Nashik

Introduction

Nashik division is one of the six divisions of India’s Maharashtrastate and is also known as North Maharashtra. The historic Khandeshregion covers the northern part of the division, in the valley of theTapti River. Nashik Division is bound by Konkan Division and the state of Gujarat to the west, Madhya Pradesh state to the north, Amravati and Marathwada Division to the east, andPune Division to the south. Nashik Region lies between 19⁰ 51’ 21⁰ 46’ north latitude and 75⁰57’and 78⁰27’ east longitude.

It comprises 5 districts namely Nashik, Nandurbar, Dhule, Jalgaon and Ahilyanagar and  situated partly in the Tapi basin and partly in the Godawari basin.It has an area of 57426 square kilometers and a population of 185.77Lakh as per the 2001 Census. It has 6719habited villages and 4969grampanchayats.

Geography

There are two main mountain systems present in the region namely Sahyadri and Satpuda.Sahyadrimountain system runs north south in the western portion while Satpuda runs east – west in north portion. From the main Sahydri range, three prominent spurs stretch out, the Selbari range, the Satmala and the Ajantha range.

The region comprises mainly of Godavari basin and Tapi basin. Main rivers are Godavari, Tapi, Girna, Pravara, Bhima, Sina, Mula and Mutha.

Rainfall

In the region rainfall shows great temporal and spatial variation which is strongly influenced by Physiography. The western part along sahydri range experiences heavy rainfall upto 3000 mm. The northern part along Satpuda range experiences rainfall upto 1800 mm. The central portion of the region has 700 – 800mm average rainfall,while eastern and south-eastern part of region has average 550 mm rainfall. Maximum number of Tahsils from region fall under DPAP areas.

Geology

The majority of region is monotonously covered by the basaltic lava flows, called the Deccan trap. These rocks have been a result of fissure type of lava eruption during the cretaceous Eocene period. The age of Deccan Trap is 45 million years and made up of various derivatives of basalt like amygdaloidal, vesicular, compact and jointed. They have the tendency to form flat-topped hills giving rise to plateau, comprising of lava flows each ranging from few meters to 30mtrs in thickness. The individual lava flows can be differentiated into three zones. 1) The upper amygdoloidal zone. 2) The middle vesicular zone and 3) bottom massive lava flow. The vesicles are filled with secondary minerals of Zeolitic group Stilbite, Natrolite Calcite, and other varieties of quartz. (Agate, Amethyst etc)

Along Tapi river at foot of Satpuda mountain area is made up of Tapi alluvium famously known as Bazada Zone. It runs east – west along Tapi river with depth goes to100 to 125 meters below ground level. Alluvium deposits also occurs in area along major river systems like, Godavari, Girana, Panzara, Pravara. In these areas depth of alluvium deposition varies from few meters to 50 meters.

Hydrogeology

Hydro-geologically region is having two distinct aquifer systems i.e. Hard rock and Alluvium. The Groundwater in hard rock aquifers occurs in the interconnecting vesicles, joints, fractures, and other secondary openings. The lava flow differs greatly amongst themselves in regard to their ability to receive, recharge, store and transmit groundwater. Differences in lava flows in respect to their productivity arise as a result of their inherent physical characteristics such as their porosity and permeability.

Alluvium is depositedalong all the major rivers. Among the alluvial deposits Bazada Zone is most productive and very rich in terms of groundwater deposits. Other local alluvium deposits are  shallow and not much productive as compared to Bazada Zobne.

The average depth of the wells in hard rocks varies from 5 -20 m bgl and diameter varies from 3 – 8 m.The range of water level varies from 2 – 10 m during winter, and 6 – 20 m during summer and the yield ranges from 50 to 100 m3/day in winter and 15-50 m3/day during summer.

The average Depth of wells in alluvium is 15 to 50 m bgl and diameter varies from 3 to 6 m. The range of water level varies from 15 – 30 m during winter, and 30 – 45 m during summer and the yield ranges from 80 to 150 m3/day in winter and 55-75 m3/day during summer. But now a days number of wells in alluvium are greatly reduced.

In bazada zone and some local alluvium areas there are only tube wells with depth ranges between 60 to 300 meters bgl with average diameter of 300 mm. Mostly all tubewells are productive with yield ranges from 200 to 300 m3/day in winter and 150 to 200 m3/day in summer.

Watersheds

The Nashik division comprises mainly of Godavari and Tapi basin. Other than these two main basins, important basins are Narmada, Sina, Bhima and Western flowing river basins.  

Groundwater resource assessment is the determination of the source, extent, dependability and quality of groundwater resources on which the evaluation of the possibilities of utilization and control depends. Estimation of groundwater is also important for the construction and the maintenance of the district water supply infrastructures, especially those dependent on the groundwater. Watershed has been proposed as a more desirable option for groundwater assessment in the district.

For the sake of accurate estimation of groundwater assessment, the region has been divided into 300 elementary watersheds.

Water Quality

            In the region Water quality is governed by networks of laboratories which is a 3 tire system consisting of Regional, District and Sub-divisional Laboratories. Chemical and bacteriological testing

of all drinking water sources is carried out 2 times in a year i. e. Pre and post monsoon. All 5 district and 1 regional laboratory are NABL accredited.