Khone Phapheng aesthetics: evaluating and ameliorating the hydraulic and visual impacts of the Don Sahong Hydroelectric Project (Lao PDR)

The Don Sahong hydropower scheme, now under construction in the Siphandone (“four

Don Sahong details

Longqingxia ! in the Basin thousand islands”) region of Khong District (of Champassak Province) in far southern Za Qu Z i Q Commissioned, Under Construction and Planned Dams u has been extremely controversial since the Memorandum of Understanding (MoU) was first in May 2013 Map Description: The map shows every known commissioned, under construction, and planned Qamdo in the basin. ‘Unknown’ dams are mainly dams and reservoirs constructed for use in irrigation and/or water supply, the names of which are currently unknown. agreed between the Lao PDR government and MegaFirst Berhad: a Malaysian company with ! Cege ! Jinhe ! Yuelong Kagong ! Data Sources : Citations for the data sources contributing to the location of the dams in this map may be found Lhasa Banda great experience in engineering and land development, but which had never previously built ! at our website - http://mekong.waterandfood.org/archives/2648 Background relief data is courtesy of Natural Earth and SRTM data from the JPL of NASA Rumei River basin boundary and river vector data is courtesy of the IWMI ! All other administrative and physiographic data courtesy of NOAA's National Geophysical Data Guxue Center's Global Self-consistent, Hierarchical, High-resolution Geography Database any hydroelectric projects. The initial dust-up was over the Lao PDR’s argument that since ! Acknowledgements: Gushui ! CPWF-Mekong gratefully acknowledges the financial support of AusAID in the production of this map. Guonian This map has been rendered by GeoSys (Lao) Co., Ltd, the full Mekong mainstem would not be blocked by the proposed design, thus only the lesser ! Hom 7, 136/09, Ban Sokpaluang, Sisattanak District, Capital, Lao PDR. Wunonglong INDIA !! INDIA Lidi Disclaimer: tributaries/distributaries submission-and-review criteria under the Mekong Compact need While every effort has been made to ensure and confirm the accuracy of these data, CPWF-Mekong, AusAID or any partner associated with the CPWF-Mekong program cannot be held responsible for any inaccuracies or omissions in this map. Observations and comments may be sent to Tuoba ! [email protected]. The designation and names of geographical entities on this map do not Huangdeng apply to their formal obligations toward the (MRC). ! imply the expression of any opinion whatsoever on the part of AusAID, CPWF-Mekong or any !! Dahuaqiao ! associated partners concerning the legal status of any country, territory, or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries or of the nomenclature deployed in

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c a n Gongguoqiaog J ! ia n g !! ( M !! !! Correct Citation: !! e The next flap was over the widely-believed —and possibly largely correct— assertion that k o n CGIAR Challenge Program on Water and Food. 2013. Dams in the Mekong Basin - Commissioned, g) Under Construction and Planned Dams in May 2013. Vientiane, Lao PDR: CGIAR Challenge Program on !! Xiaowan Water and Food. ! Manwan ! the Hou Sahong channel, which would in fact be completely blocked by the Project, was the homepage Pak Mun museum !! !! Don Sahong details Creative Commons License Dachaoshan ! This publication is licensed under a Creative Commons Attribution !! NonCommercial–NoDerivs 3.0 Unported License. ¹ !! !! !! ) This publication may be freely quoted and reproduced provided g single most critical migratory pathway for migratory fishes moving upstream during the dry !! n o !!!! k !!e!! the source is acknowledged. This publication may not be used in M

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! g n Planned e Nam OuS 3 g m LAOS ! a LAOSn Nam Nga ! Nam Tha 1 e ! !! ! B ! N m Under construction aNam Ngao k N ! o ! ! NAY PYI TAW K r ! Nam Suang 2 e e g Nam Beng ive ! a n g R Nam Suang 1 n ! M I ! Luangprabangon a Commissioned (NAYPYIDAW) e ek h m m a M Siphandone flythrough a Pak Beng ! m K N M ! NamN aKhan 3 m m ! a ! ! N Nam Khan 2 The third line of attack by the Project’s critics was that the piscivorous Irriwaddy dolphin Cancelled Ngum m a Nam Ngum 4A Nam Ngum 4B N !!!! ! ! ! Unknown (or irrigation) ! G u l f o f !! Xayaburi ! ! Nam Ngieu Nam Feuang 2 ! Nam Feuang 3 !! Nam Pay ! ! ! !! Nam San 3 Nam Pouy ! T o n k i n Mekong River System ! Nam Phouan ! Nam San 2 (Orcaella brevirostris), IUCN red-listed as “critically endangered” —of which the open water Nam Lik 2 ! ! ! ! ! Nam Mouan Hierarchy Nam Lik 1 ! Nam Ngum 1 !! ! Nam Theun 4 Nam Poun ! ! ! N ! ! Pak Lay (Option 2)a Nam Mang 1 Nam Theun 1 ! m ! ! Theun Hinboun Expansion Mainstream Pak Lay (Option 1) !! m N gu !! ! !! Nam Mang 3 Theun-Hinboun Santhing-Pakchom ! Nam Theun 2 Tributaries (lower) ! Sanakham embayment directly at the Lao-Cambodian border was permanent habitat of perhaps ten in- ! !! Nam Hinboun 1 !! Nam Hinboun 2 VIANG CHAN !! Lakes & reservoirs Me (VIENTIANE) ko ng R g Fai iv Ban e e Mekong River basin boundary Nam Un r X Xe Neua ! Xe Bang Fai ! Yangon Nong Han ! (Rangoon) ! Cites Nam Pung dividuals isolated from the rest of the slender O. brevirostris population— would be severely ! Xe Bang Hieng 2 Ubol Ratana ! P National capital ! !! ! Lam Pao !! Chulabhorn ! Hue ! Huai Kum ! !! !! R Major city ! ! Xe Pon 3 C ! Bang HiengXe Lanong 1 ! h i River ! !! Xe ! National boundary Xe Lanong 2 impacted both by the project’s presumed long-term reduction of fish prey; and by the worri- ! ! THAILAND ! ! ! Xe Bang Nouan Xekong 5 ! ! ! ! ! ! ! Xedon 2 ! !! ! ! ! ! ! N.B. Not all dam project names ! ! ! ! ! Xekong 4 Dak E Mule ! ! Xeset 1 ! ! Xe Kaman 3 ! Ban Kum ! ! un River Rasi Salai ! ! ! Xeset 2 ! M ! ! Pak Mun ! ! ! ! ! Xe Kaman 4B have been added to the map !!! ! !! ! ! ! Rasi Salai Dam ! ! Xe Nam Noy 5 !! Xe Kaman 4A some physiological effects of construction blasting on a marine mammal with hypersensitive ! Siridhorn ! ! ! ! due to space limitations ! ! ! !! ! Nam Ang - Tabeng Lam Ta Khong P.S. Hua Na ! ! ! ! ! ! ! ! !! Xekaman-Sanxay Upper Kontum Lam Takong Dam ! ! ! ! ! ! ! ! !! Xe Xou ! ! ! ! Nam Kong 1 !! !!! ! ! ! ! !!!!! ! ! ! !! ! ! !!!! Nam Kong 2 ! Plei Krong !! Dak Pla ! ! Sesan 3 ! echolocation auditory mechanisms. ! ! ! er Prek Liang 1 ! !Yali iv R Lower Sesan 3 ! !! g g ! !! KRUNG THEP ! ren n Sesan 4 S t ! Sa ! Don Sahong ! Thakho e ! !! g S !! n Sesan 4A !! (BANGKOK) o !! K O Chum 2 ! ! e e Stung TrengX Lower Sesan 2 Lower Sesan 5/1 ! ! Sre

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n Lower Sre Pok 4 k R o ! g T ! ! n o n k a n e e (In practice, the emplacement of three temporary cofferdams —one upstream at the entrance S l S ! e ! S M ! Battambang 1 a Sambor Sre pok 4A ! ! p ! ( ! ! la ! ! !!! r k ! !! !!! ve e) ! ! !!!! Ri ! !!!! !! a t Buon Kop !!!! Battambang 2 rs ! ! ! u !!! P !!! ! T ! ! !! Pursat 1 Pursat 2 o ! n ! ! le S !! Buon Tua Srah a ! p !! Duc Xuyen (

to the Hou Sahong channel, and two downstream, above and below the actual damsite— has r i v

artist's rendering Don Sahong dam !! e r ) PHNUM PENH effected all construction blasting completely in the dry.) !! (PHNOM PENH) G u l f o f Ho Chi Minh M ! ek o n g R T h a i l a n d iv e r We’ll momentarily put aside these latter two arguments (the first having been rendered 050 100 200 300 400 500 Kilometers S o u t h C h i n a 1:7,000,000 Cartographic moot), in favor of a Project impact that wasn’t even in the critical discourse until mid-2016, Design by : Datum : World Geodetic System 1984 S e a Coordinate System : Universal Tranverse Mercator Zone 48 North when it appeared that the waterfalls aesthetics issue was potentially significant, following the Lower Siphandone satellite view, showing “fall line”” escarpments and rapids, c. 5km wide www.geo-sys.net from Lee Pee (left) to Phapheng (right) stated concerns of the Lao PDR Ministry of Tourism that the beauty of the Khone Phapeng Appearance of western Khone falls (Lee-Pee Somphamit complex) site —the eastern-most, and by far most easily accessible, of the several cataracts ranged 4 March 2014: Q Pakse = 3,845 cumecs along the 5 km-wide fall line— across the Siphandone island assemblage, was being put as risk. The relevant hydraulics criteria, here highly simplified, were essentially as follows: during the dry season when overall discharge is lowest, the multiple channels traversing Siphandone are relatively discrete and semi-isolated. This is in marked contrast to monsoonal high-flow con- ditions, when many/most of the interspersing islands (and indeed, the falls escarpments) are effectively submerged and waters from the western channels will freely self-divert throughout the entire channel system: should any of them be blocked by engineering works. Under the project concept, the pre-project Don Sahong channel —which, being relatively shallow, of high roughness, and containing several internal islands of it own, is not especially hydraulically efficient— would be, and already has been, extensively deepened and partly straightened: in part as the primary source of crushed and trap rock for eventually constructing “Khone Falls: the Niagara of Southeast Asia” (and if not, why not; even if they both are Class 10, the highest?) the main dam itself (and meanwhile used for the three temporary cofferdams already in place). Compounding the likely significant Q (i.e., discharge) reduction through the Phapeng Channel above and over the falls resulting from the operations of the Don Sahong dam (the turbinated releases from which flow back into Hou Sahong below the Khone Phapheng waterfalls), to mitigate migratory fish losses due to the Project’s closure of the foremost dry season pathway, the engineered enlargements now underway of several other east side chan- nels, notably Hou Saddam and Hou Xang Pheuak, to figure much larger than in the past as alternate dry season fish migratory pathways. The problem is that the falls at Siphandone are most impressive —displaying spectacular dis- charge, persistent spray clouds, and sheer roar— at the height of the monsoonal rains, which is exactly when the fewest tourists are there; and the obverse case (which is when there’s also the minimal sediment load and the clearest, bluest water, so there’s that) but the “awe- someness factor” is then comparatively modest: yet that’s high season for tourism and what discharge there is through the Phapheng channel would be most impacted, Khone Falls: The Niagara of Southeast Asia? A common cliché regarding Khone Falls on the Mekong —of which Khone Phapheng near the left bank, and Lee Phi near the right bank are the two dominant components— is that it’s “the Niagara of Southeast Asia”. No it isn’t: Niagara Falls, including both the American and the Canadian sections, is about 850m altogether in breadth, and its drop consists largely of a single vertical escarpment of c. 52m in height. The average over-falls discharge at Niagara is c. 2,700 cumecs (i.e., cubic meters per second) which doesn’t change radically with the seasons: varying only c. 20% between annual minimum and maximum. The entire Niagara Falls assemblage can be readily viewed from many vantage points along both banks. Two grand-scale paintings entitled “Falls of Niagara”, by Frederick E. Church: the horseshoe falls only from the Canadian side (1857, Corcoran Gallery, Washington, DC), and both cataracts from the American side (1867, National Gallery, Edinburgh). Khone Falls, which lies entirely with the Lao PDR, actually describes a series of individual channels interspersed by rocky and forested islets and islands —the larger amongst them permanently inhabited and under agricul- ture— along the fall line or tectonic fault line in Siphandone (literally “four thousand islands” in Lao), which extends almost 9km from the eastern- most channel bank to the westernmost. Rather than a single escarpment, the aggregate Khone drop of c. 21m, is comprised of a cascade of relatively oblique rapids —as opposed to abrupt vertical escarpments— passing through the fault zone, sometimes occupying a longitudinal gradient of as much as 500m. The tropical monsoonal hydrological regime of the Mekong Basin result Manually stitched-up panorama from Niagara Falls, Ontario( in non-interactive PDF) in a typical annual flow variation exceeding a full order of magnitude; i.e., displaying an average dry season discharge at the Pakse gaging station of c. 3,000 cumecs (with a measured minimum of half that figure), and the peak measured rainy season flows there exceeding 40,000 cumecs. Numerous smaller tributaries debouch into those reaches of the Mekong below Pakse and above Khone. As many of the islands transected by the fall line become partly or com- pletely submerged during the monsoon, the bank-to-bank span actually then under water can be double or even triple of the dry season aggregate channel width. There is no vantage point anywhere —at any time of the year— where the complete Khone Falls assemblage is visible: other than from an aircraft or satellite. What Khone and Niagara do have in common is that of the many thousands of major waterfalls on the planet, only a relative handful are ascribed to Category/Class 10: the most spectacular, as based on a logarithmic relationship between their height and their mean discharge. Also, at least until the Don Sahong project was undertaken, Khone —unlike Niagara— had never been industrialized. drone video clips of Niagara Falls (left) and Khone Phapeng (right)