Monitoring lagoon coast dynamics with g-tech

Monitoring lagoon coast dynamics with g-tech

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Monitoring and mediating the negative consequences of land use / land cover of coastal areas while sustaining the production of essential resources has become a major priority of researchers and policymakers around the world. This article monitors the landuse / landcover dynamics of the Chilika coast in Orissa

Coastal areas have been important for human beings since the beginning of time. Building of coastal zone management platform is important to control the natural resources and monitor the coastal land use changes. LULC encompasses the most important environmental concerns of population, including climate change, loss of biodiversity and pollution of water, soil and air. Remote sensing, GIS and DGPS can be used to monitor coastal land use changes. This article monitors the landuse / landcover dynamics of the Chilika coast from 1999 to 2013 using satellite image of IRS P6 LISS III and Quick Bird. The result of change detection shows a significant decrease of agriculture area and increase in settlement area from the year 1999 to year 2013. Settlement expansion has been creating an alarming situation in all countries of the world. High rate of population growth has led to serious land use problems such as loss of agricultural land and vegetation area. It also affects coastal area erosion. Spatial information from the remote sensing satellites plays a vital role in analysis of changing land use / land cover pattern. Monitoring and mediating the negative consequences of LULC while sustaining the production of essential resources has therefore become a major priority of researchers and policymakers around the world.

INTRODUCTION

Coastline, defined as the line of contact between land and water surface and, one of the most unique features on the earth’s surface, has a dynamic nature. Coastal landuse / landcover mapping and coastal change detection are critical for safe navigation, coastal resource management, coastal environmental protection, and sustainable coastal development and planning. Changes in the shape of coastline affect the environment of the coastal zone. These may be caused by natural processes and/or human activities. Coastal regions are the most important and intensely used areas settled by humans in the world. Coastal resources have been under intensive pressure throughout history and this situation will continue. As time goes by, the demands to coastal areas which have fertile potential are increasing and tourism also cause destructions which will never recycle.

Future changes in land use in coastal zones will be dominated by the effects of climate change. The major effect of climate change on the coastal zone will be due to increasing sea level which, in combination with possible increases in the frequency and intensity of storms, will bring about: change in patterns of erosion and sedimentation, increased risk of flooding, change in the distribution and types of coastal habitats.These physical changes in the coastal zone will occur alongside, and interact with, a variety of human impacts and drivers of change. Agricultural policy reform, and changes in production in response to this and to climate change, will alter coastal landscapes as well as sediment and nutrient inputs into coastal waters.

Most of the human settlements along the coastal Chilika are located along the estuaries and deltas. In India, mangrove forests have traditionally been used for a variety of purposes like, boat-building, tannin extraction, firewood, stakes for fishing, fodder, fertilizer etc. Anthropogenic activities eliminate the protection provided by mangroves to the coastal and the inland ecosystems, further disturbing wildlife habitat and biodiversity. The factors that severely affect mangrove ecosystems are 1) diminishing fresh water inflow, 2) increasing salinity and, 3) nutrient supply (MOEF, 1987). Prawn culture in the mangroves of coastal area of Chilika lagoon (Odisha) is of great concern to different environmental groups in India. In general, the Indian mangroves are considered as degraded (Krishnamoorthy, 1995).

A coastal management mechanism must be established to prevent these problems before appearing. Therefore, developing coastal management policies and strategies are important to prevent the harmful effects of environmental changes. For this, information technologies such as GIS, remote sensing (RS), and internet are important. These information technologies considerably support managerial decision-making process to manage spatial information. GIS integrates various information resources for coastal regions’ management (Uckaç, 1998). Internet has also become a current topic recently. Internet can be used as the most efficient communication and management tool because of opportunities which internet provides for accessing and sharing information.

COASTAL ZONE MANAGEMENT

Coastal zone management is a resource management process for sustainable development in coastal regions. The aim of coastal zone management is to build a management system which permits integrated politics and strategies of public and local authorities. Monitoring platform has to be established for determining coastal land use changes. The aim of monitoring works is to protect natural environment for using public benefit. Coastal regions have to be undertaken as a whole because of they have to cover both land and sea. Different working disciplines have to work together for this. For example, some people may want to evaluate water quality, depending on measurements. A coastal zone management platform analyses different data sets and determine current changes.
 
GIS and Internet for coastal zone management

With  the  help  of  the  systems  which  can  manage  spatial  information,  the  support  to decision making process can be provided. Management mechanism solves questions like what-where-when. GIS has become more than a program since GIS is a visual and analytical tool and helps the users to understand or visualise this information in a map form and enables the users to manage this information interactively and analytically. It can be thought that using GIS technologies on coastal management is an advanced working area. Supporting a sustainable life and eliminating harmful materials can be possible with GIS query and analysis techniques. The system provides the integration of various information sources and enables common solutions for discordant decision-making mechanism.
 
STUDY AREA

The study area is the coastal Chilika, around 8 km from shoreline towards Chilika Lake in the Puri district of Odisha. It is situated between 85o 9’52.259”E to 85o 40’10.413”E longitude and 19o.27’40.447”Nto 19o.46’48.987”N latitude. The total area of the study is 47290ha.

Monitoring lagoon coast dynamics for Chilika Lake using GIS and Remote Sensing

Fig -1 Location map of study area

OBJECTIVE
The objective of the study is to describe the changes in coastal area, relate the changes to patterns of natural and human activities and make inferences about relationship between landuse / landcover changes and its succession and distribution.

DATABASE & METHODOLOGY
The data used in the study is the Survey of India toposheet 1:50,000 scale and the IRS P6 LISS III of the year 1999 and the IRS series Resourcesat 2 and Quickbird satellite image of the year 2013.

Image Interpretation and Analysis
The desired information can be extracted from the above data products through visual interpretation and digital image processing techniques. Both visual and digital image analysis techniques are complementary to each other. For large areas and spectrally homogenous scenes, digital image processing techniques may provide a quick and cost effective means of image analysis. For smaller areas and spectrally heterogeneous scenes, visual interpretation method is more suitable. However, in order to bring out the subtle variation and quantitative measurements, it is essential to perform the digital image processing techniques since classification of digital data can be done through computers with help of image processing software.

Visual interpretation techniques
Visual interpretation of remote sensing images for extracting desired information could be achieved in an efficient and effective manner by using several basic interpretation keys (or) elements (Floyd F. Sabins Jr. 1987). The basic interpretation keys are i) tone ii) texture iii) pattern iv) shape v) size and vi) location or association. All these interpretation elements are qualitative attributes and they are subjective depending on the experience and personal bias of an interpreter.

Digital image processing
The availability of remotely sensed data in digital form helps in carrying out digital image processing with aid of ERDAS-imagine image processing software. The digital image processing techniques provide flexibility in data handling due to the fact that the digital data can be numerically manipulated by using an equation (or) set of equations to get the desired details in the graphic display (or) pictorial form for further analysis ( Lillesand TM and Kiefer RW, 1987). There are many procedures/methods available for image data manipulation they can be broadly grouped into 3 categories viz. 1) image rectification and restoration also called preprocessing 2) image enhancement and 3) image classification.

Ground truthing can also be done with DGPS instrument for final classification verification.

DISCUSSION

In the year 1999, the maximum area is the agricultural land after water body i.e. 27% of the total area. Then swampy area is 16% and next highest area is the land without scrub. Here, shrimp farming is started but only 4% of the total area.

 

Landuse / Landcover map of Chilika Lake lagoon for 1999

Fig – 2 Landuse / Landcover map of the year 1999

Landuse / Landcover area of Chilika Lake lagoon for 1999

Fig – 3 Landuse / Landcover area diagram of the year 1999


In the year 2013, the maximum area is the agricultural land after water body i.e. 19.6% of the total area. Then land without scrub area is 13% and the next highest area is the shrimp farming i.e. 12.5%. Between 1999 and 2013, shrimp farming area increased to 8% of the total area. Shrimp farming has developed near the Chilika coast in the swampy areas, so the swampy land drastically decreased between the year 1999 and 2013. It has direct relation to population growth. The settlement area increased in the year 2013 up to 2.2% over 1999. The agricultural land also decreased up to 7.4% because of settlement area increasing on the agricultural land. Water body area also decreased because of human pressure.

Landuse / Landcover map of Chilika Lake lagoon for 2013

Fig – 4 Landuse / Landcover map of the year 2013

Landuse / Landcover area of Chilika Lake lagoon for 2013

Fig – 5 Landuse / Landcover area diagram of the year 2013

Chilika lagoon is a brackish water lake and it is also one of the Ramsar sites of India. It is connected with Bay of Bengal through inlets and also 52 rivers / rivulets also connected from Mahanadi System and Western catchment of Chilika. It is a mix of fresh and marine water lake. In the year 1999, the lagoon had one inlet at end of the outer channel, but in the year 2000 another man-made inlet was opened and in 2008, another natural inlet opened, 15 km from the first inlet which existed in the year 1999. The first inlet was totally closed and the new inlets have shifted 1 km towards north from its actual place because of long shore transport.

Percentage (%) Landuse / Landcover area change of Chilika Lake lagoon from 1999 - 2013

Fig – 6 Landuse / Landcover change of the year 1999 &2013

CONCLUSION
Further  studies are suggested  to  monitor  the  coastal  changes  of  the  study  area. It is recommended to collect high resolution satellite images of old and new data in order to monitor temporal changes in this area. Considering the cost and time constraint, as well as the desirable accuracy of the data generated from the mapping process, digital photogrammetric approach may be most suitable to meet the objective.

The protection of natural balance on the coastal area and shore lines, the analysis of the land  ownerships  and  the  decisions  of planning  associated  with  these  studies  can  be realised with GIS technologies. With the helping of web technology, decision making and future planning can be possible if the data is accurate and up to date. Web-based system can also incorporate up- to-date and real-time information and make overlapping inter-disciplinary information possible to manage coastal region. In monitoring the coastal regions that have a rapid changing characteristic, analysing land  use  changes  with  information  technology  is  far  more  easy and  fast  than  the classical monitoring methods, especially for administrators.

REFERENCES
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