8

Chapter 2: THE STUDY AREA

The riverine habitats in Kerala consists of 44 rivers traversing the land, of

which 41 are west-flowing and three, east-flowing. Apart from these rivers, their
tributaries and distributaries and a countless number of streams and rivulets crisscross
the verdant landscape of Kerala. The 44 rivers draining through Kerala can be
segregated into four categories on the basis of the extent of the basin. The first
category includes those with more than 1000 sq km basin area, 13 basins fall within
this category. The second category of basins more than 500 sq km area but less than
1000 sq km; include 8 basins. The third category of rivers includes basins extending
over less than 500 sq km but more than 100 sq km, include 18 basins. The fourth
category is the small coastal basins with less than 100 sq km area which includes 5
basins. Out of the 44 rivers, the area demarcated for the study consists of 20 major
west draining and one east draining rivers all of which belongs to the first three
categories having more than 40 km length.

2.1. Physiography of Kerala

Kerala lies within East Longitudes 740 52' and 770 22' and North Latitudes 80
18’ and 120 48' and constitutes 1.18 % area of the country with a total geographical
area of 38,863 km2. Geologically, Pre-Cambrian and Pleistocene formations comprise
the bulk of Kerala’s terrain. Kerala has an undulating topography with plain lands,
valleys and hills (Fig.2). The width of the State varies between 15 and 120 km and
costal belt extends up to 580 km in length.There are mainly three broad physiographic
divisions in the State, viz. high lands, midlands and low lands (Fig.3). The low land is
adjacent to the coast and extends up to an altitude of 7.5 m MSL. The high land is on
the eastern part consisting of the hills and mountains of the Western Ghats and it
extends from 7.5 to 75 m MSL and above. In between the high lands and the low
lands is the midland having an undulating topography which extends from 7.5 m MSL
up to 75 m MSL. Low land covers 10.24 %, midland 41.76 % and high land an area
48 % of Kerala State (Table 1).

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Source: http://static.maphill.com

Figure 2: The topography of Kerala State.

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 10

Source: CWRDM, Govt. of India.

Figure 3: Physiographic divisions of Kerala.

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Table 1: Physiography and land use of Kerala

Sl. No. Regions Altitude Area % Land use

1 High ranges > 600 m 20.1 Principal forest

area (28.63%)
2 Western Ghats foot hills 300 - 600 m 7.8
and plantation
3 Upland 100 - 300 m 14 crops 13.27 %

4 Undulating midland 20 -100 m

Rice and Coconut
58.1
cultivation
5 Coastal area and low lands < 20 m

Source: Chattopadhyay & Chattopadhyay, 1995; State biodiversity strategy & action plan for Kerala,
2005.

2.2. Climate and drainage in Kerala

Kerala is situated in the humid tropics where the main climatic factor is the
rainfall. Kerala's rains are mostly the result of seasonal monsoons. The average annual
rainfall of the State is 3000 mm, of which 65-70% is received during south-west
monsoon (June-August), 18-22% during north-east monsoon (October-December) and
remaining as pre-monsoon showers. Heavy rainfall coupled with tropical climate is
responsible for the high humidity throughout the year with an average of 70 %. The
mean annual temperature is 27°C. The average minimum temperature ranges from
19°-20°C where as average maximum temperature from 27°- 37°C.

Rivers of varying lengths and widths and its tributaries mainly constitute the
drainage system of the State. They are monsoon fed and fast flowing because Kerala
has a steep slope towards the Arabian sea. Out of the 44 rivers, 41 originate from the
Western Ghats and flow towards the west and drains to the Arabian sea, while three of
them originate from Western Ghats within Kerala, flow eastwards and join the Bay of
Bengal. The longest river is the Periyar having 244 km and secondly Bharathapuzha is
about 209 km in length. A river basin is the portion of land drained by a river and its

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tributaries. It encompasses the entire land surface dissected and drained by many
streams that flow downhill into one another. The rivers flow faster, owing to the high
altitudinal gradient between the Western Ghats and the Arabian sea. All the rivers are
entirely monsoon-fed and many of them shrink or dry up completely during summer.

2.3. Soil types in Kerala

Based on the physico-chemical properties and morphological features the soil

of Kerala has been classified into 10 broad groups (Table 3). The major soil types of
Kerala are shown in Fig.(4).

2.3.1. Coastal Alluvium

Along the coastal belt of the State soils are developed from marine deposits.
The soil has originated from recent deposits, predominantly marine, with some fluvial
sediment along the coast line. This soil is comparatively immature with high sand
content and low water holding capacity with pH values less than 6.5 in most of the
areas. The sand content is 82% with meager quantities of silt and clay. The soils is
nearly neutral in reaction (pH 6.6) with loamy sand to sandy loam in texture.

2.3.2. Riverine Alluvium

This type of soil, developed along river valleys, occurs throughout the State
cutting across the extensive laterite soils. The surface texture ranges from sandy loam
to clay. It is very fertile having high water holding capacity and plant nutrients which
are regularly replenished during floods. It supports cultivation of Paddy, Arecanut,
Pepper, Tapioca and a wide variety of vegetables.

2.3.3. Red Loam

This occurs mainly as colluvial deposits in isolated patches in foothills associated

with laterites. The deep red colour of these soils is due to the presence of hematite and
limonite ores. The rapid permeability of the surface soils is the common nature. The
gravel content is nearly 5% with sand 65%, responsible for the development of this
red loamy soils which are very deep in silt 18% and clay 12.4 %.

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 13

Source: CWRDM, Govt. of India.

Figure 4: Major soil types of Kerala

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Table 2: Topographic, physiographic and physiochemical features of Kerala.

Parameter Level Description

Type I Up to 500 m above MSL (Low altitude zone- hot

I. Altitude humid tropics, spread over the entire State)

Type II More than 500 m above MSL

Pattern I Both the southwest and northeast monsoons are
active and moderately distributed. (South of 11ºN
II. Rainfall latitude).
Poorly distributed rainfall; southwest monsoon
Pattern II maximum during July and concentrated in 3-4
months. Northeast monsoon relatively weak (North
of 110 N latitude).
1 Coastal Alluvium (sandy soil on coastal areas)

2 Riverine Alluvium (Alluvial soil spread over river

banks)
III. Soil types
3 Red Loam (sandy soil coastal areas)
4 Laterite soil (with AB horizon in natural midlands)
5 Greyish Onattukara (coarse grained sandy loam).
6 Acid-saline soil (Pokkali and Kaipad areas)
7 Brown Hydromorphic soil (found in wetlands)
8 Hydromorphic saline soils(coastal tracts of certain
districts)
9 Black soil (Chittur taluk of Palakkad district)
10 Forest loam (eastern part of the State within forest
area)
IV. Topography Valleys Hill tops Slopes

It is acidic with a pH range of 4.8 to 5.9. They are low in organic matter and available
nutrients, Major crops grown in these soils are Coconut and Tapioca. Parts of

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Thiruvananthapuram and Neyyattinkara taluks are characterized by these soils. The

soil being highly porous and friable is not fertile.

2.3.4. Laterite Soil

This soil is scattered throughout the State occupying 58% of the total area.
This soil, a typical weathering product under humid tropical conditions, occurs
throughout the State. Heavy rainfall and high temperature are responsible for the
leaching of bases and silica and the accumulation of iron and aluminium oxides
leading to the formation of laterites. The surface soils are reddish brown to yellowish
red in colour. The texture ranges from gravelly loam to gravelly clay loam. They are
acidic and pH is 4.3. The gravel will be around 58 %, clay 42%, coarse sand 39% and
fine sand 14 %. It shows the development of A, B (C) profiles, which are deep to very
deep. The B horizon is well developed in the most cases with abundant ferruginous
and quartz gravels. Though this soil, in general, is acidic and poor in available
Nitrogen, Phosphorus, Potash and organic matter, it is well drained, widely cultivated
and responds to management practices. A variety of crops like Aracanut, Cashew,
Coconut, Pepper, Tapioca and Rubber can be successfully grown by the proper
application of fertilizers and irrigation.

2.3.5. Greyish Onattukara soil

This soil with its characteristic grey colour occurs in the Onattukara region
comprises of Karunagapally, Karthikapally and Mavelikkara taluks of Alapuzha and
Kollam districts. It is generally coarse grained sandy loam to pure sand in texture
having a pH of 6.2 slightly towards acidity and 84% sand. The soils are highly porous
with limited capacity for retaining water and fertilisers and experiences drainage
problem. These soils are acidic and are extremely deficient in major plant nutrients.
Additions of sufficient organic matter and irrigation facilities improve the water
holding capacity for cultivation of Paddy, Tapioca and other seasonal crops in
addition to Coconut.

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2.3.6. Acid Saline soil

This soil found mainly in Kuttanad region,an area lying below sea level and
submerged for the major part of the year. Salinity and water logging have put
limitations to crop culture but with careful management, these soils can sustain good
crop production. Paddy is successfully grown in this soil. This soil is grouped into
three categories on the basis of morphological and physiochemical properties viz; the
Kayal soil (soil in reclaimed areas with high clay content) Kari soil (black soil with
high organic content developed in low lying water logged areas), and Karappadam
soil (soil along river courses with high silt content).

2.3.6.1. Kayal soil

This is formed from the Vembanad Lake and occupy about 8000 ha extending
in the two districts of Kottayam and Alleppey. This soil will be submerged in water
for 5-6 months in a year. As soon as the monsoon season ends, water is pumped into
the canals, and rice is grown. The soil is slightly acidic to neutral with low organic
matter and available nutrients. The texture ranges from silty loam to clay loam, with
sand 50%, silt 20% and at around 28% is the clay.

2.3.6.2. Kari soils

This soil is located mainly in the Ambalapuzha, Vaikom and Cherthala taluks.
It is deep, black, poorly drained, fine textured peat soils. The soil is extremely acidic
in nature as the pH shows 3.0. They are rich in organic matter.

2.3.6.3. Karapadam soils

This soil occur along the inland water ways and rivers occuping a larger area
of Kuttanad. It is river borne alluvial soils. The soil is very deep, poorly drained and
dark grey with clay loam texture with 31% clay, 45% sand and silt 17%. The pH is
5.3 indicating the acidity of the soil which results in poor availability of the nutrients.

2.3.7. Brown hydromorphic soil

This is commonly found in areas of wetlands. They are moderately rich in

organic matter, nitrogen and potash and deficient in lime and phosphate. It occur

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throughout the State but mostly confined to valley bottoms between undulating
topography in the midland and in low lying areas of coastal strips. This is formed due
to the transportation and deposition of soil from adjoining hill slopes and also through
deposition by rivers. The soils suffer impeded drainage exhibiting hydromorphic
features like grey horizons (layer of soil containing yellow and grey mottlings due to
the oxidation, reduction reactions of iron caused by water logging), streaks, hard pans,
organic matter deposition etc. it is deep, brownish and the texture varies from sandy
loam to clay. The clay percentage is 55 and sand is 30% with 5. 2 pH, which is acidic
in reaction. The saline soil of this group is observed along the coastal strip where
inundation by sea causes salinity. The problem of acidity is also observed within this
soil group in some areas.

2.3.8. Hydromorphic saline soils

Saline soils are found near the coastal tracts of the State in the districts of
Alapuzha, Ernakulam, Kannur and Thrissur. The salinity is caused by the intrusion of
backwaters and tidal waters into these areas. The soils are brownish, deep and
imperfectly drained. The soil texture varies from sandy to clayey. The amount of sand
is around 30%, clay 45% and silt is 20% in these soils. Only salt resistant varieties can
be grown. During August to December, only one crop of salt resistant rice was
cultivating. During rainy season in June-July the fields are flooded and the salt is
leached out, leaving the areas almost free of salts.

2.3.9. Black Soils

Black soil is found in the north eastern part of Palakkad district adjacent to
Coimbatore district of Tamil Nadu. This soil is dark in colour, low in organic matter,
calcareous, moderately alkaline (pH 8.0) and high in clay content (61.7%). The higher
proportion of clay makes it sticky and plastic in character. The shrinking and swelling
capacity is also high. As this soil promotes cotton cultivation, it is often referred to as
black cotton soil. The soil is very sticky and feature of shrinking and swelling
developing cracks during dry periods. Due to low organic matter and high clay
percentage, it is found suitable for a limited variety of crop. Rice is the main crop
grown on these soils.

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2.3.10. Forest loam soil

This soil is developed in the eastern part of the State within forest area on the
weathered crystalline rocks. The upper layer is highly enriched with organic matter
derived from the decomposed leaves. Due to the presence of excessive organic matter,
the soil is dark reddish brown to black in colour. This soil occupy 25% of total land
area of the State. It is loamy and silty loam in texture (40% sand, 36% silt and 22%
clay). The soil is acidic having a pH of 5.8 which leads to the poor status of available
nutrients. It is rich in nitrogen, but poor in bases. The soil is quite fertile under forest
cover and promotes prolific undergrowth in denuded areas, protection against soil
erosion is recommended. Plantation crops such as Cardomom, Rubber, Tea are grown
on these soils.

2.4. Forest types and vegetation in Kerala

There are 26 forest types identified by Champion & Seth (1968) of which
major ones are west coast tropical ever green, west coast semi ever green, southern
moist mixed deciduous, southern dry mixed deciduous, southern montane wet
temperate forest, southern subtropical hill forest, southern montane wet temperate
grasslands and mangroves. Edaphic factors also affect the vegetation development in
certain areas. Bamboo, Reed and Cane breaks, Euphorbias scrub jungle, Laterite
throne forests and Myristica swamp forests in specific locations are due to the
different edaphic conditions. Composition of plants in different strata, woody
climbers and under shrubs are differs in each forest types. The main forest types in
Kerala (Fig. 5) are described below.

2.4.1. West-coast semi-evergreen forests (semi-evergreen)

These forests occur between 600 to 800 m which are found along the banks of
rivers and streams adjoining evergreen forests with three layer stratifications. The
floristic composition is mixture of both evergreen and deciduous species in the top
storey. As the name indicates it is intermediate between evergreen and moist
deciduous types where several evergreen species are found.

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2.4.2. Southern moist mixed deciduous forests (moist deciduous)

This type of forest is seen below 700 m. The canopy looks similar to that of
semi-evergreen forests during monsoon time due to the presence of broad leaved
species, however, the species reveal their identity during summer, and they shed the
leaves and remain bare for weeks.

2.4.4. Southern montane wet temperate forests

Shola forests are unique montane vegetation. This type of forests is seen above
1200 m. The climate is almost temperate. This type is characterized by dwarf plants
with high branching. The branches are densely clothed with moss and epiphytes like
Bulbophyllum, Coelogyne, Oberonia, and Usnea. There is no stratification of trees.
Some of the common members thriving here are Actinodaphne bourdillonii,
Cinnamomum sulphuratum, Elaeocarpus munronii, Ixora notoniana, Pittosporum
nilgiriensis, Turpinia nepalensis, and Vernonia monosis.

2.4.5. Southern montane wet grasslands

This category is seen in the hill tops at high altitudes. The vegetation is
dominated by grasses. Here the soil is shallow and has high wind currents. The
common grasses are Arundinella leptochloa, Cymbopogon flexuosus, Ischaemum
indicum etc. The grassland supports the growth of several herbaceous and sub
shrubby species. The common herbaceous members include terrestrial orchids like
Arundina graminifolia, Brachycorythis iantha, Pectilis gigantean and Habenaria
longicornum.

2.4.6. Southern tropical thorn forests (scrub jungle)

This type of forests is the outcome of low precipitation, and is confined in the
eastern slopes of the Western Ghats. This area comes under the rain shadow regions
in Idukki (Chinnar) and Palakkad (Attappadi) districts. The species are adapted to
thrive the extreme climate prevailing here, and are usually xerophytic, thorny with
less branching. The major species representing the area are Albizia amara, Albizia
lathamii, Capparis sp., Strychnos potatorum etc.

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 20

Source: CWRDM, Govt. of India.

Figure 5: Major forest types in Kerala

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2.4.7. Southern dry mixed deciduous forests (dry deciduous)

The forest type is characterized by the predominance of hardwood deciduous

tree species. The canopy is open with poor undergrowth. The common species
specific to this region are Acacia ferruginea, Albizia amara, Anogeissus latifolia,
Boswellia serrata, Commiphora pubescens, Harwickia binata, Manilkara hexandra,
Santalum album and Sterculia urens.

2.4.8. Southern hilltop tropical evergreen forests

This forest type is seen only above an altitude of 1500 m. There is no

stratification of tree canopy into different tiers. The trees are stunted and often
branched from the base. The branches are thickly clothed with epiphytes and mosses.
The common species include Actinodaphne bourdillonii, Garcinia travancorica,
Isonandra candolliana, Mastixia arborea, Poeciloneuron indicum, Syzygium cumini,
Turpinia nepalensis, Vernonia travancorica, Strobilanthus luridus and Symplocos
wynadense.

2.4.9. Mangroves or tidal swamp forests

Mangrove forests are seen in the estuaries and banks of backwaters where the
influence of tidal waves occurs. Now the mangrove forests of Kerala are under severe
human pressure and are confined to only certain patches sporadically. Common
species seen in the mangrove forests are Acanthus ilicifolius, Acrostichum aureum,
Avicennia marina, A. officinalis, Bruguiera cylindrica, Cerebra odolam, Pandanus
sps., Rhizophora mucronata, Syzygium caryophyllatum, and climbers like Derris
trifoliata, Ipomoea alba etc.

In addition to the natural forest types explained above, some protected areas
like sacred groves are seen throughout the State which represents the rich vegetation
that existed in the past. Some common species seen in these patch forests protected
out of religious belief are Antiaris toxicaria, Aporusa lindelyana, Caesalpinia bonduc,
Gnetum ula, Hopea ponga, Hydnocarpus pentadra, Mimusops elengi, and
Sarcostigma kleinii.

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2.5. Riparian systems selected for the study

The 44 rivers of Kerala (Fig. 6) consists of; four large west flowing rivers,
Bharatapuha, Periyar, Pamba and Chaliyar which exceeds more than 150 km in
length; seven medium rivers having more than 100 km length but less than 150 km,
Chalakkudy, Kadalundi, Achenkovil, Kallada, Muvattupuzha, Valapattanam and
Chandragiri rivers; 13 small rivers of length between 50 to 100 km length, Manimala,
Kuppam, Vamanapuram, Kuttyadi, Karamana, Meenachil, Shiriya, Kaariyamkode,
Ithikara, Neiyyar, Maahi, Anjarakkandi and Uppala rivers; 17 smaller rivers having
less than 50 km in length, Neeleshwaram, Karuvannure, Tirror, Keecheri,
Korappuzha, Perumpa, Maugral, Thalasseri, Chittar, Kallai, Kavvai,
Ramapurampuzha, Manjeshwaram, Baikal, Kumbala, Kalnadu and Purapparamba.
The east flowing rivers Bhavani and Paampar river flows into Tamil Nadu State and
Kabani into Karnataka State. All these 44 rivers draining to a total of 3210 km length
along the State. The selected 21 rivers have a total length of 2234 km and contribute
69.5 % of the total length of all Kerala rivers (Table 3).

2.5.1. Neyyar river

The Neyyar river flows from the Agastyamala hills (Agastyarkoodam) in

Thiruvananthapuram district of Kerala State. It has a total length of 56 km. Its
tributaries includes the Kallar (river), Mullayar river, and the Karavaliyar river.
Neyyar river is the main source of water and sand mining in Thiruvananthapuram
district. The river flows through Kallikkadu, Ottasekharamangalam, Aryancode,
Kezharoor, Perumkadavila, Marayamuttom, Neyyattinkara, Poovar and ends at the
Arabian sea (Fig. 8).

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Source: CWRDM, Govt. of India.

Figure 6: River map of Kerala showing 44 river basins.

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Table 3: Length of Kerala rivers demarcated for the study.

% of the total length

Sl. No Name of river Length (km)
of all Kerala rivers
1. Periyar river 244 7.6
2. Bharathapuzha 209 6.5
3. Pamba river 176 5.5
4. Chaliyar river 169 5.3
5. Chalakudi river 130 4.0
6. Achencovil river 128 4.0
7. Kallada river 121 3.8
8. Moovattupuzha river 121 3.8
9. Valapattanam river 110 3.4
10. Chandragiri river 105 3.2
11. Manimala river 90 2.8
12. Vamanapuram river 88 2.7
13. Kuppam river 82 2.6
14. Meenachil river 78 2.4
15. Kuttiady river 74 2.3
16. Neyyar river 56 1.7
17. Mahe river 54 1.7
18. Karuvannur river 48 1.5
19. Anjarakandi river 48 1.5
20. Kariangode river 64 2.0
21. Bhavani river 39 1.2
2Demarcated 21 rivers 2234 69.5
2Excluded 23 rivers 976 30.5
2Totals 3210 100
Source: CWRDM, Govt. of India.

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Figure 7: % length of demarcated and excluded rivers in the study area

2.5.2. Vamanapuram river

The Vamanapuram river is an 88 km long river in Southern Kerala. The river

originates in the Chemunjimotta hills on the southern part of the Western Ghats at an
altitude of 1860 m above MSL. and after traversing a distance, at Kallar tributaries the
Pannivada river and the Ponmudi river join in it and takes a slightly meandering
course by confluence with the Ponmudi river. The main two tributaries of this river
are the Chittar and Manjaprayar. The river then flows westwards up to Manjappara
where the Manjappara river joins it. It continues its westward course through Palode.
About 3 km downstream of Palode, the river cascades over a 13 meter fall known as
the Meenmutti waterfall. At Choodal, the Chittar joins the main river and from here it
meanders westwards until Vamanapuram and then downstream, the Kilimannoor river
joins the main river. The river again flows westwards and falls into the Anjuthengu
lake near Varkala (Fig. 8).

2.5.3. Kallada river

The Kallada river originates from the Kulathupuzha ranges of Western Ghats,
flows towards the west mainly through Kollam district and ultimately drains in to the
Ashtamudi lake. Kallada river is mainly used for irrigational purpose in the Kollam
district and is a west flowing river which originate from the Kulathupuzha hills near

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Ponmudi, Shenthuruni ranges of Western Ghats. The tributaries are Kalthuruthi river,
Shenthuruni river and Kulathupuzha river. The Kallada river passes through the
Nedumangad, Pathanapuram, Kottarakkara, Kunnathur and Kollam Taluks and it ends
at Ashtamudi lake (Fig. 8). The length of Kallada river is about 130 km. The river
bed is of rocky, sandy and rocky crevices, deep pits and other obstructions in the
river. The famous tourist place Palaruvi waterfall is also at the beginning part of this
river.

The Kulathupuzha river flows in a north-west direction till Myalamood where

it turns and continues to flow in a northerly direction. It is joined by the Chendurni
river at Kalangkunnu. The Chenduruni river, originating from the Karimala and
Alwarkurichi Peaks flows in a north-westerly direction till it joins the Kulathupuzha
river. The Kalthuruthy river which is formed by several streams originating from the
Western Ghats mountains follows first a south-westerly and then a westerly course up
to Thenmala, where it turns south and joins the Kulathupuzha river at Parappar. From
Parappar, the river flows north-west under the name, the Punalur river through the
towns Pathanapuram and Enathu. Thereafter it follows a south-westerly course till its
fall into the Ashtamudi lake.

2.5.4. Achancovil river

Several small streams originating from the Pasukkidaimettu, Ramakkal Teri

and Rishi hills at altitudes above 300m, join together to form the Achencovil river.
The river follows a north-westerly course and from Kumbazha, it turns west and flows
in that direction for few miles, then southwards for 5 km and afterwards continues in a
westerly direction until Idappamon. Here it turns north-west up to Thazhakkara and
thereafter flows westwards. At Tharai mukku, the Kuttenperoor Canal branches from
the main river and joins the Pamba. The river then splits up into several smaller
branches and the main branch flows in a north-westerly direction to join, the Pamba
river at Veeyapuram (Fig. 8).

2.5.5. Pamba river

The Pamba is formed by the confluence of the Pamba river, Kakki river,
Azhutha river, Kakkad river and Kallar. The Pamba is the third longest river in Kerala

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have 176 kms in length. It rises in the Peermedu Plateau at an elevation of 1,670 m.
The Kakki river, which forms the major tributary of the Pamba is a much larger
stream at the beginning than the main river. The Pamba river, after receiving the
Kakki river flows in a Westerly direction till the Azhutha joins it at Pambavalley. The
Pamba continues its gush and Perunthenaruvi waterfall is on the way. At
Naranamuzhi, it turns and follows a southeastern direction until the Kakkad river
joins it. Beyond the confluence, the river flows in a southerly direction up to
Vadasserikkara where it is joined by the Kallar, which has its origin in the
Valanjakkatti hills. At Pandanad the river bifurcates, one branch taking a westerly
course. The Manimala joins the Pamba in its Neerettupuram branch. The river
thereafter flows northwards and falls into the Vembanad lake through several
branches (Fig. 8).

2.5.6. Manimala river

The Manimala river rises from Kolahalamedu near Vagamon hills at an

altitude of above 1150m above MSL. The river gains its shape only from Elankad
estate. In its downward journey the river passes through Enthayar and Kokayar area
where after it is joined by the Kokayar tributary near Kootikkal. Several rivulets also
feed the main stream in this reach. The River takes a southern course until
Mundakayam and from there it follows a westerly course while passing through the
Vellanadi and Erumely. From Manimala it traces a meandering course until its
confluence with the Pamba river at Neerettupuram. Another branch of the river flows
along Kavumbhagom, and join Pamba river (Fig. 8).

2.5.7. Meenachil river

Meenachil river is formed by the streams that have originated from the
Western Ghats. This river flows through Poonjar, Teekoy, Erattupetta, Pala,
Ettumanoor and Kottayam a length of 78 kms and ends at the Vembanad lake at
Kumarakom. The water from this river is used for drinking purposes and irrigational
uses. The main tributaries of Meenachil river are Teekoy river, Poonjar river and
Chittar river. The Teekoy river originates from Wagamon and drains a huge quantity
of water to the Meenachil river. The Poonjar river also originates from the nearest

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 28

Vagamon and Kurisumala hills. The Chittar stream that originates from Thalanadu
and another from Melukavu and Elaveezha Poonchira hills join to form a river which
is a tributary to the Meenachil River. Many small streams also join to this river. The
culture and development of Kottayam is closely related with the Meenachil river and
its tributaries (Fig. 8).There are some serious issues that affect the environment of the
Meenachil river basin badly. Some of them are disposal of wastes, construction of
check dams, mining of river sand, illegal fishing, diversion of water to Idukki dam
etc. River shows climatic extremity ie; the water from this river floods the low lying
areas on monsoon and during summer the water gets completely dried up causing
draught occurs in this river.

2.5.8. Muvattupuzha river

The name of river basin ‘Muvattupuzha’ have formed by the confluence of

three rivers, viz. Thodupuzha, Kaliyar and Kothamangalam rivers. The Thodupuzha
river originates from the Thangakkanam hills above 1100m above MSL. Flowing
down in a westerly direction, many rivulets join together and form the Vatiyar. Near
Valiakandam camp shed, the Nachar joins the Vatiyar to form the Kudayathur puzha,
one of the tributaries of the Thodupuzha river. The Thodupuzha river flows for a
length of 38 km in a north-westerly direction and joins the Kaliyar and
Kothamangalam rivers near Muvattupuzha (Fig.8). Kaliyar river is formed by the
confluence of the Kambar and the Thoniyar. The Kannadipuzha flowing from
Valiyaparantan hills joins the Kaliyar at Kannadi. Another stream originating from
Venniyarmudi also joins the main Kaliyar river. The Kaliyar flowing in a westerly
direction for about 42 km joins the Kothamangalam river near Perumattom and the
combined river flows for about 2 km before joining the Thodupuzha river.

Kothamangalam tributary originates from the Neriamangalam ranges and up

to Kothamangalam, the river flows in a westerly direction, then turns south-west, and
joins the Kaliyar river. The Muvattupuzha river, after the confluence of the three
rivers, flows in a south-westerly direction for about 2 kilometer then flows in a
westerly direction for about 13 kilometer again turns south-west and passes through
low swampy lands. At Vettikkattumukku, it bifurcates into the Murinjapuzha and the
Ithipuzha to join the Vembanad Lake through a series of channels.

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 29

Rivers: a - Neyyar, b - Vamanapuram, c - Kallada, d - Achencovil, e - Pamba, f - Manimala, g -

Meenachil, h – Muvattupuzha. Source: CWRDM, Govt. of India.

Figure 8: Rivers selected for the study-A

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 30

2.5.9. Periyar River

The Periyar is the longest of all the rivers in Kerala, and the largest in
potential. The river is formed by several streams having their origin in the Sivagiri
hills at an elevation of about 1830 meter above MSL. From its origin, the river
traverses through an immense cliff of rocks in a northerly direction receiving several
streamlets in its course. About 48 km downstream, the Mullayar joins the main river
at an elevation of above 854 m above MSL. The river flows westwards for 16
kilometer and receives a few streams from either bank. About 11 km downstream, the
river passes through a narrow gorge. Thereafter the river changes its course and flows
in a north-westerly direction and takes a winding path till it reaches Vandiperiyar. The
river then passes through another gorge, and below the gorge, the Perumthurayar joins
the river. From here, the river flows in a northerly direction for about 18 kmr until it is
joined by the Kattapanayar at an elevation of above 640 meter above MSL. It then
flows in a north-westerly direction between the Kuravanmala and Kurathimala, before
it is joined by the Cheruthoni river. Here the river turns and flows almost due north
until it is joined by the Perinjankutty river at an elevation of above 305 m.

The Periyar continues to flow in a northerly direction and takes its major tributary, the
Muthirapuzha river, coming from the opposite direction. At Kokkaranippara, the river
spills over a cliff about 30 meters in height. The Thottiyar joins the main river from
right. Further down, the river is joined by the Idamalayar river and flows through
virgin forests through Kayattuvakayam to Malayattoor by receiving few more
streams. Lower down of Malayattoor, the river takes a meandering course, and flows
very calmly for about 23 km through Kalady and Chowara and reaches Aluva, where
the river bifurcates into the Mangalapuzha branch and the Marthandavarma branch.
Upstream of this point, a branch of the river loops off the main river, near Kalady to
join the principal branch, the Mangalapuzh a branch, near Chengamanadu. The
Mangalapuzha branch drains north-west, receives the waters of the loop and is joined
by the Chalakudy river at Puthenvelikara in Ernakulam district. After receiving the
Chalakudy river, the Periyar expands itself into a broad sheet of water at Munambam
and finally merges with the Arabian sea. The other branch (the Marthandavarma
branch) flows in a southerly direction. This branch initially splits up into two and

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 31

flows through the industrial complex in the basin and before falling into the
Vembanad lake at Varapuzha, splits up further into several small channels (Fig.9).

2.5.10. Chalakudy river

The river derives its name from Chalakudy town, which is the most important
town in the basin. The Chalakudy river is formed by the confluence of five main
tributaries namely, Parambikulam, Kuriarkutty, Sholayar, Karappara and Anakkayam,
all of them originating from the Aanamalai hills of the Western Ghats. Of these, the
Parambikulam and the Sholayar begin from the Coimbatore district in Tamil Nadu,
and the Karappara and the Kuriarkutty, from the Palghat district in Kerala State.

At about 470 meter above MSL the Parambikulam joins the Kuriarkutty.
Further 9 km down, the river is joined by the Sholayar. The Karappara joins the main
river at about 455 m above MSL. The Anakayam joins the main river 8 km further
down at 365 meter above MSL.

In the initial course, the river passes through thick forests and its flow is
broken by many falls till it reaches the plains at Kanjirapally. The main falls in the
river are at Peringalkuthu and Athirapally. After Kanjirapally, the river takes a
tortuous course of 35 km through charming and fertile tracts. The banks are high and
dotted with houses and cultivated plots. The river finally empties into the right arm of
the Periyar, at Elanthikkara in Puthenvelikara village of Ernakulum district (Fig.9).

2.5.11. Karuvannur river

The Karuvannur river is fed by its two main tributaries namely the Kurumali
and the Manali. The Chimminy and Muply are the the two sub-tributaries of the
Kurumali originate from Kodasseri reserved forest at an elevation of more than 1100
m. The Chimminy and the Muply join to form Kurumali near Karikulam. The Manali
originates from Vaniampara hills at an elevation of more than 365 m. The Manali
river flows westwards up to Mandanchira and then southwards up to Nemmanikara. It
then turns towards west and subsequently to the south before joining the Kurumali at
Palakkadavu near Arattupuzha. The Karuvannur river takes a south-westerly direction
up to Panamkulam and then a westerly course. Just before it joins the backwaters, it

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 32

bifurcates and one branch flows towards south to join the Periyar at Kodungallur,
while the other branch flows northwards and enters the Arabian sea at Chettuva
(Fig.9).

2.5.12. Bharathapuzha river

The Bharathapuzha river, the second longest river of the State takes its origin
at an elevation of above 1964 meter above MSL from Aanamalai hills and flows
through the districts of Palghat, Malappuram and Trichur and joins the Arabian Sea
near the Ponnani town. The length of the river is 209 km with a catchment area of 186
sq. kilometer. The area of the basin is spread over 11 taluks from the Western Ghats
to the Arabian Sea. About two-thirds of the drainage area of the basin ie., 4400 sq. km
lie in Kerala State and the balance 1786 sq. km in Tamil Nadu. Its four main
tributaries are Gayathripuzha, Kannadipuzha or Chitturpuzha or Amaravathipuzha,
Kalpathipuzha and Thuthapuzha (Fig.9).

Gayathripuzha, one of the major tributaries, originates from Aanamalai hills.

In its downward course it touches Kollengode, Nemmara, Alathur, Vadakkancheri,
Koniazhi and Pazhayannur and joins the main river at Mayannur near Ottapalam. This
tributary has four main sub-tributaries viz., Mangalam river in which the Mangalam
dam is located; Ayalurpuzha, in which the Pothundy dam is located; Vandazhipuzha;
Meenkara river, in which the Meenkara dam is located and Chulliar, in which the
Chulliar dam is located. Cheerakuzhi weir is located across the Gayathripuzha near
Pazhayannur.

Kannadi river also starts from the Aanamalai hills, flows through
Tathamangalam and Chittur and joins the main river near Parali. Three main streams
Palar, Aliyar and Uppar combine to form this river. The Chitturpuzha project is
located on Kannadi tributary. In the upper reaches of the Aliyar, two reservoirs are
constructed by the Tamil Nadu Government.

Kalpathipuzha is formed by four streams, the Korayar, the Varattar, the

Walayar and the Malampuzha. The Korayar and the Varatar originate from the
Aanamalai hills and after their confluence, flow towards west where the Walayar

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 33

stream joins near Tampalam. The river is thereafter known as the Korayar. The
Malampuzha river joins the Korayar about 10 km downstream. The largest irrigation
reservoir existing in Kerala State, the Malampuzha, is located on this stream. The
Walayar is the second storage reservoir constructed on this tributary.

Thutapuzha starts from the Silent Valley hills and after taking a meandering
course, joins the main river about 2 km from the Pallipuram railway station. The
important streams that feed this tributary are Kunthipuzha, Kanjirapuzha and
Thuppanadpuzha.

2.5.13. Chaliyar river

Chaliyar river or Beypore river which has a length of 169 km is the fourth
longest river in Kerala. The river drains through the banks of Nilambur, Areekode,
Mavoor, Feroke and Beypore and empties in to Arabian sea. Chaliyar river originates
from the Elambalari hills on the Western Ghats near Tamil Nadu. It flows through the
districts of Wayanad, Malappuram and Kozhikode. The main tributaries are
Cherupuzha, Iruvanjipuzha, Kuthirapuzha, Kuruvanpuzha, Karimpuzha and
Pandipuzha (Fig.9).The river does not get dried up even during summer season. Years
back a pulp factory Mavoor Gwalior Rayons caused serious damage to the river by
releasing factory wastes into the river. This has polluted the water and affected the
aquatic ecosystem.

2.5.14. Kuttiady river

Kuttiady river rises from the Naripetta ranges on the Western slopes of the
Waynad hills, a part of Western Ghats, at an elevation of 1220 meter MSL. Kuttiady
river flows through Kakkayam, Vadakara, Koyilandy and Kozhikode Taluks, and falls
into the Arabian Sea at Kottakkal. Major tributaries are the Kadiyangadu,
Thottilpalam and the Madapally river (Fig. 9).

2.5.15. Bhavani river

Bhavani is a tributary of the Cauvery river with its origin in the Western Ghats
at above 2500 m elevation near Bhavaniar Betta in Nilgiri district of Tamil Nadu.
After traversing a distance of 13 km through Tamil Nadu it enters the Kerala State.

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 34

After entering Kerala, it flows southwards for about 29 km up to Mukkali and

thereafter turns around sharply circling the Malleswara peak. Beyond Mukkali the
river flows more or less in a north-easterly direction till its re-entry into Tamil Nadu
at Kalkandiyoor. Its main tributaries within the Kerala State are the Siruvani and the
Varakar (Fig.9).

2.5.16. Mahe river

The Mahe river is also known as the Mayyazhipuzha and during British ruling
period the river was known as “English channel in Kerala”. The river originates from
the forest on the western slopes of the Waynad hills forming part of the Western
Ghats, at an elevation of above 910 meter above MSL. The river has no major
tributaries but is fed by a large number of rivulets from either side, and finally falls
into the Arabian Sea near Mahe about 6 kmr South of Thalassery town in Kannur
district (Fig.9).

2.5.17. Anjarakandy river

The Anjarakandy river originates from Kannoth reserve forest, Thalassery, at

an altitude of above 600 meter above MSL. After traversing for about 16 km through
dense forest and hilly terrain, the river falls rapidly and at Kannavam, the bed level is
only near 90 m above MSL. Two small tributaries, the Kapputhodu and the
Idumbathodu join the main river near Kunderipoyil. Thereafter, the river takes a
meandering course until Orikkara, where it bifurcates into two. One branch,
Dharmadam river turns south to join the Arabian sea, three km north of Thalassery
town. The other branch falls into the Arabian sea 5 kmr north of Thalassery town.

2.5.18. Valapattanam river

The Valapattanam river originate from the Brahmagiri Ghat reserve forest in
Coorg district, Karnataka State, at an altitude ranging from above 900 m to 1400 m
above MSL. The major tributaries are Sreekandapuram river, Valiapuzha or Barapole,
Venipuzha, Aralampuzha, Cheenkannipuzha, Huruttipuzha, Koottupuzha and
Payavoor river. After flowing through the reserve forests in Karnataka State for about

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 35

Rivers: a – Periyar, b – Chalakudy, c- Karuvannur, d – Bharathapuzha, e – Chaliyar, f – Kuttiadi, g –

Bhavani, h – Mahe river. Source: Govt. of India & CWRDM.

Figure 9: Rivers selected for the study-B

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 36

19 km, it passes through the villages of Iritty, Peringanna, Ambayathodu, Kottiyoor,

Aaralam, Kelakam, Irikkur, Payavoor, Sreekandapuram, Parassinikadavu,
Pappinissery, Kollasseri and Valapattanam. The basin is very undulating, the
cultivable land lying mostly in the valleys. River drains into the Arabian sea at
Azhikkal along with the Kuppam river (Fig.10).

2.5.19. Kuppam river

The Kuppam river or Mattol river originates from Coorg district of Karnataka
State at an elevation of 1650 m from Padinalknad Ghat reserve forests and it flows
almost parallel to the Valapattanam river through Thaliparamba in Kannur district.
The river has a steep course in its initial reaches in Karnataka State for a distance of
12 km and when it enters Kerala State, its bed level falls to nearly 120 m due to
Western Ghats slope. The main tributaries of this river are Pakkatupuzha,
Alakuttathode, Kuttilolpuzha, Mukkuttathodu and Chiriyathode rivers. Later it joins
with the Valapattanam river at Mattool. It has a length of 82 km and it finally empties
into the Arabian sea. Before its exit into the Arabian sea, it is joined by the
Valapattanam river from the south. The Azhikkal minor port is at the mouth of the
river (Fig.10).The river together, with its tributaries and streams drains an area of 539
sq. km of which an area of 70 sq. km lies in Karnataka State.

2.5.20. Kariangode river

Kariangode river, the second longest river in Kasaragod district, Kerala which
flows through a total area about 64 km, passes through both Kasaragod and Kannur
districts before it drains into the Arabian Sea.This river flowing through the hills and
valleys of Hosdurg Taluk. Padinalkad Ghat Reserve Forest in Coorg district,
Karnataka is the place where it begins its flowing by the confluence of several small
streams from the hills. Its two main tributaries, Mundore, Padimalahole and
Ariakkadavu hole are the main tributaries of the river.The river is known as
Pulingoruchal. The Mundroth Hole rises from the Brahmagiri is the source of the
Cavery river. The Kariangode river passing through the villages of Cheemeni and
Karindalam, the river flows west till Kilayiakote, turns and flows south for 3 km then
again turns west and flows in that direction till it is joined by the Nileswaram river

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 37

from the north. The river then splits up into several branches before falling in to the
Arabian sea near Thuruthi in Kasaragod district. (Fig.10).

2.5.21. Chandragiri river

The Chandragiri river has two tributaries Payaswani and Chandragiri. These
tributaries originate in Karnataka, from Sullia hills reserve forest bordering Karnataka
and Kasaragod, and drains into Arabian sea. The Payaswani river and the Chandragiri
river originates from Patti Ghat reserve forest at an altitude of about 1400 m above
MSL. Patti Ghat is one among 6 Ghat Forests, and 23 Reserve Forests in Kodagu,
Karnataka State. Chandragiri river joins to Payaswani river near Machipuram
(Mahalaxmipuram Temple near Chattamchal). These two tributaries combine to form
Chandragiri river about 15 km upstream of its mouth, near Kalnad railway station and
Kasaragod harbor, and exit into the Arabian sea (Fig.10).

Rivers: a–Valapattanam, b-Kuppam, c-Kariangode, d-Chandragiri. Source: Govt. of India & CWRDM.

Figure 10: Rivers selected for the study-C

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