PART I

CHAPTER - I

INTRODUCTION CHAPTER I

Introduction

Climatology is a science that seeks to describe and explain the nature of climate, why it differs from place to place and how it is related to the other elements of natural environment. Climatology involves the collection and interpretation of observed weather data for developing generalization and also for testing theories. It necessitates instrumental and statistical techniques and hence is regarded as a study of causal system based on mathematical structure.

The 'geographical climatology1, as the name suggests is the combination of climatology as physical science and geography as the field science with special reference to biotic life in relation to space and time. Climatology in its investigation of spatial relationship makes abundant use of tools of geography and mathematical models. However, these mathematical models, when applied to large area may not explain completely all the observed facts of climate. It is the function of the geographical climatology to describe and interpret the actual facts of climate (Stringer, 1972). The usual method of presenting these facts is in the form of maps or verbal 2

statements or in the form of statistical tables from which the maps or verbal statements are derived. Geographical climatology considers atmosphere as an entity with its movement and momentum as are affected by geographic factors such as latitude, altitude, topography and distribution of land and i/ater.

It has been a long felt need for the geographers and the students of climatology in getting coherent information about the spatial and temporal behaviour of climatic elements for the state of . The geographical disposition of Maharashtra in has a great bearing on the climatological studies of the entire sub-continent. The burst of monsoon over the coast, is of great significance to the people of Deccan plateau, Central India and over northern India as a whole; rather than the initiation of monsoon arrival, along the coast. Geographical climatology, as it primarily deals with the regional distribution of climatic elements, has been restricted in this present study to the two distinct geographical units of Maharashtra, the coast (Konkan) and the plateau (Desh). The study of geographical climatology offers a helpful approach In planning the agricultural operations, developing resort centers and for planning and executing various irrigation projects etc.

Objectives of the Present study :

The primary aim of the study is to map, describe and interpret the various climatic elements in relation to the climate of Maharashtra with a geographical background.

Rainfall analysis has been emphasised amongst all the climatic elements. The rainfall data is analysed with an altogether different Astro-climatological approach. Astro- cliiaatology deals with the spatial and temporal distribution of primary and derived climatic element* in correlation with the occurrence of the various astronomical phenomena viz. the a. transit of the sun into the signs of zodiac, solar transits in the various fixed star constellations (Nakshatras) the conduction of the inner planets mercury and Venus with the sun and their setting durations phases of the moon etc.

An investigation of the climatic appliances related t water budget, the moisture indices has been stressed in greater length;as these aspects find a very little place in the work done so far, in relation to Maharashtra, In additic some aspects of applied climatology, especially the comfort 4

zones and architectural layout for some stations in Maharashtra have been dealt with.

previous work done and the present need s

Most of the published work in the subject, namely the distribution of climatic elements, climatic classification based on Koppen and Thornthwaite systems, is related to India as a whole. The climatological investigations with special reference to Maharashtra are rare; mention may, however, be made to a few studies in which some attention has been paid to this theme and region. Prominent amongst these are the papers by Raghavendra and by C.R.V. Raman. Raghavendra has studied the trends and periodicities of rainfall in Maharashtra and applied various fcfcc statistical parameters to rainfall analysis; while C.V. Raman's investigations are related to the dates of commencement of sowing rains in Maharashtra.

The publication in the series "State Climatological Summaries"; the "Climate of Maharashtra State" is of formative type and concerns mainly with the facts and information about the climatic elements. A detailed study, on the climatological aspects of Maharashtra with special emphasis to astro- -climatology has been a neglected topic in the existing 5

literature on climatology.

Although the statistical information about precipita­ tion data is available on daily basis over a large number of years at various Taluka places there is comparatively paucity of data on temperature which is available for some district places, and that too for a comparative short period. This has always resulted in confining the climatologlcal studies, especially dealing with climatic classification to district places only. Constraints of similar nature have limited the scope of deliberations related to applied climatology. The computation of daily rainfall data on Naks hatr awls e basis In this study therefore has been restricted primarily at the district level. The present approach of the Nakshatrawise analysis of the,rainfall will, in future, create a new opening for the estimation and evaluation of the minor regional variations in the precipitation characteristics at Taluka level.

The basic climatic data used in this work consists of the monthly and yearly rainfall figures for the various district places over a period of 70 years from 1901 to 1970 and the temperature and humidity data available for the limited G

number of years during this period. This data was supplied by Indian Meterological Department, Pune; while the old issues of Gazetteer part III from 1948 to 1970,were the main source of the daily rainfall data.

Proposed outline of the work :

The study of geographical climatology has been organized into three sections x

(i) Physical setting (ii) Spatial distribution of various cJ-imatic elements , and (ill) Climates of Maharashtra and some aspects of applied climatology.

The first section describes briefly the physical setting, soil types and natural vegetation.

The second part on basic climatic elements is mostly devoted to spatial and temporal variations in the distribution of climatic elements. The Chapter three in this section mainly concerns with the distribution of primary climatic elements such as temperature, pressure, relative humidity and cloud amount. These elements in the original and in derived forms are illustrated by graphs and maps. In addition to 7

Isothermal maps for different seasons the hysteresis curves of relative temperature have been dram for various places, in order to bring out the influence of continentallty on the yearly march of the seasons. The average pressure conditions for various seasons and the distribution of relative humidity at 8.30 and 17.30 hours during the four seasons of the year are discussed with the help of maps. Seasonal and diurnal variations in the wind direction influencing the local weather condition are studied \d.th the illustrations from the wind ros e maps.

This is followed by the investigations of the main rainfall characteristics and the temporal variations of the dry and wet years during the last 70 ye£.rs. An attempt is also made to examine the drought and excessive rainfall years and to find out the probability of occurrence of droughts in the state. The next chapter of this section has been specially devoted to ITakshatrawise rainfall analysis, in Indian farmer is mostly habituated to plan his agricultural activities with the rainfall incidents in various Hakshutras. The division of a solar yetr into the various Nakshatra periods has a special astronomical connotation and therefore an attempt in search of 8

the Interrelationship between the rainfall amounts and various Nakshatras is made. Rainfall distribution in the fourteen Nakshatras from Kruttika to Vishakha according to the Hindu Calender forms the basis of the present study on the rainfall analysis. This analysis of rainfall data is relevant to 28 parts in all of the fourteen Nakshatras? as a Nakshatra period is further divided each into two parts I and II. Rainfall averages and variability have bean calculated Nskshatrawise and represented by means of naps. A matrix of simple eorrelatlonfl between the 28 input variables Tor each of the 26 district places has been evaluated by using the eomptttorf st 2.I.F.R. Bombay, and Regional Computer Centre, Puna. This matrix has been used to investigate the correlation between the various distinct grou^3 of variables which are significant at different levels of Ji^iiricance. This analysis further concentrates for a search of those BTakshatra groups which will be useful from the point of long range forcasting of rainfall.

The third section focust&* on climates of the State and some aspects of Applied Climatology. The chapter six is mainly devoted to climatic classification and it deals with a critical account of the application of the various schemes putforth by Koppan, Lang, de-Mortonne, Miller and Thomthwaite 3

for dassifing the climates. Considering further the importance of heat and moisture factors in eco-climatic studies, an attempt is made to examplify how the Thomthwaite's scheme based on the concept of the potential evapotranspiration meets the full ecological requirements of climatic classification with reference to Maharashtra. Water balance charts for 26 district places have been used to delimit the areas of water surplus and deficit in the State.

Deliberations related to 'discomfort indices' are confined to the last chapter in this section. The analysis of discomfort indices, both for morning as well as for evening is made in order to recognize suitability of climates for human comfort. In this very chapter, the architectural layout in relation to the varied climatic conditions for the four selected stations in the state has been studied.

The last part deals with the findings and conclusions mainly based on facts discussed previously. It is hoped that the present work will lead to the general advancement of knowledge in the fields of applied climatology and forcasting of weather. The final detection of closed groups of Nakshatras and the results of ,T' test for these groups are likely to be 10

beneficial as an additional instrument in the branch of long range forcasting of rainfall during the forth coming monsoon season in India.

The study of seasonal variations in moisture regime as well as water deficiency for a particular place will be useful for proper planning in the administration of supplementary irrigation schedules, and the execution of the medium and large scale irrigation programmes of the state especially for the drought prone areas.

These findings will be of fundamental importance to all those who are engaged in climatological services, such as the long range and short range for casts and to those dealing with agricultural activities, irrigation needs and water supply etc. A number of illustrations in the form of maps and charts will be useful to geographers and to those interested in the academic and applied aspects of the climatology of Maharashtra. This approach of" peeping through the window of Astroclimatology in the search of vast reserves of climatological knowledge may find a new opening towards the betterment of mankind in future. PART I

CHAPTER II

MAHARASHTRA i INTRODUCTION 11

CHAPTER II

Maharashtra

Introduction

The Maharashtra as is today was bom as a State within the Indian Union on the First of May 1960. It covers a major part of the western portion of peninsular India and represents the third largest state of the Indian Republic both in area and total population. It is a region of physical homogeneity and cultural identity.

o • Geographically the state extends from 15 45 North to 22°l' North latitudes and 72°'45' East to 80°45' East longitudes. Maharashtra has Gujrat to its north-west, Madhya Pradesh to its north and east, and the states of , and Andhra Pradesh to its south and southeast respectively.

Size :

The western border along the Arabian sea is about 825 km; 1725 km in the north bounded by the states of Gujrat and Madhya Pradesh; 750 km in the east bounded also by Madhya Pradesh, and 1875 km in the south bounded by Andhra Pradesh and Karnataka; comprising the total land area of 3.06,345 sq.km. 12

Administration t

For the purpose of administration the 26 districts of the Maharashtra state have been grouped into four commissioners division viz. Bombay, Pune, Aurangabad and Nagpur with Bombay as the state Capital. Geographically the area has a distinct physical aspect.

From May Is*, 1981, the state comprises of 28 districts. The two newly added districts are Sindhudurg and Jalna. The district of Sindhudurg consists of the southern portion of the Ratnagiri district and a few number of villages from Kolhapur district. The district of Jalna was formerly a part of the district of Aurangabad. Similarly, the district, formerly known as Kolaba is now renamed officially as 'Raigarh1 after/name of the well known FORT RAIGARH.

However, the map of Maharashtra with preexisting 26 districts boundry forms the basis of the present study map. no. 2.1.

Historical Background J

Maharashtra has a magnificent historic personality. The present state was a part of the Mourya Empire (325 B.C.-125B.C. < or \- x [/) < ft < I 2•1 13

till the rise of Satvahanas. The history of the fourth century is obscured but it is known that the region was ruled over by small dynasties like the AbhlraJ and Trikutakas.

The next three centuries witnessed a mighty struggle between Chalukyas and the Rashtrakutas. The decline of Chalukyas marked the end of Hindu period. Between the fourteen and sixteen centuries the Bahamanis gave rise to small independent Muslim kingships which disintegrated with the rise of power. By the middle of 18th century when Maratha power was at its zenith, the ruled over Maharashtra and the beglnlng of the 19th century the region passed into the hands of British till the Independence of India 1947.

Geology

The major natural regions of the earth are climatic in character. But the most satisfactory basis for the sub-division of these regions is the landform types. A survey of the geological past of Maharashtra is valuable from this point of view.

The starting point In the study of geology and geography of India is the well known three fold divisions of India into 14

Deccan Peninsula, the Indo Gangetlc basin and the Himalayan arc. In India there are two older periods, without any definitely recognisable remains of life known as the Archaean and the Purana constituting Precambrian Era. The Dravidian and the Aryan are the two younger rock formations containing abundant remains of life. The Dravadian group contains rock units from the Cambrian to the middle Carboniferous; whereas the Aryan group contains all strata from the upper Carboniferous to the present day.

Precambrian Era :

Precambrians, is generally divided into Archaean and Purana. The later being further sub-divided into the cuddapahs and the vindhyans. The Deccan Peninsula is one of the most ancient and stable parts of the earth. The first physiographic shape of the Peninsula seems to have been that of the vast plateau at the northern end of which stood the Aravalli mountains and beyond them lay the primeval seas. Holland, T.H. (1907). Subsequently the plateau became a part of the Gondwana land that extended in the southern hemisphere from South America to the Malaya Archipelago. The Archaean rocks, originating from the processes of mechanical sedimentation, later folded into great Jo

mountain masses and subsequently denuded to a base level of erosion, form the basal complex of this region. All the precambrian rocks are unfosslliferous and comprise gneisses, granite, sandstone and schists. These formations carry well marked bands of iron-ore. These rocks are found at (1) Chandrapur district, (2) Extreme eastern talukas of Nanded district and (3) The Kankauli, Malvan Sawantwadl talukas of the Ratnagiri district (Slndhudurg).

The gneiss, granite complex cf Archaeans have accumulated in their tectonic depressions the sediments later metamorphosed into Dharvarian rocks which contain very valuable raireral and ore deposits such as granulites, dolomite marble mica.

The Purana Era :

The lower palaeozoic period is known as Purana period in the Indian geology and is represented by rocks cf the Cuddapah and Vindhyan systems.

The rocks of the Cuddapah system are local3.y known as Kaladgi series. They are found in patches, near Malwan and around Ramghat and in the valleys of the Vedganga and the Dudhganga in the Ajra taluka of the district Kolhapur. These 1G

rocks are composed of quartzites, shales and limestones. The rocks of Vindhyan system are highly localized and not very significant in the state.

The Dravidian Era :

The next geological era, the Dravidian (upper palaeozoic) is completely unrepresented in Maharashtra.

The Aryan Era :

The rocks of the next, the Aryan era, commencing vith the Upper Carboniferous period, are known as the Gondawana system; and are entirely composed of fluviatile and lacustrine deposits. This has given rise to thick seams of coal lnterbedded within these rocks.

The end of the Gondwana period (mesozoic era) and the begining of the Tertiary Era were marked by stupendous changes in the physiography of the land. It was a period of intense volcanic activity resulted by the outpouring of enormous lava flows which spread over vast areas of western, central and southern India. The lava spread out far and wide as nearly horizontal sheets. Eventually it was converted into a volcanic plateau over 1800 metres in height occupying 1,00,000 sq.km area. 17

The lava flows appear to have been erupted sub-aerially (Krlshnan, M.S., 1960) as there are no evidences of subaqueous deposition. Because of their tendency to form flat topped plateau like features and their dominantly basaltic composition. Such lavas are called plateau basalts. The flows are called traps because of the step like or terraced appearance of their outcrops.

The trap country is characterised by flat top hills and step like terraces. This topography is a result of the variation in the hardness of the different flows. The flows may alternate with each other, or they may be separated by thin beds of volcanic ash. These ash beds are particularly well seen in the upper parts of trap around Bombay, Pune and .

This basaltic plateau, with the 1000 m fault escarpment to its western margin is the principal element in the litho- logical formation of the region. The post trappean fault possibly associated with the 'Continental Drift' appears to have occurred during the Eocene giving rise to the present shore line of the Arabian Sea. While the subsequent recession of the escarpment has produced the Konkan low land. Dikshit, K.fc. (1971). IB

Subsequent to the volcanic out-pourings of the Deccan Trap Formation, Maharashtra, has remained in an undisturbed state except for local changes of the Konkan coast.

Relief

Geological structure and relief together provide the guidelines for dividing the state into macro-divisions such as

(1) the narrow coastal low lands, (2) the Sahyadry and its transverse ranges, (3) the Maharashtra plateau,

(1) The Coastal low lands (The Konkan) :

The narrow strip of land, between the Arabian sea to the west and the Sahyadry range to the east is known as •KONKAN1. It stretches north-south from Daman to Terekhol for 720 km and its width ranges between 40 to 95 km.

This coastal low land is an emerged wavecut platform strewn with low hills or ridges. Unlike other level coastal plains of India, this low land is uneven and is interspersed with river valleys, creeks and ridges. The hills descend from the western ghats and stretch westwards, some even up to the 10

coast separating the valleys from one another. The hills though irregular at places, do not permit easy access from valley to valley. During rainy season when rivers are in spate movement over land becomes still more difficult. These relief features peculiar to this region have so far baffled all the attempts for establishing road and rail communication in the south Konkan.

The hills are flat topped and decend to plain in terraces. The streams are actively busy in cutting back the abruptly rising escarpment of the western ghats during the rainy season. As a result of this headward erosion, the streams have entrenched many deep valleys and gorges in the west facing steep slopes of the western ghats.

These coastal low lands are distinguished by their heavy rainfall low level laterites, rice-cum coconut culture and a general maritime outlook of the life of the people. This narrow strip of lowland is further divided into four regional units based upon economic characteristic.

(1) South Konkan - the coast from Terekhol creek to Shastri river; (2) Central Konkan - between Shastri and Patalganga valley; 20

(3) North Konkan - north of Patalganga upto the northern border of the state. (4) Greater Bombay.

(2) The Sahyadry and Its transverse ranges :

Sahyadris are the conspicuous group of mountains running from the Navapur gap in the north to beyond the southern limit of the state. From north to south Sahyadry follows a sinous line caused by unequal recession of the scarp and is therefore not always parallel to the coast. The crest line forming the water divide between the two water systems, one directed to the Bay of Bangal and other to the Arabian sea does not always coincide with the top of the escarpment and in few cases occurs much to the east. The crest line locally called 'GHAT MATHA1 presents variable altitude in different parts reaching higher elevations in northern sections. Through­ out the area the ghat ranges in elevations between 900 m to 1400 a, (1646 m) near Igatpuri, (1567 m), (1424 m) and (1438 m) are among the important elevations in Maharashtra Fig. 2,2. The erosional surfaces in the source regions of the rivers breaking the contiguity of the mountain chain are marked by saddle. I

/- ,&13 i • >^:; •

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— 21

These low saddles, when traversed by roads are locally known as 'GHATS'. Nowhere these ghats are higher than 700 m A.S.L. Some of the well known ghats from north to south are Thai ghat, , Nane ghat, Bor ghat, Warandha ghat, Kumbharli ghat, Aiaba ghat, Phonda ghat, aid AiEboli ghat. Sahyadris, the northern half of the western ghats from Belgaum to Tapi presents a stairlike aspect and the crest are dominated by natural fortresses which were used to great advantage by Marattas in days of their supremacy. (3443*), Torana (4604'), Purandhar (4560'), (43201) are among the important forts in the state.

Extending for over 45) km from north to south with its heavy rainfall dissected terrain deep red or lateritic soil and an evergreen floral landscape Suhyadry though structurally a part of the plataau presents a different environment that is not in the least similar to the plateau region.

The Maval : The Maval is the transitional strip on the eastern slopes of the Sahyadry, which marks the changes in the landscape from the western humid hilly tracts to the drier and undulating rolling plateau in the east. 22

From the north-south mountainous back-bone of the Sahyadry several spurs are thrown out in the easterly direction o i across the plateau. At about 20 23 N branching off from the Saptashringi peak, the Satmala-Ajantha range separates Tapi basin to the north from the Godavari valley to the south. At the eastern extremity, this range disintegrates into two distinct spurs, the northern one traversing through Yeotmal district is locally called as the while the Southern one passing through the districts of Parbhani and Handed is known as Nirmal range. These Ajantha Satmala ranges carry on their tops the plateaus of Malegaon and Buldhana. The gaps Chandor, Manmad and Nandgaon are more significant relief features in the general physiographic set up of this hilly tract.

South of Thai-ghat at about 19 37 N from Kalsubai another branch runs towards east. This is the Harishchandragad range, known as Balaghat range, in its eastern half. ThJj range separates the Bhima basin frcm that of Godawari. In general, the height of the Balaghat range varies between 850 metres in the wast to 600 metres in the east. The central highland portion of plateau in this range attains the maximum elevation of 987 metres in Kanhur area. 23

The third is Mahadev range which branches off from o the main ridge at about 18 N near the Mahabaleshwar complex. It forms a water divide separating the two river basins of 3hima and Krishna. Aundh and Khanapur plateau attaining an elevation of 850 metres above sea level are the T<r\ar\"\4 of the old surface of errosion in this arer.

To the north, Sahyadry touches the east west trending Satpura ranges known by different names in different parts. In Dhule district this is known as Toran-Mal Plateau (1150 metres), however the highest peak in this region is Astamba Dongar (1325 metres). In its eastern part it is known as Gawilgarh hills with Chikaldara (1068 metres), as the highest point.

The Sahyadry is well wooded with monsoonal vegetation on the side that faces Konkan, Ghat terraces and valley floors generally contain rich stands of teak and other representative types, but the evor-groen sti^ds are rare. Higher valley slopes promote a poorer type of forest very often it is scrub. Wherever basalt, outcrops in a massive form there is practically no vegetation. The reason for this variation lios partly in the nature of soil but mainly in the amount of moisture *4

available. Vegetation becomes poorer with a decreasing rainfall. But irrespective of rainfall, contrast is introduced by the low level and high level laterite, which on account of the poverty of the soils, offer a very barren and desolate appearance.

Maharashtra Plateau :

The Sahyadry running north and south and the Satpudas running east and west culminates In the north-western part of Dhule district. These two mountain ranges enclose between them the vast plateau of Maharashtra. It covers about 48,000 km. It is made up of Impervious base of basaltic rock overlaid with the Deccan traps. The average height of the plateau is 600 metres in its western part however towards the north and east its height decreases to less than 300 metres. Along the extreme eastern boundary of the state in the Chandrapur district a series of detached low hills rise to about 500 m in elevation. These hills of Chandrapur district are a mere continuation of the Bastar hills in M.P.

The rather complex physical set up of the Deccan plateau can be best understood in terms of the great river valleys. In between the Satpudas in the north and Satmala- ^0

-AJantha range In the south lies the great Tapi trough to include the sub basin of its main tributary Purna. Farther east is the Wardha-Wainganga valley. The Wardha river is in fact follows the eastern fringe of Deccan Trap.

The remaining part of the plateau to the south of Satmala-Ajantha ranges covers the seven upland districts of western Maharashtra; which is drained by the three main rivers Godavari, Bhima and Krishna. It is popularly called as (Desh). The Balaghat range separates the Godavari basin from that of Bhima basin while Mahadeo range is a ridge between Bhima and Krishna basins.

Topographically the state of Maharashtra comprises five distinct physiographic units :

1. The Konkan coastal low lands 2. The Sahyadry mountain 3. The Tapi-Purna basin 4. The Maharashtra plateau (Desh) with alternating Godavari - -Pravara, Bhima and Krishna basins separated by Balaghat and Mahadeo ranges respectively. 5» The Wardha Wainganga alluvial low land. Rivers and River basins :

The rivers of Maharashtra may be broadly distinguished into two broad classes :

(1) Those belonging to the Konkan coastal land (2) Those which belong to the plateau proper including Tapi.

(1) Rivers of Konkan : The coastal low land is dissected by numerous short streams draining into the Arabian Sea. The Vaitarna and Ulhas, the longest of Konkan rivers drain comparatively the broader low lands of north Konkan. In the relatively narrow central and south Konkan, the Patalganga the Amba, the Kundalika, the Savitri, the Vashisthi, the Shastri and the Kajvi are the swift flowing rivers generally in floods during the rainy season (Fig. 2,3),

Tapi : Like the rivers of the Konkan, Tapi flows towards west. There are not many off shoots from these ranges. The Tapi valley is therefore more flat than other river valleys in the state and has large stretches of deep black soil areas. The Tapi, rises near Betul in Madhya Pradesh and enters Jalgaon district from the north.

The right bank tributaries of Tapi, originating along V. y fci ' l. r-• •"

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'<£ the steep southern slopes of Satpudas are short and swift. They are of little significance as comparedto left bank tributaries like the Puma, the Bogavati, the Vaghur, the Girna, and the Bori, from the south.

Narmada : Forming a part of the northern boundary along a stretch of 54 km in Dhule district has a limited area in the state.

Rivers of upland Maharashtra : Godavari, Bhima and Krishna are the main rivers of plateau. Wardha and Wainganga are also important rivers draining the Vidftrbha region. Godavar-l is the largest and longest river occupying more than half the area of the State. Its basin is known the cradle of Maharashtra culture. In its upper reaches the Godavari covers the districts of Nasik and north Ahmednagar up to its confluence with Pravara which flows in between the ranges of Kalsubai and Baleshwar. The Mula an important tributary of Pravara finds its course through the hills of Baleshwar and Harishchandra ranges. In its middle course Godavari drains the districts of Aurangabad^ POrbhani and Nanded in the Marathwada region. The Manjra, the lower Puma and Dudhana are the main feeders in this middle section of the river Godavari. Z8

The third independent significant zone of the Godavari basin within the boundries of the Maharashtra state belongs entirely to Viderbha region. In this zone the Penganga, the Wardha and the Walnganga are the important feeders of the main river Godavari.

The Wainganga rises near Seoni in Madhya Pradesh and flows through Bhandara, the central and eastern parts of Nagpur and Chandrapur districts. The river Wardha rises on Multai plateau and joins the Wainganga in Chandrapur district draining through western part of Nagpur district. Penganga rises in the Deulghat hills in the Buldhane district and joins Wardha in Yeotmal district. The combined streams of Penganga Wardha and Wainganga, now known as Pranhita joins Godavari outside the state of Maharashtra.

The Jndravari river rises in eastern ghats an

Bhima : The Bhima drains a large part of the central Maharashtra plateau through Its own tributaries - The Ghod. The Mula, the Mutha, the Nira, the Man-and Sina the only^vrith its source in Balaghat range near Ahmednagar. The river Bhima rises near Bhimashankar in Pune district. Its basin lies between the Balaghat. and Mahadeo ranges and the river flows through the districts of Pune, Satara, north Ahmedriagsr and south . The system is the dominant feature in the physiography of southern Maharashtra. It extends right from Mahadeo ranges to the southern border of the state. It takes its source in the Mahabaleshwar area in Sanyadry. The Venna, Koyana, the Varna and the Panchaganga are the main tributaries of Krishna. The upper Krishna basin spreads over Satara, Sangli and Kolhapur districts. The Sahyadry on the vrest, with its tranverse extension, the Mahadeo hills, encloses the upper Krishna valley.

The Panchaganga, flowing through Kolhapur districts has its own tributaries - the Kasari, the Kumbhi, the Tulsi and the Bhogavati. The fifth river is supposed to be the underground channel so

Soils

Soil has been variously defined. Dr. Bennett, H.M. (1921) defines soil as "a layer of unconsolidated material at the earth's surface which has been derived from rocks and organic matter through agencies of decay and disintegration". Kellogg, C.E. (1956) observes that "the soil that support us are the products of different combinations of rocks, climate, slope, vegetation and time".

Climate as a soil forming factor in Maharashtra :

Of the five factors of soil formation and development viz. climate, relief, parent rock material, biotic life and time; only the first two climate and relief have predominantly influenced the process of soil formation in Maharashtra. Further soil formation process is closely related to spatial distribution of the two basic climatic elements, temperature aid rainfall in the state. Rainfall through its erosive action produces thin soils on the steep slope end deeper soils in gently sloping valley areas due to the deposition of soil material down the hill slopes. Good example of this can be seen on the eastern slopes of the Sahyatiry ranges, although derived from the same parent rock these soils vary in depth 31

from a few cms on steep slopes to nearly one metre in low lying river valleys.

The amount of precipitation, its seasonal distribution, changes in the humidity and temperature of the air have considerable bearing on movement of water through the soil. A leaching process which removes bases and colloides is known as •eluviation' while the reception of these material by a lower sub soil layer is termed 'illuviation1.

In low rainfall areas of Ahmednagar, Aurangabad, Bid, Solapur districts very little leaching takes place. According to Koppen's classification these districts have 'Bsh' type of climate, where evaporation is always greater than precipita­ tion. Through the capillary actior jime accumulation takes place near the surface, ultimately giving rise to the formation of calcareous soil, moderately alkaline in reaction. Such process is called 'calcification1. In contrast to this, the areas of heavy rainfall in Konkan and high altitude regions of Sahyadry calcium is completely leached out of the soil profile. Cki the other hand iron and aluminium concentrations at or near the surface have resulted in the formation of 'lateritic soil'. 32

Climate also Influences soil formation indirectly largely through its action on vegetation. Forest associations are the dominant vegetation in humid climate. The development of soil horizon is more clearly marked in the formation of soil profiles in regions of forest climates than in those of semiarid areas covered by grass. Semiarid climate helps in the formation of deep dark, uniform surface soil. In arid climate sparse and short natural vegetation unables in giving adequate protection to the land against erosion, naturally under such conditions the soils formed get largely eroded and become poor in fertility.

Seasonal variation in the nature and intensity of weathering processes, during the short-wet-hot and long dry seasons over the Maharashtra plateau i3 also responsible for the regional variations of soil types in the state.

Following are the major soil types found in Fig. 2,4.

GO Black Soils or Regur : These are the most important soils covering the maximum area in the state. The uniform minerological and chemical composition of the trap rocks and the semiarid conditions under which they decompose are the two factors which are responsible for some of the important 1 mI ' i o g -- in • i E c a 10 1/1 TJ 4 'J a: at 33

properties of the soil. The grass land vegetation in semiarid climate promote the formation of uniform deep dark coloured soils due to the presence of abundant humus contents in the upper horizons near the surface. These are clayey soils with 30 to 60 % clay content. According to their topographical situations they vary in depth from a few cms on steeper slopes to more than 60 cms in valleys, and can thus be classified as (a) shallow, light black soils found on ridges (b) medium black soils as noticed in the intermediate positions and (c) deep black soils in low lying areas. The shallow, black soils are lighter in colour and their depth is about 30 cm. The medium black soils are more clayey than above and their depth is around about a metre. These deep black soils are mainly developed on alluvial material along the courses of big rivers like Tapi, Godavari, Pravara, Bhima, Nira, Krishna etc. These black soils being clayey in texture, are moisture retaintive, and are sticky when wet. When moist they expand and contract on drying. This self reversal process in these soils makes them very fertile.

(2) Red Soils : In western Maharashtra 'Red Soils' are observed in the districts of Konkan and the eastern parts of the 34

districts Pune, Satara, Solapur, where they are originated from the besaltic rock formations. In the east they are also noticed in Chandrapur and Bhandara districts -where they have formed from the mixed parent rocks such as granite, gneiss, schists etc. The 'Red Soils* of Konkan and eastern most Maharashtra are lateritic in origin while those of upland districts of Maharashtra owe their existance due to hot and dry climatic conditions where rainfall is less than 50 cms.

On hill slopes the soils are coarse, sandy In nature, while in valleys they are clay loams. The soils of hill slopes are 9 cms to 45 cms in depth while those on the flat- lands and in valleys are deeper than 60 cms. The red colour of these soils is attributed to the diffusion of ferric oxide and its distribution is ascribed to alternating wet and dry seasons. These soils are poor in humus nitrogen and phosphorus, so also in soluble exchangeable bases.

(3) The lateritic soils : On account of the forest vegetation and warm-humid climate, the basalts have given rise to the laterites and lateritic soils in the southern part of Kolaba (Raigarh), and Ratnagiri; Western high land portions of Nasik, Pune, Satara, Sangli and Kolhapur districts. On account of the &tkline reaction of percolating waters, the silica from the original rock is differentially leached leaving a residue of sesquioxides in the rock as well as in the soil. Intense leaching accompanying the high rainfall has removed from the soils all the bases giving It a'distinctly acidic character. There is complete absence of calcium carbonate and the soils are very poor in fertility specially in their contents of phosphate and potash. The soils in texture are usually sandy loams fairly deep with low retentivity of moisture. These are thirsty soils and can stand well on irrigation.

These lateritic soils have three varieties viz. rice soils, warkas soils and garden soils. The 'rice' soils are generally in low lying areas which receive the washings from forest uplands and are usually rich in organic matter. The 'warkas1 soils which are on hill slopes are shallow and eroded coarse in texture and yellowish red in colour. Kagli is the principal crop grown on these poor soils. The 'garden* soils are light easily workable, yellowish brown in colour and mostly support arecanut and coconut plantations.

(4) Coastal Alluvial and Coastal Saline Soils : These soils occur along the west coast. They are silty and sandy in 3G

nature. The alluvium is mostly derived from trap and the soils are impregnated with salts to varying extent according to their location with respect to sea. In the immediate vicinity of the coast or creeks they are highly saline and inspite of the high precipitation they are not capable of supporting any crop except the salt-bush type of vegetation. As one proceeds away from the sea the coastal saline soils merge into coastal alluvium. While the salinity has masked th( influence of other soil forming factors in case of coastal saline soilsj the topography has influenced soil development in case of coastal alluvium.

(5) Coarse soils on hill slopeg and clay loams in valleys : These soils are also derived from trap and occupy the mountainous terrain in the west in the districts of Nasik, Ahmednagar, Pune, St-tara, Sangli and Kolhapur. According to their typical situation they vary in depth from a few cms on steep slopes to more than one metre in valleys. As the rain­ fall in this tract is comparatively high the soils are low in base status. Those on steep, slopes locally known as •Kumaris' are terraced and put under hill millets once in six or seven years, and then allowed to be under grass for the remaining years to regain its fertility. The soils in 87

valleys which receive washings from hill slopes are comparatively more fertile and constitute what are known as •rice fields'. These rice soils vary in texture from clay to clay-loam and are neutral in reaction.

Summary :

The soils of Maharashtra offer a distinct contrast to those of many other states in as much as they are very old, fully matured and do not in many cases show padogenic processes and the close relationship between the soil and its rocky substratum. As noted already, Deccan plateau is the most ancient land mass of India and a great portion dates back to the Archean times. The soils developed are therefore very old and highly mature. An examination of these shows that although the nature and composition, reflect to some extent the composition of original rocks from which they are derived, they are the results to a considerable extent of the relief climate, particularly the amount and seasonal distribution of rainfall.

Natural vegetation

The floristic wealth of Maharashtra is rich and varied both in composition and value on account of the wid? range of 33

physiographic and climatic factors. Of the climatic elements rainfall and temperature with their seasonal and total distribution are by far the most important. It was shown earlier by Subrahmanyan (1958) that the distribution of thermal efficiency over India and its seasonal variation are more than adequate to support the most luxuriant type of vegetation. For this reason therefore, moisture effectivlty and its variation through the year alone determine the nature and extent of vegetation development and its distribution. The variation in the seasonal moisture regime of climate over the different parts of the state results in broadly categorising the vegetation of the state into (i) the 'humid type' consisting of tropical and subtropical evergreen, semievergreen and moist deciduous monsoonal types found in all areas with annual rainfall of 150 cm (ii) the 'dry type' found in areas with rainfall less than 100 cm. This type consists of the thron and scrub Jungles found over almost the entire Maharashtra plateau.

As one traverses the state from the coast across the Ghats onto the drier plateau region the rapid changes in the floristic patterns become quite apparent. The fairly dense, rich and luxuriant evergreen and semi-evergreen forests of 33

the coastland and the western slopes of the Ghats get replaced by the dry deciduous more open teak jungles on the eastern slopes that gradually degenerates eastward into shrub jungles that have a paucity of trees. Farther eastwards across the plateau into the Vidarbha plains and hills the vegetation tends to become denser and of the wetter type.

Edaphic conditions, topography and natural drainage conditions also play a significant role in the make up of natural vegetation cover of the state. The west facing slopes more exposed to the rainbearing winds of the western ghats support a more luxuriant and dense vegetation in contrast to the slopes in on the lee side.

Forest types in the state :

The following are the main forest types occurring in Maharashtra. Classification of forest types by Champion and Seth (1963) is mentioned in the brackets during the course of discussion on natural vegetation to follow Fig. 2.5.

(1) The Evergreen Forest s Western sub-tropical hill forest (8A/C2); These are mostly restricted to the high ridges of western ghats and occur around Mahabaleshwar, , Amboli, Bhimashankar and parts of Pune and Thane , 1

l/l . j

o o u u Iv •0-. O C > V . C —ra . 1 1 i i ill rc o -.. u v .. t - • a v 71

-~r 40

districts. They occur mostly at an elevation between 1000 to 1400 metres with rainfall varying between 3600 to 6000 m. The important species found in this type are Jamun, An.lani* Per.1ambul. Hirda. Katekumbel, Pisa. Kokam. Bhoma. Amba. and various others.

These forests have been subjected to considerable biotic influence in the past due to shifting cultivation with the result that they are full of blanks and the nature of vegetation is mostly stunted the multistoried character of the typical evergreen type is almost absent in this area except in a few undisturbed sheltered situations.

(2) The semi-evergreen type (West coast, semi-evergreen forest : 2A/C2) : These forests occur on the western ghats between the evergreen and moist deciduous forests at altitudes varying from 450 to 1050 metres. They are mainly situated on hill slopes with rainfall between 2000 to 2500 mm. These forests are observed in isolated areas of Suwantwadi in south Ratnagiri (Raigarh), Ajra and Chandgarh of Kolhapur, Koyna of Satara districts. Kindal, Nana, Behera, Ain are the important associates of these forests.

Depending upon the local variations in soil and 41

moisture conditions the following two eadphic types are found within this zone of semi evergreens :

(i) Cane brakes (E^ : These are not the typical cane brakes as found in the evergreen as they are very much localised to a very narrow width, a long nala banks where soils is wet for longer periods. Calamus species are conmon. These types occur locally in parts of Sawantwadi and Kolhapur forests.

(ii) fraterltic semi-evergreen forests (2/E4) * These occur in localised areas of semi-ever green forests of Kolaba (Raigarh). They are characterised by presence of Xylia xolocarpa.

(3) The moist deciduous forests (33) : These occur on the gentler slopes of western ghats as well as in the plains with high rainfall. They are found In districts of Kolaba (Raigarh), Ratnagiri, Thana, Nasik, Chandrapur and Bhandara.

The moist deciduous type is further sub-divided into moist, teak bearing forests (3B/C1) and the southern moist mixed deciduous forests (3B/C2). A typical example of the moist teak bearing forest can be found in Allapalli forests of Chandrapur district. In the moist deciduous forests the percentage of teak is usually less and the other associates 42

predominate. They are generally found in certain parts of Chandrapur and Nagpur districts.

(4) Tropical dry-deciduous forests (Sub-group 5A) : They are formed by mixture of trees most of which are deciduous during the dry season for several months. The number of species is much less than in the moist deciduous type and although a few tend to predominate over any selected area the majority are not particularly gragrious with the result that more or less pure associations can usually be traced to soil peculiarities or human interference. The following two climax types of these forest are generally found in Maharashtra state :

(i) Dry teak bearing forests (5A/C1) : occur in areas receiving less than 900 mm, soils are shallow and infertile. Teak in low to fair amount occurs with dry deciduous species. The forests of this sub-type occur in Aurangabad, part of Nanded, Dhule and Jalgaon districts •

(ii) Southern dry mixed deciduous forests (5A/C3) » Here the percentage of teak is much lower. Thorny plants occur and tend to increase in proportion with the heavy grazing, fires etc. Bamboos are generally absent. This type occurs in parts of Chandrapur, Bhandara, Nagpur, Dhule and Jalgaon districts. 43

In addition to the above main types due to variation in soil conditions and influence of various biotic factors the following edaphic types are seen in these forests,

(a) Bos veil i a forests (5/E2) : Due to constant fires, the site conditions in many places have been rendered drier, with the result/only these species capable of withstanding these, predominate. Tihe vegetation here consists mostly of Boswellia serrata 12 to 15 m in height. This type is found in parts of Jalgaon, Dhule, Nanded and Aurangabad districts.

(b) Babul forest (5/E3) : This type occurs mostly on black cotton soils In parts of Akola, Amaravati, Pune and Parbhani districts.

(c) Hardwickla forests (5/E4) s This is found in Jalgaon and Buldhana districts on shallow and gravelly soils.

(5) Southern tropical Thorn forests (6A/C1) : These types are met with, in drier areas of Pune, Ahmednagar, Satara, Dhule, Jalgaon, Solapur districts. The vegetation consists of hardy and thorny species.

(6) The Littoral Forests (4A/L1) : These occur on the coastal areas of Ratnagiri, Sindhudurg and Thane districts where the soils are sandy and saline.