Low Impact Development (LID) can help Bangladesh’s cities reduce rainfall-driven waterlogging by capturing and managing runoff close to where it forms. Rain gardens, permeable surfaces and rainwater storage work best alongside functioning drains, canals and flood protection systems. Together, these measures can reduce pressure on urban drainage while improving green space.

What Low Impact Development means

LID seeks to preserve or reproduce natural hydrological processes through infiltration, storage, filtration and evapotranspiration. Typical measures include green roofs, bioretention cells, vegetated swales, permeable paving and rainwater harvesting. They can be introduced at building, street or neighborhood scale. Related approaches, including Sustainable Drainage Systems, Water Sensitive Urban Design and sponge-city planning, share an emphasis on managing stormwater within the urban landscape. The choice of measures must reflect local land, soil and drainage conditions. [4]

How it reduces urban runoff

Temporary storage slows the delivery of runoff to drains and can lower peak discharge. Infiltration, evapotranspiration and reuse may also reduce the volume discharged; detention alone mainly changes its timing. Vegetation and filter media can improve water quality. Performance depends on available storage, soil wetness, storm intensity and maintenance. Benefits generally decline as rainfall intensity increases, so safe overflow routes remain essential. LID primarily addresses local rainfall runoff; river floods, storm surge and flash floods from large upstream catchments require wider flood-risk measures. [2, 4]

Evidence and relevance for Bangladesh

A review of 96 studies reported average reductions of 42% in peak runoff and 34% in runoff volume. These figures combine different practices, climates and study settings; they indicate potential, rather than guaranteed performance for a particular project. [1]

In Dhaka, a planning scenario for the Hatirjheel–Gulshan–Banani lake system assumed permeable or vegetated treatment of 30% of existing built-up surfaces. Estimated peak discharge decreased by 11.1% for a five-year design event, with a sensitivity range of 7.9–12.7%. The authors identify this as a planning-level estimate, not measured field performance. It supports local feasibility studies and monitored pilot projects. [3]

Practical applications and implementation

Public campuses, housing developments, footpaths, parking areas and road corridors offer potential locations for LID. Roof runoff can feed storage tanks, landscaped areas can accommodate bioretention, and suitable paved areas can use permeable surfaces. Green roofs require checks on structural capacity, waterproofing and maintenance access. Existing canals, lakes and open spaces must retain their drainage and storage functions.

Design must reflect site conditions. Poorly draining soils may require underdrains and controlled discharge. Infiltration needs assessment of seasonal groundwater levels, contamination and nearby foundations. Coastal and low-lying sites require checks on river or tidal backwater, while hilly areas need attention to slope stability, sediment and safe overflow routes. [4]

Implementation should begin with catchment mapping, surveys and drainage assessment. Compare options using hydrological and hydraulic modelling, then pilot measures where ownership and maintenance responsibilities are clear. Monitor rainfall, ponding duration, water levels and upkeep costs before scaling. Routine removal of litter and sediment is essential to preserve inlets, outlets and permeable surfaces.

Conclusion

For Bangladesh, LID offers a practical way to manage part of the urban runoff burden when combined with drainage improvements and protection of water spaces. EQMS Consulting Limited’s environmental assessment, water resources management and flood-risk analysis can support site selection, design and monitoring, with realistic performance objectives and maintenance needs.

References

[1] Huq, M. E., et al. (2026). Emerging insights into low impact development (LID) strategy for urban flood resilience under climate change. Environmental Development, 58, 101430. 10.1016/j.envdev.2026.101430

[2] Sohn, W., et al. (2019). The influence of climate on the effectiveness of low impact development: A systematic review. Journal of Environmental Management, 236, 365–379. 10.1016/j.jenvman.2018.11.041

[3] Haque, M. M., et al. (2026). Low-impact development and sponge city adaptation for urban stormwater retention in Dhaka: Assessing the Hatirjheel–Gulshan–Banani lake system. Asian Journal of Water, Environment and Pollution. 10.36922/AJWEP026190136

[4] U.S. Environmental Protection Agency. Green Infrastructure Design Strategies. Accessed 29 September 2026. EPA design guidance