Source: Mitigation of Pamba River Pollution options strategies and responsibilities (April 27-29, 2004 CESS)
The water of the River, Pamba is influenced by * the waste water from the pilgrim centre Sabarimala in the upper reaches of the river including the place, Pamba, where the pilgrims arrive.
*the discharge of waste water from Municipalities in the middle and lower reaches of the Pamba.
forestry and farming especially, the application of fertilizers and pesticides used in plantations and *other sources like rubber factories and further industrial and commercial activities.
The first point is the most important for the rapidly increasing water pollution, noticed in the recent years. So that is the main object of our concept. The Sabarimala temple area is placed in the upper Pamba River catchment area in the centre of a large forest, Pamba itself is about 4 km downstream. The temple is open during two main seasons, one from November 16 to Dec. 26 and Jan 1 to 14, the other 14 days around Easter, in addition each month from the 16th to 21st. But the influence on the water quality is not limited to the high season of the pilgrim. The heavy rainfalls during the monsoon period lead to a steady wash out from the soils directly into the river.
d) Wastewater Treatment
The water of the Pamba River is influenced by bacteria, a huge amount of nutrients and oxygen consuming matter discharged during the three months pilgrim season.
Those affected by Pamba pollution are not only the pilgrims, but also the downstream populations, flora and fauna of the river and the upper Vembanad estuary.
River Sand Mining
The river basins and their extensive sandy plains are part and parcel of Kerala’s cultural heritage. The extensive sandy plains at Maramon and Cherukole in Pamba are traditionally being used for holding annual religious congregations. The river segment near Aranmula is used annually for holding the famous Uthritathi boat race in connection with the Onam Celebrations. The sandy plains of Manimala near Manimala town and Kallooppara host the annual CSI Christian Convention and festival in connection with the Kallooppara Devi temple, respectively.
The Pathanamthitta district is drained by four major perennial river of Kerala, such as Manimala, Pamba, Achankovil and Kallada. Of these, Pamba and Achankovil rivers drain more than 70% of the total area of the district.
Manimala river is one of the pernnial rivers of Kerala with a length of about 90 km and a catchment area of about 847 km2. The river originates from the Thattamalai hills at an elevation of 1156m above msl and drains through the highland, midland and the lowland physiographic provinces of Kerala. The river Spreads over Idukki, Kottayam and Pathanamthitta districts and empties into the Vembanad lake, after merging with the Pamba at Valanjavattom near Thiruvalla. Manimal river displays a dendritic drainage pattern. The extensively developed sandy plains and point bars, used for holding annual religious congregations are vanishing at rapid rate due to indiscriminate sand mining.
2.5.2 Pamba River.
Pamba river is the third largest river in Kerala. It has a length of about 176 km and a catchment area of about 2235 km2. The river originates from Pulachimala in the Western Ghats at an altitude of about 1650m above msl and flows through highly varied geologic and geomorphic provinces of the state. The river drains through Pathanamthitta (Major portion) and Alappuzha (minor portion) district and debounches into the Vembanad lake near kainakkari. The river displays dendritic to suddendritic drainage pattern. The main tributaries of the river are Kakki Ar, Azhuta Ar, Kakkad Ar, Kallar, Manimala and Achenkovil
2.5.3 Achankovil river
The Achankovil river originating from Pasukida Mettu of the Western Ghat Mountain ranges at an elevation of over 700 m above msl, is a pernnial river flowing through the Pathanamthitta district. A minor portion of the river in the upstream falls within the Idukki district and another portion in the downstream falls within Alappuzha districts. The river has a length of about 128 km and a catchment area of about1484 km2. It is formed by the confluence of tributaries originating from Pasukida Mettum, Ramakkal Teri and Rishi Malai of the Western Ghat mountain ranges. The river generally flows westerly and is controlled mainly by the Achankovil Shear Zonc (ASZ). The Achankovil river merges with the Pamba river at Viyyapuram near Thiruvalla. The river exhibits dendritic drainage pattern and its source area, but becomes trellis and subtrellis towards low lands.
2.5.4 Kallada River
Kallada River flows through the southern border of the Pathanamthitta district. It is a seventh order pernnial river with a length of about 121 km and a catchment area of about 1699 Km2. Although the river basin spreads mainly in Kollam district, a small portion falls in Pathanamthitta district as well. The river is formed by the confluence of three major tributaries namely Kulathupuzha, Chendurni and Kalthuruthy. The basin reaches it highest elevation of 175m above msl at Karimalaikodakal and reaches down almost to sea level, near Munrothuruthu. The river finally merges with Ashtamudi estuary.
Sand Mining From Pathanamthitta District
All the four rivers flowing through the Pathanamthitta district viz; Manimala, Pamba, Achankovil and Kallada rivers are subjects to reckless exploitation for river bed materials. There are about 169 Kadavus identified in the district, out of which 69 are Manimal, 4.5 in Pamba, 44 in Achenkovil, and the remaining 11 in Kallada river.
3.2) Natural replenishment
The stream discharge data of CWC stations in the Manimal, Pamba, Achankovil and Kallada river basins have been analysed to get an idea about the natural replenishment of these rivers. It is estimated that about 65899 MT (equivalent to 8237 truck loads) truck loads) as per year of sand is being transported downstream of the respective gauging stations as suspension. The sand discharge of individual rivers per year are 17925 MT (equivalent to2240 truck load) for Manimala, 27354 MT (equivalent to 3419 truck load) for Pamba, 11485 MT (equivalent to 1436 truck load) for Achankovil.
3.3 Environmental Problems
The Manimala, Pamba, Achankovil and Kallada rivers provide drinking water to several lakhs of people in the respective basins. Unfortunately the rivers are on the verge of severe deterioration due to indiscriminate quarrying of sand for constructions.
It is estimated that the river bed has been lowered to about 1.2 m in Manimala river during 1990-2000 (bed lowering = 12 cm/yr) 1.23m in Pamba river during 1985-2000 (8cm/yr). 1.3 in Achankovil river during 1980-1995 (8.7 cm/yr). This is an indicator to the extent of channel degradation to which the river systems are subjected consequent to indiscriminate sand mining.
3.5.2) Pamba river.
A total of 16 local bodies located on either sides of the tributaries as well as the master channel of Pamba river flowing through the Pathanamthitta district are engaged in sand mining.