CHAPTER 5: VALUED ENVIRONMENTAL COMPONENT: AQUATIC HABITAT Rationale for Screening Baseline Conditions The impacts of hydropower development on aquatic Elevation Profile of the Trishuli River Basin biodiversity are well known and are summarized in (TRB) IFC (2018a). In addition to barriers to fish migration and dispersal, hydropower projects may also alter Figure 5.1 illustrates the elevation profile of the Trishuli downstream flow and sediment volumes, timing, River and the distribution of elevation and temperature predictability, and flow change rates, which, together zones. The upper reach of the river from the Chinese with temperature, water clarity, and other water quality border up to the Upper Trishuli-3B hydropower plant changes, can alter species composition and relative (HPP) is steep with an average slope of 3 percent. abundance, and can disrupt flow-related cues that From Upper Trishuli-3B to just above the Tadi Khola trigger important fish life milestones such as migration confluence, the river is moderately steep, with an average or spawning. slope of 1 percent. From there onward, downstream of Super Trishuli, the Trishuli River has a relatively mild slope with an average slope of 0.3 percent. Map 5.1 of the TRB portrays these zones geographically. Figure 5.1 Elevation Zones of the Trishuli River with Slope and Temperature Zones 2,500 Moderately steep Steep section of river section of river Section of river with mild slope 2,000 Cold water zone Cold-cool water zone Cool-warm water zone Rasuwagadhi Rasuwa Bhotekoshi 1,500 Upper Trishuli-2 Chilime Elevation (m) Upper Trishuli-1 EF 1 EF 3 Upper Trishuli-3A 1,000 EF 2 Mailung UT-1 Cascade Trishuli HEP Upper Trishuli-3B EF 4 Devighat HEP 500 Salankhu Khola Trishuli Galchi EF 6 Third Trishuli Nadi EF 5 Super Trishuli HPP /Phalanku Khola of Kali Gandaki Confluence International boundary Tadi Khola Mahesh Khola Seti River Devighat Cascade Budhi Gandaki EF 7 Marsyandi River 0 0 20 40 60 80 100 120 140 160 Distance (km) Hydropower plant (HPP) location River elevation profile River confluence Existing Environmental Flows (EF) Sites Source: DRIFT Model Report, September 2018, Appendix D. 83 Map 5.1 Delineation of Elevation and Temperature Zones Source: DRIFT Model Report, September 2018, Appendix D. Fish Diversity in the Trishuli River Basin eDNA is a new sampling and monitoring method for aquatic diversity and has increasingly appeared A total of 60 species of fish have so far been reported to be a promising noninvasive method for improving for the TRB (Table 5.1). Rajbanshi (2002) provides a aquatic biodiversity monitoring. eDNA sampling summary of fish species from previous studies, while involves collecting a sample of water, filtering out additional field research by Nepal Environmental and the detritus, and analyzing the water for DNA, genetic Scientific Services (NESS 2012a, 2012b, and 2014a), material from aquatic organisms. eDNA is still in Sweco (2016), and the Center for Molecular Dynamics- experimental stages and thus the analyses conducted Nepal (CMDN 2018) added species to the list. The are considered preliminary and need to be confirmed International Union for Conservation of Nature Red List and tested with further studies. of Threatened Species (IUCN 2019) and the Fishbase database (Fishbase 2019) have been used to update The eDNA study tentatively identified 25 species of the nomenclature. fish across the six eDNA sampling locations (Table In March and April 2018, researchers from CMDN 5.1), although some were only identified to the genus applied and tested environmental DNA sampling, also level (for example, Barilius sp. and Schizothorax sp.). known as eDNA, along the Trishuli River as part of A major challenge is that the reference eDNA database the Cumulative Impact Assessment and Management (National Center for Biotechnology Information (CIA) study. The CMDN team collected fish and water GenBank) has limited data available on Himalayan samples at six of the seven EFlows sites (EF1 was fish species, which creates uncertainties in the species excluded) (CMDN 2018). See Map 5.2. identifications from the eDNA study. 84 Cumulative Impact Assessment and Management: Hydropower Development in the Trishuli River Basin, Nepal Table 5.1 Fish Species Recorded in the Trishuli Basin English Latin name IUCN Nepal Endemic Rajbanshi NESS Sweco CMDN name Red List status to Nepal (2002) (2012a, (2016) (2018) status (MoFSC 2012b, (version 2014) 2014a) 2018-1) Chaguni Chagunius LC VU No chagunio Spotted Channa LC Snakehead punctata Angra Labeo angra LC No Labeo Rohu L. rohita LC No Unknown L. dyocheilus LC No Kuria L.gonius LC No Labeo Kalabans Bangana dero LC No Copper Neolissocheilus NT VU No Mahseer hexagonolepis Mahseer Tor tor NT VU No Golden Tor putitora EN EN No Mahseer Rosy Barb Puntius LC No conchonius Dark Naziritor VU Mahseer chelynoides Gangetic Crossocheilus LC No Latia latius Indian Raiamas bola LC No Trout Barred Barilius barila LC No Baril Barna Baril Barilius barna LC No Indian Raiamas bola LC No Trout Hamilton’s Barilius LC No Baril bendelisis Tileo Baril Barilius tileo LC No Vagra Baril Barilius vagra LC No Continued on the next page Chapter 5: Valued Environmental Component: Aquatic Habitat 85 English Latin name IUCN Nepal Endemic Rajbanshi NESS Sweco CMDN name Red List status to Nepal (2002) (2012a, (2016) (2018) status (MoFSC 2012b, (version 2014) 2014a) 2018-1) Giant Danio DD Yes Danio aequipinnulus (upper and middle reaches of Koshi, Gandaki, and Mahakali Rivers) Bengal Danio devario NA No Danio Leopard Danio rerio LC VU No Danio Flying Barb Esomus LC No danricus Blue Laubuka NA No Laubuca laubuca Gora Chela Securicula LC No gora Large Salmostoma LC No Razorbelly bacaila Minnow Annandale Garra LC No Garra annandalei Gotyla Garra gotyla LC No Gangetic Tariqilabeo LC No Latia latius Brown Oncorhynchus LC No (intro- Trout mykiss duced) Common Schizothorax VU VU No Snow Trout richardsonii Chirruh Schizothorax NA No Snow Trout esocinus Dinnawah Schizothorax LC VU No Snow Trout progastus Balitora Psilorhynchus LC No Minnow balitora Continued on the next page 86 Cumulative Impact Assessment and Management: Hydropower Development in the Trishuli River Basin, Nepal English Latin name IUCN Nepal Endemic Rajbanshi NESS Sweco CMDN name Red List status to Nepal (2002) (2012a, (2016) (2018) status (MoFSC 2012b, (version 2014) 2014a) 2018-1) Unknown Schistura LC No savona Unknown Schistura LC No multifasciata Stone Schistura LC No Loach corica Stone Cat Glyptosternum LC No (Myersglanis) blythi Unknown Glyptothorax LC No telchitta Three Lined Glyptothorax LC No Catfish trilineatus Glypto- Glyptothorax LC No thorax indicus/ Catfish garhwali Unknown Glyptothorax LC No cavia Mrigal Cirrhinus LC No Carp cirrhosus Common Cyprinus LC No Carp carpio Goldfish Carassius LC No (intro- auratus duced) Stone Carp Psilorhyn- LC Yes choides (however pseudecheneis extends into the Ganga River system slightly south of the Indo- Nepal border) Stone Nemacheilus No Loach rupicola Gray’s Balitora NT No Stone brucei Loach Continued on the next page Chapter 5: Valued Environmental Component: Aquatic Habitat 87 English Latin name IUCN Nepal Endemic Rajbanshi NESS Sweco CMDN name Red List status to Nepal (2002) (2012a, (2016) (2018) status (MoFSC 2012b, (version 2014) 2014a) 2018-1) Mottled Acanthocobitis LC No Loach botia Stone Nemacheilus LC No Loach corica Creek Schistura LC No Loach beavani Unknown Schistura LC rupecula Guntea Lepidocephalus LC No Loach guntea Almorha Botia LC No Loach almorhae Yoyo Botia LC Loach lohachata Catfish Amblyceps LC No mangois Sucker Pseudecheneis LC No Throat sulcatus Catfish Torrent Euchiloglanis LC No Catfish (Parachilo- glanis) hodgarti Dwarf Bagarius NT No Goonch Note: IUCN = International Union for Conservation of Nature; MoFSC = Ministry of Forests and Soil Conservation; NESS = Nepal Environmental and Scientific Services; CMDN = Center for Molecular Dynamics-Nepal. IUCN conservation status: EN = endangered, VU = vulnerable; LC = least concern; DD = data deficient, NA = not assessed. 88 Cumulative Impact Assessment and Management: Hydropower Development in the Trishuli River Basin, Nepal Map 5.2 EFlows Sites and Hydropower Projects Source: DRIFT Model Report, September 2018, Appendix D. Aquatic Habitat for Fish Species along the with the Tibet Autonomous Region (NESS 2012a) Mainstem reports three species of fish within the project’s area of influence;Glyptothorax telchitta, Glyptothorax This baseline establishes the key sites for migration, trilineatus (Three-Lined Catfish), andPsilorhynchus foraging, and spawning across the mainstem of the pseudecheneis (Stone Carp). Given the altitudinal river and the tributaries. Due to their higher water range of the Common Snow Trout (Schizothorax temperature, tributaries are considered more conducive richardsonii), 300 meters to 2,810 meters (IUCN for spawning for several species. 2019, vers.2018-1), this species is also likely found along the river in the Tibet Autonomous Region. Cold Zone (Upstream) Along the Trishuli River, fish are found right up to the At the Rasuwagadhi site, except for the fecal coliform Tibet Autonomous Region border. Due to minimal and turbidity, physical and chemical parameters of the hydropower development in the Tibet Autonomous Trishuli River are well within the parameters of the Region, lower population density, relatively pristine Nepal Drinking Water Quality Standards (NDWQS) habitat, and altitudes conducive