support practices (P)
|
0.5
|
1
|
0.70
|
0.024
|
Cover Management (C) (Average NDVI 2017/11/01 to 2018/04/30)
|
0.07
|
1
|
0.418
|
0.009
|
Cover Management (C) (Average NDVI 2018/11/01 to 2019/04/30)
|
0.02
|
1
|
0.40
|
0.106
|
Soil Loss (t ha-1 yr-1) (2017/11/01 to 2018/04/30)
|
0
|
4.122
|
1.141
|
0.101
|
Soil Loss (t ha-1 yr-1) (2018/11/01 to 2019/04/30)
|
0
|
10.937
|
3.036
|
0.208
|
Table 7 R values for meteorological stations in the study area.
Stations
|
X-UTM[1]
|
Y-UTM
|
Elevation
(m)
|
R
(2017/11/01 to 2018/04/30)
(MJ mm ha-1 h-1 y-1)
|
R
(2018/11/01 to 2019/04/30)
(MJ mm ha-1 h-1 y-1)
|
Khorramabad
|
807284
|
3707810
|
1155
|
40.63
|
158.8
|
Azna
|
909226
|
3716455
|
1872
|
76.46
|
160.6
|
Selseleh
|
802053
|
3751983
|
1567
|
58.18
|
167.6
|
Aligudarz
|
943316
|
3702023
|
1980
|
71.56
|
139.6
|
Borujerd
|
846159
|
3758832
|
1629
|
51.06
|
156
|
Poldokhtar
|
752774
|
3671066
|
700
|
71.49
|
176.3
|
Dorud
|
874732
|
3716097
|
1450
|
65.02
|
165.8
|
Delfan
|
760806
|
3777710
|
1830
|
56.03
|
154.3
|
Kuhdasht
|
731015
|
3718147
|
970
|
46.63
|
148.5
|
Table 8 The acreage of soil erosion risk classes in the study area
Classes
|
Soil erosion risk classes
(pre-flood)
|
Soil erosion risk classes
(post-flood)
|
Erosion risk class
|
Area (ha)
|
Area (%)
|
Erosion risk class
|
Area (ha)
|
Area (%)
|
Very low
|
0-1
|
1092698
|
68.20
|
0-1
|
659625
|
41.17
|
Low
|
1-2
|
406638
|
25.38
|
1-2
|
356969
|
22.28
|
Moderate
|
2-5
|
102861
|
6.42
|
2-5
|
324445
|
20.25
|
High
|
-
|
-
|
-
|
5-8
|
147883
|
9.23
|
Very high
|
-
|
-
|
-
|
>8
|
113275
|
7.07
|
Table 9 Soil erosion in the study area in 2070 under different climate change-land use change scenarios
Erosion risk class
|
SSP1-RCP 2.6
|
SSP2-RCP 4.5
|
SSP5-RCP 8.5
|
Area (ha)
|
Area (%)
|
Area (ha)
|
Area (%)
|
Area (ha)
|
Area (%)
|
Very low
|
98772
|
3.52
|
185680
|
6.62
|
177001
|
6.31
|
Low
|
174989
|
6.24
|
137241
|
4.89
|
145920
|
5.20
|
Moderate
|
731551
|
26.07
|
934327
|
33.29
|
486849
|
17.35
|
High
|
892285
|
31.79
|
1071395
|
38.18
|
1220833
|
43.50
|
Very high
|
908804
|
32.38
|
477758
|
17.02
|
775797
|
27.64
|
Sum
|
2806400
|
100
|
2806400
|
100
|
2806400
|
100
|