Floodplain: Issues associated with it

What is a floodplain?

That portion of a river valley, adjacent to the river, that is built up of alluvium deposited during the present disposition of the stream flow. It is covered with water when the river overflows during flood periods. Meandering streams are typical features of floodplains. During the process of lateral erosion, the form of a meandering stream is altered by reduction, trimming, and cutting through, until all that remains is a crescentic mark, a floodplain meander scar, indicating the former position of a river meander on a floodplain. The beginnings of a floodplain are represented by lunate or sinuous strips of coarse alluvium along the inner bank of a stream meander. These are called point bars.

Floodplain is the area adjacent to a river that is not always under water, but is prone to flooding. It is an extension of the riverbed. In the case of the Yamuna in Delhi, the area that is likely to get submerged at least once in a 25-year period has been classified as its floodplain. The floodplains are not separate from the river. They are an integral part of any river-system, and are an ecologically sensitive area.

Why was Yamina Floodplains in news?

The biggest ever festival of music and dance organized by The Art of Living saw 3.5 million people attending to it. A huge 7-acre stage apparently the world’s largest ever, was erected. Several tents have been put up, pontoon bridges are being laid, dirt tracks were being laid, and heavy equipment have been deployed. Vegetation has been cut to make way for the temporary constructions. A major portion of the area has been flattened.

Environment  impacts on Flood plain.

1. One of the important functions of the floodplains is groundwater recharge. In the process of flattening, the surface is to be hardened, and that can severely impact its groundwater recharge capability.
2. Such works can also change the natural gradient of the floodplain, which can diminish its flood-carrying capacity.
3. Small water bodies and wetlands are filled up which absorb rainwater.
4. Some vegetation necessarily gets cleared up which has a role in either diverting the water flow and or increasing the biodiversity.

But what did the committee say?

A committee appointed by the NGT did make a site visit, and recorded its observations in a report to the court. But it was based on just a three-hour inspection, and not a proper scientific assessment.

In his observations, one of the members of the committee, said that

q  the site had been cleared of all natural vegetation, raised with the help of JCBs

q  huge amount of debris and construction waste had been dumped into the main channel of the Yamuna

q  The  activity was in no way benign and would have a permanent footprint on the floodplain.

It recommended that the organisers restrict the area of their operation to the bare minimum, and pay for the entire cost of the restoration. It said that a strong message should be sent to the DDA so that such violations are not repeated, and a restoration plan is prepared and its implementation monitored strictly.

An assessment

The area be restored to its original condition with not too much amount of difficulty. The clearing of debris can be done comparatively easily. Some other works can take several years. However, the problem in this case is that the authorities don’t even know what the original condition was. No study or assessment was done before the Art of Living Foundation was allowed to make changes to the floodplain for the event. In the absence of a baseline scenario, there is no way to assess whether the original condition has been restored.

Depending on what the impacts are, the monetary costs of restoration can be very high. The NGT-appointed committee had estimated that between Rs 100 and Rs 120 crore might be required for the restoration. It had recommended that the organisers be asked to deposit this amount in a separate account ahead of the event.

But the Akshardham temple and Commonwealth Games Village too stand on the Yamuna floodplains. They also caused damage. On both occasions, activists and citizens petitioned the courts, and the matter reached the Supreme Court. On both occasions, the apex court finally cleared the construction. In the CWG Village case, the court ruled that the site did not constitute the floodplains of the river.

In scale and size, these two are several times bigger than the Art of Living Foundation’s event. Activists and experts say the two gigantic, permanent structures have caused irreparable and irreversible damage to the river. But again, no scientific assessment has ever been made of the precise impact.