If Bangladesh fails to maintain environmental flow requirements (EFRs) in river ecosystems, it will face a food production loss of up to 23 per cent in the future, says an international study, reports UNB. It highlights that India, Bangladesh, Uzbekistan, Afghanistan, Italy and Greece, among others, would face a food production decline of 15-23 per cent for lack of water flow in rivers.

Safeguarding river ecosystems is a precondition to attainment of the UN Sustainable Development Goals (SDGs) related to water and the environment, while rigid implementation of such policies may hamper achievement of food security, says the study published recently in a peer reviewed journal - Nature Communications.

River ecosystems provide life-supporting functions that depend on maintaining environmental flow requirements). And the current food production thus heavily relies on water that would actually be needed to sustain riverine ecosystems.

The study tilted, 'Reconciling irrigated food production with environmental flows for Sustainable Development Goals implementation' indicates that 41 per cent of current global irrigation water use (997 km3 per year) occurs at the expense of EFRs.

"If these volumes were to be reallocated to the ecosystems, half of globally irrigated cropland would face production losses of about 10 per cent, with losses of 20-30 per cent of total country production especially in the Central and South Asia, including Bangladesh," the study says.

The researchers of the study lay out the regions and the degree to which EFRs are currently undermined to sustain the human water demand, which is the case especially in Central and South Asia, the North China plain, the Middle East, the Mediterranean region and North America.

However, the study shows that the improvement of irrigation practices can widely compensate for such losses on a sustainable basis. Integration with rainwater management can even achieve a 10 per cent global net gain. Such management interventions are highlighted to act as a pivotal target in supporting the implementation of the ambitious and seemingly conflicting SDG agenda.

It predicts: "Gains are naturally marginal in countries operating highly efficient systems already, but major gains are possible in countries with presently predominately large-scale surface irrigation systems and unlined conveyance canals such as Pakistan, Afghanistan, Uzbekistan and Bangladesh."

The study finds alarming violations of EFRs along many rivers such as the Indus River, the Amu Darya, Euphrates, Yellow River, Ganges (known as Padma in Bangladesh), Murray and Rio Grande.

Global irrigated kcal production would be subjected to a 13.9 per cent loss, corresponding to a 4.6 per cent loss of total production.

This number is significant, given that irrigation water sustains only 15 per cent of total global kcal production, illustrating that maintaining EFRs will impinge on about a third of the current overall contribution to agricultural production made by irrigation - in the absence of water management improvements, according to the study.

Freshwater is a finite resource, which is over-exploited around the world, and aquatic ecosystems are rapidly degrading in many regions.

Restoration of currently compromised river ecosystems through securing environmental flow requirements (EFRs) - that is, the daily river flow needed to maintain aquatic ecosystem services and the human livelihoods that rely on them - would entail a substantial reduction in water availability for irrigated food production.