Project Team P. Rajaneesh Luqmanul Hakeem S. P. Ravi Dr A. Latha Sreejesh Babu Kodakara Sreevidyaof Kerala Vancheeswaran Ajlal C.M Nikhil Avinash Don Govt. Work done by River Research Centre, ‘Karthika’, Ollur P. O., Thrissur-680306 Phone: 0480-2706331, 9249898773, 9847283120 Email: [email protected], [email protected], [email protected] Contents 1 Acknowledgement 1 2 Introduction 2 3 Methodology and Field Observations 7 4 Recommendations 17 6 Maps of Profile locations 18 7 River Profiles with Temporary Bench Mark (TBM) photos 31 8 Salient Findings, Sand Details 119 9 Annexure 134 of Kerala Govt. Acknowledgements We express our gratitude to the Revenue Department, Government of Kerala, Headed by the Hon. Secretary and the High Level Committee members for entrusting the task of sand auditing in Karuvannur River to us. The support and advises of the High Level Committee members, during review meetings was crucial in the progress of the task. The Thrissur district administration was all along supportive of the entire exercise. They were keenly following the progress of the activity and were considerate in accommodating the delay in completion of the work. The opportunity provided by the Hon. District Collector, to present the findings, at her chamber was really encouraging to us. We express our wholehearted gratitude to the entire district administration. Without the River Management Cell officials at Thiruvananthapuram, the sand auditing could not have been completed. They were always at hand for providing necessary technical assistance and had done the field evaluation of the auditing. We thank K Madhusoodhanan coordinator of RM cell, Sri Shaji and Ms. Saniya for all the support they had provided. The village officers along the river bank were all supportive in the process. We thank each and every Village officers, assistants and other staff for providing necessary help. We also thank all the Grama Panchayath Presidents and members for the enthusiasm shown by them in ensuring a scientific assessment of sandof availa Keralability in the river bed. In any field surveys, the support and active involvement of the local community is vital. At Karuvannur, we were blessed with the active involvement of a large number of local people. The number is so large that naming each of them would be difficult. The local community provided necessary information on the river, water level, history of sand mining etc; they often helped identifying bench marks; assisted in field survey; provided hospitality; provided security to the field staff…. Govt.We express our sincere thanks to each of the local community who had supported this. Last but not the least, the entire process would not have been possible without the blessings of the River and Mother Nature. We bow our heads to the River 1 of Kerala Govt. Introduction Background In the last couple of decades, construction has become the biggest economic activity in Kerala. The employment opportunities created in this sector is so high that Kerala is now the most favoured destination for job seekers from eastern and north eastern states. The shift towards concrete structures since around 1970s and the increased building construction activity necessitated large quantities of river sand in Kerala. By the turn of the new millennium, almost all rivers in the state had lost its historic deposits of sand to indiscriminate mining. This, along with other factors like forest loss in the upper catchment areas, dams and diversions, pollution etc. has affected the health of our river systems. In order to protect our river systems from further deterioration due to indiscriminate sand mining, the government enacted “The Kerala Protection of River banks and Regulation of Removal of Sand Act 2001”. Among other provisions, the act stipulates periodic assessment of availability of sand in each ofriver through Kerala sand auditing. River Research Centre, Thrissur was entrusted with the task of sand auditing in Karuvannur River, vide GO (Ms) No. 161/11/RD dated 2 -4 -2011 & letter D.O 158/P3/11/RD Impacts of river sand mining “Mining from, within or near a river bed has a direct impact on the stream’s physical characteristics, such as channel geometry, bed elevation, substratum composition and stability, in stream roughnessGovt. of the bed, flow velocity, discharge capacity, sediment transportation capacity, turbidity, temperature etc. Alteration on modification of the above attributes may cause hazardous impact on ecological equilibrium of riverine regime. This may also cause adverse impact on instream biota and riparian habitats. This disturbance may also cause changes in channel configuration and flow-paths.” (A Model Document on Impacts and Methodology of Systematic and Scientific Mining of the River Bed Material – Geological Survey of India) 2 “Extraction of alluvial material from within or near a streambed has a direct impact on the stream’s physical habitat characteristics. These characteristics include channel geometry, bed elevation, substrate composition and stability, instream roughness elements (large woody debris, boulders, etc.) depth, velocity, turbidity, sediment transport, stream discharge and temperature. Altering these habitat characteristics can have deleterious impacts on both instream biota and the associated riparian habitat. The detrimental effects to biota resulting from bed material mining are caused by three main processes: (1) alteration of the flow patterns resulting from modification of the river bed, (2) an excess of suspended sediment and (3) damage to riparian vegetation and instream habitat. The disturbance activities can also disrupt the ecological continuum in many ways. Local channel changes can propagate impacts upstream or downstream and can trigger lateral changes. Alterations of the riparian zone can result in changes in channel conditions that can impact aquatic ecosystems in a similar way as some in-channel activities.” (Preliminary Guidance document for Authorisation and Licensing of Sand Mining / Gravel Extraction, in terms of Impacts on Instream and Riparian Habitats -L. Hill & C.J. Kleynhans -March 1999) The Rivers in Kerala are relatively short with their length ranging from 16 kms (Manjeswar River to 244 kms (Periyar River). Only four of the 41 west flowing rivers with catchment area of above 2000 squire kilometers qualify as medium rivers (catchment area between 2000 sq.kms and 20,000 sq.kms) and the rest are technically rivulets only. However, these rivers perform all the functions of a river system and as the stream order are generallyof fourth Kerala to sixth and hence are considered as small rivers. The Kerala Rivers generally originate at elevation above 1000 meters MSL and fall to below 50 m MSL within a very short distance. Due to these unique features, our rivers are highly vulnerable and any intervention in the river system shall only be carried out in a scientific manner based on a thorough and participatory environment impact assessment. Unfortunately, this approach is not generally visible in practice in our interventions with the river systems, including river sand mining that gained momentumGovt. since 1970s. The aquatic ecology is very much dependent on the sand deposit in the river bed (along with the riparian vegetation). River sand also performs the very critical function of maintenance of water quality in the river. The sand deposit in the river bed helped maintain a fairly high water table in most parts of midland Kerala. The removal of sand deposits, that had built up over millennia has had multiple effects on the river system. The present drinking water scarcity in many parts of the state also has direct link with the indiscriminate sand mining in many of the rivers. The impact of sand mining on water quality as well as aquatic fauna has not been extensively studied in the state. 3 The most visible impacts of river sand mining are lowering of the water table and erosion of river banks. In most of the rivers, initially, the sand available above the water table was extracted. Once this was exhausted, in- channel mining started, lowering the river bed. This resulted in lowering of surface water level, which in turn lowered the water table in the adjacent land areas. Over the last three decades, many perennial wells along the river banks of all our rivers have become seasonal. As per relevant acts, sand extraction is not permitted for a 10 meter stretch from both the banks. However, in practice sand is often extracted close to the river banks. At many places, even the banks are scoured to collect the sand trapped below the top soil along the banks. This resulted in bank erosion at many places. Lots of people have lost their land to the river due to caving in of the river banks. Riparian vegetation along the banks is also lost due to this. Impact on aquatic fauna is one of the most significant adverse effects of extraction of sand from the river beds. Shallow stretches near the river banks, coupled with favourable temperature regime created by riparian vegetation are favourable breeding grounds for fishes, mayfly and dragonfly etc. As discussed earlier, this habitat is lost due to indiscriminate sand mining resulting in decline aquatic species. Sand mining has resulted in changes in stream flow pattern. In stream mining at one location can results in modification of river bed characteristics in a much larger area as the river system tries to regain its equilibrium by bringing sediments from adjacent areas. From a wide, shallow system, the channel is changed to a deep narrow system. Also, the gradient along the river course, which influences the flow pattern, is also altered. Ultimately the hydrological regime is modified. Water quality deterioration is another importantof impa ctKerala of sand extraction. When the river channel is devoid of sand, the natural filtering process done by the sand is no more available. The changes in river morphology results in increased BOD and decreased DO levels.