Meenachil River discharge doubles Malampuzha Dam live capacity during monsoon fury

Relentless downpour between July 31 and August 6 in Kerala saw an unprecedented volume of water gushing through the major river systems of Kottayam district. According to figures compiled by the district hydrology department, the Meenachil River discharged more than double the entire live storage capacity of the Malampuzha Dam. Similarly, the Manimala River carried a volume of water that surpassed the usable storage capacity of the massive Kallada Dam.

Hydrological measurements recorded at the Peroor station on the Meenachil River showed a discharge of 416 million cubic metres (MCM) over the seven-day period. To put this in perspective, the active live storage of the Malampuzha Dam—the state's largest irrigation reservoir—stands at 214 MCM. This means more than twice the dam's full usable capacity rushed through the Meenachil River in just one week.

Similarly, the Manimala River, measured at the Manimala station, recorded an enormous discharge of 576 MCM. This exceeds the active capacity of the Kallada Dam, which has a live storage of 507 MCM. For reference, live storage refers to the volume of water in a reservoir that can be put to active use for irrigation, drinking water, and power generation.

A critical factor that worsened the flood crisis this season was the unusually sluggish drainage of water. Instead of draining quickly into the Vembanad lake system, floodwaters stagnated, leaving several regions submerged for days on end. Local experts point to high tides, heavy run-off, and siltation in the lower reaches as key reasons for the slow run-off.

The delay in water recession varied significantly across different terrains in the district. In the eastern upland region of Erattupetta, where floodwaters typically recede in two to four hours, the inundation lasted for eight hours. Further downstream in the midland town of Pala, water remained high for three days instead of the usual half-day to one-day window.

In Peroor, closer to the western plains, the flood dragged on for five days compared to the average two to three days. In the low-lying western fringe of Kumarakom, residents had to endure waterlogging for ten days, well beyond the normal six to eight days typically seen during seasonal surges.