CCHHAAPPTTEERR 22 NNAATTUURRAALL SSEETTTTIINNGG OOFF TTHHEE SSTTUUDDYY AARREEAA 51 CHAPTER 2 NATURAL SETTING OF THE STUDY AREA 2.1. THE STUDY AREA The study area lies within the basin of the Tapi River, and is located close to Yawal town in the Jalgaon District of Maharashtra. The area of interest extends from 75 031’E to 75 045’E and from 21 01’N to 21 09’N, covering an area of approximately 348 km 2. Fig. 2.1 shows the study area. The banks along this stretch of the Tapi River are subject to the processes of gullying and ravination, which have transformed a major part of the landscape into badland terrain. The location of this place being very close to the tehsil headquarter town of Yawal or Yaval, the region is also known as the Yawal Ravines. This particular stretch of the badlands shows certain distinct characteristics. Since about the year 2000, large patches of the badlands have been reclaimed for the purpose of cultivation. Yet, at the same time, certain parts of this gullied topography lie totally undisturbed and in their natural state without any human interference whatsoever. A Google Earth image provided in Fig. 2.2 demonstrates this. The area thus, is a classic example of the invasion of agriculture into a hostile terrain. For this purpose this region has been selected for the present research. In the following paragraphs the area has been described in greater detail. Fig. 2.3 and 2.4 show some of the uncultivated badlands from the study area while Fig. 2.5 and 2.6 show agriculture being practiced right on the badlands. 2.2. THE TAPI RIVER BASIN Tapi is the second largest west flowing river of Peninsular India. It has its source near Multai Reserve Forest in Betul District, Madhya Pradesh, at an elevation of 752 m ASL in the Satpura Range. The Tapi River flows for a length of 724 km from its origin to the outfall and drains an area of 65145 km 2 before emptying into the Gulf of Khambat near Surat, Gujarat. Of 52 Tapi River 53 Waghur River Fig. 2.1.The Study Area Badlands along Tapi 54 Deeply disturbed and cultivated Fairly undisturbed patches of badlands badlands Fig. 2.2. Google Earth Image of the Study Area 55 Fig. 2.3. Uncultivated Badlands Fig 2.4. Uncultivated and Undisturbed Badlands 56 57 Fig. 2.5. Agriculture on Badlands Fig. 2.6. Cultivated Badlands 58 the total catchment area of the river, nearly 80% lies in the state of Maharashtra. The basin area of Tapi is nearly 2% of the total geographical area of the country. The river basin is bound by the Satpura Range in the north, the Mahadeo Hills in the west, the Ajanta and Satmala Ranges in the south, and the Arabian Sea in the west (CWC, 2015). The Tapi River has as many as fourteen major tributaries. However, as far as the Jalgaon District is concerned the major right bank tributaries are Bhokar, Suki, Mora, Harki, Manki, Gulli and Aner while the major left bank tributaries include Purna, Bhogavati, Waghur, Girna, Bori and Panjhara. The Purna and the Girna rivers are considered as two most important left bank tributaries as they together account for nearly 45% of the total catchment area of the Tapi. The Purna originates in Betul District in the Gawilgar Hills of the Satpura Range and drains three districts of the Vidharbha region, viz. Amravati, Akola and Buldhana. The Girna has its source in the Western Ghats and drains Nasik and Jalgaon Districts (CWC, 2015). 2.3. PHYSIOGRAPHY Jalgaon exhibits a wide variety of topographical features including, hills, ridges, pediments, plains, valleys, badlands etc. Three well-marked physiographic divisions can be identified, running almost parallel to the Tapi River. These include: the high hills of the north, the Tapi valley at the centre, and the ridges and valleys of the south and southwest (Rane et al., 2008). The following subsections contain a brief account of each of these physiographic divisions. 2.3.1. The Hills of the North This mainly includes the Satpura Range. It stretches almost like a wall bordering the flank of the Tapi Valley. The central crest of the Satpura has an elevation of 609 m ASL. The peaks of Pancha Pandu in the east and Mondhiamal overlooking Yawal have elevations over 900 m ASL (Rane et al., 2008). 2.3.2. The Tapi Valley The Tapi is undoubtedly the major river of the district. The river flows through a flat and well-tilted valley. The banks rise high and are bare except where they are joined by tributaries. 59 Though the valley consists of a vast alluvial plain, gully erosion and ravination are the most striking features of the landscape. About 18 m above the river bed each bank has a double terrace. The lower one comprising yellow earth is much ravinated while the upper one coincides with the level of the country ground. It is believed that presently the Tapi River has entered into Jalgaon through a new channel. Its former channel is further north along a deep gully that joined the present channel near the village of Ainpur, east of Bhusawal (Maharastra State Gazetteers, 1962). 2.3.3. The Hills, Ridges and Valleys of the South The topography of the south is far more varied than elsewhere, comprising the valleys of rivers Purna, Waghur and Girna from east to west, as well as the Hatti and Ajanta Hills. The Hatti hills bounding the Purna valley on the east, run north-west and south-east, and pass through the south-east corner of Jalgaon. Rising gradually from the Tapi valley, they are initially low. Further east, they rise to over 1200 m ASL and finally merge with the Nagpur hills (Rane et al., 2008). The Ajanta Range, also known as Chandor or Satmala Hills, borders the entire southern part of the district. The hills show a series of basalt pinnacles and ridges. They act as a sort of boundary between Jalgaon and the Deccan tableland. The ranges are mostly bare with some scattered vegetation (Rane et al., 2008). 2.3.4. DEM and Slope Map of the Study Area A DEM of the precise study area appears in Fig. 2.7. The DEM of the study area was created by Joshi (2015) using Cartosat-1 stereo pairs (2.5 m resolution, 8 scenes) using dGPS and Leica Photogrammetry Suite 9.2. The author is grateful to the aforementioned for allowing her to use the DEM. It has a resolution of 10 m. The DEM clearly shows that within the area of interest the elevation varies between 131- 254 m ASL. The average elevation of the area is 182 m ASL. The northeastern corner of this portion of the Tapi Basin shows higher elevations than the southern part. The Tapi River flows southeast to northwest right across the centre of the study area. The valley of the Tapi River can be clearly seen in the DEM. 60 61 Fig. 2.7. DEM of the Study Area 62 Fig. 2.8. Slope Map of the Study Area The slope map of the area (Fig. 2.8), extracted from the DEM, reveals an interesting pattern. While maximum percentage of the area of interest has slope below 10 0, some of the steeper slopes ranging 10 0-20 0, and at times exceeding 25 0 occur in patches along the banks of the Tapi River. This is because of the presence of deeply gullied badlands along the banks where the slopes become steep. 2.4. GEOLOGY Most of the area is underlain by the Deccan Trap, which has been formed from the outpouring of massive amounts of lava over the greater part of Peninsular India during the Mesozoic Era. The lava is often known as ‘plateau basalt’ because of the vast basaltic plateau that it formed. Because of the stepped or terrace-like appearance of hill slopes, they are also known as ‘trap’. The volcanic trap rocks range in thickness between 30 and 300 m. The traps are compact and hard and exhibit vertical prismatic and columnar jointing. The colour varies from dark to greenish to brownish grey. The amygdaloidal variety forms the valley floors and is comparatively softer, showing greenish to purplish colour. The main minerals dominating the trap rocks include labradorite and enstatite-augite. Since the traps have cavities in them, these are filled with secondary minerals like quartz, chalcedony, agate, jasper, rock crystal, zeolites and calcite. Porphyritic basalt is also occasionally observed, showing phenocrysts of feldspars and glassy substance. Magnetite and olivine too may be seen. The basin is full of cuts and valleys in this part. In the right hand side of the basin, on the southern slopes of the Satpura Range the black soils are thick and deep. In the left part the slopes of the Sahyadris consist of dykes, red murrum soil and bare rocky outcrops (Ghatak and Ghatak, 2011). 2.5. SOIL The soils of the region are essentially a product of weathering of the underlying Deccan Trap basalt. Four broad types of soil are found in Jalgaon. They are: Deep black soils, Medium black soils, Loamy and sandy soils, and Forest soils. Deep black soils cover the talukas of Amalner, Erandol, Jalgaon, Bhusawal and Muktainagar (Edlabad). The soil has a high content of montmorillonite clay. They are neutral to alkaline. Medium black soils cover the central Tapi 63 valley and the hills of the south. They are rich in lime, fair in phosphates, poor in organic matter and nitrogen, and are alkaline.