Navigating Salinity Challenges in the Polders of Coastal Bangladesh: AI-Based Advisories for Farmers and Water Managers

by Mahesh Jampani, Karthikeyan Matheswaran, Dipaka Ranjan Sena, Manoranjan Mondal, Shreya Chakraborthy, Deepa Joshi

As part of CGIAR’s Scaling for Impact program and Area of Work 2- scaling pathways in agrifood systems, the effort supports the water management practices at the landscape level and scaling of adaptive and data-driven irrigation advisory services for managing salinity in polders towards resilient agriculture in Bangladesh.

In Bangladesh, salinity is a significant challenge to agriculture, particularly for the polders in the coastal region. To address this pressing issue, supported by the Scaling for Impact Program, the International Water Management Institute (IWMI) is collaborating with the International Rice Research Institute (IRRI) and the Institute of Water Modeling (IWM), Bangladesh, to implement a series of integrated activities under the Scaling for Impact (S4I) program. This initiative builds on the foundations laid by the Asian Mega Deltas (AMD) research initiative, which focused on enhancing resilience and adaptive capacity within Bangladesh’s coastal farming communities.

At the core of the intervention is an innovative AI-driven salinity modeling system designed to predict salinity levels in rivers and thereby provide salinity forecasts for irrigation advisory services. Piloted across two coastal polders, this system leverages machine learning models, open-access datasets, and localized data collection to deliver short-term salinity forecasts. By providing timely and accurate salinity predictions, the system enables farmers and water management groups to make informed decisions about irrigation scheduling and sluice gate operations.

Salinity mismanagement can lead to significant crop losses, undermining food security and rural livelihoods. The AI-based irrigation advisories produced through this intervention are crucial in mitigating these risks. The model was developed with AMD support, and CGIAR Scaling for Impact Program implemented and issued salinity advisory pamphlets to around 200 farmers in three polders. In addition, the Salinity Outlook Bulletin is given to extension agents to indicate an opportunity for optimal irrigation between July 9 and July 14, when salinity levels in the Rupsa-Kazibacha river are predicted to fall below 4 dS/m. This window is ideal for transplanting Aman paddy.

Farmers were encouraged to adjust their water intake for land seedbeds and land preparation. During this low-salinity period, especially during the ebb tide, the river water is less saline. This strategic timing ensures timely transplanting and optimum yield of wet-season rice, thereby maximizing the benefits of freshwater availability and promoting healthier crop growth. Furthermore, this advisory also provides a time window for when salinity levels are below 4dS/m, so that less saline river water can be stored in the canals within the polders by closing the sluice gates for the winter rabi cropping season.

The Salinity Outlook Bulletin offers more than just forecasts, providing tailored advice on crop suitability and practical agronomic practices, such as applying organic amendments and selecting salt-tolerant varieties of Aman rice. The bulletin aims to safeguard crop yields and promote sustainable agricultural productivity in regions grappling with salinity challenges.

Further, to identify scaling pathways for this AI-based advisory system and tackle larger issues of salinity in the deltaic systems of Khulna, IWMI recently organized a regional workshop, ‘Irrigation Advisories for Salinity Management in the Polders Downstream of Khulna for Resilient Deltaic Systems’ together with IWM and IRRI in Khulna city on 23rd September 2025. The workshop brought together government stakeholders, researchers and academics, and farmer representatives from Water Management Groups (WMGs) of three different polders. The event aimed at collecting valuable lessons from the piloting of the salinity forecasting system, engaging stakeholders to identify scaling opportunities and challenges, and co-developing pathways for integrating forecasts into water and agricultural management. Key highlights included evidence from the pilot, engaging stakeholder dialogues, and strategies for sustainable partnerships.

As salinization continues to threaten the agricultural landscape of coastal Bangladesh due to the impacts of climate change and ineffective water management, the need for effective, data-driven solutions becomes increasingly urgent. This is where sophisticated modeling is used to provide practical information on salinity that is accessible to farmers. Moving forward, the focus will be on expanding the forecasting system across additional polders and enhancing information dissemination to benefit and empower farmers to tackle the challenges posed by salinity collectively.