The Kerala Forest Research Institute (KFRI), Peechi, has come out with a manual on riverbank protection, recommending a three-tier system giving importance to indigenous species of trees and grass in the wake of the damage caused by the floods of 2018 and 2019 and the extreme climate change phenomena like heavy rain in the State.
Riverbanks are ecologically fragile systems, which faced serious threat from human activities as well as natural phenomena like heavy rain. Protection of the riverbanks is important to ensure the stability of the water course and make the banks more productive. Stable riverbanks also have a positive impact on socio-economic activities as well as conservation of biodiversity, according to the manual.
A bio-restoration programme using indigenous trees and grass could replace the traditional engineering structures and techniques that were now being re-evaluated for their effectiveness and impact on the environment, said Syam Viswanath, director, KFRI. S. Sandeep, V.B. Sreekumar, M.S. Sanil and R. Vishunu are the other scientists involved in the development of the manual.
The manual pointed out that the planting of trees, shrubs, herbs or grasses along the riverbanks is a vegetative method of stabilisation whereby the root system hold the soil in place instead of engineering structures that are costly and require continuous upkeep.
Bio-stabilisation
The KFRI manual provides a general guideline of bio-stabilisation to control river flow, stabilise channel alignment, protect stream banks and rebuild habitats.
The manual also provided technical advice to local government bodies, communities and land-holders to restore and protect riverbanks, said Dr. Viswanath. He said the preparation of the manual was helped by the practical experience gained from the restoration of the Manalippuzha riverbank stabilisation programme.
Indigenous species suited to the local climatic conditions should be selected while their root anchoring capacity, tolerance to adverse conditions like salinity, drought, waterlogging and high growth rate should be considered when they are selected for the riverbanks protection programme.
Suggested species
The manual suggests Adenanthera pavonina (Manjadi), Artocarpus heterophyllus or jack fruit (Plaavu), Callophyllum inophyllum (Poon), Caryota urens (Choondappana), Corypha umbraculifera (Kodappana) Elaeocarpus binata (Rudraksham) as among those suitable for the upper zones of the riverbanks.
Aporoasa acuminata or Neervetti (swarnavetti), Barringtonia acutangula (Iluppa), Garcinia gummi-gutta or Kodampuli, Ochlandra travancorica or Eetta, Pandanus (screw pine) or Kaitha are among those recommended to be planted in the middle zone.
Rotula aquatica or Kalluvanchi and Lagenandra ovata or Aandavazha are among those suggested for the lower reaches of the riverbanks.
Published - December 22, 2021 06:34 pm IST
