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Landuse change analysis of three selected panchayats in Kuttanad using Remote Sensing data and GIS
John C. Mathew
GIS Consultant cum Research Student
Centre for Environment and Development
Thiruvananthapuram, Kerala - 695001
John C. Mathew
GIS Consultant cum Research Student
Centre for Environment and Development
Thiruvananthapuram, Kerala - 695001
An analysis of the nature and rates of
environmental change over recent decades is essential for a proper understanding
of why present environmental problems have arisen. It is also necessary to allow
formulation of accurate productive models of environmental change. In this
respect, information on the existing land use/land cover pattern, its spatial
distribution and changes in the land use pattern is a pre-requisite for
planning, utilisation and formulation of policies and programmes for making any
micro and macro-level developmental plan.
Land has been going through tremendous transformations due to sprawls in agriculturalisation, industrialisation and urbanisation. The changes in land use affect the ecosystem in terms of land cover, land quality and capability, weather and climate, quantity of land that can be sustained and in short the whole population and socio-economic determinants.
Land use change detection using remote sensing data (satellite and aerial) and analysis using GIS has been applied to both rural and urban areas. The method is very efficient for assessing the change or degrading trends of a region. Change detection involves the use of multi-date (time series) aerial photos or satellite imageries of the study area, from which land use maps can be generated by visual interpretation or digital image processing. GIS analysis will give the actual area of each and every land use classes and the area changed, through the overlay operation.
Present study
Kerala lying between 8o18’ to 12o48’ N latitude and 74o25’ to 77o22’ E longitude is one of the small but beautiful narrow strip of land in the south-western corner of the Indian Peninsula. The land use of the State marks unique zonation from the hill ranges to the coast. The riverine alluvium and the longitudinal stretch of coastal alluvium combination covers nearly 10% of the total area and are potential for wetland paddy cultivation. The upper reaches of the rivers particularly Periyar plateau in the south and Wayanad plateau in the north, are significantly covered with plantation crops like tea, coffee and cardamom. The midland zone or foothills are primarily covered by rubber in the southern part; and tapioca, cashew and pepper in the northern part. Coming further down; tapioca, coconut and other tree crops are recorded, interspersed by paddy cultivation in the river valleys. The low land, covering the coastal area is dominated by coconut and partly by cashew and paddy. The diversity of tree crops is mostly marked in the lowland-midland junction. The enriched forests having high bio-diversity and economic value are confined to the highlands mostly above 100m contour. The plantations are accommodated by converting the forest area, as inherited from the colonial legacy of developmental setting.
A major land use change that has occurred in Kerala is the conversion and reclamation of paddy cultivated areas, both in the lowlands and uplands to non-agricultural uses jeopardising the food security of the State, when it is designated as a ‘Statutory Ration State’ with over 60% need of food grain met by imports. Kuttanad region, known as the ‘rice bowl of Kerala’ is a predominant rice growing agricultural wetland ecosystem of Kerala. The area under paddy cultivation in Kerala has reduced from 8.02 lakh ha in 1980 - ’81 to more than 4.71lakh ha in 1995 – ’96. The State is worst affected by this phenomenon, because of its impact on the health and socio-economic and living conditions of the people and the ecological and environmental condition, with the state government spending over 600 Crores of Rupees every year for rice imports from other states.
The present study is envisaged to analyse the causes and consequences of land use changes at the cadastral level and to formulate an environment management plan in three selected panchayats of Kuttanad region, viz, Pallipad, Ramankari and Kumarakom.
Objectives
The prime objective of the study is to analyse the land use changes of the Kuttanad area with special focus on paddy field reclamation. This study also intends to organise a decision support system (DSS) for the area under study towards micro-level regional planning around a GIS package. The major objectives of the present study are,
The study area includes the three panchayats in Kuttanad region – Kumarakom, Ramanakari and Pallipad, located between 908’ to 9052’ north latitudes and 76019’ to 76044’ east longitudes. It is having the influence of marine, estuarine and fluvial systems. Kuttanad has a total area of about 1157 sq.km comprising 66048 ha of wetlands; 31,086 ha of dry garden lands and 18623 ha. of back waters.
Pallipad is the largest panchayat located in the Harippad block of Karthikappally taluk in Alappuzha district comprising both the parts of upper Kuttanad and Onattukara region. The total area of the panchayat is 16.93sq.km with a total population of 23,606. The Panchayat is bordered in the south by Thrikkunnapuzha-Mavelikkara road, the Chettikulangara, Chennithala and Mannar Panchayats on the east, the Mannar, Veeyapuram Panchayats on the north and to the west is the National Highway-47, which separates Pallipad from Haripad and Karthikappally panchayats.
Ramankari is located about 14 km west of Changanassery in the Velianad block of Alappuzha district. The geographical area of the panchayat is 16.17 sq.km supporting a population of about 14026. The panchayat is bordered by Pamba River and Velianad panchayat on the north, Muttar and Kozhimukku panchayats on the south, Champakkulam panchayat on the west and to the east by Velianad and Muttar panchayats.
Kumarakom (90 37’N Lat. and 760 25’E Long.; 51.67 sq.km) is situated on the eastern banks of Vembanad estuary, about 10km west of Kottayam Out of this total area, about 24.13sq.km. is the Vembanad Lake. The total population of the Panchayat is 22,232. The Kavanar River and Aymonom village are on the north, the Thiruvarpu village on the east and to the south is the Allappuzha-Kottayam canal.
The major environmental issues in the study area can be titled into following points.
Methodology
The whole methodology adopted for the study is presented in the fig.1. The detailed methodological details are as follows.
First, the different data products such as cadastral maps, aerial photographs and resource maps were acquired. This is followed by the collection of secondary data from various departments, libraries and offices like village office, Panchayat office, Kerala State Land Use Board, Kerala Agricultural University, Directorate of Economics and Statistics, Fishermen co-operative societies etc.
Land use/ land cover mapping was done through actual field study. For that the land use classification scheme adopted in all the three panchayats is given in the table (1.1). Here the paddy double crop means, they are the popular puncha lands, and they are not regularly double cropped in the literal spirit. They are much lower than the virippu paddy lands. Traditionally the Puncha lands are double cropped, so they are designated as paddy double crop. Paddy with Aquaculture category includes both paddy cultivation and aquaculture in an alternative way as a part of the Integrated Farming System. There are people inhabited areas and these are settlements with mixed trees and mixed crops categories, which forms the main habitational areas. The marsh category in this study only means the uncultivable waterlogged fallow areas and not the conventional marshy ecosystem.
Table 1.1 Land use classification scheme adopted
The whole technical methodology included the following activities.
Flowchart of Paddy Area Change Analysis in a GIS Environment
Results and Observations
The comparative analysis of land use changes through the Overlay operation of ARC/INFO given the following datials. This will also give a comparison between the three study areas representing the total entity of Kuttanad wetland ecosystem.
Pallipad The comparative analysis of land uses of 1997 with the status in 1988 clearly defines the changes taken place during the last decade. The changes are mainly in the form of reclamation, conversion and degradation of paddy cultivating areas comprising both puncha and virippu fields to other non paddy land uses such as coconut, mixed crops, plantain, mixed crops and marsh. The total area of paddy which occupied 742.18 ha. (56.6 percent of total geographical area of 1311.21 ha) in 1988 has been reduced to 652.01 in 1997 and this shows a 12.15 percent reduction in paddy area i.e., the paddy area which was represented in about 56.6% of the total area in 1988 has been reduced to 49.72% in 1997.
The major change from paddy was to settlements with mixed trees category coming to about 73.69 percent of the total paddy change, i.e., from 541.55 ha. in 1988 to 608 ha. in 1997. The area of paddy cultivation changed to coconut comes about 13.24 percent (from 1.25 ha. to 16.89 ha) ,to mixed crops comes to about 2.66 percent, to plantain 0.31 percent and to the water areas which comes to about 1.03 percent. About 8.93 percent of the change was to marsh. A slight increase in area of pond, and river is noticed from 3.02 to 3.54 hectares and 23.21 to 23.55 hectares respectively. The new categories of land uses evolved mainly through the conversion of paddy are mixed crops, comprising 2.71 ha, plantain comprising 0.37 ha. and marsh comprising 10.27 ha.
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Ramankari The comparison of land use in 1997 with the status in 1990 derives the changes taken place during the last 8 years. Here also the change is mainly in the form of reclamation and degradation of rice cultivating puncha fields to other non paddy uses of land such as settlement with mixed trees, culturable waste etc. The area of paddy which occupied 1136.42 ha. in 1990 has been reduced to 984.5 ha. in 1997 and this shows a 13.37 percent reduction in paddy area, i.e., the puncha area which was represented in about 77.1% of the total geographical area in 1990 has been reduced to 66.78% in 1997.
The major conversion of paddy was to settlement with mixed trees category forming about 88.62 percent of total reduction in paddy area. The conversion to one time paddy and one time aquaculture (paddy with aquaculture) category comprises about 5.5 percent. About 5.48 percent of the change have been to culturable waste lands.
There is an increase in area of land use categories such as settlement with mixed trees from 16.89 percent to 26.63 percent, and coconut from 0.21 percent to 0.24 percent while slight decline in area was noticed in the case of mixed crops (from 1.99% to 1.60%), and River (from 3.8% to 3.58%) categories. The new categories evolved in the land use dynamics are Paddy with Aquaculture, pond and culturable waste comprising 0.56%, 0.03% and 0.58%; whereas the plantain category has been eliminated and changed to mixed crops category.
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Kumarakom The comparison of land use in 1997 with land use in 1936 reveals drastic change in the components and pattern of land use over the last 6 decades. The main category where major change occurred is the paddy - double crop which formed about 96.37 percent in 1936 now reduced to 63 percent of the total geographical area of 2378.92 ha. The lake area has also decreased considerably from 13.37 ha. (0.56 percent) in 1936 to about 1.73 ha. i.e., 0.07 percent in 1997.
Out of the total paddy area conversion of 791.95 ha. (34.54% of the paddy area in 1936), the majority was to mixed crops category coming to about 577 ha. i.e., 72.86 percent of the total change in paddy cultivating area. The area changed to settlement with mixed trees category is 111.22 ha. forming about 14 percent. The major conversion is to coconut plantation of 75.92 ha. i.e., 9.59 percent. The conversion to other classes such as paddy with aquaculture, plantain, cocoa, pond and mango constitute 1.16, 1.12, 0.32, 0.23 and 0.16 percent respectively. The marsh and culturable waste comprise 0.92 and 0.28 percent respectively.
The main habitational land use categories viz., mixed crops and coconut have increased from 2.44 % and 0.31% in 1936 to 26.92% and 3.31% in 1997 respectively. Another major habitational category i.e., settlement with mixed trees evolved constitutes about 4.99 percent. The other new categories in land use are paddy with aquaculture, cocoa, plantain, mango and culturable waste each contributing only very small percentages. Slight increase has been shown in the area of pond and marsh during the period, although, some filling of these areas and conversion for habitational space have happened in the recent past.
The reclamation of lake and conversion of paddy fields to habitational land is concentrated along areas adjacent to the Vembanad estuary on the western side of the panchayat, especially along the banks of estuary and canals and on the sides of roads.
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Comparison of the three study areas in the back ground of land use changes to get assessment of the changes in the whole Kuttanad region is discussed here, although the exact comparison is not possible as the time periods for our study in three panchayats slightly vary from each other. The number of land use categories in to which the paddy is converted is very limited in Ramankari when compared to the other two panchayats. Paddy with Aquaculture land use system is not introduced in Pallipad. The settlement with mixed trees category was more and the change of paddy to this category is much less in Pallipad compared to other panchayats. The virippu fields are not represented in Kumarakom and Ramankari. In Kumarakom most of the change of paddy was to mixed crop category unlike the other two panchayats. The degradation of paddy areas to culturable waste was not taken place in Pallipad unlike the other two panchayats.
The land use dynamics in Ramankari and Kumarakom is similar except the high pace of conversion at Kumarakom in recent years. Major observations on the land use comparison are,
Cause - consequence analysis of land use changes :
The information on the causes and consequences of the above land use changes has been mainly derived through a technique popularly known as Participatory Rural Appraisal (PRA) which involves field observations, discussions and interviews with local people and also by overlaying the road, rail and drainage map on the land use change map in the GIS environment.
Causes The main causes of the conversion of paddy cultivation to other non paddy uses and the increase in the area of habitational land uses in all the three study areas are, (i) the paddy cultivation is non-profitable in most time considering the various socio-economic factors and (ii) the increasing demand for habitational space due to the increasing population supported by the ignorance of the people about the long lasting serious consequences of the conversion.
Pallipad:- The virippu fields which were cultivated a decade ago is now fallow lands mainly due to the water logged condition which was the result of unscientific conversion and reclamation of low lands drainage channels. The developmental activities like railway lines, roads, foot paths, irrigation canals (PIP canal and its distributaries) and land filling damaged the natural drainage system. The virippu fields were converted much more than the puncha fields because they are easy to convert as the height difference between the actual dry land and the field is less compared to that between puncha and dry land. Another reason is the proximity of virippu fields to the existing habitational area. The reclamation of puncha lands need much more time, money, energy and effort than the virippu fields. Earlier the cultivation in the virippu fields, both rice and pulse, were a community effort and locally generated farmyard manure was utilised. Now the commercialisation and the introduction of modern agricultural practices like the use of chemical fertilisers, pesticides and weedicides have totally changed the operationalisation and have reduced the co-operation between farmers considerably. The large-scale reclamation of puncha fields at `Nalukettum Kavala’ shown in the inset of the map is due to the construction of water intake plant of Kayamkulam Thermal Power Plant situated at Choolatheruvu, which draws water from the Achenkoil River.
Ramankari: - The method of aquaculture with paddy which is recently introduced in Ramankari panchayat is much more profitable when compared to cultivating paddy alone and this encouraged the farmers for a shift from paddy to the new combined system. The financial and technical support of the State Government also made this change much easier. The areas adjacent to canals and roads are more converted. The slight decrease in river area is because of the reclamation of the river by the people living on the banks of it.
Kumarakom: - The boost in the conversion of paddy fields in recent years all along the lake side areas owes to the intensive tourism industry activities such as the construction of star hotels, restaurants and tourist complexes. This is also the reason for extensive reduction in mangrove areas shown as marsh in the Map. Here the paddy with aquaculture land use system is in conjunction with the integrated farming practices, which is a further progressive step along the way to make paddy cultivation remunerative.
In general the causes can be listed as follows,
The most important and immediate impact of paddy land conversion is the adverse effect on the rice production in the State and also the socio-economic conditions of the farmers and farm workers. It is calculated that there are more than nine lakhs of farm workers in the State, who get their earning mainly from paddy cultivation. There should be a mechanism to conserve the existing paddy lands and also to implement an action programme for increasing the production and productivity of paddy by providing essential science and technology input.
The rice fields have several ecological functions also. It act as a very viable ecosystem for innumerable number of organisms. In addition to this they act as a good drainage basin, to collect the rain water and run off and slowly penetrating it in to the ground water aquifer, thus helping for ground water recharging. The loss of high productivity and nutrient export to other regimes, supporting very complex food web and acting as natural nurseries and breeding grounds of native fishes, molluscs and crustaceans which have very high nutritive and food value led to the decrease in fish catches. The destruction of mangrove ecosystem also result in the loss of wind breaking action and checking of soil erosion and the natural land building capabilities.
The loss of drainage facilities and water logging has led to the increased run off, soil erosion, and frequent floods and droughts. This also increased concentration of pollutants in the water, like the pesticide residues, which resulted in the recent fish diseases in Kuttanad, and the frequently occurring water borne diseases in the area.
The conversion of fresh water ponds, which were drinking water sources in the earlier times in many places, has led to scarcity of drinking water.
The land use changes have its own impact in contributing to the weed menace and the narrowing of natural canals leading to serious consequences on water transport, water flow and giving extra pace to the on going eutrophication of water bodies.
According to a study conducted recently in Kumarakom panchayat, the total number of species of natural vegetation has decreased considerably. A drastic reduction in the density of population in each species is also noted, especially in the case of aquatic medicinal plants like Brahmi (Bacopa monnieri). This study also reports the over-population of aquatic weeds like Eicbhorina crassipes.
The pest and invader problem is also the consequences of land use changes. The change in environmental conditions, microclimate and quality of water has resulted in the sudden out break of diseases and pests and the invasion of new exotic species of plants and animals.
Conclusion and Recommendations The land use change analysis of Pallipad, Ramankari and Kumarakom panchayats of the Kuttanad region clearly reveals the pattern and extent of land use changes, its causes and consequences. The major change is the conversion of paddy fields to non-paddy or non-agricultural purposes. The constraints in paddy cultivation and the huge demand for land for non-agricultural purposes especially for settlements due to the population pressure should be taken in to account when we formulate an action plan. The qualitative and quantitative aspects of he biophysical resources should be taken into account when we introduce a new land use pattern in the area.
Based on the information generated through this study, some management options has been formulated. But very detailed study and action plan is required for evolving an appropriate land and water management policy for the State.
The major areas of interventions required are as follows:
Land has been going through tremendous transformations due to sprawls in agriculturalisation, industrialisation and urbanisation. The changes in land use affect the ecosystem in terms of land cover, land quality and capability, weather and climate, quantity of land that can be sustained and in short the whole population and socio-economic determinants.
Land use change detection using remote sensing data (satellite and aerial) and analysis using GIS has been applied to both rural and urban areas. The method is very efficient for assessing the change or degrading trends of a region. Change detection involves the use of multi-date (time series) aerial photos or satellite imageries of the study area, from which land use maps can be generated by visual interpretation or digital image processing. GIS analysis will give the actual area of each and every land use classes and the area changed, through the overlay operation.
Present study
Kerala lying between 8o18’ to 12o48’ N latitude and 74o25’ to 77o22’ E longitude is one of the small but beautiful narrow strip of land in the south-western corner of the Indian Peninsula. The land use of the State marks unique zonation from the hill ranges to the coast. The riverine alluvium and the longitudinal stretch of coastal alluvium combination covers nearly 10% of the total area and are potential for wetland paddy cultivation. The upper reaches of the rivers particularly Periyar plateau in the south and Wayanad plateau in the north, are significantly covered with plantation crops like tea, coffee and cardamom. The midland zone or foothills are primarily covered by rubber in the southern part; and tapioca, cashew and pepper in the northern part. Coming further down; tapioca, coconut and other tree crops are recorded, interspersed by paddy cultivation in the river valleys. The low land, covering the coastal area is dominated by coconut and partly by cashew and paddy. The diversity of tree crops is mostly marked in the lowland-midland junction. The enriched forests having high bio-diversity and economic value are confined to the highlands mostly above 100m contour. The plantations are accommodated by converting the forest area, as inherited from the colonial legacy of developmental setting.
A major land use change that has occurred in Kerala is the conversion and reclamation of paddy cultivated areas, both in the lowlands and uplands to non-agricultural uses jeopardising the food security of the State, when it is designated as a ‘Statutory Ration State’ with over 60% need of food grain met by imports. Kuttanad region, known as the ‘rice bowl of Kerala’ is a predominant rice growing agricultural wetland ecosystem of Kerala. The area under paddy cultivation in Kerala has reduced from 8.02 lakh ha in 1980 - ’81 to more than 4.71lakh ha in 1995 – ’96. The State is worst affected by this phenomenon, because of its impact on the health and socio-economic and living conditions of the people and the ecological and environmental condition, with the state government spending over 600 Crores of Rupees every year for rice imports from other states.
The present study is envisaged to analyse the causes and consequences of land use changes at the cadastral level and to formulate an environment management plan in three selected panchayats of Kuttanad region, viz, Pallipad, Ramankari and Kumarakom.
Objectives
The prime objective of the study is to analyse the land use changes of the Kuttanad area with special focus on paddy field reclamation. This study also intends to organise a decision support system (DSS) for the area under study towards micro-level regional planning around a GIS package. The major objectives of the present study are,
- To prepare land use/land cover maps of the three panchayats using cadastral maps, aerial photographs and ground truth survey.
- To analyse the land use/ land cover changes during the last few years.
- To assess the various causes and consequences of the land use changes and its impact on the wetland agricultural ecosystem of Kuttanad.
- To suggest environment management options for the area based on the study.
The study area includes the three panchayats in Kuttanad region – Kumarakom, Ramanakari and Pallipad, located between 908’ to 9052’ north latitudes and 76019’ to 76044’ east longitudes. It is having the influence of marine, estuarine and fluvial systems. Kuttanad has a total area of about 1157 sq.km comprising 66048 ha of wetlands; 31,086 ha of dry garden lands and 18623 ha. of back waters.
Pallipad is the largest panchayat located in the Harippad block of Karthikappally taluk in Alappuzha district comprising both the parts of upper Kuttanad and Onattukara region. The total area of the panchayat is 16.93sq.km with a total population of 23,606. The Panchayat is bordered in the south by Thrikkunnapuzha-Mavelikkara road, the Chettikulangara, Chennithala and Mannar Panchayats on the east, the Mannar, Veeyapuram Panchayats on the north and to the west is the National Highway-47, which separates Pallipad from Haripad and Karthikappally panchayats.
Ramankari is located about 14 km west of Changanassery in the Velianad block of Alappuzha district. The geographical area of the panchayat is 16.17 sq.km supporting a population of about 14026. The panchayat is bordered by Pamba River and Velianad panchayat on the north, Muttar and Kozhimukku panchayats on the south, Champakkulam panchayat on the west and to the east by Velianad and Muttar panchayats.
Kumarakom (90 37’N Lat. and 760 25’E Long.; 51.67 sq.km) is situated on the eastern banks of Vembanad estuary, about 10km west of Kottayam Out of this total area, about 24.13sq.km. is the Vembanad Lake. The total population of the Panchayat is 22,232. The Kavanar River and Aymonom village are on the north, the Thiruvarpu village on the east and to the south is the Allappuzha-Kottayam canal.
The major environmental issues in the study area can be titled into following points.
- Degradation in the quantity and quality of water due to water pollution and stagnant nature or lack of flow, leading to increasing incidence of water borne diseases.
- Problems due to lack of tidal flushing and salinity intrusion - weed menace, increase of poisonous snakes etc.
- Lack of fertility and productivity of both wetland and dryland soil.
- Agricultural pollution - pesticide and fertiliser. Nutrient enrichment of water bodies, weed menace and eutrophication - inland destruction of earthworms.
- Frequent floods and droughts.
- Conversion of traditional natural freshwater ponds and other water bodies acting as the local source of safe drinking water.
- Threats of biologically rich zones of the area like mangroves and the consequent reduction of Biodiversity.
Methodology
The whole methodology adopted for the study is presented in the fig.1. The detailed methodological details are as follows.
First, the different data products such as cadastral maps, aerial photographs and resource maps were acquired. This is followed by the collection of secondary data from various departments, libraries and offices like village office, Panchayat office, Kerala State Land Use Board, Kerala Agricultural University, Directorate of Economics and Statistics, Fishermen co-operative societies etc.
Land use/ land cover mapping was done through actual field study. For that the land use classification scheme adopted in all the three panchayats is given in the table (1.1). Here the paddy double crop means, they are the popular puncha lands, and they are not regularly double cropped in the literal spirit. They are much lower than the virippu paddy lands. Traditionally the Puncha lands are double cropped, so they are designated as paddy double crop. Paddy with Aquaculture category includes both paddy cultivation and aquaculture in an alternative way as a part of the Integrated Farming System. There are people inhabited areas and these are settlements with mixed trees and mixed crops categories, which forms the main habitational areas. The marsh category in this study only means the uncultivable waterlogged fallow areas and not the conventional marshy ecosystem.
Table 1.1 Land use classification scheme adopted
| Sl.No. | Landuse Classes |
| 1 | Paddy - Double Crop (Puncha) |
| 2 | Paddy - Single Crop (Virippu) |
| 3 | Paddy with Aquaculture |
| 4 | Mixed Crops |
| 5 | Coconut |
| 6 | Cocoa |
| 7 | Plantain |
| 8 | Mango |
| 9 | Settlement with Mixed Trees |
| 10 | Pond |
| 11 | River |
| 12 | Lake |
| 13 | Marsh |
| 14 | Culturable waste |
The whole technical methodology included the following activities.
-
Collection of Data and Preparation of Maps.
- Preparation of Base Map Base maps of the study areas were prepared in the cadastral scale of 1:5000 using the village cadastral maps of each panchayats. All other thematic maps were prepared based on this base map.
- Data Interpretation of Basic Tax Register The plot wise information on land use from Basic Tax Register of Revenue Department procured from village offices in each panchayats were encoded, interpreted and transferred to the base map for identifying the survey number / plot wise land use pattern.
- Interpretation of Aerial Photographs Interpretation of Aerial photographs of the study areas for the period of 1990-’91 was also carried out at Kerala Forest Research Institute, (KFRI), Peechi, Thrissur. Altogether 14 Photographs were interpreted in the scale of 1:15000.
- Field Survey In the field
survey, both field mapping of land use, and Participatory Rural
Appraisal (PRA) was done.
The mapping of recent land use (1997) in all the three panchayats were conducted using the base map prepared from the village cadastral maps in the scale of 1:5000. This field reality formed the basis to interpret the Aerial photographs. The mapping was done by identifying the survey plot in the ground and in the cadastral base map by comparing the survey plot number and other land marks shown in the base map.
The Information on the causes and consequences of the land use changes were gathered through the technique popularly known as Participatory Rural Appraisal (PRA) which involved field observations, interviews and discussions with local people.
Data Products Used For the Study
Pallipad- Cadastral maps (1:5000) of 1988
- Basic Tax Register (BTR) of 1988
- Aerial photographs of 1990-’91 (1:15000)
- Cadastral maps (1:5000) of 1988
- Aerial photographs 1990’-91 >
- Cadastral map (1:5000) of 1988
- Basic Tax Register (BTR) of 1936 and 1988
- Aerial photographs of 1990-’91 (1:15000)
- Panchayat Resource Map of 1992 (1:5000).
- Preparation of Thematic Maps Time series thematic maps on Land use / Land cover has been prepared based on the interpreted data and the field survey. Thematic map depicting the accessibility and drainage were also prepared as a separate coverage for overlaying on the Land use map.
Pallipad- Land Use - 1988 (BTR)
- Land Use - 1990 (Aerial photographs)
- Land Use - 1997 (Field survey)
- Accessibility and Drainage>
- Land use - 1990 (Aerial photographs)
- Land use - 1997 (Field survey)
- Accessibility and Drainage
- Land use - 1936 (BTR)
- Land use - 1988 (BTR)
- Land use - 1990 (Aerial photographs)
- Land use - 1992 (Resource Map)
- Land use - 1997 (Field survey)
- Accessibility and Drainage
- Digitisation of Maps The various
thematic maps of 1:5000 scale were reduced to a scale of 1: 23,000
(Ramankari and Pallipad) and to 1: 25,000 (Kumarakom) using the `Optical
Pantograph’ at KFRI, Peechi, Thrissur. These were scanned and a raster
to vector conversion was carried out in AutoCAD (R14). A preliminary editing
of these vectorised maps was done using AutoCAD itself and exported in DXF
format.
Analysis using ARC / INFO The digitised thematic maps in the DXF format were imported to ARC/INFO as coverages. After executing ‘CLEAN ‘ command for topology creation, the dangle node errors were removed interactively in ARCEDIT module. After all offshoot / undershoot errors have been removed, Feature Attribute Table (FAT) was created using `BUILD’ in ARC prompt. A master TIC file has been created and projected to UTM. The coverages were then transformed to the copies of the projected TIC file with output unit in metres. Then each land use/land cover category was assigned a code and these codes were attached to appropriate records of FAT interactively. A Look - Up Table (LUT) was also created to assign a shade symbol for each land use / land cover category.
Flowchart of Paddy Area Change Analysis in a GIS Environment
Results and Observations
The comparative analysis of land use changes through the Overlay operation of ARC/INFO given the following datials. This will also give a comparison between the three study areas representing the total entity of Kuttanad wetland ecosystem.
Pallipad The comparative analysis of land uses of 1997 with the status in 1988 clearly defines the changes taken place during the last decade. The changes are mainly in the form of reclamation, conversion and degradation of paddy cultivating areas comprising both puncha and virippu fields to other non paddy land uses such as coconut, mixed crops, plantain, mixed crops and marsh. The total area of paddy which occupied 742.18 ha. (56.6 percent of total geographical area of 1311.21 ha) in 1988 has been reduced to 652.01 in 1997 and this shows a 12.15 percent reduction in paddy area i.e., the paddy area which was represented in about 56.6% of the total area in 1988 has been reduced to 49.72% in 1997.
The major change from paddy was to settlements with mixed trees category coming to about 73.69 percent of the total paddy change, i.e., from 541.55 ha. in 1988 to 608 ha. in 1997. The area of paddy cultivation changed to coconut comes about 13.24 percent (from 1.25 ha. to 16.89 ha) ,to mixed crops comes to about 2.66 percent, to plantain 0.31 percent and to the water areas which comes to about 1.03 percent. About 8.93 percent of the change was to marsh. A slight increase in area of pond, and river is noticed from 3.02 to 3.54 hectares and 23.21 to 23.55 hectares respectively. The new categories of land uses evolved mainly through the conversion of paddy are mixed crops, comprising 2.71 ha, plantain comprising 0.37 ha. and marsh comprising 10.27 ha.
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Ramankari The comparison of land use in 1997 with the status in 1990 derives the changes taken place during the last 8 years. Here also the change is mainly in the form of reclamation and degradation of rice cultivating puncha fields to other non paddy uses of land such as settlement with mixed trees, culturable waste etc. The area of paddy which occupied 1136.42 ha. in 1990 has been reduced to 984.5 ha. in 1997 and this shows a 13.37 percent reduction in paddy area, i.e., the puncha area which was represented in about 77.1% of the total geographical area in 1990 has been reduced to 66.78% in 1997.
The major conversion of paddy was to settlement with mixed trees category forming about 88.62 percent of total reduction in paddy area. The conversion to one time paddy and one time aquaculture (paddy with aquaculture) category comprises about 5.5 percent. About 5.48 percent of the change have been to culturable waste lands.
There is an increase in area of land use categories such as settlement with mixed trees from 16.89 percent to 26.63 percent, and coconut from 0.21 percent to 0.24 percent while slight decline in area was noticed in the case of mixed crops (from 1.99% to 1.60%), and River (from 3.8% to 3.58%) categories. The new categories evolved in the land use dynamics are Paddy with Aquaculture, pond and culturable waste comprising 0.56%, 0.03% and 0.58%; whereas the plantain category has been eliminated and changed to mixed crops category.
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Kumarakom The comparison of land use in 1997 with land use in 1936 reveals drastic change in the components and pattern of land use over the last 6 decades. The main category where major change occurred is the paddy - double crop which formed about 96.37 percent in 1936 now reduced to 63 percent of the total geographical area of 2378.92 ha. The lake area has also decreased considerably from 13.37 ha. (0.56 percent) in 1936 to about 1.73 ha. i.e., 0.07 percent in 1997.
Out of the total paddy area conversion of 791.95 ha. (34.54% of the paddy area in 1936), the majority was to mixed crops category coming to about 577 ha. i.e., 72.86 percent of the total change in paddy cultivating area. The area changed to settlement with mixed trees category is 111.22 ha. forming about 14 percent. The major conversion is to coconut plantation of 75.92 ha. i.e., 9.59 percent. The conversion to other classes such as paddy with aquaculture, plantain, cocoa, pond and mango constitute 1.16, 1.12, 0.32, 0.23 and 0.16 percent respectively. The marsh and culturable waste comprise 0.92 and 0.28 percent respectively.
The main habitational land use categories viz., mixed crops and coconut have increased from 2.44 % and 0.31% in 1936 to 26.92% and 3.31% in 1997 respectively. Another major habitational category i.e., settlement with mixed trees evolved constitutes about 4.99 percent. The other new categories in land use are paddy with aquaculture, cocoa, plantain, mango and culturable waste each contributing only very small percentages. Slight increase has been shown in the area of pond and marsh during the period, although, some filling of these areas and conversion for habitational space have happened in the recent past.
The reclamation of lake and conversion of paddy fields to habitational land is concentrated along areas adjacent to the Vembanad estuary on the western side of the panchayat, especially along the banks of estuary and canals and on the sides of roads.
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Comparison of the three study areas in the back ground of land use changes to get assessment of the changes in the whole Kuttanad region is discussed here, although the exact comparison is not possible as the time periods for our study in three panchayats slightly vary from each other. The number of land use categories in to which the paddy is converted is very limited in Ramankari when compared to the other two panchayats. Paddy with Aquaculture land use system is not introduced in Pallipad. The settlement with mixed trees category was more and the change of paddy to this category is much less in Pallipad compared to other panchayats. The virippu fields are not represented in Kumarakom and Ramankari. In Kumarakom most of the change of paddy was to mixed crop category unlike the other two panchayats. The degradation of paddy areas to culturable waste was not taken place in Pallipad unlike the other two panchayats.
The land use dynamics in Ramankari and Kumarakom is similar except the high pace of conversion at Kumarakom in recent years. Major observations on the land use comparison are,
- The actual paddy cultivating area has been reduced considerably over the years with increased pace during recent times.
- The habitational land use classes represented by settlement with mixed trees and mixed crops have increased considerably.
- The new category of land use system like aquaculture along with paddy has already found a place in the Kuttanad region recently.
Cause - consequence analysis of land use changes :
The information on the causes and consequences of the above land use changes has been mainly derived through a technique popularly known as Participatory Rural Appraisal (PRA) which involves field observations, discussions and interviews with local people and also by overlaying the road, rail and drainage map on the land use change map in the GIS environment.
Causes The main causes of the conversion of paddy cultivation to other non paddy uses and the increase in the area of habitational land uses in all the three study areas are, (i) the paddy cultivation is non-profitable in most time considering the various socio-economic factors and (ii) the increasing demand for habitational space due to the increasing population supported by the ignorance of the people about the long lasting serious consequences of the conversion.
Pallipad:- The virippu fields which were cultivated a decade ago is now fallow lands mainly due to the water logged condition which was the result of unscientific conversion and reclamation of low lands drainage channels. The developmental activities like railway lines, roads, foot paths, irrigation canals (PIP canal and its distributaries) and land filling damaged the natural drainage system. The virippu fields were converted much more than the puncha fields because they are easy to convert as the height difference between the actual dry land and the field is less compared to that between puncha and dry land. Another reason is the proximity of virippu fields to the existing habitational area. The reclamation of puncha lands need much more time, money, energy and effort than the virippu fields. Earlier the cultivation in the virippu fields, both rice and pulse, were a community effort and locally generated farmyard manure was utilised. Now the commercialisation and the introduction of modern agricultural practices like the use of chemical fertilisers, pesticides and weedicides have totally changed the operationalisation and have reduced the co-operation between farmers considerably. The large-scale reclamation of puncha fields at `Nalukettum Kavala’ shown in the inset of the map is due to the construction of water intake plant of Kayamkulam Thermal Power Plant situated at Choolatheruvu, which draws water from the Achenkoil River.
Ramankari: - The method of aquaculture with paddy which is recently introduced in Ramankari panchayat is much more profitable when compared to cultivating paddy alone and this encouraged the farmers for a shift from paddy to the new combined system. The financial and technical support of the State Government also made this change much easier. The areas adjacent to canals and roads are more converted. The slight decrease in river area is because of the reclamation of the river by the people living on the banks of it.
Kumarakom: - The boost in the conversion of paddy fields in recent years all along the lake side areas owes to the intensive tourism industry activities such as the construction of star hotels, restaurants and tourist complexes. This is also the reason for extensive reduction in mangrove areas shown as marsh in the Map. Here the paddy with aquaculture land use system is in conjunction with the integrated farming practices, which is a further progressive step along the way to make paddy cultivation remunerative.
In general the causes can be listed as follows,
- Non remunerative nature and other constraints of paddy cultivation.
- Huge demand for land for habitational purposes due to increasing population.
- Lack of knowledge of people about the and serious consequences of the conversion./ reclamation.
- Developmental activities making the land unsuitable for farming.
- Commercialization of cultivation in virippu fields instead of the earlier sustenance farming.
- Tourism industry and related activities.
- Proximity of transportation facilities.
- Lack of serious support from the government and society at large to the paddy farmers.
The most important and immediate impact of paddy land conversion is the adverse effect on the rice production in the State and also the socio-economic conditions of the farmers and farm workers. It is calculated that there are more than nine lakhs of farm workers in the State, who get their earning mainly from paddy cultivation. There should be a mechanism to conserve the existing paddy lands and also to implement an action programme for increasing the production and productivity of paddy by providing essential science and technology input.
The rice fields have several ecological functions also. It act as a very viable ecosystem for innumerable number of organisms. In addition to this they act as a good drainage basin, to collect the rain water and run off and slowly penetrating it in to the ground water aquifer, thus helping for ground water recharging. The loss of high productivity and nutrient export to other regimes, supporting very complex food web and acting as natural nurseries and breeding grounds of native fishes, molluscs and crustaceans which have very high nutritive and food value led to the decrease in fish catches. The destruction of mangrove ecosystem also result in the loss of wind breaking action and checking of soil erosion and the natural land building capabilities.
The loss of drainage facilities and water logging has led to the increased run off, soil erosion, and frequent floods and droughts. This also increased concentration of pollutants in the water, like the pesticide residues, which resulted in the recent fish diseases in Kuttanad, and the frequently occurring water borne diseases in the area.
The conversion of fresh water ponds, which were drinking water sources in the earlier times in many places, has led to scarcity of drinking water.
The land use changes have its own impact in contributing to the weed menace and the narrowing of natural canals leading to serious consequences on water transport, water flow and giving extra pace to the on going eutrophication of water bodies.
According to a study conducted recently in Kumarakom panchayat, the total number of species of natural vegetation has decreased considerably. A drastic reduction in the density of population in each species is also noted, especially in the case of aquatic medicinal plants like Brahmi (Bacopa monnieri). This study also reports the over-population of aquatic weeds like Eicbhorina crassipes.
The pest and invader problem is also the consequences of land use changes. The change in environmental conditions, microclimate and quality of water has resulted in the sudden out break of diseases and pests and the invasion of new exotic species of plants and animals.
Conclusion and Recommendations The land use change analysis of Pallipad, Ramankari and Kumarakom panchayats of the Kuttanad region clearly reveals the pattern and extent of land use changes, its causes and consequences. The major change is the conversion of paddy fields to non-paddy or non-agricultural purposes. The constraints in paddy cultivation and the huge demand for land for non-agricultural purposes especially for settlements due to the population pressure should be taken in to account when we formulate an action plan. The qualitative and quantitative aspects of he biophysical resources should be taken into account when we introduce a new land use pattern in the area.
Based on the information generated through this study, some management options has been formulated. But very detailed study and action plan is required for evolving an appropriate land and water management policy for the State.
The major areas of interventions required are as follows:
- Programme for identifying and solving the constraints in the paddy sector like reducing the cost of cultivation, marketing, increase in production and productivity and thus to make paddy cultivation profitable to the farmers.
- Conversion and reclamation of paddy lands should be banned; except for some specific cases, which should be done after detailed environmental impact assessment.
- The government and society should extend maximum support to farmers and farm workers in the form of both financial as well as technical assistance.
- All the activities related to paddy cultivation carried out by different agencies should be integrated and the activities of Krishi Bhavans should be restructured to make it more useful for getting the technical assistance to farmers.
- Above all the popularisation of the great progressive step in land use practices initiated by the farmers itself called the Integrated Farming which combine paddy cultivation with aquaculture in `polders’ or `padasekharams’ (earlier called as inland fish baskets) and animal husbandry, piggery, duck and chicken farming in garden land or `raised beds’ popularly known as the `bund homesteads’ should be given urgent attention. This will increase the total economic return several folds and help to overcome most of environmental problems being experienced by the region as these problems had arisen from the pattern of cultivation and its back ground facilities. [Appendix I]. Special care should be given to identify the probable impacts of these activities and the activity should be carried out only after the impact assessment.
- Make the local people aware about the serious consequences of the conversion of paddy fields. This can be done through the neighbourhood groups (NHG), schools and other NGO units working in the panchayat.
- A Biodiversity Registration Programme should be initiated by each panchayat and a detailed Biodiversity Register should be prepared, with people’s participation and with the help of technical and scientific institutions and experts in this field.
- A local `gene bank’ of all types of agricultural and wild, native and medicinal flora and fauna should be established, it is worth to mention in this connection, the conservation, protection and restoration of small sacred groves in Pallipad panchayat.
- An Ecotourism and Environment Monitoring Cell should be established immediately in Kumarakom Panchayat at a suitable location by the Panchayat Authorities giving the service of both paid and voluntary technical staffs to give proper guidance to domestic and foreign tourists.
- The tendency of riverside people to reclaim the river should be strictly banned.
- Existing fresh water ponds should be preserved to assure the self-sufficiency and sustainability in drinking water sector.
- Clean and deepen the criss-crossing canals in all the panchayats, to increase the water flow and drainage and reduce the pollution levels. An action plan and Land Policy should be prepared by each panchayats based on the study and management options. But all the options should be considered in an integrated manner and not in a fragmented manner.
- A detailed land use plan should be prepared for each panchayats in Kerala before implementing any Land and Water management activities.
- A task force should be set up by the government to look into the various aspects of land use management and to evolve a proper land use policy for Kerala.