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Published by Ugyen Wangchuck Institute for Conservation and Environmental Research (UWICER), Department of Forests and Park Services, Ministry of Agriculture and Forests, Royal Government of Bhutan, Bumthang and WWF Bhutan Programme Office, Thimphu.

To mark World Water Week 2018 (27-31 Aug)

Compiled by: Dr. Norbu Wangdi, Mr. Dawa Yoezer and Mr. Jigme Wangchuk– Center for Water, Climate, and Environmental Policy, UWICER.

Ms. Sonam Choden, Freshwater Practice Lead, WWF Bhutan Program Cover photo ©Jigme Wangchuk/UWICER Layout: Sonam Chophel, Communications, WWF Bhutan Program

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BHUTAN WATER FACTS 2018

FRESHWATER RESOURCES OF BHUTAN

Freshwater sustains life and nature. Freshwater constitutes only about 0.3 percent of the earth’s surface water, which supports diversity of life including aquatic biodiversity. Bhutan has rich freshwater resources in the form of glaciers, lakes, wetlands, marshes, springs, streams and rivers, which are important not only for drinking and irrigation but also for hydropower and tourism, the two pillars of our economy. Thus it is important to know and value our freshwater resources and use it wisely for the benefit of both present and future Bhutanese. We have compiled this information from different sources to help the users with easy access to some of the key facts on water resources of Bhutan including aquatic biodiversity, river basins and hydropower generation. We hope that this publication will be useful and hope to update it as and when new information becomes available. We would like to acknowledge all the authors and organizations for use of their data from the published reports, which are mentioned in the references. • Bhutan is known to have abundant freshwater resources with per capita availability of

94,508 cubic meters per person annually, one of the highest in the world. • Most of the river discharge is fed by rainfall, supplemented by an estimated 2-12% glacial

melt and another 2% from snow melt. The combined outflow of the rivers is estimated at 70,576 million m3 per annum or 2,238 m3/s.

• 70% of annual precipitation is concentrated during the 4 months monsoon season (June to

September). Monsoon and pre-monsoon contribute 88% of the annual precipitation which means a major portion of the water volume in the basins is attributed to rain fed recharge.

• Bhutan has about 72% forest cover, and snow and glaciers constitutes about 7.5% of total

land cover (NEC 2016). Glaciers • Glaciers and ice covers about 1.6% of Bhutan’s total land area. • Bhutan has 885 clean ice, and 50 debris covered glaciers covering an area of 642 and 16.1

km2 respectively according to the Landsat satellite image analysis. • Bhutan’s glaciers are found within the elevation range of 4,050 to 7,230 m.a.s.l with 466

glaciers in Punatsangchhu basin; 58 in Wangchhu basin; 287 in Mangdechhu basin; and 124 in Drangmechhu basin.

• The largest glacier in Bhutan with an area of 36 km2 is found in the Punatsangchhu basin. There are 2674 glacial lakes in Bhutan (Bajracharya, S. R., et al. 2014)

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Wetlands • A total of 3027 high-altitude wetlands, including supra-snow lakes, glacial lakes and supra-

glacial lakes and marshes above 3000 m.a.s.l has been mapped (Wangdi et al. 2010). • High Altitude Wetlands cover about 0.26% Bhutan’s total land area.

Ramsar Sites • Bhutan ratified the Convention on Wetlands of International Importance (Ramsar

Convention) on 7 September 2012 and currently has 3 Ramsar wetland sites designated with total area of 1225 hectares (WMD 2012 and WMD 2015).

o Khotokha (113.5 Ha) under Wangduephodrang district o Gangtey-Phobji (970 Ha) under Wangduephodrang district o Bumdeling (141.5 Ha) under Trashiyangtse district and falls under the Bumdeling

Wildlife Sanctuary Hot-springs (Tshachhus) and Mineral-springs (Menchhus) of Bhutan • 10 popular Tshachhus and 26 Menchhus are documented from across the country (Dorji et

al. 2014). • Tshachhus and Menchhus are considered sanctified and therefore, regarded to have

immense therapeutic values.

Socio-economic uses of Bhutan’s Freshwater Resources • On the whole, Bhutan’s agriculture sector is a heavy user of the country’s freshwater

resources, relative to other sectors (FAO 2011). • 94.08% is used for Agriculture • 5.03% for domestic consumption and • 0.89% for Industrial purposes • 99.5% of the households are reported to have access to improved drinking water (NSB 2017)

though there are increasing reports of water scarcity and water sources drying up. AQUATIC BIODIVERSITY

Fishes of Bhutan • Bhutan has 167 fish species of which Golden Mahaseer Tor putitora (Hamilton 1822),

Pterocryptis cf. barakensis (Peters 1861), Clarias magur (Hamilton 1822) are endangered as per the IUCN status.

• From the total record, 38 species are reported up to genus level which is expected to be either new record or new species in the country. Parachiloglanis bhutanensis (Thoni & Gurung 2014), Garra bimaculacauda (Thoni, Gurung & Mayden 2016) and Garra parastenorhynchus (Thoni, Gurung & Mayden 2016) were described as new species to science, former one described from eastern (Khaling, Trashigang) Bhutan and later two were described from central (Panbang, Zhemgang) and southeastern (Samdrupjongkhar) Bhutan (Thoni et al. 2016).

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• Including Aborichthys boutanensis McClelland & Griffith (1842) there are four species described from Bhutan.

Freshwater Otters

• Amongst 13 otter species in the world, Bhutan hosts three species of otter; Lutrogale perspillata, Lutra lutra and Aonyx cenereus (Chettri & Savage 2014; Wangchuk et al. 2004).

• Amongst the three Lutra lutra is near threatened and other two species are vulnerable as per the IUCN status.

Freshwater Macro-invertebrates

• There are 38 species of stoneflies are recorded, out of which 19 species, namely; Haploperla longicauda, Amphinemoura bella, A. dentata, A. exigua, A. fusa, A. fucipes, A. lurida, A. nigrifrons, A. pulchra, A. simplex, Indonemoura geminus, I. rubrifasiata, I. shergooni, Nemoua abscissa, Rhopalopsole gladifera, Acroneuria distingguenda, Kamimuria lutulenta, Neoperla montivaga, and Phenoperla himilayana are described by Zwick (1977) and one species, Classenia drukpa by Stark & Sivec (2010). However, 12 species were reported up to genus level.

• Caddisflies were first recorded in 1972 and there are 172 species recorded so far in Bhutan. Eighteen species, which were reported at genus level are also accounted in total records. Of the total 36 species namely; Agapetus oinopion, A. wolframi, Apatania ottomoogi, Chimarra mars, C. megara, C. oinone, C. oreithyia, C. pasiphae, C. pontos, C. semiramis, C. talos, C. vesta, Dinarthrum ma, D. menoitios, D. liber, Ecnomus hyas, Glossosoma lar, Hydromanucus makareaus, H. gkarmai, Kisaura maia, K. teisiphone, Lepidostoma leucothoe, Paraphlegopteryx astridae, Rhyacophila melanippe, R. mnemesyne, R. Pyrrha, Setodes Sychaeus, Cheumatopsyche ningmapa, Hydropsyche dhusaravarna, Oecetis dvichakha, Neurocyta drukpa, Polycentropus kapchajalaja, Psychomyia dugpa, Psychomyia bhutana, Setodes fragilis and S. er were described from Bhutan of which 27 species, six species, two species and one species were contributed by different authors; Malicky (2007), Schimid (1975), Olah (1985) and Malicky and Chantaramongkol (2006) respectively.

• Under the order Diptera, there are 33 species recorded until now as per the works of Lewis (1974), Chaudhuri and Gosh (1985), Datta (1991), De and Gupta (1995), Takaoka and Praya (2008). This also include five species which were reported at genus level. A total of 16 species; Cricotopus pyrus, Neopodonomus similis, Mulgravia bhutanica, M. detriculata, M. spinisterna, Simulium bumthangense, S. pradyai, S. dattai, S. rangjungense, S. mongarense, S. thrimshinglaense, S. taktsangense, S. demolense, S. deothangense, S. bhutanense, and S. chuzargangense, were described from Bhutan.

• The works of Wewalka (1975), Sato (1977) and Smetana (1977) recorded 41 species under the order Coleoptera and four species were reported at genus level. A total of 11 species; Platumbus bhutanensis, P. wittmeri, Rhantus gogonensis, Zaitzevia bhutanica,

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Hydraena dochula, H. karmi, H. takin, Ametor wettmeri, Enochrus convexius, Anchocerus punctatissimus and Quedius akalitaare were described from Bhutan.

• From the record of five species belonging to freshwater aquatic mites, Sperchon himalayus and Torrenticola bhutana were described from Bhutan (Pešić & Smit 2007).

• There are 12 species under the order Hemiptera contributed in series of work by Zettel (2017); Zettel (2013) and Zettel and Duc (2007). Two species were reported at genus level. Amongst three species described from Bhutan, two species Timasius bhutanensis and Aquulavelia lautereri were described by Zettel (2007; 2013) respectively while one species Onychotrechus jaechi was described by Zettel and Duc (2007).

• From the records of 14 species under Mollusca, nine species were from the order Caenogastropoda and five species from Pulmonota (Gittenberger et al. 2017). So far only one species Erhaia Wangchuki (Gittenberger, Sherub & Stelbrink 2017) was described from Phobjikha, one of the Ramser sites in Bhutan.

• There are 114 species from seventeen families under the order Odonata. Megaletes gyalsey (Gyeltshen, Kalkman & Orr 2017) named in honour of His Royal Highness Crown Prince Jigme Namgyel Wangchuck is only species described from Trongsa, Bhutan.

• A lone species Neochauliodes indicus belonging to family Corydalidae was recorded under the order Megaloptera (Liu & Yang 2010).

• There are about 18 species of Decapods (Pretzmann 1975; Glenn 2006; Dorji 2016; Samdrup 2017). From the total, two species belong to freshwater shrimps (Dorji 2016) while rest belongs to freshwater crabs. Liotelphusa wuermlii is the only species in the country described by Pretzmann (1975).

Amphibians

• Currently there are 48 species of amphibians recorded by the works of Das and Pelden (2000), Wangyal and Gurung (2012), Wangyal (2013) and Das (2016).

• So far, only one species, Cat-eyed Toad (Scutiger bhutanensis) is endemic to Bhutan. Freshwater Algae

• 75 species of freshwater algae are recorded since 1958. • These species comprise mainly of diatoms and desmids belonging to three different

kingdoms; plantae, chromista and bacteria. • The specimens were collected from northern part of Bhutan covering places like Gasa,

Laya, Selela, Pemetsho and Tsamba (Hirano 1965).

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MAJOR RIVERS AND BASINS

• Bhutan has five main river systems which are Amochhu, Wangchhu, Punatsangchhu, Mangdechhu and Drangmechhu. The other five smaller river systems are Jaldakha, Aiechhu, Nyera Amari, Jomori and Merak-Saktengchhu.

• These river systems also form five major river basins and five smaller river basins. Punatsangchhu river basin is the largest basin with an area of 9,645 km2 and represents 25% of the country’s total land area.

• Mangdechhu and Drangmechhu basins combined together is also known as the Manas basin but for the purpose of management, they are considered as two separate basins as per the National Integrated Water Resources Management Plan, 2016. Wangchhu basin is the first basin to have the Integrated River Basin Management Plan since 2016. Kholongchhu, which is a sub-basin of Drangmechhu in eastern Bhutan has the first Integrated sub-basin Management Plan developed since 2017 (NEC 2016).

Figure 1. River Basins and Drainage Network (Source: National Atlas of River Basins and Water Infrastructure in Bhutan, NECS 2016)

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Table 1: River Basins of Bhutan

River Basins Catchment (Km2)

Annual Flow (Million m3)

High Altitude Wetlands

Glaciers

Aiechhu 1937 6,989 0 0 Amochhu 2310 9,375 115 0 Jaldakha 942 0 0 Drangmechhu 8457 13,569 431 124 Mangdechhu 7380 11,797 1173 287 Punatsangchhu 9645 19,130 904 466 Wangchhu 4596 5,209 324 58 Nyera-Amari 2348

4,507

10 0 Jomori 642 0 0 Merak Saktengchhu 137 70 0

Total 38394 70,576 3027 935 Source: Adapted from National Integrated Water Resources Management Plan, NEC 2016 Watersheds

• The country is divided into 186 watersheds (WMD, 2011). • A total area of 5,18,882 Ha has been identified as critical watersheds in different basins. • Kurichhu sub-basin has the largest area (1,32,083 Ha) of critical watershed.

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Figure 2. Map of Critical Watersheds. (Source: Watershed Management Division, DoFPs 2018) Table 2: Basin wise Critical Watersheds and Area statistics

WS_ID Dzongkhag Basin Name Area_Ha Total Area_Basin Wise ( Ha)

56 Bumthang Chamkharchhu_subbasin 11100.11543 11100.11543

32 Tashi Yangtse Khulongchhu_subbasin 25211.74092

120866.1177

33 Tashi Yangtse Khulongchhu_subbasin 17423.17298

42 Tashi Yangtse Khulongchhu_subbasin 19198.26628

43 Tashi Yangtse Khulongchhu_subbasin 20576.47159

63 Tashi Yangtse Khulongchhu_subbasin 38456.46591

40 Lhuentse Kurichhu_subbasin 45524.96101

132083.5144 55 Lhuentse Kurichhu_subbasin 23553.71035

95 Mongar Kurichhu_subbasin 30629.71434

126 Mongar Kurichhu_subbasin 32375.12866

70 Wangdue Mangdue_subbasin 45125.96737 71498.63028

109 Zhemgang Mangdue_subbasin 26372.66291

58 Wangdue Punatsangchhu_MajorBasin 14658.17473

77078.68787

121 Tsirang Punatsangchhu_MajorBasin 17502.43567

133 Tsirang Punatsangchhu_MajorBasin 10996.81611

144 Dagana Punatsangchhu_MajorBasin 22433.42911

151 Tsirang Punatsangchhu_MajorBasin 11487.83225

67 Thimphu Wangchhu_MajorBasin 22486.88649

106254.8733

68 Thimphu Wangchhu_MajorBasin 10445.45592

158 Chukha Wangchhu_MajorBasin 73322.53084

TOTAL ( Ha) 518881.9389 Source: Watershed Management Division, DoFPS 2018.

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HYDROPOWER GENERATION

• Bhutan’s river systems are very important for the country’s socio-economic development. A fifth of Bhutan’s GDP results from hydropower revenue (WWF & NEC 2016).

• Bhutan's river systems are evaluated to have 30,000 MW of hydropower generation potential.

• But technically and economically feasible hydropower potential is slightly lower ~ 23,760 MW.

• The Power System Master Plan of Bhutan (2003-2022), identified 76 potential sites for hydropower projects (10 MW size or more) with 70 run-of-the-river projects and 6 reservoir projects.

• About 1600 MW commissioned from the five major hydropower plants under operation; o Tala HP (1020 MW), o Dagachhu HP (126 MW) o Chukha HP (336 MW), o Basochhu HP I & II (64 MW), o Kurichhu HP (60 MW).

There are 10 micro-hydropower and 13 mini-hydropower that contributes 8.8 MW of electricity (BEA 2014). • Hydropower plants under construction

o Phuntsangchhu HP I (1200 MW) & II (1020 MW), o Mangdechhu HP (720 MW) and o Nikachhu HP (118 MW) o Kholongchhu HP (600 MW)

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References

Bajrachary, S. R., S. B. Maharjan and F. Shrestha. 2014. The status and decadal change of glaciers in Bhutan from the 1980s to 2010 based on satellite data. Annals of Glaciology 55(66): 159-166.

BEA (2014). Annual report 2013-2014. Retrieved from http://ccrweb.ca/sites/ccrweb.ca/files/ccr_annual_report_2013_2014.pdf Chaudhuri, P. K & M. Ghosh (1985). Cricotopus (Cricotopus) pyrus sp.n., an Orthocladiid Species from Bhutan (Diptera: Chironomidae), Aquatic Insects. International Journal of Freshwater Entomology 7(1): 45-48, DOI: 10.1080/01650428509361198 Chettri, P & M. Savage (2014). A distribution survey for otters along a river in central Bhutan. IUCN Otter Spec. Group Bull, 31(2). Das, A (2016). Addition to the herpetofauna of Royal Manas National Park, Bhutan, with six new country records. Herpetology Notes 9: 261-278

Das, I & J. Palden (2000). A herpetological collection from Bhutan, with new country records. Herpetological Review 31(4): 256-258 Datta, M (1991). A preliminary report on the blackflies (Diptera :Simuliidae ) from Bhutan. Journal of Bengal Natural History Society 10(2): 29-37. De, A & J.P. Gupta (1995). A review of the genus Mulgravea with descriptions of four new species from Bhutan (Diptera: Drosophilidae). Oriental Insects 29(1): 359-369; DOI: 10.1080/00305316.1995.10433745 Dorji, K (2016). Diversity of freshwater decapods in western Bhutan. Royal University of Bhutan, College of Natural Resources. Thesis. Dorji, T.,Wangdi, N.,and Wangdi, K.(2014). Hot Springs and Mineral Springs of Bhutan. Ugyen Wangchuck Institute for Conservation Environment. Lamai Goempa. 1:54. FAO (2011). Bhutan :Aquastat, FAO: 1-12. Gittenberger, E., P. Leda., K. Wangdi & S. Sherub (2017). Bhutan freshwater gastropods and trematodes, with a warning. Biodiversity Journal, 8 (4): 895–906 Gittenberger, E., S. Sherub & B. Stelbrink (2017). Erhaia Davis & Kuo (Gastropoda, Rissooidea, Amnicolidae) also in Bhutan. ZooKeys ZooKeys 679: 21–28; doi:10.3897/zookeys.679.13326 http://zookeys.pensoft.net Glenn, C.R (2006). “Earth’s Endangered Creatures- Liotelphusa sp. “Facts” (online) licensed article from wikipidia the free Encyclopedia. Accessed on 25/03/2018 at http://earthsendagnered.com/profile.asp?sp=10990&ID=3 Gyeltshen, T., V. Kalkman & A. Orr (2017). A field guide to common dragonflies & damselflies of Bhutan. National Biodiversity Center, Kensel Corporation limited, Thimphu Hirano, M (1965). Freshwater Algae of Bhutan. Acta Phytotax. Geobot. The Japanese Society for Plants Systematics, 21:181-192 Liu, X., F. Hayashi & D. Yang (2010). Revision of the fishfly genus Neochauliodes van der Weele (Megaloptera: Corydalidae) from India and adjacent regions of South Asia. Zootaxa 2692: 33–50. Malicky, H & Chantaramongkol, P (2006). Beiträge zur Kenntnis asiatischer Setodes (Trichoptera, Leptoceridae). Linzerbiol. Beitr. 38(2): 1531:1589 Malicky, H (2007). Köcherfliegen aus Bhutan (Insecta, Trichoptera). Linzer biol. Beitr, 475-570 pp. NEC (2016). National Integrated Water Resources Management Plan 2016. Thimphu, National Environment Commission: 1-131. NEC (2016). National Atlas of River Basins and Water Infrastructure in Bhutan. Thimphu, National Environment Commission: 1-47. NSB (2017). Bhutan Living Standards Survey Report. Thmphu, National Statistics Bureau: 1-226. Pešić, V & H. Smit (2007). First Records of Water Mites (Acari: Hydrachnidia) from Bhutan, with description of two new species. Zootaxa 1613(1613): 45-56

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Pretzmann, V.G (1975). Potamiden und Parathelphusiden aus Bhutan (leg. WÜRMLI 1972). Ann. Naturhistor. Mus 79, 609-613pp. Samdrup. T (2017). Habitat Use and Diversity of Freshwater Crabs under Jomotshangkha Wildlife Sanctuary, Samdrupjongkhar. Royal University of Bhutan, College of Natural Resources. Thesis Sato, M (1977). Results of the Bhutan Expedition 1972 of the Natural History Museum in Basel Coleoptera: Fam. Hydrophilidae, Dryopidae and Elminthidae. Entomologica Basiliensia 2: 197-204. Schmid, F (1975). Results of the Bhutan Expedition 1972 of the Natural History Museum in Basel. Trichoptera. Entomologica Basiliensia, 77-87pp. Smetana, A (1977). Results of the Bhutan Expedition 1972 of the Natural History Museum in Basel. Coleoptera: Fam. Staphylinidae Tribus Quediini. Entomologica Basiliensia 2: 243-250. Stark, B.P & B.P. Sivec (2010). Systematic notes on the genus classenia wu (Plecoptera: Perlidae), with description of new species. Illiesia, 6(24): 303-314. Takaokai, H & S. Pradya (2008). Eleven new species and one new record of black flies (Diptera:Simuliidae) from Bhutan. Med. Entomol Zool 59(3): 213-262. Thoni, R.J & D.B. Gurung (2014). Parachiloganis bhuranensis, a new species of torrent catfish (Suliriformes: Sisoridae) from Bhutan. Zootaxa 3869 (3): 306-312, http://dx.doi.org/10.11646/zootaxa. 3869.3.5 Thoni, R.J., D.B. Gurung & R.L. Mayden (2016). A review of the Genus Garra Hamilton 1822 of Bhutan, including the description of two new species and three additional records (Cypriniformes: Cyprinidae). Zootaxa 4169(1): 115–132 WMD (2011). Rapid Classification of Watersheds in the Wang Chhu Basin Thimphu. Thimphu, Waterhed Management Division, Department of Forests and Park Services: 1-28. WMD (2012). Ramsar Information Sheet, Khotokha and Bumdeling Ramsar Sites. Thimphu, Waterhed Management Division, Department of Forests and Park Services : 4-29. WMD (2015). Ramsar Information Sheet, Gangtey-Phobji Ramsar. Thimphu, Waterhed Management Division, Department of Forests and Park Services : 1-3 Wangchuk, T., P. Thinley., K. Tshering., C. Tshering & D. Yonten (2004). First field guide to the mammals of Bhutan. 179p. Wangdi, N., et al. (2010). An Inventory of High Altitude Wetlands in Bhutan: 1-31. Wangyal, J.T (2013). New records of reptiles and amphibians from Bhutan. Journal of Threatened Taxa 5(13): 4774–4783 Wangyal, J.T & D.B, Gurung (2012). Amphibians of Punakha-Wangdue Phodrang valley, Bhutan. Frog Leg 18: 31-44. Wewalka, G (1975). Results of the Bhutan Expedition 1972 of the Natural History Museum in Basel Coleoptera: Fam: Dytiscidae, taking into account some species from neighbouring areas. 151-164 WWF & NEC (2016). Bhutan – Water Risk Scenarios and Opportunities for Resilient Development (Vol 1 and 2). Thimphu. WWF Living Himalayas Programme and National Environment Commission: 4-5. Zettel, H & T.A. Duc (2007). On Gerridae (Insecta: Heteroptera) from Bhutan, with description of a new species of Onychotrechus Kirkaldy 1903. Zootaxa 1467: 43–49 Zettel, H (2007). Eine neue Art der Gattung Timasius DISTANT, 1909 (Insecta: Heteroptera: Hebridae) aus Bhutan. Anna leu des Naturhistorischen Museums in Wien 108 (b): 83-87 Zettel, H (2013). Two new species of the enigmatic genus Aquulavelia (Hemiptera: Heteroptera: Veliidae) from Nepal and Bhutan. Acta Musei Moraviae, Scientiae biologicae 98(2): 327-334 Zwick, P (1977). Ergebnisse der Bhutan-Expedition 1972 des Naturhistorischen Museums in Basel. Plecoptera. Entomol. Basiliensa

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The Ugyen Wangchuck Institute for Conservation and Environmental Research is a government based research and training institute based in Bumthang. We strive to foster better stewardship of our natural heritage – land, water, air and species therein – through rigorous science based research and transmission of cutting edge science results to field practitioners, environmental leaders and policy makers. Our current focus areas are defined by needs and challenges within Bhutan and outside. We recognize inter linkages between the way forestry is practiced to the dynamics of species conservation and persistence. We understand the implications of land use practices and global climate change on water resources and energy requirements. Above all, we appreciate and seek to understand human impacts and impacts on humans by studying social patterns and economic implications of management and policy interventions. In addition to conducting research, we provide a two-year certificate course in environment, forestry and conservation. We also offer tailor made course within the field of conservation biology, sustainable forestry and water resources for professionals working in these field. We also offer opportunities for undergraduate students to conduct research projects as part of their Honours program. As part of our initiative to encourage discourses and dialogue within the environmental community, we regularly organize seminars and host conferences at both national and international level. Administratively, we are housed under the Department of Forests and Park Services in the Ministry of Agriculture and Forests.

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Aerial view of UWICER Head Office, Lamai Goempa, Bumthang (2800 masl)

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