Blango et al. (2025) Enhancing Water Productivity in Inland Valley Swamps: Sustainable Strategies and Practices

Identification

• Journal: Environmental sciences
• Year: 2025
• Date: 2025-11-07
• Authors: Mohamed M. Blango, Emmanuel Kangoma, Navo Yambasu
• DOI: 10.5772/intechopen.1010272

Research Groups

• Njala University, Njala, Sierra Leone (Mohamed Matthew Blango, Emmanuel Kangoma, Navo Yambasu)

Short Summary

This paper synthesizes sustainable strategies to enhance water productivity in Sierra Leone's Inland Valley Swamps (IVS) for improved food security, demonstrating how integrating small earth dams, floating rice, and water-saving techniques like Alternate Wetting and Drying (AWD) and Aerobic Rice Systems (ARS) can increase rice yields and optimize water use, while also considering climate change impacts on water resources.

Objective

• To explore the potential of Inland Valley Swamps for improving rice production in Sierra Leone and identify opportunities for enhancing Water Productivity.
• To evaluate sustainable strategies and practices, including small earth dams, floating rice cultivation, and water-saving techniques (AWD, ARS), for optimizing water use and increasing agricultural output in IVS.
• To model and assess the projected effects of climate change on water storage in IVS reservoirs, emphasizing the need for adaptive management strategies.

Study Configuration

• Spatial Scale: Sierra Leone, specifically focusing on Inland Valley Swamps (IVS) which cover 690,000 hectares across the country. The study context is a tropical climate with high humidity.
• Temporal Scale: Year-round farming potential, with distinct dry (December–March) and wet seasons (contributing over 80% of annual rainfall). Field experiments mentioned for specific dry seasons (e.g., 2015/2016, 2016/2017). Climate change projections for the future (2081–2100) are compared to a baseline period (1981–2000).

Methodology and Data

• Models used: Hydrologic models, Global Climate Models (GCMs), and SWAT (Soil and Water Assessment Tool) for modeling climate change effects on water storage.
• Data sources: Observed rainfall data, results from 31 field experiments on Alternate Wetting and Drying (AWD), specific field experiments comparing Aerobic Rice Systems (ARS), AWD, and continuous flooding, and existing literature and reports from organizations like FAO, MAFS, and USDA.

Main Results

• Integrating small earth dams, floating rice, and water-efficient farming significantly enhances Water Productivity in IVS.
• Small earth dams enable rainwater storage for irrigation, facilitating double cropping and increasing rice yields from 1.7–3.2 metric tons per hectare (t/ha) in the rainy season to 2.5–4.7 t/ha in the dry season.
• Earth dams also support integrated farming systems (fish farming, livestock) and contribute to groundwater recharge (e.g., a 25,000 cubic meter (m³) check dam contributed 3.1 million m³ annually to aquifer recharge).
• Cultivating floating rice in reservoir areas upstream of earth dams optimizes land use in flood-prone regions, bringing otherwise unproductive land into cultivation.
• Water-saving techniques like Alternate Wetting and Drying (AWD) and Aerobic Rice Systems (ARS) reduce water use by 15–30% compared to continuous flooding.
• AWD increased Water Productivity in 92% of 31 field experiments, even with yield reductions, due to proportionally greater water savings.
• Aerobic systems used significantly less water (790–1430 millimeters (mm)) compared to flooded fields (1240–1880 mm), despite 22–32% lower yields.
• During the 2015/2016 dry season, continuous flooding used 114% more water than the aerobic system for only 15% more rice, demonstrating superior water efficiency of ARS and AWD.
• Hydrologic models predict a reduction in reservoir storage volume in the future (2081–2100) compared to the baseline (1981–2000) due to climate change, underscoring the urgency for adaptive strategies.

Contributions

• Provides a comprehensive synthesis of sustainable strategies (small earth dams, floating rice, AWD, ARS) specifically adapted for enhancing water productivity and food security in Sierra Leone's Inland Valley Swamps.
• Quantifies the benefits of these integrated approaches in terms of increased rice yields, significant water savings, and diversified agricultural outputs, offering practical solutions for smallholder farmers.
• Emphasizes the critical need to incorporate climate change projections into water management planning for IVS, advocating for adaptive and resilient agricultural systems.
• Offers a valuable framework for optimizing land and water resources in climate-vulnerable regions, contributing to long-term food security and rural economic development.

Funding

The authors acknowledge the contributions of those whose work and data guided the process of achieving food security in Sierra Leone. No specific projects, programs, or reference codes are listed.

Citation

@article{Blango2025Enhancing,
  author = {Blango, Mohamed M. and Kangoma, Emmanuel and Yambasu, Navo},
  title = {Enhancing Water Productivity in Inland Valley Swamps: Sustainable Strategies and Practices},
  journal = {Environmental sciences},
  year = {2025},
  doi = {10.5772/intechopen.1010272},
  url = {https://doi.org/10.5772/intechopen.1010272}
}

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