The state of Kerala experienced a devastating flood between 8th to 19th August 2018. The flood, which affected 12 out of 14 districts of the state, has been estimated as 1 in 100 year flood. Six districts namely: Ernakulam (Cochin), Trichur, Idukky, Alappuzha, Pathanamthitta and Kottayam were most affected by the deluge. The worst affected towns were Chengannur, Pandanad, Edanad, Aranmula, Kozhencherry, Ayiroor, Ranni, Pandalam, Kuttanad, Aluva, Chalakudy, N.Paravur, Chendamangalam, Eloor and a few places in Vypin Island.
The team from NPMU, Senior Joint Commissioners Mr. Rakesh Kashyap and Mr. Neeraj K. Manglik, accompanied by technical team from TAMC conducted site visit and meetings with the concerned official of various departments/organisations who were involved in water resources/flood management of the State of Kerala. This was a commendable effort made towards coordinating actions among all the stakeholder organisations taking part in water resources development/flood management in the region.
Under NHP an updated network of meteorological and hydrological observation stations is proposed by the Kerala state, with a focus on improvement of flood forecasting and early warning in the region, with inputs from TAMC/NPMU. It is proposed to have discharge measurements on tributaries as much upstream as possible, so as to gain on lead time for forecasting, where emergency flood evacuation measures are needed to be adopted. To make sure that these upstream gauge stations do not capture insignificantly small discharges, the stations are planned to be placed in such a manner that a minimum catchment area of 100 km² would be intercepted by them. Also, the minimum river lengths of about 2 km upstream and presence of a visible river channel is was considered in finalising location of stations.
In a similar manner, new rain gauge stations are proposed by the State with a focus on capturing the rainfall pattern at upper parts of catchments on the higher reaches of Western Ghats. There remained a scope to augment the rain gauge network in these upstream reaches, primarily owing to the existence of forests in the area that prevented implementation of an extensive network earlier. The newly proposed network will help to capture the spatial variation of rainfall with elevation, and will contribute to better assessment of inflow into the reservoirs.
As per the suggestions in the Cabinet Approval of the National Hydrology Project, the Implementing Agencies are mandated to install at least 10 numbers of hydro-met equipment in the School/ College/ Panchayat/ Community Halls Premises for public awareness. Using this criteria and considering the typical topography of Kerala and the presence of dense forests in higher reaches, NPMU has suggested to place some ARG stations in Engineering Colleges, Schools / Post Offices/ Forest Department Office in areas on high mountains. However, the practicability of establishing and maintaining the hydrological and meteorological network proposals rests with the State authorities and field staff.