2 Background

1 BACKGROUND

Free-flowing rivers (FFRs) are the freshwater equivalent of wilderness areas. They are amongst the most ecologically important freshwater habitats and many are critical to both people and nature. A river is “free-flowing” if the connectivity of the river is maintained along all river reaches within the river from its source to outlet. This means that water, species, energy and sediment can move both up and downstream, as well as into its connected floodplain and riparian areas.

A free-flowing river is one where the natural aquatic ecosystem functions and services are largely unaffected by changes in the fluvial connectivity (Grill et al., 2019). Fluvial connectivity encompasses the following components: a) longitudinal (river channel), b) lateral (floodplains), c) vertical (groundwater and atmosphere), and d) temporal (intermittency). Connectivity can be compromised by physical infrastructure in the river channel, along riparian zones or in adjacent floodplains, by hydrological alterations of river flow due to water abstractions or regulation, and by changes to water quality that lead to ecological barrier effects caused by pollution or alterations in water temperature. Figure 1 describes how river connectivity acts through space and time, and how obstructions can fragment or regulate rivers, and consequently affect the river connectivity.

LONGITUDINALLY

which refers to connectivity between upstream and downstream. Dams are the most common distrupter of longitudinal connectivity.

LATERALLY

which refers to the ability of a river to swell and shrink, rise and fall naturally, and connect to its floodplains. This is distrupted when roads, buildings or other development (including agriculture when it is protected by leaves or dikes) takes place on floodplains, limiting their ability to absorb the river’s flows.

TEMPORALLY

or the natural ability of river flows to change intermittently. For example, when a dam is built, it consistenly holds a volume of water behind the structure and releases water in a way that does not match the timing of the river’s natural flows.

VERTICALLY

which refers to the ability of a river to draw water from or contribute water to underground aquifers and the atmosphere. This can be interrupted by overabstraction of groundwater and impermeable development on flood plains, among other causes.

1.1 BENEFITS

FROM FREE- FLOWING RIVERS

Healthy rivers provide a broad set of services and deliver many benefits to people, the economy and nature. Dams, levees, channels, diversions, and other river infrastructure alter the natural flow of a river in many ways, for example: increasing the amount of land which can be irrigated, energy production, flood controls, transporting drinking water, goods and people across distances, or providing ample water supply for industrial production.

While such infrastructure can fuel development, it also fragments rivers, jeopardizing their ability to provide the services that people and nature rely upon, such as carrying sediment downstream, balancing nutrients in soils, maintaining floodplains that act as protection against extreme weather events, fisheries for human consumption and providing opportunity for recreation or spiritual fulfilment. In addition to these services, FFRs are home to vulnerable freshwater biodiversity. Figure 2 illustrates some of the values and processes FFRs provide.

Rivers are also central to the history and culture of many nations, weaving their way through songs, stories and myths (Ripl, 2003). Decision makers often only view the direct benefits gained from “traditional” infrastructure investments, such as electricity or irrigation-water from dams, and disregard the much broader set of existing benefits rivers are already providing. The value of this broader set of benefits include, and may exceed, the value of the water they carry (Opperman et al., 2018), however they often remain unseen or undervalued by decision makers until a crisis arises.

Floodplain agriculture requires a flowing river to bring nutrients, sediments, and water.

Connected rivers support sediment transfer to healthy floodplains, which help reduce risks from floods and droughts and provide critical habitats and food sources for animal and plant life.

Rivers with high connectivity are among the most ecologically important freshwater habitats, places where vulnerables species - including a myriad of migaratory fish and river dolphin - can thrive. In places around the world, free-flowing rivers hold cultural and spiritual importance for people.

River flows carry sediment downstream to build up and maintain deltas. Without them, deltas will succumb to rising sea levels.

Tens of millions of people depend on freshwater fish populations, which require certain natural conditions - such as seasonal flows and temperature changes - in order to breed and thrive.

Natural river flows recharge vast networks of underground water, which are increasingly strained by growing human demands.

Figure 2: River processes in free-flowing rivers which create important values to Myanmar society, economy and nature (source: http://www.free-flowing-rivers.org).

1.2 DAMS AND CONNECTIVITY

A GLOBAL OVERVIEW

Of the many developments that have influenced and impacted river connectivity, dams are known to have some of the strongest and most long-lasting impacts (WCD, 2000). Despite this, more than 3,700 hydropower dams (>1 MW) are currently planned or are under construction worldwide (Zarfl et al., 2014). Asia is a hotspot for dam construction, with a capacity of over 15 GW added in 2016. The Balkans, the Amazon, China and the Himalayas are the regions facing major booms in hydropower construction (Winemiller et al., 2016; International Hydropower Association, 2018). The tropics and the Arctic are the final frontiers for long FFRs. Governments in tropical countries are faced with a steady increase in the demand for electricity, putting the integrity of FFRs at risk.

Acknowledging the importance of preserving river connectivity, the Brisbane Declaration (Brisbane Declaration, 2007) called for the identification and conservation of “a global network of free-flowing rivers” a decade ago. However, until recently no global information system enabling the monitoring of the actual state and trends of riverine connectivity existed, apart from some snapshot assessments that assessed connectivity at the basin scale.

Better resolution and access to global hydrological data allowed a team of researchers to assess river connectivity in a comprehensive and spatially detailed way on a global scale, leading to the first ever global overview on FFRs (Grill et al., 2019). This assessment defined FFRs in terms of connectivity (including river flow), assessed the status of 12 million kilometres of rivers and identified those that remain free-flowing along their full length. It thus provides a high-resolution global assessment of the location and extent of remaining FFRs.

This global assessment by Grill et al. shows that only 37% of the very long rivers (>1,000 km) worldwide are left to flow freely, and even less, namely 23%, of the very long rivers connecting to an ocean remain free-flowing. The FFRs remaining today are largely restricted to remote regions of the Arctic, the Amazon, and the Congo Basins. In densely populated areas of the world, such as North America, Europe and South Asia, only a few very long rivers remain free-flowing. Most notable among these are the Irrawaddy and Salween rivers - the last free-flowing large rivers of Southeast Asia. These two rivers are recognised for providing crucial sources of protein from fisheries and the flow regimes maintain extensive floodplain agriculture which feeds tens of millions of people (WWF, 2018a).

1.3 WHY ASSESS

RIVER CONNECTIVITY IN MYANMAR?

The Salween and Irrawaddy are the last long FFRs in Southeast Asia. Furthermore, rivers are the lifeblood of Myanmar society. The Myanmar economy depends on healthy rivers, productive deltas, and riverine/coastal agriculture (Taft and Evers, 2016). In addition, industry and the transport sector are highly dependent on rivers. This has led to high interconnectivity between the health of a river and the economy of the country, people’s livelihoods, religion and physical well-being (WWF, 2018a).

Myanmar’s rivers provide natural dynamics and ecosystems for many important activities such as fishing, irrigation, aquaculture, supplying drinking water, ecotourism or inland water transport (Binney et al., 2017; WWF, 2018a). These ecosystem services of rivers are critical. For example, fisheries play an important role for food security, providing approximately two thirds of animal protein for a typical Myanmar diet, and for livelihoods, with over 6 percent of the population directly employed in the fishery and aquaculture sectors (Binney et al., 2017). Rivers also deliver sediment to deltas and coastal areas which in turn ensures coastal stability, fertile agriculture, and productive coastal fisheries. For the Irrawaddy River alone ecosystem services were quantified to be worth $ 2-7 billion a year (HIC, 2017).

Furthermore, Myanmar is known for its very high freshwater species endemism (Zöckler, Christoph; Kottelat, 2017) and given the large geological variations and altitudes, it follows that individual rivers contain a variety of ecosystem types. Rivers are also seen as part of the national heritage and play important roles in the different cultures of the country (WWF, 2018b).

1.4 FREE-FLOWING RIVERS

IN MYANMAR

To date, there has not been a systemic analysis at the national scale of the current state, trends and potential future developments on the connectivity of Myanmar rivers. The recently published Strategic Environmental Assessment of the Hydropower Sector (IFC, 2018) provides a framework to assess the possibilities of harnessing hydropower potential with less negative environmental and social impacts. However, it does not provide the essential understanding of the value of rivers and river stretches in respect to biodiversity, ecosystem services and social values, nor in respect to how individual river infrastructure development will cumulatively impact the connectivity of river basins in Myanmar.

Grill et al. showed that the Irrawaddy and the Salween are the last long FFRs in Southeast Asia. Both basins are located in one of the most biologically diverse regions of the world. For example, this area is ranked as the 19th richest region of bird diversity worldwide (Zöckler, Christoph; Kottelat, 2017).

The Irrawaddy river is called the Ayeyarwady locally, a name which is believed to originate from the Sanskrit term meaning “elephant river”. It is the second largest river basin in the region after the Mekong, flowing approximately 2,000 km, with a basin covering 413,710 km2 (eWater and CSIRO, 2017). It starts among alpine shrubs and meadows and reaches delta mangroves and mudflats, covering a total of 12 diverse eco-regions as it flows (Zöckler, Christoph; Kottelat, 2017). Ninety-one percent of the river basin lies in Myanmar, 5% in China and 4% in India (Ketelsen et al., 2017). It is a truly unique river, as although it is the 22nd largest river in the world in terms of water discharge, it carries the 5th largest annual suspended sediment load, with a dynamic - often called dancing - riverbed in many parts, and an enormous and naturally growing delta. Thirty-four million people, some two thirds of the population of Myanmar, live in the river basin (WWF, 2018a).

A total of 1,400 mammal, bird, and reptile species are known to live in the basin, of which more than 100 species are globally threatened (Zöckler, Christoph; Kottelat, 2017). One of them is the iconic Irrawaddy River Dolphin with an estimated population of 79 individuals permanently living in the Irrawaddy river (Aung, 2020). Around 400 fish species have been identified, but the total is estimated to be around 550. There is currently only minimal and scattered knowledge of most taxa. This is especially pronounced for amphibians, and even more so for invertebrates.

The State of the Basin Report for the Irrawaddy River quantified that the services provided by the Irrawaddy River alone contribute 2-7 billion USD to the Myanmar economy every year from different sectors such as agriculture, fisheries, mining and extractives, oil and gas, industry and manufacturing, navigation, construction, tourism and energy (Binney et al., 2017). This makes up 5 to 16% of the Gross Domestic Product per capita.

The Salween river basin, known as Thanlwin in Myanmar and Nu in China, is 2,820 km long (Lamb, Middleton and Win, 2019), making it the second longest river in the region, covering a total basin area of 283,500 km2 (Johnston et al., 2017). In China, the Salween passes through a UNESCO World Heritage Site known as the Three Parallel Rivers site, alongside the Mekong and Yangtze rivers. Forty-four percent of the area of the basin lies in Myanmar, 48% in China and 7% in Thailand. Over 10 million people live in the basin - 3.8 million in China, 6.1 million in Myanmar, and 0.6 million in Thailand (Johnston et al., 2017). Livelihoods in this large basin are diverse, ranging from fishing-based livelihoods in the estuary, to farmers practicing shifting agriculture and rice cultivation in Myanmar and Thailand, to livestock herders managing rangelands in the Tibetan Plateau (Lamb et al., 2019). Although the Thanlwin provides strong support to both local and commercial fisheries, there is limited information available on the volume, species and value of fish catch (Johnston et al., 2017)

Civil society representatives have stressed the biodiversity values of the Salween for many years (Middleton, Scott and Lamb, 2019), but there is no in-depth information on the biodiversity of the Salween basin as a whole. However, the claim that this basin is of immense value in terms of biodiversity in “one of the richest temperate regions of the world” (UNESCO, 2003) can be regarded as unchallenged.

UNESCO calls the Three Parallel Rivers World Heritage Site “an epicenter of Chinese biodiversity”. In Thailand, the river flows through the Salween National Park and the Salween Wildlife Sanctuary and supports wildlife along a 120 km long Thai-Myanmar border stretch. In Karen State there are two wildlife sanctuaries and the Khoe Kay river bend is known to support many endemic species, of which 42 are IUCN Red Listed species (KESAN, 2008). The unique Thousand Islands area in Shan State is also significant in that it not only supports rare species, but is also home to rare limestone formations (ASSR, 2016; OBL, 2016).

In Myanmar, biophysical information on the Salween River system is generally sparse and relies heavily on global datasets supported by some more detailed studies at very few sites (i.e., Inle Lake or the river mouth at Mawlamyine). The river has been described to host the world’s greatest diversity of turtles (Wong CM, Pittock, J, Schelle, 2007). Inle Lake is known for hosting many endemic fish and gastropods (snails and slugs) including the Inle carp, a cultural symbol of the local people and an important food source (Johnston et al., 2017). Mangrove forests occur at the mouth of the Salween around the island of Bilugyun; there is, however, limited information on their extent and condition.

In addition to the Irrawaddy and the Salween, Myanmar also has many other rivers with a high degree of connectivity. These rivers include the Naf, Kaladan, Lemro, Mayu, Kaleindaung, Pathein, Pyanmalot, the Irrawaddy tributaries (Yin, Yaw, Chindwin, Taping, N’Maika, Malika River), Thandi, Yangon, the Salween tributaries (Ataran, Gyaing, Yunzalin, Moei, Nam Pang, Pawn, Pai, Teng, Hsim, Nam and Naiding Rivers), Ye, Heinze, Dawei, Great Tennasserim, Lenya, Kraburi, and Chaungmagyi Rivers and the Mekong tributaries (Kok, Ruak and Loi). Although they are not as long and well known as the Irrawaddy and the Salween rivers, they are sizable tropical rivers that play an important role in providing services to nature and society, such as fisheries or fertilizing riverine agriculture.

1.5 HYDROPOWER STATUS

AND DEVELOPMENT IN MYANMAR

Myanmar has a substantial need for power. The country has the lowest grid-connected electrification rate in Southeast Asia, with only 40% of the population connected. Official estimates project that 500 MW of additional generation capacity is required to come online annually in order to meet domestic demand in 2030. Extensive plans for building hydropower dams have been developed over the past few decades. Estimates for the theoretical hydropower potential of Myanmar go well beyond 100,000 MW, while the current hydropower capacity installed in Myanmar is approximately 3,300 MW (World Bank, 2018).

The former government agreed on nearly 70 large hydropower dam projects, which would lead to the development of around 45,000 MW, 15 times the current capacity. The Strategic Environmental Assessment of the Myanmar Hydropower Sector concluded that if this scenario is left to unfold without an sustainable development plan, the building of dams would have dramatic impacts on system connectivity, basin processes and ecosystem services (IFC, 2018).

1.6 AIM OF THIS STUDY

It is crucial to create a better understanding of the current state of river connectivity and FFRs in Myanmar using national data in order to allow for more informed decisions regarding river management. To establish this knowledge, we used the existing global analysis from Grill et al. as a base and improved the underlying data on barriers from additional sources. The resulting river model was used to:

A Provide data and maps on the state of river connectivity in Myanmar’s river basins, including which rivers remain free-flowing, and

B Provide a first assessment and maps of the impacts of planned dam development on the connectivity of rivers in Myanmar

The results provide a comparative and spatially explicit overview of the state of connectivity of Myanmar’s rivers. They can help inform water management and energy planning, and could be applied to the development of a national strategy to maintain the connectivity of rivers in Myanmar. Maintaining river connectivity in strategic parts of the basin could help ensure that certain services provided to nature and people by rivers could be conserved on a local, national and regional scale. Consequently, this work can be a basis for discussing an adequate policy to sustainably manage valuable FFRs and river stretches. Additional work is needed to determine which particular free-flowing rivers or stretches of river are most critical for maintaining particular economic, cultural, social and biodiversity values.