Ensuring water security Vs conserving biodiversity: The challenge

Water related SDGs have often been found to be difficult to implement in the context of water security. This is because they involve different and competing ways of using water for irrigation, urban and industrial supply and hydropower generation. All these needs are met through construction of dams, barrages and water diversions that alter the natural river flows that sustain freshwater ecosystems.

This paper titled 'Exploring trade‑offs between SDGs for Indus River Dolphin conservation and human water security in the regulated Beas River, India' published in the journal Sustainability Science informs that while conservation of freshwater ecosystems is covered in target 6 under SDG 6, in practice, rivers are diverted to meet drinking water needs of cities and towns. The ecological dimensions that are needed to sustain freshwater ecosystems are often ignored or sidelined in the process.

This can pose a significant risk for freshwater biodiversity conservation by masking the existing trade-offs in water management between human demands, climate change mitigation and ecological conservation.

Climate change, population growth and economic development are further expected to intensify the pressure on water resources leading to further regulation and use of water resources in India. This can adversely impact freshwater environments, biodiversity and the ecosystem services they provide.

The regulated Beas and the threatened Indus river dolphin

Nowhere is this more obvious than in case of the river Beas in Northwestern India where numerous interventions on the river ecosystem to secure water for irrigation, urban supply and hydropower have threatened two species of endangered river dolphins in the Indian subcontinent.

The Beas flows from the Western Himalayas to the plains of Punjab, India, where it supports urban as well as rural areas through hydropower generation and irrigation and is then diverted to the states of Haryana and Rajasthan. The river is also an important conservation area for endangered Indus River Dolphin (IRD).

The Beas has been regulated since the late nineteenth century by constructing the Pong dam in 1975. Since water is transferred from Pandoh reservoir on the Beas to the Sutlej, the Pong, Pandoh and Bhakra (on the Sutlej River) dams are managed together for hydropower generation, flood control and irrigation. These dams, along with the Harike barrage, commissioned in 1953 at the confluence of the Beas and Sutlej rivers, supply water for canal irrigation to Punjab, Haryana and Rajasthan,.

The Beas River flows 185 kms between Pong and Harike and has been declared as the Beas Conservation Reserve that houses a small population of 5 to 11 dolphins, the only IRD population in India.

Evidence shows that there were around 52 to 87 dolphins at the time of the construction of the Harike barrage in the early 1950s, but regulation in the flows of the Beas–Sutlej gradually reduced the area available for IRD from 380 km to about 50 km (by about 87 percent), with the highest declines happening between 1953 and 1975, that led to the decline of the dolphins. 

Threats to the dolphins continue to grow with the most recent being in March–April 2017, when the Beas River experienced water stress as water released from the Pong dam was stopped to desilt the Harike barrage. This forced the dolphins to swim in restricted areas. On 25th March 2018, the flow released from the Pong dam was reduced from around 340 m3/ s to around 55 m3/ s that led to severe disruptions in longitudinal connectivity and area available to dolphins.

What does the future hold for the dolphins and what can be done

The paper discusses the findings of a study that used water resource systems model and a forecast extinction risk model to analyse how alternative conservation strategies in the Beas river can help the survival of the endangered Indus River Dolphins (IRD) in India in the face of climate change and its impacts on river hydrology and human water demands.

The study predicts that drier conditions will persist in the region in future and the survival of IRD in the river will depend on adequate dry-season water releases from the Pong dam into the Beas and management of allocations to hydropower, urban and irrigation demands.

While glacial melt will lead to an increase in future summer stream flow, this will be gradually followed by decrease in dry-season flows in the region due to reductions in glacial extent leading to uncertainity over water availability in the future.

The contribution of winter rains to ecologically compatible flows in the Beas in the dry season too will depend on the strength of tele-connections (climate anomalies related to each other over long distances) with Western Disturbances that are responsible for precipitation in the Himalayas under future climate change. Population growth and increase in water demands for drinking, irrigation and energy production will further increase pressure on the water resources in the region.

In case of drought-like conditions, reservoir storages will be needed to meet the water demands of urban and rural populations and could spell doom for the Indus River Dolphin due to changes in river flows. How these tradeoffs can be reconciled is a challenge for water management and conservation policy for the state water management institutions such as the Bhakra–Beas Management Board.

The study argues that a simple ecologically oriented and adaptive reservoir management strategy that can assure a guaranteed release of water from the from Pong dam in response to changes in water availability will greatly help in the survival of IRD.

Specifying “minimum flows” for management will however serve as a limited approach. Rather, taking into consideration the entire ecological flow regime that includes the entire range of flow conditions and dynamics will greatly help to ensure survival of the dolphins.

The paper argues for the need to:

• Conduct further studies that focus on defining the ecological flows in the Beas River and also include ecological flow and sediment requirements of other species like the gharial in the Beas.
• Plan studies that will assess the potential of the Sutlej river upstream of Harike under improved water quality and flow conditions for restoration of river dolphins and gharials.