Flood Management in Imphal
- Understanding the Problem and Practical Solutions -
- Part 1 -

Chingangbam Nivason / Khangembam Yumjao *

Extensive flooding at JNIMS Hospital in Imphal East on 01st June 2025 :: Pix - Khaba Kh

Manipur’s Geography and Flood Risks

Manipur is a small & unique state in Northeast India, where nearly 90% of the land is covered by hills, and the remaining 10% forms the Imphal Valley at the center. The valley is shaped like a bowl, surrounded by hill ranges such as Koubru, Nongmaiching, Patkai, and Churachandpur.

All major rivers — including the Imphal, Iril, Thoubal, and Nambul — flow down from the hills into the valley before eventually draining into Loktak Lake. Because most of the population, towns, and farmland are concentrated in this low-lying valley, the area is highly vulnerable to flooding causing hardships to inhabitants.

Floods in Imphal occur due to a combination of reasons which are natural and human-made. Heavy rainfall in the hills sends huge volumes of water rushing into valley rivers. Deforestation and soil erosion in the hills have increased over the years, causing deposition of silt on river bed and thus reducing their capacity to carry water.

Wetlands such as Lamphelpat and Porompat, which once acted as natural storage areas, have been encroached upon or filled with garbage, leaving less space for floodwater to get recharged. Poor drainage in the city, garbage disposal into rivers and drains, and unplanned construction in low-lying areas further worsen the problem.

In short, Imphal’s bowl-shaped valley, shrinking wetlands, silted rivers, and weak urban drainage make the city highly prone to floods. Managing these floods requires solutions that are both effective and feasible given the state’s limited resources.

Practical Solutions for Flood Management

1) Strengthening River Embankments

One of the immediate problems during floods is the breaking of river embankments, which allows water to spill into residential areas and fields. Many embankments in Imphal are temporary measures, built quickly during the monsoon without proper planning or design. It is like mending a torn roof on rainy days.They are usually weak, made with local earth or sandbags, and are poorly maintained.

As a result, these embankments often fail under heavy or prolonged rainfall, causing sudden flooding in nearby areas. Because they are short-term solutions, communities have to rebuild or repair them every year, which is both time-consuming and inefficient.

The solution is to repair and strengthen embankments with better materials & design, while also raising them where necessary. At the same time, rivers should be desilted regularly so that more water can flow safely within their channels. This combination of stronger embankments and deeper rivers can significantly reduce the risk of sudden flooding in vulnerable areas.

2) Improving Rivers and Drainage Channels

The rivers and drains of Imphal carry water from both rainfall and hill streams. Over time, these natural and artificial channels have become narrow, shallow, and clogged with silt and garbage. This reduces their carrying capacity and causes water to overflow into residential areas during heavy rains.

Improving these channels involves deepening, widening, and cleaning them on a routine basis. Where necessary, new diversion channels can be created to guide excess water into Loktak Lake or nearby wetlands. Local drains in the city also need to connect properly with bigger rivers so that water can flow out quickly. If done systematically, this will allow Imphal’s waterways to function smoothly and reduce both river floods and city waterlogging.

3) Urban Drainage and Waterlogging

Even when rivers are under control, Imphal often suffers from waterlogging inside the city. This happens because many stormwater drains are too small, blocked, or poorly maintained. When heavy rain falls, the drains overflow, and with rivers already full, the water finds no outlet. Residential areas located amongst rivers such as the Iril, Kongba, Imphal, and Nambul are particularly affected.

To reduce this, the city’s drainage system should be redesigned with larger capacity. Regular cleaning before the monsoon is essential, along with stricter rules against throwing garbage into drains. Rainwater harvesting in houses and public buildings can also help by reducing the amount of runoff. If drains are kept clear and designed properly, Imphal can prevent urban flooding even during heavy downpours.

4) Wetland and Retention Basin Restoration

Imphal Valley once had many wetlands like Lamphelpat, Yaralpat, Porompat, and Khabam. These acted as natural storage tanks, holding excess rainwater and releasing it slowly after the monsoon. Over the years, these wetlands have been filled up or built over, leaving the city more vulnerable to floods.

Restoring these wetlands is one of the most effective natural solutions. For example, Lamphelpat can be revived as a large retention basin for Imphal city. Protecting these areas from further encroachment ensures that excess floodwater has a safe place to go. Wetlands also improve groundwater recharge, support fish and bird life, and provide open green spaces for the public. Bringing them back will serve both flood management and environmental conservation.

5) Flood Forecasting, Early Warning alerts and automated check Dams.

One of the biggest risks in Imphal is the sudden nature of floods. Heavy rains in the surrounding hills can quickly raise river levels in the valley, often catching people unprepared. To avoid this, a proper flood forecasting and warning system is needed.

This means setting up rain and river-level monitoring stations in upstream areas like Senapati, Ukhrul, and Thoubal. The data from these can be used to predict how much water will flow into the valley rivers. With mobile alerts and local disaster groups, people can be warned in advance and move to safer places. Even a few hours’ warning can make a huge difference in saving lives and property.

Gates at check dams at various locations could be link to flood monitoring system and its opening/closing could be controlled by software program, enabling water to flow as per design.

6) Long-Term Structural Solutions

While short-term measures are useful, Imphal also needs long-term structural projects for lasting protection. Retention reservoirs can be built in the upper catchments to hold back floodwater before it reaches the valley. Spill channels or tunnels can be designed to divert extra water into Loktak Lake or other safe zones. In the most flood-prone parts of the city, raised embankments or protective ring roads can act as permanent barriers.

These projects require bigger investment and careful planning, but once built, they will provide strong protection for decades. When combined with wetlands, stronger embankments, and better drains, they can create a complete flood defense system for Imphal.

7) Strict Adherence to Local Body Approvals (Bye-Laws)

Whenever an infrastructure development project has to take place, the concerned executing department like PWD or any developer must first obtain clearance like EIA ( environment impact assessment), forest clearance, consent to erection etc. from concerned government department, before starting a project. This step will ensure proper and justified work for necessary development of the state, otherwise unregulated projects will be harmful to the society and environment.

8) Bioengineering: The Most Feasible Solution for Manipur

Manipur is a resource-constrained state, making large-scale civil works difficult. In this context, bioengineering using plants, bamboo, stones, and soil becomes the most practical and sustainable approach. These solutions work with nature to stabilize slopes, slow water flow, and prevent soil erosion at low cost.

On hills surrounding the valley, deep-rooted grasses like vetiver, bamboo clumps, and native trees can hold soil together and reduce runoff. Small check dams and gully plugs made of bamboo, brushwood, or stones temporarily hold rainwater and trap sediment, lowering the peak flow into the valley. Contour bunds and terraces on farmland and degraded slopes allow water to soak into the soil rather than rushing into rivers.

Along riverbanks and wetland edges, planting grasses, shrubs, and reeds protects the soil and slows water, acting as living embankments. These methods rely on locally available materials, can be implemented by communities, and do not need expensive machinery. Over time, bioengineering gradually reduces flood frequency and intensity, improves groundwater, supports biodiversity, and provides employment opportunities for local residents.

For Manipur, bioengineering is not just an alternative but the most realistic, sustainable, and community- friendly solution to manage floods effectively. While it may not provide instant protection like heavy infrastructure, it builds resilience naturally and gradually across the valley.

Deep-Rooted Grass/Plants in Manipur

1. Vetiver (Chrysopogon zizanioides) - Kouna
2. Bamboo (Bambusa spp.) - Uying
3. Wild Sugarcane (Saccharum spontaneum) - Meibong-kaba or Kaingaa or Khass/Khus
4. Talipot Palm (Corypha umbraculifera) - Toumishi or Kunahumai
5. Banyan Tree (Ficus benghalensis) - Khou / Thaong / Khongnang
6. Neem (Azadirachta indica) - Seijrak or Neem Angangba
7. Earleaf Acacia (Acacia auriculiformis) - Akashmoni
8. White Leadtree (Leucaena leucocephala) – Khok / Thongam-Lei / Khongnang Ton
9. Gmelina (Gmelina arborea)- Wang / Somra or Somra Gamari / Umangsong
10. Champaca (Michelia champaca) - Leihao
11. Duabanga (Duabanga grandiflora) - Uthum
12. Bakul (Mimusops elengi) – Bokul Leihao
13. Phoebe (Phoebe hainesiana) – Uningthou

Conclusion

Flooding in Imphal is a complex problem caused by its bowl-shaped geography, heavy hill rainfall, silted rivers, shrinking wetlands, and weak drainage. Large civil engineering solutions may not be practical for a state like Manipur. However, a combination of river and drainage improvement, wetland restoration, early warning systems, strict bye-laws and especially bioengineering using local resources can significantly reduce flood risk.

By implementing these measures in a sustainable, law-abiding and community-driven way, Imphal can gradually become more resilient, protecting lives, property, and the environment while using the resources it already has. We intend to continue this edition.