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Remote Sensing and GIS for sustainable forest management plan - A case study of bichhua forest range, Chhindwara district(M.P.)
Subhan Khan, S. Rehan Ali and M. Asif. National Institute of Science, Technology and Development Studies New Delhi-110012
Abstract
Area-wise planning needs a concerted effort to arrive at a decision for any development activity incorporating all limiting and de-limiting factors, their correlation and interaction. The basic need in any planning exercise is to have a well-defined database. For this, remote-sensing data plays an important role because of its wide coverage and unbiased representation. An attempt has been made in the paper to monitor and record data as well as to have a systematic understanding of the forest resource base. Mapping and monitoring of forest cover for effective management of Bichhua forest range along the Pench River was carried out. The study area of Bichhua range lies within the latitude range 21°37´ to 21°52´ N and longitude range 78° 59´ to 79°15´ E. It falls in the district of Chhindwara of Madhya Pradesh. Multi-date images of March and Oct/Nov 1989 and 1992 as well as multi-sensors, i.e. both Land-sat TM and IRS LISS II data, have been used for the purpose. Twenty maps on various themes were prepared for sustainable forest management of the area. Five maps were selected for this paper to understand the management and planning for development of the forest. PC ARC/INFO, ARCVIEW, GIS softwares were used to prepare the maps for monitoring of forest cover. Findings and conclusions of the study are presented in the paper. The area is largely covered by Deccan Basalt and altered gneissic rocks exposed along the river valleys, which cut through the thick basalt layers. The NW and SW parts of the range have a thicker alluvium developed by the weathering of basalt as well as the alluvium brought by the river. The central, northern and NE are more or less devoid of soil cover, which acts as recharge surface by infiltration. Hydrogeomorphologically, the area is an active zone of recharge as infiltration from streams and rivers as well as rainfall received during monsoon period is quite high. Since spatial distribution of groundwater depends on the geomorphic and hydrological set-up of the area, an indirect approach of hydrogeomorphological investigation has been followed in the study area. Paper to be presented in GIS forum, South Asia ’99 an international conference scheduled to be held during April 15-16, 1999 at Kathmandu, Nepal. Introduction Indian civilization and culture grew under the greenwood trees. Therefore, forest has a major influence on India’s social, economic, political and philosophical life and development. But the increasing rate of deforestation is causing a tremendous loss for the country. Information on loss and existence of forest covers needs to be updated. In this regard, GIS and Remote Sensing (RS) can play an important role. Not only India, but the whole world is under the threat of environmental crisis mainly due to deforestation. Under these circumstances the study of forests for their sustainable management and planning for development is essential. It is in this context, the study of Bicchua range of Chhindwara district of M.P., for preparing a working plan has been under taken. Study Area The study area Bichhua range, fall under the south forest division, which lies within the latitude range 21?37? to 21?52? N and longitude range 78?59? to 79?15? E. It lies in the district of Chhindwara of Madhya Pradesh. Bichhua range covers 45% of the Bichhua developmental block of Sausar tehsil. The area covered is 360 sq. km. The block has 147 villages which, are mostly covered by Deccan Trap basaltic rock. Objectives The aim of the exercise is to monitor and record data as well as to have a systematic understanding of the forest resource base in the area. Mapping and monitoring of forest cover for effective management of Bichhua range along the Pench river was carried out. Data Sources
The methodology adopted involves assimilation of GIS techniques by incorporating spatial (thematic maps) and non-spatial (attribute defined) data for effective utilization and management of forest resources and to conceptualize an integrated approach to create a forest information database and remote sensing utilities to arrive at an effective management model for forest offices and other concerned users and planners. Result and Dicussions i) Landuse/Land Cover The major land use/ landcover categories that are identified in Chhindwara district are shown in Table 1:
ii) Geology The oldest formations occurring in this district comprise of Archean rocks. The rocks exposed in the area are granite, pegmatite, gneiss, schist, amphibolite, quartzite, crystalline limestone, marble, silicate rocks etc. The Deccan trap flows are resting over the older lithologies (Map1). Daccan traps are of varying thickness, of basaltic and dolomitic rocks. iii) Soils Five types of soils are present in the district. Alluvial soil is commonly associated with rivers and streams. Silty soil is occurring on the bank of river Kanhan near Sausar town. Lateritic Soil is occurring in the eastern and south-western part of the district. Sandy soil is associated with Pench and Kanhan rivers. Black cotton soil is occurring in the central, northern and southern parts of the district. Soil of recent origin is developed in low-lying valleys. iv) Forest The extent of forest as in 1992 was interpreted from landsat-TM diapositive is given in Map 2. The total forest broadly classified into two categories-dense forest and degraded forest. Except for a few isolated patches, dense forest is restricted to eastern and western parts of the range. Degraded forest occurs both within the dense forested areas and areas close to other landuse categories. The sand exposure has been demarcated to get an idea of pre-monsoon retreat of water boundary of the reservoir. From this, it has been calculated that 40% of the reservoir gets devoid of water during summer months. All along the reservoir, besides sand, forest is largely degraded because of main hamper tree growth Due to near surface water table conditions. v) Hydrogeomorphology Water resources have an intimate relationship with forests. It gives integrated information, which is essential for any planning for developmental activities. The study area is mostly Deccan trap area with extensive exposure of plateau basalt, which has been modified by the erosive activity of numerous streams and a few perenial rivers. Under the structural origin class, the area has been further classified into three classes, namely, plateau top area, highly dissected basaltic plateau and moderately dissected basaltic plateau, which are self-explanatory (Map 3). The dissection intensity is directly proportional to the relief, slope and drainage density. The more the number of streams, the more is the dissection of the topography. The denudational origin category has been subdivided into four types: Denudational hill, Pediment, Mesa and Butte. The denudational hill is more or less restricted to the south-west part of the range. A continuous stretch of pediment development is encompassing the moderately dissected areas at a low attitude. The Mesa and Butte are restricted close to the top of the northern plateau, which signifies that they are the remnant of the same plateau top. A few lineaments/ joints faults have been demarcated on the basis of the interpretation of images. Some local nalas and streams follow these weaker zones.
Hydrogeomorphologically, the area is an active zone of recharge, as infiltration from streams and rivers as well as rainfall received during monsoon period is quite high. As the range covers an extensive forest area, groundwater uptake by the trees is also high. The highly dissected basaltic plateau and the pediment are better groundwater exploration as development sites compared to any other landform categories (Map 3). As the spatial distribution of groundwater depends on the geomorphic and hydrological set-up of the area, an indirect approach of hydrogeomorphological investigation has been followed. vi) Water Yield In the study area the yield of water varies from N.A. to 1000 gallons/h (Map 4). It shows greater yield of water over a smaller capturing area and smaller yield over a large area. Forest management can alter the water budget of the watershed by modifying the hydrologic processes involved therein. The studies conducted throughout the world have demonstrated that the water yield increases on implementation of upstream forest management practices. The increased water yield may be caused in part by changes in one or more of the following hydrologic factors as a result of forest management:
Based on the results of various studies, efforts have been made to quantify water yield from various land covers in terms of rainfall runoff ratio. In general, the results indicate that vegetation management has the potential for increasing water yield from upstream catchments. The practices of partial cutting/thinning and forest conversion seem to be promising for improves water yield without causing appreciate soil erosion and at the same time maintaining substantial yields of forest products. In general, the water yield in hilly regions from natural, ill managed or untreated agricultural lands appears to vary from 10 to 45% of animal rainfall, whereas in well managed or treated agricultural lands, i.e. lands on which soil conservation measures have been adopted it could vary from 4 to 34% of animal rainfall, depending upon the type of conservation measures. In the case of forested watersheds, water yield as percentage of rainfall to runoff appears to vary from 1 to 43 % in hilly regions. vii) Drainage All the three rivers basins of the area are having bifurcation ratio values between 4 and 6, which implies that the area is more or less homogeneous with little variation due to local modification of lithological changes which control the intensity of the development of drainage patterns.(Map 4) Drainage densities for the three basins are somewhat different. Kulbhera basin is having subdendritic pattern, Sovna basin has subdendritic to dendritic pattern, except SW part of the area, where it marks parallel drainage. Pench river basin have dendritic pattern. Table indicates the frequency values of the three rivers (no. of streams divided by area. The major part of the range drams through pench river and its tributaries, showing a higher drainage density, because the area it drains largely falls under the highly dissected plateau and pediment area.
In the western part of the reservoir, the problem of waterlogging is prevalent more extensively after the monsoon rain, which submerges a large part of the forested area and degradation of the forest and resources takes place. An urgent decision is to put a contour bund to restrict the flooding of water in this low lying area. viii) Morphometic analysis The area is drained by numerous local nadis and nalas (most of them are non perennial) which ultimately merge either with Kanhan or pench, river basin and Kulbhera river basin, whereas only Sovna nadi basin falls under the Kanhan watershed in this range. A detailed account of the drainage basin is given in Table.
ix) Assessment of Water Potential The recharge potential for Bichhua Development block has been calculated to be 67.20 million cubic meters/year (MCM) and the present animal draft of underground water is meagre (6.91), which is about 9% of the potential. The rest 91% is still to be tapped from. This data, it can be said that the area have enough water potential and there is ample scope to plan deep tubewells for both irrigation and drinking purposes. x) Hydro-geological investigations For healthy growth of a forest, database regarding underground water is essential to plan of forestation work. The available data has been collected villagewise and a spatial database has been generated with the help of GIS software PC Arc/Info, from which any information, be it a village, compartment, block or even coupe, can be linked and retrieved. The data was collected by Public Health Engineering (P.H.E), Bichhua, and the 1991-92 data has been entered in the database. From the borehole data, the general strata found in this range have 0 to 6 m overburden (soil horizon), below that up to 50-60 m hardrock (block fractured basaltic) and below that sandy and clay material. The village-wise database has information regarding total number of pumps in the village, initial water table during drilling, present pre-monsoon and post-monsoon water table, peak summer W.T., drawdown both pre and post-monsoon as well as peak summer condition and yield (i.e. discharge) in gallons per hour. In pre-monsoon period, 25 villages comprising about 40% of the area largely in the north, west and southern parts have W.T. between 10 and 15 m. There are 19 villages marking four patches have W.T. in the range 16-20 m. Most of this category (13 out of 19) villages are in the central part and cover the moderately dissected plateau land which shows less fracture and weathering. The north-central and west-central part covers 17 villages having W.T. in the range 21-25 m, as the area is more close to the northern plateau top area and runoff is high because of steep slope, thereby reducing the recharge by infiltration. In the post-monsoon period, on an average, there has been rise of water table by 5 m except in a few villages. Out of 25 villages having 10-15 m W.T. in pre-monsoon period, only 10 villages shows rise of water table by 5 m. Ten villages show no change in Water Table position, it remained in the 10-15 m range. Map 6 shows data on fluctuations of Water Table. Overall, the villages show fluctuations ranging from 1 to 7 m. The western part comprising 17 villages shows fluctuation of 5 mts which is conspicuous. One village shows a fluctuation of 1m and four village that of 2 m in the central part. Nine villages are in the 3 m category, sixteen in 4 m range and 11 in 7 , fluctuation range. There are three river basins in the region having a bifurcation ratio value between 4 and 6 indicating that the area is more or less homogeneous which is very helpful in preparing a working plan for a forest. The studies have indicated that a reduction in the densities of forest over storeys and other vegetative cover types can increase water yield. However, it is difficult to predict the response of vegetation management on water yield, as the result obtained in various studies have been of diverse nature and suggest complexity of the hydrologic factors involved. The area is largely covered by Deccan basalt and altered gneissic rocks exposed along the river valleys which cut through the thick basalt layers. The NW and SW parts of the range have a thicker alluvium developed by the weathering of basalt as well as the alluvium brought by the river. The central, northern, and NE are more or less devoid of soil cover, which acts as a recharge surface by infiltration. The recharge potential for Bichhua Development Block has been calculated to be 67.20 million cubic meters/year and the present annual draft of underground is meagre (6.91) about 90% of the potential, the 91% is still to be tapped. From the borehole data, the general strata found have 0-6 meters overburden (soil horizon), below that upto 50-60 meters hardrock (black fractured basaltic rock), and below that sandy and clay material. The approach to spatial analysis involves the evaluation of natural resources in terms of their potential, limitations, etc. and assessment of felt needs and priorities of the local people. Mainly map data were used for natural resources analysis and socio-economic data for need aspect analysis. Since the data sets were available in different forms, to standardize them, these were reformatted and suitably converted to a form amenable for data storage in GIS. Conclusions Though the study has been carried out only on a small forest range (Bichhua) for formulation of a working plan, the process can be used for the whole forest area. Efforts are needed to be made to establish acceptable compromised solutions for deciding the amount of forest vegetation to be treated, including the type of treatment without substantially reducing the yields of the forest produce. Amenities are available in only 7-8 out of 32 villages. To create an efficient forest management, adequate amenities need to be provided in a large number of villages. Strong precautionary measures need to be taken to protect rapid devastation of the forestland to stop the agents at work. Studies need to be carried out to evaluate the effects of vegetation management, specifically partial cutting/thinning and forest conversion on water yield, as the same has a great potential to increase water supplies for downstream users. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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