District -Sindhudurg

HYDROGEOLOGICAL CONDITIONS OF SINDHUDURG DISTRICT

The importance and need of water in day to day life needs no emphasis. The demand for water is increasing in almost all sectors. The agriculture in most parts of the country depends upon the monsoon, which is confined to three to four months of the year. When monsoon fails, the rain fed crops also fail to good yield. The only reliable source then for agriculture is groundwater on which we have to depend upon for nearly eight months oftheyear. The state of Maharashtra is one of the low rankingstate in the country as far as utilization of groundwater for irrigation is concerned, i.e. because of its peculiar morphological and hydro geological set up. 

INTRODUTION

Konkan Region marks the western boundary of the state of Maharashtra. The eastern side of the region is occupied by hill ranges known as “Sahyadri” and western side is occupied by “Arabian Sea” The region receives high rainfall It ranges between 3000-3500 mm. Sindhudurg is one of the districts of Konkan also falling in very high rainfall zone. Even then the district is facing shortage of drinking water in late summer because of its peculiar physiographic set up. The major portion of the rainwater goes as ‘runoff.’ An adverse geological strata also affects the poor storage of water in aquifers and less recharge due to heterogeneous nature of aquifers. The western portion of the district also have problem of potable water due to intrusion from sea water and creeks.

LOCATION & EXTENT

District Sindhudurg is the southernmost district of the state, is located along the west coast of India. It spreads between 15^o 37′ and 16 ^o 40′ north latitudes and between 73^o 19′ and     74 ^o 13′ east longitudes. The district is surrounded by Kolhapur district in the east, Ratnagiri district in the north, Arabian Sea towards the west and Karnataka and GoaStates to the south. On the west, Arabian sea gives the district a seaboard of about 121 kilomertres. The district now comprises the tahsilskudal, Malvan,Deogad,kankavli,Sawantwadi,andVengurla carved out from Ratnagiri district and the new tahsils of Vaibhavwadi and Dodamarg created by transfer of the villages from district Kolhapur.

The district has an area of 5,207.0 sq.kms. This area accounts for 1.7 percent of the total area of the state. The population density of the district is 167 persons per sq.km. The headquarters of the district is at Oros Bk. which is also named as Sindhudurgnagari which lies in tahsilKudal. The district is well connected to Mumbai and Kanyakumari by the Konkan Railway, which traverses through the district. It also has a good network of roads connecting it to other parts of the country.

PHYSIOGRAPHY

District Sindhudurg falls under the Maharashtra littoral micro region of the Coastal Plains. The district forms a part of the traditional ‘konkan lowlands’ which is a platform of marine denudationraised to form a narrow plain. But ruggedness and uneven topography form the governing theme in its physical features. A major portion of the district is hilly. On the basis of local variation in relief and other characteristics the district can be grouped into three parts

(i) The Sahyadri Hills-the main system of hills which runs along the eastern boundary of the district. The Sahyadri hills cover the eastern portion of the district in three parts. The hills have an elevation of over 200 metres at the bottom while at the upper reaches they attain a height of about 700 metres. This region has very steep slopes and is fairly covered by forests. This is the source region for most of the rivers in the district.

(ii) Sindhudurg Plateau extends in a north-south direction through the central portion of the district and covers parts of all tahsils of the district except Vaibhavvaditahsil. It has transverse chains of small hills, which are projecting from the Sahyadri hills; develop higher elevation in middle portions. The hill runs parallel to each other and forms small valleys in the intervening land. In general the plateau attains height varying between 100 and 200 meters but there are a number of spot heights that rise to more than 200 meters, 455 metres in Sawantwaditahsilbeingthe highest. The plateau is drained mainly by parallel westward flowing streams. Forest cover is limited in this region. The soils on the slopes of the hills are partly eroded, yellowish red and poor in fertility having shallow depth and coarse texture. These soils are known as Rice soils and Varkas soils.

(iii) Sindhudurg Coast is situated along the extreme western fringe of the district and comprises of parts of Devgad, Malwan, Vengurla and Sawantwaditahsils. It is a long narrow strip of land running the entire length of the district and generally lies below 100 metres. In this region unlike the coast around Mumbai and to the north, which is low lying, this coast is cliffy.

DRAINAGE

All the rivers of the districtareorginate from the Sahyadrirange and flow from east to west and merge in the Arabian Sea. The important rivers are Vaghotan,Devgad, Karli, Terekhol, Sukhshanta, Gadh, Kalaval, Achara and Mochemad. The Creeks of Achara, Mochemad and Devgad and the rivers in this district are of little value from navigation and fisheries point of view.

RAINFALL & CLIMATE

The district receives an average of 3609.98 mm. rainfall from South-West monsoon during June to Sept. every year. The climate of the district is generally hot & humid. The maximum & minimum temperature varies between 16.3° c to 33.8° c 

SOILS

The soils of the district are generally classified into three parts

• Laterite soil- The predominant soils in the district are laterite soils and extensive spreads of laterites are noticed throughout the district. They vary in colour from red to brownish red, owing to the preponderance of hydrated iron oxides.
• Salty soil, Due to the inundation of the sea, a part of the coastal soils has become salty. They are locally known as ‘Khar’ or ‘Khajan’. In Devgad, Malwan and Vengurlatahsils, the entire western strips are salty
• Coastal alluviums- The coastal strips have deep sandy loams

GEOLOGYThe main geological formations of the district areArcheans, Kaladgis and Deccan traps. The Stratigraphic Succession within the districtisgiven below.

Soil, Laterites, Kankar, etc.          –  Recent to Sub-recent

Laterites                                        – Pleistocene

Deccan Traps                                – Cretaceous to Eocene

———————————————-Unconformity ——————————————

(Conglomerates, cherty limestones,    

Kaladgis  — cherty limestones, quartzites and                             Upper Pre-cambrian   

shales associated with limestones)

Archaeans – ( Pegmatites   and  quartz   veins,

                             Basic dykes,  Granulites and  

                             Granite gneisses, Hornblende schists,            Lower Pre-cambrians

                             Mafic and Ultra-mafic rocks, Amphibolites,

                             Banded ferruginous quartzites )

STRUCTURE

i) Archaeans:

            The regional trend of foliation observed in the schistose formations is generally NNW-SSE to NW-SE conforming to the Dharwarians However the trends is found veering to ENE-WSW exihibiting acute folding. The rocks have steep dips of 60⁰ to 80⁰ mostly to the west. The following four sets of joints are common in these rocks.

1. N75⁰E-S75⁰W dipping 75⁰ South  2. N50⁰W-S50⁰E dipping 60⁰ East

      3.N60⁰E-S60⁰W vertical                     4.    E-W Vertical

ii) Kaladgis:

The regional strike of the Kaladgi formation veer from NNE_SSW to NW-SE dipping at low to moderate angles of 5⁰ to 20⁰ towards west. The shales are almost horizontally bedded at places. The strike N80⁰W-S80⁰E with gentle dip towards south. The kaladgi formations display joints in diverse directions. The following set of joints is more common.

1. N-S vertical ii)         2. N40⁰W-S40⁰E vertical

      3. N10⁰E-S10⁰Wdipping 60⁰East  4.   N10⁰W-S10⁰E dipping 70⁰ East

iii) Deccan Basalts:

            The Deccan lava flows are horizontally disposed and are traversed by vertical and horizontal joints. Two sets of vertical joints striking NW-SE and NE-SW and horizontal joints are common.

HYDROGEOLOGICAL CONDITIONS

Archeans,Kaladgi formation, Deccan Trap lava flows  Laterite and Alluvial deposits are the water bearing formations observed in Sindhudurg district. However Kaladgi formation occurs in very limited patches and does not form potential aquifer in the district. The Alluviums also has limited areal extent found mainly along the coast.TheArcheanmetasediments and intrusions are devoid of primary porosity and permeability. The major aquifer formations are Granitic Gneisses and Granites, which are banded or jointed, locally sheared and weathered, that facilitates movement and storage of water. The secondary porosity and permeability thus developed gives rise to moderately yielding aquifers. Granulites are dense and compact and hence not suitable for storage or transmission of ground water.TheKaladgi rocks are mainly represented by orthoquartzite, sandstone and shales. They are jointed in diverse directions and this along with weathered portion controls the water bearing properties.

The primary porosity is negligent in the Deccan trap basalts. The secondary porosity imparted due to jointing, fracturing plays an important role in ground water circulation. In the basaltic terrain ground water occurs under unconfined conditions in the phreatic zone up to a depth of 15 meters in the weathered zone, fractures and joints in the massive unit and weathered/fractured vesicular units. The basalts occupying higher elevations do not form good aquifers however the basalts occupying lower elevations give rise to good aquifers.

Laterite has better porosity due to intricate network of sinuous conduits making it porous formation. The ground water circulates through a network of voids and conduits, joints and fractures. The local water table aquifer develops in the topmost layer down to the depth of 20 m bgl under unconfined conditions. The wells in these areas show rapid decline in water levels during post monsoon season and go dry in peak summer due to lateral movement at lithomarge/laterite contact and through spring discharge. Only dug wells are found in this formation.

The Alluvial deposits are found along the coastal areas in few isolated patches having limited areal extent and limited thickness as Beach Sand. The ground water occurs in inter-granular pore spaces of sands, gravels and silts. The ground water occurs under phreatic/unconfined aquifer at relatively shallow depths.

            The yields of the wells are the functions of the permeability and transmissivity of aquifer encountered and vary with thickness of the aquifer zone encountered, location, diameter and depth etc.  The average Static Groundwater level in pre monsoon season is 7.2 mbgl and The average Static Groundwater level in post monsoon season is 3.9mbglGround water in the area is being developed by two type of abstraction structures i.e., borewells and dugwells. However dugwells are the main ground water abstraction structures in the district. Majority of dugwells in the district are basically used for domestic purpose. The formation-wise depth and yield of dugwells and borewells are given below.

Ground Water Resources Central Ground Water Board and Ground Water Survey and Development Agency (GSDA) have jointly carried out Taluka and Watershed wise estimation of ground water resources of Sindhudurg district for base year 2008-09 according to GEC methodology- 1997.Ground Water Resource Estimation figures as a whole for Sindhudurg district indicates that Net Ground Water Availability is 26196.06 ha-m and Existing Ground Water Draft for all uses is 7262.86 ha-m. After making provision for Domestic and Industrial Supply for next 25 Years as 3651.19 ha-m, Ground Water Availability for future Irrigation is 17107.6 ha-m. Over all Stage of Ground Water development of the district is 27.73%.  indicating there is ample scope for ground water development in the district. All Talukas of Sindhudurg district are categorized under “Safe Category”. Taluka wise figures of ground water resources are reveling that stage of ground water development  in the district is varying from 14.94%  at SawantwadiTaluka to 35.055 at KudalTaluka and all Taluka are categorized under “Safe Category” where there are scope for future development of ground water resources in Sindhudurg district.

CULTURAL ACTIVITIES AND TOURISM

Historical forts like Malwan fort (SindhudurgKilla), Vijayadurg, Ranganagad, manasantoshgad, Bhawantagad, bharatgad, Manasantoshagad and Yashavantagad are main historical forts. The hill station Amboli and Mangeli waterfall attractstourists in rainy season. Entire length of coastal region and cliffy beach attracts tourists. Dashawatar is a major cultural form of the district. 

COMMON FESTIVALS

Holi, Ganeshchaturti, Diwali, RakshaBandhan,Shimga, NaaraliPaurnima, Christmas are the common festivals. The annual festival of Kunkeshwar and Anganewadi are famous which attracts major portion of pilgrims of the state.