Field Survey
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CHAPTER - III Field Survey 29 Keeping in mind the objectives of study, there were three major steps involved in Field survey. Mumbai (formerly Bombay) is one of the major and well known metropolitan, located on the western coast of India. This area being along the creek and an urban region has undergone rapid changes due to reclamation and discharge of waste resulting into depletion of mangroves. Remote Sensing and GIS technique had helped me to locate the areas where mangroves could be present. (Ref: Satellite Imagery 1). Keeping the objectives in mind, mangrove localities were selected in Mumbai region for the study. Collection and sampling of mangroves was done from different locations in Mumbai. [Map 1] 3.1 Remote Sensing and GIS Studies: Study Area: Mumbai Region (Maharashtra) [19°18'.0” N to 73°.0'.0”E] Mumbai is one of the major metropolitan cities of India. (Mapl) Methodology: Visual interpretation, digital analysis, and applying band ratio technique were used to map the area of mangroves. Differentiation between vegetation and urban community was studied through the available satellite data. Visual Interpretation, essentially involves (a) Preparation of base maps using Survey of India toposheets incorporating salient features such as low waterline, land use, village boundaries, etc., and (b) transferring the interpreted details from the satellite imagery on the base map so as to prepare the preliminary maps for ground truthing. The visual interpretation of satellite data is mainly based on the various interpretation elements such as color, pattern, texture, location, etc. Digital Analysis was done in Maplnfow software computer system. The study area was initially identified from survey of India toposheet. Required subscene area was exfracted from the entire loaded IRS IB LISS III image. 30 The training sets were checked for their pixel values in all the bands. Finally, entire area was classified using these training sets. Area calculation: The unsupervised classification of satellite imagery was analyzed, confusion matrix and classification statistics were performed and the number of pixels pertaining to each class was determined [see table 3.1]. The number of pixels pertaining to vegetation is 129042. Out of total area cover only 7.2% is occupied by vegetation. Field studies revealed that red colour in above classified satellite image coincides with mangrove vegetation patches. Although, plants other than mangroves can also grow in the vicinity of these areas, maximum mangrove patches were seen through ground truth referencing. Discussion: Remote sensing technique coupled with land survey was used to make assessment of mangrove coverage throughout Mumbai. Digital analysis for the above satellite imageries describes each class for its pixel value and area (Sq.km.). There are maximum of 15 classes in remote sensing data. It was also clear except for few classes all other were different settlement area of urban city. Water bodies in Mumbai are represented by class 1 in imagery. Class 3 to class 15 are the different settlements in Mumbai. The data revealed about 7.23% vegetation throughout Mumbai represented in class 2. [Table 3.1] With the help of this study it was possible to locate distinct patches of mangrove vegetation near Thane creek region, Elephanta Island, Mahim, Malad, and few scattered mangroves over places like Gorai, Borivali, Ghatkopar, and Vashi. The ground referenced data helped in selecting the sites for further study on mangroves with respect to bioaccumulation of persistent pollutants. 31 t.2 Field Survey and Collection: lie collection sites were categorised in mainly two parts: . Ecologically disturbed region: Thane Creek Area also called as Trans Thane >eek (TTC) and Thane-Belapur Industrial Area (TBIA) is Mumbai’s most popular ndustrial region. Besides human settlement, majority of small and large scale actories and industries are located in this region. Also, the majority of mangrove latch in Mumbai was found to be located in this region. Thane creek area was chosen or sampling. Different sites namely, Koparkhairane, Ghatkopar, Vashi, Kharghar ind Gorai showed patches of mangrove vegetation. Also Mahim [Map 1] which is 3cated at North of Mumbai shows very few scattered patches of Avicennia marina. Ecologically undisturbed area: Elephanta Island - Elephanta Island is situated bout 9km away from gateway of India and is one hour journey by boat. Tiis Island situated away from the hustle and bustle of Mumbai metropolitan life. Mangrove cover throughout the periphery of this Island makes it scenic and refreshing lace to visit. This place was selected keeping in view the comparatively cleaner nvironment for Mangroves. 'ollection and Processing of Samples: Leaf, root and sediment samples of different pecies were collected from various locations of Mumbai. Leaf and root samples were mdomly hand picked. Leaf and root sample from three to four trees from same site ^ere collected and was treated as one sampling unit. Similarly surface sediment ample was collected from each site. Thus, from each sampling station, root and leaf amples of each mangrove species along with the sediment sample of that area was ollected. These samples were washed to remove the dust and coastal mud on the (lant parts. The fresh weight and dry weight of samples was noted. These samples vere dried and crushed to fine powder and stored for extraction and analysis. 34 Mapl. Map showing location of Mumbai and sampling sites. K a ly a n . I ; £ J o g e s / iw a n Am.her,WeM7"' 'SfS' j' V ile Part J Andheri East Powail OI: Kopar Khairane W e s t • Vikhroli We^t SEA 4. ' Vile Parla East /ikhroli Juhu ; A Airport-^* Ghatkoo E a s t V a s h i K h a r W ea s s l y iS ^ t GHatkopar EasI fH an c lfa e a s ^ f* ^ ------- Bartdra W e^ g /“^v i r l a ' • ,^Govan<li E M t ChefVMour.,. M a t. S io n A n u s h a k li twofl' /' N a g a r W|V^>( *'.Shastrt Navi Mumbai ; N a g a r T r o m b a y P ra b h a D e v O a d a r E a s t W orfi "/ / ; ■■' I \ p ' Tafd^ I Harbour Butcher N h a v e is la n d {' Kal^^^devt M a ta b a r HMI j Raj EU-iavan ^ Chi^Vch Gate Major Roads B ack B a y \ Railway Line Narim an A irp o rt P o in t Cuffe Parade %S* C o la b a O y e s te r ts(and 1. Elephanta Island Z.Koparkhairane 3.Kharghar 4.Gorai S.Taloja 6.Ghatkopar 7.Vashi S.Mahim 35 Collection Sites in Mumbai: Sitel. Kharghar: Kharghar is a node of Navi Mumbai, conceived and constructed by CIDCO. It comes in the Raigad district and is developed and maintained by CIDCO. Kharghar is located on the Mumbai-Pune highway (NH 4) at a less-than-one hour drive from the heart of Mumbai city. The Area started developing in 1995 and now it boasts of number of ready and under-construction projects both in the commercial and residential segments. 36 Site2. Vashi: Unlike most other towns in the country, and in contrast to its older and larger neighbor Mumbai, Vashi was planned before being constructed, as was the city of Navi Mumbai itself Vashi was one of the first "nodes" developed by CIDCO in the city. It is one of two Navi Mumbai nodes that directly connect to Mumbai across Thane Creek (via the Mankhurd-Vashi Bridge), the other being Airoli to the north. Vashi has grown to become the commercial heart of Navi Mumbai. In recent years, Vashi has flourished due to businesses, and also more businesses moving or expanding into Vashi from Mumbai. There is continued growth of its resident and commuter population. Vashi is told to be amongst the top ten most developed zones in the Mumbai Metropolitan area. 37 Site3. Koparkhairane: Koparkhairane is a node of the city of Navi Mumbai. It was built mostly on reclaimed land by CIDCO. It is situated at a distance of 12 km from Thane railway station and 7 km from Vashi railway station. The corporate house by Reliance Industries would be located in the huge tract of land in Koparkhairane. Also located closely is Millennium Business Park (MBP) which houses quite a few software consulting companies like Patni Computer Systems, Mastek Ltd, L&T InfoTech, and L&T Control & Automation Unit. 38 Site4. Ghatkopar: Ghatkopar was a quaint village in 1920’s and 30’s. It came under Municipal Corporation of Greater Mumbai. It was not a part of Mumbai. Mumbai's limits were up to Sion only and Ghatkopar came under district Thane. Ghatkopar derived its name from the fact that it was the Khopara (Marathi for "Comer") of Western Ghats (Ghat- khopra). By 1916, Ghatkopar had developed sufficiently that a municipal council for Ghatkopar-Airol was set up. In 1945, Ghatkopar was absorbed into Greater Mumbai. The Sewri Mangrove Park was declared a protected area by the Mumbai Port Trust on January 15, 1996. It will also attempt to influence the chemical industries along the coastline to check air and water pollution by reinforcing effluent control measures. Similar efforts have been made to replant mangroves in Vikhroli-Ghatkopar in the early 90s. This was done BNHS and the Soonabai Phirojsha Godrej Foundation. The BMC also has plans for replanting mangroves in the Thane creek region. 39 SiteS. Mahim: Mahim was one of the seven islands that originally made up Mumbai. Mahim is surrounded by Bandra in the North, Arabian Sea in the West. Mahim, or Mahikawati as it was known, was the capital of Raja Bhimdev, who reigned over the region in the 13th century.