Human Intrusion in Talpona River-I By NANDKUMAR KAMAT Monday, 12 October 2009
A SCRUTINY of media reports over the causes of Canacona's floods reveals 12 different schools of thought-ranging from the extended effect of the tsunami, cloud burst to landslides. Canacona flood is the final warning signal for the government and the people. Nobody should interfere with river ecosystems and natural drainages evolved over millions of years. It is always convenient for government to consider such events as 'Act of God' because it helps hide the truth. The truth is very simple. All of Goa's 11 rivers and their 41 tributaries are under phenomenal stress. The basic stressors are land use changes, damages to watersheds, removal of indigenous vegetation and encroachments in riverbeds and on banks. For freshwater zones of the rivers no setback lines are observed for constructions, industries and farms. Many rivers like Assonora, Baga, Arambol, Mandrem, Sinquerim, Santana are facing slow death. Their channels are rapidly losing the capacity to contain floods. Relocation to Higher Ground: Historical records of rainfall measurements indicate that similar intense showers had earlier occurred in Sanguem and Canacona but these had not caused the disastrous situation that was witnessed between October 1-3. The northeastern catchment area of Talpona River had a rainfall of half a meter in less than 24 hours. With unsaturated aquifer, unobstructed channel, an intact flood plain and without heavy sediment load, this volume of water would have easily drained out within 12-18 hours. But Talpona river has lost its' channel capacity. There are more than 30 islands of silt in its' channel. Its' mouth near the port of Talpona has been reduced to a narrow channel owing to formation of mudflats and a deep sand bar. Therefore the wall of water from the upstream region fell with unprecedented ferocity in its' down stream area damaging property and taking lives. Canacona is still not free from possibility of similar or worse floods in future. This would have to be factored in before rehabilitation plans are hastily drawn. It would be wise to relocate the people to higher and safer grounds as a permanent solution. Otherwise Canacona floods would be a recurrent situation like Sanquelim and Bicholim, which have been tormented by flooding in the past. Cause of Flash Floods: I was a non-official member of the expert panel constituted in 2001 by the Water Resources Department to prepare the master plans for utilisation of waters of Zuari, Talpona and Galjibaga rivers. We had then examined the meteorological and hydrological data of Talpona and Galajibaga rivers in minute details. We were also aided by Survey of India toposheets and contour maps. Specific recommendations had been given to the government in the Master plan. We had no access to high quality satellite images of the basin and channel of Talpona River in 2001. Recently when I examined the 2003 series of satellite images-the causes of the flash floods became clear. Although the granite deposits of Palolem Canacona are more than two and half billion years old, considering Deccan volcanism and orogeny of the Western Ghat Mountains-Talpona River has been flowing for at least 45 million years. No paleochannels of the river are found, although minor channel drift might have occurred. The erosive power of the recent floods might have also resulted in minor alteration of the normal course of Talpona River but this is a matter of investigation for the WRD. The very location of the Vaishnavaite muth-the monastery of revered Swamiji of Partagal on the banks of the river proves that it was a carefully chosen location beyond the highest historical limit of the Talpona Rivers' flood plain. The monastery is more than 500 years old. But for the first time in its' history it was affected by the recent floods. This is clearly the outcome of continuous human interference in Talpona river ecosystem. Impact of Land Use Change: Four government departments-revenue, mining, forests and water resources can be identified for having failed in monitoring land use change and its' secondary impacts. Revenue officers are fully empowered under the 1968 Revenue Code and Rules to check the status of all the rivers and spot any encroachments. But both the collectorates have completely neglected their duties. Mining department should never consider leases for mining or quarrying in sensitive watershed areas, especially when these are close to the sources of a major river or tributary. But the massive excavations in Ravona mountain watershed that drains into Talpona River caused unprecedented erosion discharging millions of tones of sediment in the upstream region of Talpona River. When the floods rise, people are disturbed by the reddish, muddy waters. But what's the source of this mud? It is haemorrhage from a bleeding earth. The shaving of the hills in Virdi, Maharashtra for creating monoculture commercial plantations increased the sediment load in Valvonta River, resulting in flash floods in Keri-Sattari a few years ago. It is a tragedy that due to its' failure to understand forests of Goa as integrated ecosystems, Goa's forest department dismisses any responsibility of maintaining the health of streams and rivers passing through protected areas such as Cotigao. The greater irony is that despite handling both the portfolios of water resources and forests, which are complementary, our young minister has not been able to discipline his officers and make them work to protect both the river and forest regime in areas which fall under his jurisdiction in an integrated manner-a standard international scientific and ecologically sound practice. Talpona floods could have been avoided by a better knowledge management system. But there is no coordination between the above four departments. The Irrigation Act, 1973 is outdated and doesn't give the government clear and adequate powers over the state's lentic and lotic waterbodies. For 12 years, I have been writing on the possibility of natural disasters while suggesting effective ways for disaster management. I have been warning the government about the price the people would have to pay for neglecting the consequences of human interference in sensitive watersheds and river ecosystems. All 11 rivers of Goa need computerised optical fibre cable networked, satellite linked eco-hydrological monitoring stations and early warning systems. Since local observatory data is not reliable, the government can outsource this work to experienced private parties. The corporate sector of India is now purchasing high quality weather data from private parties. If it is Canacona this year-what next? Salcete taluka is a sitting duck for the coming deluge-simultaneous attacks from the Arabian sea and the silted River Sal. Taleigao, Panaji, Assagao, Anjuna, Baga, Arpora, Guirim, Chimbel, Chinchinim, Velim face danger of submergence too (to be continued). http://www.navhindtimes.in/opinions/4039-human-intrusion-in-talpona-river-i
