Watershed Data Report

This report was created with the free Global Watersheds web app on . Creative Commons License BY 4.0.

Contents

  1. Political Boundaries
  2. Population
  3. Land Cover
  4. Hydrology
  5. GRACE Terrestrial Water Storage
  6. Irrigation
  7. Dams
  8. Longest River
  9. Topography
  10. References

This report is for the watershed with an outlet near 24°37'40"N, 88°07'55"E, or (24.628, 88.132), with a drainage area of around 928,000 km².

Political Boundaries

The watershed is located in four countries, as shown below in Table 1 below.

Table 1. Countries in the watershed.

Country Area (km²) Percent of watershed
India 744,000 80%
Nepal 147,000 16%
China 37,700 4%
Bangladesh 244 0%

Data on political boundaries comes from Natural Earth, https://www.naturalearthdata.com.

Population

The watershed has an estimated population of 550,000,000 in the year 2020. Figure 1 shows how population has changed from 1990 to 2020. The population grew at an average rate of 1.9% per year over this time period.

Figure 1. Estimated watershed population from 1990 to 2020.

Population data comes from GlobPop, Global Gridded Population Estimates, created by researchers at Beijing Normal University (Liu 2024).

Human population growth can affect water quality via increased pollution from households, industry, and agriculture. Further, land use and land cover change associated with population growth can have a major impact on watersheds (see the next section of this report).

Land Cover

The most common land cover type in the watershed is cropland, covering 458,000 km² in 2020. More detailed information about land cover and how it has changed is shown in Table 3 and Figure 2 below. Pairs of bars represent the area for each land cover type in the years 2000 and 2020.

Figure 2. Land cover in the watershed.

Table 3. Land cover in the watershed.

Land Cover Type Area in 2000, km² Area in 2020, km²   Change
Cropland 431,000 458,000 6%
Dense short vegetation 206,000 164,000 -20%
Tree cover 135,000 133,000 -1%
Built-up 39,200 68,900 75%
Semi-arid 61,800 52,800 -14%
Desert 22,300 23,800 6%
Open surface water 10,900 12,200 12%
Snow and ice 13,200 11,200 -15%
Wetland + tree cover 2,850 2,830 0%
Wetland + dense short vegetation 5,160 2,030 -60%
Wetland + sparse vegetation 1,990 1,380 -30%

Land cover data comes from the GLAD: Global Land Cover and Land Use Change, 2000-2020 (Popatov et al. 2022). This dataset, created by researchers at the University of Maryland, is available online here. Classification is based on satellite imagery from Landsat and machine learning tools.

Land cover change can profoundly influence watershed hydrology and water quality. Urbanization and development can increase the impervious cover, causing more water to run off rather than infiltrate into the ground. This can decrease groundwater recharge and river baseflows, or the flows that occur during dry times. Deforestation and agricultural development are often accompanied by an increase in soil erosion and sediment loads. Other land use types are associated with water pollution. For example, agriculture can increase loads of pesticides and nutrients (nitrogen and phosphorus) from fertilizers. Urbanization and industrialization can cause contamination from a wide range of chemicals used in households and industry.

Hydrology

The average annual precipitation over the watershed is 1,058 mm/year. (Precipitation includes all forms of water, including snow and rain.) Some of this water leaves the watershed surface via evaporation and transpiration, or the loss of water from plants. Annual evapotranspiration is estimated at 522 mm/year. The basin climatology, or the monthly average precipitation and evapotranspiration, is shown in Figure 4.

Figure 4. Watershed climatology: monthly average precipitation and evapotranspiration over the watershed.

Precipitation data comes from WorldClim, a global gridded dataset by researchers at the University of East Anglia (Harris et al. 2020). This dataset is based on downscaling and bias-correcting the CRU-TS dataset (Fick and Hijmans 2017), which is based on a large collection of station observations that span 1901–2018.

Evapotranspiration is even more difficult to estimate than precipitation. Here, we use a dataset, GLEAM v3.6B, which combines modeling and remote sensing data (Martens et al. 2017; Miralles et al. 2011).

It is difficult to estimate water cycle variables over large areas. So you should keep in mind that these estimates are uncertain (not perfect).

Terrestrial Water Storage Anomaly

The GRACE satellites provide information about changes in the amount of water over different locations on the Earth. Figure 3 shows the average terrestrial water storage anomaly over the watershed.

🖱️Mouse wheel to zoom Click & drag to pan 📱Pinch to zoom on mobile

Figure 3. GRACE terrestrial water storage anomaly from 2002 to 2025.

The GRACE satellites make highly accurate measurements of the Earth's gravitational field, and provide measurements of changes in the mass of water on a monthly time scale. These measurements do not tell us how much water there is in a region, but rather, how it the amount of water has changed compared to a baseline. The measurement includes all forms of water, including water in rivers, lakes, and reservoirs, soil moisture, groundwater, glaciers, snow, and ice. For an introduction to GRACE, see the section of my PhD thesis on Remote Sensing of the Water Cycle.

The total amount of water in the watershed appears to be trending downwards at a rate of -15.3 cm per decade (P < 0.01). This P-value suggests that the observed trend is statistically significant; it is unlikely the trend is due to random chance.

GRACE Terrestrial Water Storage Anomaly data is from the Center for Space Research at the University of Texas, Austin (Save et al. 2016, 2022).

Irrigation

The watershed had about 281889.1 km² of land equipped for irrigation in 2005. This is about 30.4% of the watershed. Figure 5 shows the development of irrigated area from 1900 to 2005. These estimates are based on a global dataset published by an international team of researchers (Siebert et al. 2015).

Figure 5. Area equipped for irrigation in the watershed from 1900 to 2005

Irrigation brings many benefits for growing crops. In arid regions, it enables production where it would be otherwise impossible. In humid regions, irrigation can increase crop quality and yield, and provide more certainty against unpredictable climate. Yet, the expansion of irrigation can have impacts on watersheds that need to be carefully managed.

Increased irrigation usually requires more water to be withdrawn from rivers, lakes, or groundwater sources, which can reduce streamflow and alter natural flow patterns. This reduced flow can harm aquatic ecosystems and diminish the water available downstream for other uses. Irrigation often introduces fertilizers and pesticides into the watershed, and may increase soil erosion and sediment transport. When nutrients run off into rivers and streams, they can lead to nutrient pollution, algal blooms, and eutrophication. This plus chemical pesticides and herbicides negatively impacts aquatic life and water quality for human uses.

Dams

This watershed contains 751 dams identified in the Global Dam Watch database, with a total storage capacity of 92,600 million m³.

Information on these dams is listed in Table 4. The number and size of dams in a watershed is one measure of hydromodification, or how much the natural hydrologic cycle is influenced by human activities.

Table 4. Dams in the watershed. Unknown or missing data shown with a dash.

Dam Name Reservoir Name River Main Use Year Dam Height (m) Capacity (10⁶ m³) Latitude Longitude URL
23.753 79.136
Koshi Barrage Koshi Built 1962 26.531 86.923 link
23.736 77.787
23.789 79.336
23.751 78.809
23.879 77.916
23.281 75.464
23.130 75.791
23.380 76.691
23.614 75.836
22.970 76.343
23.616 77.126
28.904 79.012
26.646 88.394
23.924 76.314
28.802 79.188
23.965 76.777
23.116 81.815
23.191 81.997
24.052 84.497
24.070 79.087
24.789 81.310
24.997 86.213
25.052 84.633
28.664 77.399
23.613 77.855
24.627 79.141
23.249 75.780
26.685 87.879
26.823 87.892
24.057 79.465
26.928 83.983
27.437 82.937
28.342 80.775
28.797 79.810
29.710 80.685
24.167 81.898
24.860 81.312
27.137 85.483
29.981 80.572
27.878 85.126
27.963 85.171
24.045 77.180
28.041 81.955
28.417 87.760
25.036 81.728
25.057 81.671
28.064 85.207
23.883 82.742
24.205 79.642
24.241 79.658
24.290 79.724
Alaknanda -Badrinath Hydroelectricity 30.239 78.834
24.318 79.789
28.065 80.967
25.556 86.079
24.741 80.010
25.043 81.759
24.188 81.297
29.047 80.109
23.605 78.326
25.464 87.198
22.971 76.677
23.781 77.844
Upper Marsyangdi A Gandak Hydroelectricity 28.314 84.402
24.611 79.186
Upper Chaku A Sapt Hydroelectricity 27.865 85.968
24.068 76.956
27.443 77.714
28.290 79.370
23.903 77.927
Lower Modi 1 Gandak Hydroelectricity 28.235 83.715
Jhyari Khola Sapt Hydroelectricity 27.776 85.677
23.365 77.713
23.635 79.078
23.865 77.891
24.054 79.176
Farakka Ganges Navigation Built 1974 16.0 35730.0 24.785 87.935 link
Rihand Govind Ballabah Pant Rihand Hydroelectricity Built 1962 91.0 10600.0 24.201 83.007
Gandhi Sagar Gandhi Local Nalla Irrigation Built 1960 62.0 7322.8 24.700 75.554
Bansagar Dam Bansagar Lake Irrigation Built 2006 67.0 5410.0 24.190 81.288 link
Tehri Bhagirathi Irrigation Built 2006 261.0 3540.0 30.375 78.476 link
Rana Pratap Sagar Rana Pratap Chambol Irrigation Built 1968 54.0 2898.7 24.917 75.580
Ramganga Ramganga Irrigation Built 1974 128.0 2450.0 29.521 78.760
Rajghat Rajghat Betwa Irrigation Built 1992 44.0 2172.0 24.760 78.231 link
North Koel North Koel Irrigation Built 1993 68.0 1170.0 24.410 83.856 link
Matatila Matatila Betwa Irrigation Built 1964 46.0 1132.7 25.097 78.372
Madikheda Sindh Hydroelectricity Built 2008 62.0 1105.2 25.556 77.845 link
Bisalpur Built 1993 40.0 1095.8 25.925 75.459
Sarda Sagar Chauba Irrigation Built 1962 16.0 406.3 28.763 80.108
322.9 24.865 82.402
Built before 1990 308.4 26.224 76.118
Built 1992 275.5 23.323 81.031
259.8 24.438 82.965
256.4 25.823 74.805
Pagara 256.2 26.271 77.839
Halali Halali Irrigation Built 1976 30.0 252.8 23.501 77.551
Sirsi Bakahar Nala Irrigation Built 1958 21.0 215.0 24.839 82.500
Built 2016 210.3 24.140 75.899
Nanak Sagar Deoha Irrigation Built 1962 17.0 209.0 28.946 79.825
207.6 25.693 74.573
Harsi Parwati Irrigation Built 1935 29.0 207.0 25.751 77.921
Maudaha Birma Irrigation Built 1994 33.0 200.0 25.588 79.710
199.3 24.611 83.173
187.6 25.735 74.951
Naugarh Karmnasa Irrigation Built 1966 19.0 178.4 24.859 83.349
Built 2002 168.0 23.723 78.755
Rangawan Bannel Nalla Irrigation Built 1957 27.0 164.2 24.685 79.859
Pathkhauli Hathia Khand Irrigation 18.0 163.0 27.393 81.732
156.9 25.385 79.677
Musa Khand Karmnasa Irrigation Built 1967 34.0 155.8 24.975 83.298
Jirgo Jirgo Irrigation Built 1958 30.0 150.8 25.047 82.949
147.8 25.035 74.313
Built 2002 147.3 23.664 76.919
Chandan Chandan Irrigation Built 1974 40.0 146.2 24.676 86.914
144.6 28.940 79.581
Tigra Sank Irrigation Built 1917 24.0 130.0 26.223 77.998
Shahjad Shahjad Irrigation Built 1992 29.0 130.0 24.948 78.521
Badua Badua Irrigation Built 1965 42.0 128.4 24.884 86.640
Built before 1990 128.0 25.672 77.885
125.7 24.784 82.314
Lower Khajuri Khajoori Irrigation Built 1949 18.0 120.4 25.080 82.605
Gangau Ken Irrigation Built 1915 16.0 120.0 24.626 79.861
Urmil Urmil Irrigation Built 1994 26.0 116.6 25.131 79.701
114.2 25.439 79.897
Chandra Prabha Chandra Prabha Irrigation Built 1966 20.0 113.3 24.929 83.171
Kotabarrage Chambal Irrigation Built 1960 52.0 108.1 25.175 75.826
107.3 25.452 74.567
Rajsamand Rajsamand Gomti Banas Irrigation Built 1671 39.0 107.1 25.061 73.894 link
Mahan Mahan Built 2011 104.0 24.224 81.543
Built 1998 102.6 25.217 81.133
Built 1991 98.3 24.826 74.523
Govind Sagar Shahjad Irrigation Built 1953 18.0 96.9 24.673 78.415
Built before 1985 96.5 25.933 74.555
Meja Kothari Irrigation Built 1956 14.0 96.2 25.395 74.542
Gudha Mechambal Irrigation Built 1958 25.0 95.7 25.498 75.459
Tumaria Dhela Irrigation Built 1961 23.0 94.3 29.308 78.939
Sagar Sagar Betwa Irrigation Built before 1990 27.0 93.7 24.341 77.838
Built before 1989 93.1 24.561 76.334
Jamni Jamni Irrigation Built before 1990 26.0 92.9 24.364 78.690
Kotwal Local Nalla Irrigation Built 1919 11.0 91.5 26.489 78.126
91.0 28.274 81.086
Built 2013 90.3 25.356 77.998
Koteshwar Bhagirathi Irrigation Built 2011 98.0 88.9 30.260 78.497 link
Built before 1989 85.9 29.364 78.785
Kulekhani Kulekhani Hydroelectricity Built 1982 114.0 85.3 27.591 85.158
Ruthiai Chopan Irrigation Built 1991 31.0 85.0 24.548 77.233
Sajnam Sajnam Irrigation Built 1990 22.0 83.5 24.522 78.594
82.8 27.443 83.911
Ghunghuta Ghunghuta Irrigation Built 1986 32.0 82.0 23.026 83.220
Built 1988 80.8 27.579 82.598
Kaketo Parwati Irrigation Built 1934 34.0 80.5 25.899 77.694
Built before 1989 80.3 26.897 77.372
78.9 25.181 80.794
Paricha Betwa Irrigation Built 1886 17.0 78.8 25.514 78.781
Chhapi Irrigation Built 2000 34.0 78.5 24.342 76.472
Saprar Saprar Irrigation Built 1952 17.0 76.2 25.213 79.088
75.4 25.966 77.760
Built 2011 74.4 24.368 76.581
74.1 27.034 76.259
Built before 1990 74.0 25.077 78.758
Built before 1991 71.7 25.213 76.768
Built 1993 71.7 22.834 76.597
Built 1999 71.0 23.243 76.259
Baigul Baigul Irrigation Built 1968 14.0 70.7 28.887 79.621
Built 2002 69.1 24.655 75.171
68.9 26.605 77.589
Built before 1989 66.6 25.519 79.148
65.5 28.202 83.963
Built before 1990 61.7 23.027 77.488
Ahraura Garai Irrigation Built 1954 23.0 60.2 24.998 83.038
59.6 29.411 78.609
Panchana Gambhira Irrigation Built 1977 33.0 59.5 26.560 77.005
Phuwaria Tilaiya Irrigation Built 1988 30.0 59.0 24.596 85.493
Sindhwarni Mani Irrigation 21.0 58.6 25.133 86.521
58.5 24.723 82.048
58.3 25.168 75.053
58.2 23.654 75.694
Haripura Bhakra Irrigation Built 1975 11.0 58.2 29.116 79.325
Dhekwan Betwa Irrigation Built 1909 19.0 57.8 25.188 78.547
57.5 24.806 86.072
Built before 1991 56.0 26.539 76.682
Aoda Seep Irrigation Built 1934 17.0 55.7 25.517 76.790
Built before 1985 54.9 25.715 78.756
53.9 26.411 75.759
Built before 1988 53.1 25.260 79.578
Tillar Tillarchambal Irrigation Built before 1989 23.0 52.2 23.598 76.110
Orni Dakra Irrigation Built 1998 23.0 51.6 24.963 86.830
Built 2011 50.1 23.941 80.246
Built before 1990 50.0 24.644 78.845
Built 2015 48.7 24.270 77.723
48.2 24.028 77.760
46.2 28.169 84.094
Built 2015 45.2 23.398 78.789
Upper Khajuri Khajoori Built 1958 44.7 24.996 82.610
44.3 24.353 74.913
Built 1992 43.7 23.672 77.513
43.6 24.797 79.871
43.6 25.134 81.032
43.0 25.395 74.394
42.6 24.155 82.452
Built before 1985 42.3 24.831 86.814
Kalisil Kalisi Banas Irrigation Built 1956 25.0 41.7 26.271 76.769
Built before 1989 40.8 27.519 76.535
Built before 1989 40.7 26.710 76.777
40.6 25.030 74.824
Majhgawan Local Nalla Built 1914 20.0 40.5 25.192 79.548
Built before 1990 40.4 25.052 78.820
Built before 1985 40.2 23.168 81.659
Built 1992 39.9 25.891 75.171
39.9 24.852 86.560
39.6 23.722 80.428
39.0 24.602 73.679
38.5 25.185 78.698
Built 1992 38.3 25.856 75.126
Built before 1990 37.2 24.374 77.241
37.1 23.119 83.265
36.9 25.011 79.044
36.4 25.001 75.880
36.2 24.869 81.168
Kaliasote Kaliasote Irrigation Built 1993 34.0 35.9 23.200 77.408
Dongari Built before 1990 35.8 25.381 78.460
35.0 25.463 78.325
Chhilar Chhilar Irrigation Built 1972 21.0 34.8 23.396 76.290
34.8 24.847 86.440
34.6 23.919 84.285
34.5 23.489 80.819
34.4 23.242 77.112
33.2 24.065 83.817
Built 1993 32.9 24.702 81.151
32.9 25.635 75.444
Built 1994 32.8 23.209 75.636
Built 2004 32.3 23.973 78.769
Built before 1985 32.3 22.826 75.694
31.9 23.795 75.172
Built before 1990 31.8 24.527 77.684
31.5 24.752 79.068
31.5 23.396 77.187
Built before 1990 31.5 26.719 77.098
Built before 1990 31.3 25.034 77.889
31.2 25.035 79.139
31.0 24.044 81.896
Built before 1990 30.8 22.950 77.700
Sundar Sundar Irrigation Built 1977 25.0 30.8 24.943 87.391
30.7 24.840 79.639
30.5 24.724 77.273
30.2 25.432 77.710
Built 2003 29.9 24.067 77.312
29.4 24.263 85.152
Built before 1989 29.3 24.773 77.177
29.0 25.035 86.294
Built 2015 28.9 23.427 81.641
28.7 25.703 74.280
Built before 1990 28.6 26.981 76.230
28.3 24.821 76.096
28.0 24.259 79.031
Built before 1988 27.0 25.409 79.972
26.9 24.822 86.403
Built before 1985 26.6 27.871 86.465
Built 2002 25.8 22.901 83.176
Kerwan Local Nalla Irrigation Built 1975 33.0 25.0 23.165 77.371
24.5 27.597 82.450
24.1 22.960 83.026
Built before 1985 23.9 26.598 76.669
23.9 27.171 76.292
23.9 27.615 82.659
23.6 23.723 76.102
Pillowa Local Nalla Irrigation Built 1914 10.0 23.2 26.450 78.146
22.9 25.891 74.949
Built before 1990 22.7 25.130 78.661
22.3 22.592 75.671
Built before 1985 22.3 26.125 77.141
22.2 25.054 82.521
22.2 27.482 76.131
22.0 24.969 79.453
Built before 1989 21.8 23.248 75.827
Built before 1990 21.7 24.701 74.731
Built before 1990 21.1 24.127 74.831
21.0 23.827 78.745
21.0 25.132 86.220
Built before 1991 20.9 26.318 77.190
20.6 25.118 80.581
20.6 22.989 76.803
20.5 25.048 76.829
Built 2003 20.5 23.773 76.126
20.2 23.420 78.972
Built 1995 20.1 25.853 76.138
Mala Son Built 1929 16.0 20.0 23.695 79.737
Bhainsora Marahawa Nalla Irrigation Built 1926 11.0 19.8 24.781 83.218
Pahuj Pahuj Irrigation Built 1909 11.0 19.8 25.501 78.531
19.4 23.056 80.511
Built before 1991 19.2 25.673 78.398
19.2 24.640 80.363
Built before 1989 18.9 26.138 78.059
Built before 1989 18.9 25.317 74.996
Built before 1990 18.9 25.073 77.960
Built before 1985 18.8 29.958 78.181
18.1 24.927 73.780
18.1 27.220 76.420
18.0 25.148 76.044
Built 1995 18.0 26.685 76.739
Built before 1989 17.9 26.953 75.855
Built before 1990 17.5 25.365 79.043
17.0 25.201 79.838
Built before 1988 17.0 24.581 74.623
16.9 23.651 80.387
16.8 25.209 78.719
Built 1999 16.8 25.084 77.817
16.8 29.057 80.119
Built before 1990 16.7 25.246 75.209
16.6 25.614 75.286
16.6 25.318 78.829
Built before 1989 16.5 26.448 76.331
16.5 24.119 83.551
Hathaikheda Ghorapachad Irrigation Built 1962 17.0 16.3 23.271 77.501
16.0 22.489 75.706
16.0 24.599 83.036
16.0 23.116 77.683
15.6 24.840 80.090
Built 1998 15.5 23.902 79.849
15.5 24.359 81.889
15.2 25.416 75.111
15.0 26.909 76.476
14.8 27.616 82.353
14.7 25.020 76.283
Built before 1989 14.7 27.490 76.584
Built before 1990 14.7 25.069 75.285
14.5 27.119 76.410
14.4 24.443 80.498
14.3 24.907 74.498
Built 2012 14.3 24.214 82.445
Built before 1990 14.2 23.277 77.532
Built 1997 14.1 25.952 75.888
14.1 25.020 83.240
14.0 23.306 76.799
Kanheinalla Kanheinalla Built 1975 18.0 13.9 24.674 83.379
Built before 1990 13.8 23.541 78.112
13.7 24.609 79.336
13.7 24.334 82.362
Built before 1990 13.6 25.422 77.067
13.5 25.565 75.398
13.3 25.552 73.930
13.2 25.325 74.347
13.2 25.288 78.912
12.9 30.075 78.290
Built before 1990 12.9 25.485 78.919
12.9 23.923 80.940
12.9 25.076 82.180
12.6 22.780 81.740
Built before 1989 12.5 23.155 77.128
12.4 25.091 74.211
Built before 1990 12.4 24.762 77.861
12.1 23.370 83.195
Rohini Rohini Irrigation Built 1983 18.0 12.1 24.358 78.792
Built 1991 12.0 24.685 73.848
Built 1997 12.0 25.723 77.467
Govindgarh Local Nalla Irrigation Built 1956 12.0 12.0 24.377 81.271
12.0 25.446 76.704
Built before 1988 11.9 25.243 75.123
Built before 1990 11.7 26.180 78.122
Built before 1991 11.7 24.831 78.423
Built before 1989 11.6 22.935 76.940
11.6 22.889 76.809
11.5 25.802 77.718
11.5 23.413 76.142
11.5 24.972 79.136
11.5 25.069 81.106
11.5 25.832 77.719
Built before 1985 11.4 25.260 78.960
Built before 1989 11.4 26.651 77.753
Built 2009 11.4 23.483 81.560
Pagara Local Nalla Irrigation Built 1948 12.0 11.3 26.400 78.141
Built before 1990 11.2 25.897 77.547
Built before 1990 11.2 23.915 78.153
11.1 27.448 83.144
Built before 1990 11.1 25.630 78.340
11.1 23.751 79.410
Built before 1989 11.0 23.213 75.832
10.9 23.843 79.828
Built before 1990 10.9 25.314 79.092
10.9 25.131 82.055
10.9 27.624 82.421
10.9 25.994 77.369
Built before 1989 10.7 24.543 76.168
10.6 24.844 74.784
Built before 1990 10.6 25.615 78.324
10.6 26.434 76.958
10.5 22.663 75.869
10.5 23.144 81.912
10.5 25.719 75.106
10.4 25.834 76.787
10.2 25.794 77.501
10.2 25.137 81.571
Built before 1989 10.1 25.371 77.099
10.1 25.767 76.150
Built before 1985 10.0 23.559 79.719
Built 2000 10.0 25.520 75.342
Built before 1990 10.0 26.007 78.293
9.9 25.056 77.135
9.9 23.685 79.608
Built before 1990 9.9 25.436 78.452
9.9 25.181 74.631
Built before 1989 9.8 23.419 75.938
9.7 27.854 82.058
Built 2000 9.7 23.611 79.406
Built before 1989 9.7 25.447 74.913
Built 1993 9.6 24.935 74.960
9.6 27.628 82.532
9.5 25.410 74.076
Built before 1990 9.4 25.302 79.042
9.4 24.726 79.049
9.3 24.577 73.823
9.3 22.970 76.408
9.3 23.277 77.791
9.3 23.286 82.656
9.2 24.710 77.156
Built before 1990 9.2 25.086 76.110
9.1 25.924 76.442
Built 1991 9.0 23.641 80.572
Built before 1990 9.0 24.306 74.886
Built before 1990 8.9 25.459 78.085
Built before 1988 8.9 25.327 80.106
8.9 28.424 81.381
8.8 24.815 80.705
8.7 23.094 77.041
Built before 1990 8.7 23.217 77.763
8.6 24.903 79.250
8.6 25.481 79.123
8.5 23.778 79.435
Bhonka Bhonka Irrigation Built 1951 15.0 8.5 24.902 83.010
8.5 23.751 80.478
Built before 1989 8.3 26.127 78.026
Built before 1989 8.3 23.150 77.075
8.2 22.618 76.323
Built 1991 8.2 23.294 80.691
8.2 23.822 80.563
8.2 24.860 79.027
8.2 27.869 75.952
Built before 1990 8.2 26.614 77.251
8.1 23.227 76.548
8.1 25.005 83.118
8.1 27.925 84.498
8.1 24.307 79.152
Built before 1990 8.1 25.058 76.109
8.0 24.822 79.135
8.0 23.327 79.318
Railway 7.9 25.427 78.505
7.9 27.795 82.137
7.8 25.029 81.097
7.7 25.010 80.976
7.7 23.746 80.875
7.7 27.770 82.225
7.6 24.655 77.165
7.6 22.958 76.822
7.5 25.713 76.180
7.4 24.979 83.492
Built before 1990 7.4 25.744 77.478
7.4 24.706 83.357
Built before 1989 7.4 23.810 76.131
7.3 26.138 76.266
7.3 23.319 81.694
7.2 25.027 81.035
7.1 27.045 76.059
Built before 1989 7.1 25.294 77.057
Built before 1991 7.1 26.667 76.721
Built before 1990 7.1 25.543 78.080
7.0 25.288 79.693
Built before 1985 7.0 23.801 79.491
7.0 25.290 74.230
Built before 1989 6.9 23.410 75.947
6.9 24.956 86.744
6.9 22.671 75.649
6.9 23.575 79.606
Built before 1989 6.8 23.085 76.314
Built before 1990 6.8 25.695 75.652
6.8 22.487 75.644
Built 1999 6.8 23.976 76.473
6.8 25.319 74.314
6.7 23.102 83.095
6.7 25.514 74.043
6.7 25.048 74.356
6.6 23.886 76.118
6.5 23.903 81.990
Built before 1990 6.5 24.693 78.544
6.5 23.721 80.310
Built 1999 6.5 25.461 75.284
6.5 23.806 79.823
6.4 26.596 77.779
Built before 1990 6.4 24.589 77.802
Built before 1985 6.4 23.636 78.809
6.3 23.415 83.541
Built 1995 6.3 23.157 76.302
Built before 1990 6.3 24.289 75.528
6.3 23.710 79.920
6.3 24.738 83.425
6.3 25.322 74.385
6.2 24.980 83.249
6.2 23.633 79.649
6.1 26.675 77.208
6.1 25.009 83.091
6.0 25.184 81.218
6.0 26.713 77.012
5.9 23.948 84.085
Built before 1989 5.9 23.656 76.131
5.9 24.202 82.477
Built before 1985 5.9 24.407 83.622
5.8 23.839 80.461
5.8 24.374 77.877
Built 2007 5.8 23.923 76.820
Built 1999 5.7 23.232 76.520
Built before 1985 5.7 26.726 77.038
5.7 26.635 77.678
5.7 24.869 74.917
Built before 1985 5.7 26.787 75.455
5.7 23.877 84.778
5.6 25.310 79.366
5.6 23.203 77.420
5.6 24.939 79.370
5.6 25.192 76.400
Sijar Sijar Irrigation 14.0 5.6 25.203 79.195
5.6 30.436 77.666
Built before 1991 5.5 24.135 75.706
Built before 1989 5.4 30.503 77.798
5.4 23.685 81.478
5.4 22.914 82.034
5.4 24.518 74.651
Built 2004 5.3 25.381 76.253
Built 2009 5.3 28.190 84.418
Built before 1989 5.2 22.935 76.395
5.2 25.027 81.086
5.2 23.303 82.756
5.2 25.081 76.799
5.2 23.843 76.130
5.1 24.188 83.146
Built before 1985 5.1 29.344 79.560
Built before 1990 5.0 24.914 76.858
Built before 1985 5.0 25.020 81.076
Built 1994 5.0 25.351 75.177
5.0 25.183 81.268
4.9 27.759 75.967
Built before 1988 4.9 23.638 79.689
4.8 24.838 79.082
4.8 25.883 76.278
Built before 1989 4.8 23.802 77.077
4.8 23.771 79.546
Built before 1990 4.8 25.438 78.269
Built 1994 4.8 23.227 80.720
4.8 24.228 83.192
4.7 23.274 83.236
Built before 1985 4.6 23.846 79.783
4.6 24.109 83.057
4.6 23.353 79.411
Built before 1985 4.6 25.644 79.206
4.6 24.918 86.703
4.6 24.480 74.664
4.6 23.245 80.720
4.5 24.343 84.197
Built 1996 4.5 23.151 83.099
4.5 23.616 78.784
4.5 23.471 83.117
4.5 23.406 78.967
4.5 25.117 78.861
Built 1996 4.5 23.247 83.164
4.5 26.608 77.206
4.4 25.138 78.920
4.3 23.193 76.495
Built before 1990 4.3 23.305 77.887
Built 2004 4.3 27.980 83.582
4.3 25.164 76.734
4.2 25.203 77.033
4.2 25.809 74.905
4.2 25.070 86.215
4.2 25.803 76.343
Built 1990 4.2 23.898 80.145
4.2 25.175 81.405
4.2 24.872 86.818
Built before 1990 4.1 26.428 78.430
Built 1996 4.1 25.649 75.580
Built before 1989 4.1 26.631 77.794
Built before 1989 4.0 25.231 79.135
4.0 24.232 83.210
Built before 1990 4.0 26.876 77.034
3.9 23.831 79.526
3.9 25.155 78.939
3.9 26.026 78.310
Built before 1990 3.8 26.882 77.014
3.8 24.765 83.406
3.8 28.142 76.940
Built 1993 3.8 27.503 75.851
3.8 26.699 77.263
Built 2010 3.8 24.246 76.644
Built before 1989 3.7 26.256 77.772
3.6 25.205 79.131
3.6 23.944 84.281
3.6 24.224 74.861
3.6 23.935 83.113
3.6 23.725 81.443
Built 1992 3.6 25.415 79.037
Built before 1985 3.6 26.599 77.556
Built before 1989 3.6 24.114 75.798
Built before 1987 3.6 25.213 81.372
Built before 1989 3.5 25.994 75.022
Built 1991 3.5 23.122 80.618
3.5 25.002 76.810
3.5 26.359 78.240
3.5 23.241 81.981
Built before 1989 3.4 23.659 77.092
3.4 25.138 77.062
3.4 23.334 82.680
3.4 23.387 83.367
Built before 1989 3.4 23.445 75.919
Built 2014 3.3 23.287 81.557
Built 1994 3.3 24.352 75.896
Built before 1988 3.3 23.855 80.036
3.3 25.775 76.861
3.3 25.862 76.192
Built before 1989 3.3 25.386 75.328
3.3 26.667 77.800
Built before 1991 3.3 26.330 76.790
Built before 1990 3.2 23.250 77.821
3.2 23.815 79.552
3.2 22.929 83.016
3.2 25.186 81.327
3.2 23.703 80.841
3.2 24.961 79.276
Built 1991 3.2 24.619 83.280
Built before 1989 3.1 25.005 76.296
3.1 25.038 82.349
3.1 27.874 82.033
3.0 24.644 79.463
2.9 23.474 83.102
2.9 26.842 76.650
2.9 23.087 80.629
Built 1994 2.8 23.167 76.313
2.8 25.726 74.134
2.8 25.293 79.808
2.8 23.951 83.070
2.7 23.201 83.139
2.7 25.304 75.447
2.7 25.222 81.424
Built before 1988 2.7 23.657 79.715
2.6 24.755 79.032
Built 1998 2.6 25.764 74.193
2.6 26.593 77.037
Built 2017 2.6 23.168 81.908
Built before 1987 2.6 25.020 80.882
Built 1997 2.5 22.950 77.593
Built 1990 2.5 24.735 83.357
2.4 27.103 76.130
2.4 25.134 76.672
2.4 24.198 83.226
2.4 30.588 77.467
Built before 1990 2.4 25.286 78.861
2.4 23.211 81.802
2.3 25.082 81.129
Built before 1985 2.3 24.180 83.259
2.3 26.340 76.897
2.2 25.323 75.157
2.2 25.082 82.373
Built before 1990 2.2 25.154 75.139
2.2 23.805 79.784
2.1 23.841 84.645
2.1 27.244 76.393
Built before 1989 2.1 23.712 77.091
2.1 24.204 83.125
2.1 22.893 83.074
2.1 26.205 76.812
2.1 23.873 84.504
2.0 23.256 80.636
2.0 27.124 76.155
2.0 26.623 77.447
2.0 27.581 75.826
Built 1994 2.0 27.598 75.856
2.0 24.743 73.719
Built 1991 1.9 26.035 76.579
Built before 1989 1.9 25.563 74.917
1.9 24.060 83.113
1.9 26.648 77.198
Built before 1989 1.9 23.415 76.535
1.8 25.427 77.717
1.8 28.094 80.464
Built 1990 1.8 26.898 76.559
Built 1992 1.8 25.477 78.187
Built 1997 1.7 26.572 77.166
1.7 25.109 82.311
1.6 25.117 80.134
Built before 1989 1.6 26.689 77.823
Built 1992 1.6 26.597 77.490
Built before 1989 1.6 27.809 76.466
1.6 25.823 74.988
1.5 24.166 82.492
1.5 23.213 83.165
1.5 22.932 83.163
1.4 24.897 83.668
1.4 25.213 81.446
Built before 1990 1.4 26.164 77.208
Built before 1990 1.4 24.400 76.262
1.4 24.134 83.025
Built 1992 1.3 24.534 76.415
1.3 23.870 84.623
1.3 23.509 80.808
1.2 25.059 74.525
1.2 23.196 80.609
Built before 1985 1.1 26.510 77.186
1.1 22.950 83.179
1.1 25.082 78.941
1.0 26.613 77.789
0.9 25.062 74.503
Built 1996 0.9 26.382 76.934
Built before 1989 0.9 27.740 75.976
0.9 26.688 77.863
Built 1999 0.9 24.172 82.504
Built 1997 0.9 26.584 77.186
0.8 24.087 83.052
0.8 27.619 75.853
0.8 23.998 83.084
0.8 28.197 83.969
0.7 26.576 77.203
0.7 26.479 77.104
0.7 27.090 76.261
0.6 26.595 77.200
0.6 24.198 82.391
Built 1996 0.6 24.908 83.683
0.5 24.017 83.038
Built 2000 0.5 27.788 75.942
0.5 24.141 83.051
0.5 24.921 83.614
0.4 26.682 77.819
Built before 1985 0.4 28.286 83.753
0.4 26.510 77.091
0.4 25.085 81.161
Built 1999 0.4 25.697 74.142
Built 2003 0.3 26.313 76.887
Built before 1985 0.3 26.503 77.157
Built before 1985 0.3 26.510 77.220
0.3 24.141 83.445
0.3 26.547 77.138
0.3 27.538 76.506
Built 2004 0.3 27.561 75.848
Built before 1985 0.3 26.810 75.793
Built 1996 0.3 26.711 77.189
0.3 25.008 74.678
0.3 25.006 80.861
0.2 24.224 83.178
0.2 27.949 83.679
Built before 1985 0.2 25.740 74.158
Built before 1989 0.2 26.674 77.813
0.1 26.686 77.846
0.1 26.684 77.835
Built 1997 0.1 26.508 77.073
0.1 25.061 74.155

Dams serve many useful purposes including electric generation, water supply, irrigation, flood control, and recreation. However, if not carefully planned and managed, dams can have a heavy environmental impact. Today, many governments are removing dams to bring rivers back to life.

For a detailed look at the impact of dams on people and the environment, I encourage you to read the book Silenced Rivers by Patrick McCully. To help conserve free-flowing rivers, consider supporting the nonprofit International Rivers.

Data on dams comes from the Global Dam Watch database, published in July 2024. For more details, see the journal article by lead researchers at McGill University (Lehner et al. 2024).

Longest River

The longest river is the watershed is 2,710 km long. It is shown highlighted in the map in Figure 5 below.

This is the longest continuous flowline in the source dataset, MERIT-Basins. It is not necessarily the mainstem of the river, or the one with the same name. When it comes to naming rivers, historical, legal, and cultural influences are also important.

Figure 5. The longest river that flows to the watershed outlet (highlighted).

Figure 6 shows the elevation profile of the longest river reach. Elevations on the plot are in meters above mean sea level. The river begins at 4,610 m, and the outlet is at 16 m.

🖱️Mouse wheel to zoom Click & drag to pan 📱Pinch to zoom on mobile

Figure 6. Elevation profile of the longest river reach.

Elevation data for the profile plot is from MERIT-DEM (Yamazaki et al. 2017). Actual distances on the plot may be underestimated somewhat. This is because river paths are based on a grid or raster data, which simplifies the meandering path of real-world rivers.

Topography

Terrain elevations in the watershed range from 21 m to 7,900 m above sea level. The average, or mean, elevation is 860 m. Figure 7 shows a distribution of terrain elevations in the watershed.

Figure 7. Distribution of terrain elevations in the watershed.
Scale for x-axis: Linear   Log

Elevation data is provided by EarthEnv (Amatulli et al. 2021), and is based on the Global Multi-resolution Terrain Elevation Data 2010 dataset (GMTED2010). Statistics are based on gridded elevation data with pixels that are about 5 km on a side. Because of the size of the pixels, some smoothing takes place, and so the statistics reported above may not capture the true minimum and maximum elevation.

References

Amatulli, G., Domisch, S., Tuanmu, M.-N., Parmentier, B., Ranipeta, A., Malczyk, J., & Jetz, W. (2018). A suite of global, cross-scale topographic variables for environmental and biodiversity modeling. Scientific Data, 5(1), 180040. https://doi.org/10.1038/sdata.2018.40

Fick, S.E., and R.J. Hijmans. 2017. “WorldClim 2: New 1‐km Spatial Resolution Climate Surfaces for Global Land Areas.” International Journal of Climatology 37 (12): 4302–15. https://doi.org/10.1002/joc.5086

Harris, I., Osborn, T.J., Jones, P. et al. Version 4 of the CRU TS monthly high-resolution gridded multivariate climate dataset. Scientific Data 7, 109 (2020). https://doi.org/10.1038/s41597-020-0453-3

Lehner, B., Beames, P., Mulligan, M. et al. The Global Dam Watch database of river barrier and reservoir information for large-scale applications. Scientific Data 11, 1069 (2024). https://doi.org/10.1038/s41597-024-03752-9

Liu, L., X. Cao, S. Li, and N. Jie. “A 31-Year (1990–2020) Global Gridded Population Dataset Generated by Cluster Analysis and Statistical Learning.” Scientific Data 11, no. 1 (January 24, 2024): 124. https://doi.org/10.1038/s41597-024-02913-0

Martens, B., Miralles, D.G., Lievens, H., van der Schalie, R., de Jeu, R.A.M., Fernández-Prieto, D., Beck, H.E., Dorigo, W.A., and Verhoest, N.E.C. 2017. GLEAM v3: satellite-based land evaporation and root-zone soil moisture, Geoscientific Model Development, 10, 1903–1925. https://doi.org/10.5194/gmd-10-1903-2017

Miralles, D.G., Holmes, T.R.H., de Jeu, R.A.M., Gash, J.H., Meesters, A.G.C.A., Dolman, A.J. 2011. Global land-surface evaporation estimated from satellite-based observations, Hydrology and Earth System Sciences, 15, 453–469. https://doi.org/10.5194/hess-15-453-2011

Potapov P., Hansen M.C., Pickens A., Hernandez-Serna A., Tyukavina A., Turubanova S., Zalles V., Li X., Khan A., Stolle F., Harris N., Song X.-P., Baggett A., Kommareddy I., Kommareddy A. (2022) The global 2000-2020 land cover and land use change dataset derived from the Landsat archive: first results. Frontiers in Remote Sensing. https://doi.org/10.3389/frsen.2022.856903

Save, H., S. Bettadpur, and B.D. Tapley (2016), High resolution CSR GRACE RL05 mascons, Journal of Geophysical Research Solid Earth, 121. https://doi.org/10.1002/2016JB013007

Save, H., 2020, "CSR GRACE and GRACE-FO RL06 Mascon Solutions v02." https://doi.org/10.15781/cgq9-nh24

Siebert, S., M. Kummu, M. Porkka, P. Döll, N. Ramankutty, and B. R. Scanlon. “A Global Data Set of the Extent of Irrigated Land from 1900 to 2005.” Hydrology and Earth System Sciences 19, no. 3 (March 25, 2015): 1521–45. https://doi.org/10.5194/hess-19-1521-2015.

Yamazaki, D., D. Ikeshima, R. Tawatari, T. Yamaguchi, F. O’Loughlin, J.C. Neal, C.C. Sampson, S. Kanae, & P.D. Bates. (2017). A high‐accuracy map of global terrain elevations. Geophysical Research Letters, 44, 5844–5853. https://doi.org/10.1002/2017GL072874.