The gentle gurgle of the Moyar River is unmistakable as we walk through the ravine of Sathyamangalam Tiger Reserve. We are out in the field to carry out River Health Assessment (RHA), as part of the Noyyal-Bhavani basin conservation program under Rivers, Wetlands and Water Policy division of WWF-India.


Measuring the river flow (Credits: S. Arunvenkatesh/WWF India)

River Health Assessment is an attempt to measure the health of the river and is based on physical, chemical, and biological aspects. It’s a team effort involving our partner organizations Ashoka Trust for Research in Ecology and the Environment (ATREE) and SIRUTHULI, to document the characteristics of the river including land use, the land cover of banks, sighting of terrestrial and aquatic animals, flow and quality of water.


Black buck (Credit: D. Sowmiya Devi/WWF India)

The sights and sounds of the forest
So, armed with sample collection bottles, weighing machine, measuring tape and hand meters to assess pH, Electric Conductivity (EC) and Total Dissolved Solids (TDS)of the water, we set out towards the Moyar. In addition to the learning and assessments, the sight and sound of the forest is a treat to the senses during RHA. Amidst melodious bird calls, towering bamboo thickets rustling in the wind, butterflies fluttering, bumble bees and dragonflies buzzing, we sight a family of spotted deers and shy blackbucks hurriedly tucking themselves behind the bushes.


Golden-ringed dragonfly (Cordulegasterboltonii)(Credit: D. Sowmiya Devi/WWF India)


Crimson Marsh Glider (Trithemis aurora)(Credit: D. Sowmiya Devi/WWF India)

Spellbinding natural bounty
As we move ahead glimpsing and making notes of our observation, wechance upon the sight a mugger crocodile, basking in the sun. Just as we freeze the moment on the lens, the reptile takes a leap into the flowing water and disappears below the waves. 


Mugger crocodile on the banks of the Moyar river (Credit: Sanket Bhale/WWF India)

Back on the banks, when we observed scratch marks on the gigantic Arjuna trees “Tigers mark their territorial boundaries by scratching on the bark of the trees” explained Selvam an anti-poaching watcher with the Forest Department. We excitedly make a note of that along with Otter scat.And as we leave the river side, a herd of elephants greet us from the opposite bank and it was a blissful sight to behold.


Asian elephants sighted on the opposite bank of the Moyar river (Credit: S. Arunvenkatesh/WWF India)


Macroinvertebrate collection(Credit: S. Arunvenkatesh/WWF India)


Diatom collection (Credit: S. Arunvenkatesh/WWF India)

We have carried out similar RHA exercises in the upper reaches of the Noyyal and the Bhavani Rivers and the scenes of natural bounty we come across are spellbinding. Survey of biota and fish diversity is an interesting aspect of RHA as we engage with local communities in the area to learn about the native varieties of fish. Some of the endemic fish species that we have documented are Puntius carnaticus, Bariliusbakeri, Ompokmalabaricus in Moyar, Upper Noyyal and Middle Bhavani zones of the basin.

Pollution, a major concern
However, RHA activities at points where the rivers reach the plains and pass through cities, present a totally different scenario. Both Noyyal and Bhavani rivers meander through urban and residential pockets along the plains of Coimbatore, Tiruppur and Erode districts and are heavily polluted due to industrial and domestic waste.


Noyyal Near Tiruppur (Credit: Richu baby/WWF India)

The Noyyal for instance has become a repository of urban sewage and effluents from the textile industry and as a result an unbearable stench laces the air near the river. The river also suffers from encroachments and land use changes. In the RHA, we documented no or very few fish varieties and lots of red worms, an indicator of polluted water. We also tested EC (Electrical conductivity) and TDS (Total Dissolved Solids)levels which were more than 2000 ppm in certain parts of the river.


Water Quality testing with TDS meter (Credit : S. Arunvenkatesh/WWF India)

The importance of RHA
RHA is important in a river rejuvenation process, as it throws light on the status of the river in terms of water quality, richness of biodiversity and environmental flows required for the endemic fish to survive. The RHA study is being carried out in Noyyal and Bhavani by our teams in three different land use and cover scenario viz. forest, urban/industries and agriculture in pre and post monsoon seasons. During the study, we observed no fish in the Noyyal downstream due to urban sewage and industrial effluents mixing in the river, which was appalling.

Based on the observation, the point source of pollution, need of sewage treatment plants and threats like encroachments and solid waste dumping in river banks, water diversion for agriculture etc, would be further studied. Accordingly, a conservation plan would be developed.

Rivers have been the cradle of human civilisation since time immemorial and it is imperative for us to ensure their health and ecosystem, as they are the lifelines of both the jungles and the cityscapes. Together, with the help of on-ground studies and concerted actions by multiple stakeholder, we can conserve these incredible rivers for people and nature.