Table 2. 1. The Salient features of the Shumburit reservoir (source from design document)
Item
|
Features
|
unit
|
Dam height
|
16
|
m
|
Dam crest length
|
338
|
m
|
Gross Freeboard
|
2.5
|
m
|
Spillway crest length
|
10
|
m
|
Live storage at Full supply level, FSL
|
216.75
|
(ha.m)
|
Gross storage at FSL
|
261.52
|
(ha.m)
|
Gross storage at max. full supply level
|
394.7
|
(ha.m)
|
Irrigable lands size
|
270
|
ha
|
Watershed size
|
13.5
|
Km2
|
Table 2 .2. Watershed slope characterization based on (FAO, 1989) classification
Slope (%)
|
Description
|
Area (ha)
|
Coverage (%)
|
0-2
|
Flat/gentle
|
144.517
|
11.19
|
2-8
|
Gently sloping
|
620.837
|
48.06
|
8-15
|
Moderately steep/ gently rolling
|
429.099
|
33.22
|
15-30
|
Moderately steep
|
97.0479
|
7.51
|
30-50
|
Steep/Hilly
|
0.34332
|
0.03
|
total
|
|
1291.84422
|
100
|
Table 2. 3. Types of land covers an area coverage in the watershed
LULC type
|
area (in ha)
|
area coverage in %
|
Pasturage and Degraded Grass
|
266.15
|
19.81
|
Shrub land
|
256.6
|
19.1
|
build-up area
|
30.07
|
2.24
|
Cultivated
|
720.29
|
53.63
|
Forest
|
9.45
|
0.7
|
Bare land
|
33.23
|
2.47
|
water
|
27.39
|
2.04
|
Table 2.4. Soil types and area coverage in the Shumburit watershed
Soil Type
|
Area ( ha)
|
Coverage (% )
|
Chromic vertisol
|
888.14
|
66.05
|
Pellic vertisol
|
456.42
|
33.95
|
sum
|
1344.56
|
100
|
Table 2.5. Sediment core sampling location
point
|
easting
|
northing
|
1
|
325972
|
1147847
|
2
|
325455
|
1147108
|
3
|
325297
|
1147352
|
4
|
325220
|
1147027
|
5
|
325032
|
1146494
|
6
|
324823
|
1147519
|
7
|
324897
|
1147695
|
8
|
325426
|
1147697
|
Table 2.6. Kerby Equation Retardance Coefficient Values
Generalized terrain description
|
Dimensionless retardance coefficient (N)
|
Pavement
|
0.02
|
Smooth, bare, packed soil
|
0.10
|
Poor grass, cultivated row crops, or moderately rough packed surfaces
|
0.20
|
Pasture, average grass
|
0.40
|
Deciduous forest
|
0.60
|
Dense grass, coniferous forest, or deciduous forest with deep litter
|
0.80
|
Table 2.7. P- Value (Wischemeier and Smith, 1978)
Land use type
|
Slope %
|
P-factor
|
Agricultural land
|
0-5
|
0.1
|
5-10
|
0.12
|
10-20
|
0.14
|
20-30
|
0.19
|
30-50
|
0.25
|
50-100
|
0.33
|
Other land use
|
All
|
1.00
|
Table 3. 1. Interpolation methods
Interpolation method
|
MAE
|
RMSE
|
R2
|
IDW
|
1.35
|
1.92
|
0.938
|
OK
|
0.693
|
1.116
|
0.944
|
GPI
|
3.576
|
4.288
|
0.169
|
LPI
|
0.696
|
1.179
|
0.938
|
RBF
|
0.806
|
1.321
|
0.922
|
Table 3. 2. Area coverage at different depth
No
|
depth
|
area in (ha)
|
area coverage (%)
|
1
|
0-2
|
40.76
|
70.08
|
2
|
2-4
|
6.9
|
11.86
|
3
|
4-6
|
5.2
|
8.94
|
4
|
6-8
|
3.8
|
6.53
|
5
|
8-10.1
|
1.5
|
2.58
|
|
total
|
58.16
|
100
|
Table 3.3. Area and volume calculation summary
Reservoir area and volume in 2016
|
Reservoir area and volume in 2021
|
Elevation (m)
|
Area (ha) in 2016
|
volume(ha-m) 2016
|
Area (ha) 2021
|
volume (ha-m) 2021
|
|
2117
|
0
|
0
|
0
|
0
|
|
2118
|
0
|
0
|
0
|
0
|
|
2119
|
0.52
|
0.17
|
0
|
0
|
|
2120
|
2.04
|
1.24
|
0.83
|
0.3
|
|
2121
|
3.88
|
4.11
|
3.24
|
2.13
|
|
2122
|
5.88
|
8.8
|
5.3
|
6.48
|
|
2123
|
8.33
|
15.7
|
7.1
|
12.58
|
|
2124
|
11.29
|
25.56
|
9.83
|
20.59
|
|
2125
|
14.39
|
47.01
|
12.37
|
28
|
MDDL
|
2126
|
17.65
|
53.99
|
15.62
|
45.33
|
|
2127
|
21.49
|
73.17
|
19.11
|
62.64
|
|
2128
|
26.15
|
96.85
|
23.14
|
82.97
|
|
2129
|
31.28
|
125.71
|
28.12
|
108.84
|
|
2130
|
35.88
|
159.5
|
32.25
|
139.17
|
|
2131
|
39.83
|
197.79
|
35.83
|
173.8
|
|
2132
|
42.07
|
239.46
|
38.6
|
211.42
|
|
2132.5
|
42.39
|
260.7
|
40.3
|
231.36
|
FSL
|
2133
|
42.61
|
281.96
|
40.88
|
270.72
|
|
2134
|
42.95
|
394.7
|
42.82
|
365
|
|
Table 3.4. Location of sediment core sampling
Description
|
Easting
|
Northing
|
|
Sample 1
|
325972
|
1147847
|
1.2198
|
Sample 2
|
325455
|
1147108
|
1.2196
|
Sample 3
|
325297
|
1147352
|
1.2198
|
Sample 4
|
325220
|
1147027
|
1.2198
|
Sample 5
|
325032
|
1146494
|
1.2198
|
Sample 6
|
324823
|
1147519
|
1.2203
|
Sample 7
|
324897
|
1147695
|
1.2203
|
Sample 8
|
325426
|
1147697
|
1.2198
|
average
|
|
|
1.22
|
Table 3.5. Value of K factor
Soil Type
|
source
|
K-factor
|
Area ( ha)
|
Coverage (% )
|
Chromic vertisol
|
Hurni (1985), SCRP (1996)
|
0.2
|
888.14
|
66.05
|
Pellic vertisol
|
Hurni (1985), and SCRP (1996)
|
0.2
|
456.42
|
33.95
|
sum
|
|
|
1344.56
|
100
|
Table 3. 6. Land cover factor in the study area
LULC type
|
Source
|
C-factor
|
area (in ha)
|
C-factor*area
|
area coverage in %
|
Pasturage and Degraded Grass
|
Hurni, 1985
|
0.05
|
266.15
|
13.31
|
19.81
|
Shrub land
|
BCEOM,1998)
|
0.02
|
256.6
|
5.13
|
19.1
|
build-up area
|
Ongsomwang and Thinley
|
0.85
|
30.07
|
25.56
|
2.24
|
Cultivated
|
(FAO, 1984)
|
0.2
|
720.29
|
144.06
|
53.63
|
Forest
|
(Hurni, 1985)
|
0.01
|
9.45
|
0.09
|
0.7
|
Bare land
|
(Erdogan et al., 2006)
|
0.6
|
33.23
|
19.94
|
2.47
|
water
|
Ongsomwang and Thinley,2009
|
0
|
27.39
|
0
|
2.04
|
Total
|
|
|
1343.18
|
208.09
|
99.99
|
weighted average Value of C
|
|
|
|
0.15
|
|
Table 3. 7. Land cover classification accuracy assessment at 2021
LULC type
|
Pasturage and Degraded Grass
|
Shrub land
|
build-up area
|
Cultivated
|
Forest
|
Bare land
|
water
|
Total
|
User accuracy
|
producer accuracy
|
LULC type
|
|
|
|
|
|
|
|
|
|
|
Pasturage and Degraded Grass
|
19
|
1
|
0
|
0
|
0
|
0
|
0
|
20
|
95
|
100
|
Shrub land
|
0
|
8
|
0
|
0
|
2
|
0
|
0
|
10
|
80
|
72.7
|
build-up area
|
0
|
0
|
13
|
0
|
0
|
1
|
0
|
14
|
92.9
|
92.9
|
Cultivated
|
0
|
0
|
0
|
26
|
0
|
0
|
0
|
26
|
100
|
100
|
Forest
|
0
|
2
|
0
|
0
|
6
|
0
|
0
|
8
|
75
|
75
|
Bare land
|
0
|
|
1
|
|
0
|
7
|
0
|
8
|
87.5
|
87.5
|
water
|
0
|
0
|
0
|
0
|
0
|
0
|
8
|
8
|
100
|
100
|
Total
|
19
|
11
|
14
|
26
|
8
|
8
|
8
|
94
|
|
|
Diagonal pixel sum
|
|
|
|
|
|
|
87
|
|
|
|
Overall accuracy (%)
|
92.55
|
|
|
|
|
|
|
|
|
|
Kappa coefficient
|
0.91
|
|
|
|
|
|
|
|
|
|
Table 3. 8. The weighted average value of the P factor
P -Factor
|
Area in ha
|
P-Factor*Area
|
area coverage in %
|
0.1
|
386.7
|
38.67
|
29.92
|
0.12
|
565.56
|
67.87
|
43.77
|
1
|
319.32
|
319.32
|
24.71
|
1
|
20.28
|
20.28
|
1.57
|
1
|
0.38
|
0.38
|
0.03
|
Total
|
1292.23
|
446.52
|
100
|
Weighted average
|
|
0.35
|
|
Table 3.9. Shows the annual sediment yields from 2016 to 2021
year
|
runoff volume(M3)
|
total rainfall factor
|
Cumulative Rainfall factor
|
rainfall factor per ha
|
total sediment in each year
|
cumulative Sediment (tons)
|
2016
|
6700449.74
|
2502997.9
|
2502997.9
|
1854.07
|
26961
|
26960.9
|
2017
|
11244548.06
|
4400292.63
|
4400292.63
|
3259.48
|
51747
|
78708.4
|
2018
|
9208425.97
|
3475147.11
|
3475147.11
|
2574.18
|
51085
|
129793
|
2019
|
9041465.63
|
3370978.24
|
3370978.24
|
2497.02
|
42946
|
172739
|
2020
|
8421494
|
3108379.93
|
3108379.93
|
2302.5
|
39601
|
212340
|
2021
|
9124427.734
|
3426000.12
|
3426000.12
|
2537.78
|
43923
|
256263
|