Application of Remote Sensing in Spatial and Temporal
Analysis of Coastal Wetland Vulnerability - A Case Study on Samang Lake of Orissa
P. Kumar, M. K. Sanabada and P. R. Mohanty
Orissa Remote Sensing Application Centre
Post Box - 119, Bhubaneswar - 751 001, India
Abstract
The coastal wetlands have a significant role in our ecosystem. They have multiple use values which become obscured by wrong assessment or adoption of development measures. It has been long felt that integrated resource appraisal - in terms of spatial and temporal context, assessment and evaluation of various structural components of wetland system and suggestive use options are prime requisite for developing the wetland. Samang Lake near puri lying stage. Heavy silt deposition, growing urbanization and drainage routing etc make the lakes as a sink and vulnerable to a single landuse practice i.e agriculture. Multidate and multi platform data like 1973 and 1990 aerial photographs, Landsat-5 TM (FCC) of 1986 and IRS IB data of 1993 have been studied in generating various spatial information about the lake. Various landuse / landcover types have been delineated and analysed in terms of their geomorphic setup. Shrinkage of water spread area is also assessed from temporal data. Hydromorphological classification of the wetland is also attempted.
The study reveals potentially of pace/air borne data in resource appraisal of vulnerable wetlands and assessment of several variables of the structural elements of the lake. The growing agricultural practice and chocking due to urbanization and drainage routing are the major concern now and to be dealt with care while planning developmental measures.
Introduction
Depletion of wetland resources is a worldwide phenomenon and the growing concern to conserve them and establishing values on the vulnerable wetlands in respect of preservation, conservation, utilization or development purposes need continuous information in both historical and real time terms. Study on changes occurred due to natural anthropogenic causes is also very essential in detecting, recognizing and evaluating the linkages of the biotic and abiotic components. Keeping aside the advantages of the conventional data source, the remotely sensed data can be used to span temporal and spatial scales using multi sensor and multitemporal data sets. In the present study both aerial and space borne data have been used to present study both aerial and space borne data have been used to generate most of the thematic information in spatial and temporal context.
Study Area
Samang Lake of Orissa lies in the lower Mahanadi delta having latitudes 1900 49' to 190 52' N and longitude 850 47' to 850 51' E which is 1 km on the northern side of the Puri town and 3.5 km from the coast of Bay of Bengal. The lake is connected tot eh Bay of Bengal by a tidal outlet called Mangala nala. The area experiences a humid tropical climate. Interestingly the daily mean temperature of the area also rises from 26.890C (1936-40) to 27.270C (1981-85). Average annual rainfall recorded is around 1372.6mm at Puri.
Methodology
Data used :
Aerial photographs pertaining to 1973 adn1990 in 1:29, 000 and 1:8,000 scales and LANDST-5 TM (FCC) data(18.2.1986) as well as IRS IB LISS-II data (24.2.1993) have been studies in generating various spatial information about the lake. Survey of India topographic sheet (surveyed in 1972-73) is used as the base map.
Data analysis :
All the aerial as well as satellite data have been visually analysed using field validated interpretation key. Thematic information on geomorphology, hydrology, water spread and landuse types have been generated. Interpreted results were transferred to the base map and registered using the optical pantograph. Finally areas of different landuse units have been calculated.
