The document summarizes a hydrogeological study of the Barazan plateau region in North Goa, India. Key findings include: - The plateau acts as a water tower, recharging springs that provide water to surrounding villages. The springs are fed by porous laterite aquifers overlying impermeable metamorphic basalt. - 12 perennial springs were identified, discharging a total of over 2 million cubic meters of water annually. This pristine spring water is an important local resource. - Proposed infrastructure like an airport risks disturbing the plateau's recharge zones and aquifers, threatening the springs and local hydrology. Protecting the plateau and its springsheds is important

1. HYDROGEOLOGICAL STUDIES
ON AND AROUND
BARAZAN PLATEAU, NORTH GOA
DISTRICT, GOA STATE
Advanced Center for Water Resources Development and
Management
(ACWADAM)
acwadam@vsnl.net / www.acwadam.org
ACWADAM technical report no.
ACWA/Hydro/2015/H39
November 2015

2. HYDROGEOLOGICAL STUDIES
ON AND AROUND
BARAZAN PLATEAU, NORTH GOA DISTRICT, GOA STATE
Principal authors
Jairaj Rajguru
Rakesh Gupta
Associate author
Dr. Himanshu Kulkarni
Technical Report: ACWA/Hydro/2014/H39
Advanced Center for Water Resources Development and
Management
Plot 4, Lenyadri society, Sus road, Pashan, Pune – 411021
Phone: +92 20 25871539
Email: acwadam@vsnl.net
Website: www.acwadam.org

3. Table of contents
Background 1
Introduction 1
Location, geomorphology and drainage of the area 2
Geology of the area 5
Hydrogeology of the area 7
Bibliography 11
Glossary – some explanation of concepts 13
Salient photographs 15

4. 1
Hydrogeological status of Barazan plateau
Background
Villagers surrounding Barazan plateau requested ACWADAM to conduct a rapid
hydrogeological assessment of the Barazan plateau particularly with regard to the impact
of the proposed airport and related infrastructural activities on the natural systems,
especially springs, around the plateau. This report is a result of a rapid study of the area,
based on a short visit and analysis of available data in the form of spring inventories,
toposheets and Google Earth imageries. A buffer of 10 km radius around the proposed
airport at Mopa village is considered for preparation of most of the maps. The report
derives from ACWADAM’s extensive experience of working on springshed management
programmes across various mountain ranges in India.
Introduction
Large parts of the country suffer from acute water scarcity. Most responses to tackle this
scarcity include construction of new wells, deepening pre-existing wells, drilling deeper
(borewells / tubewells), installation of pumps of high capacities on these wells and locating
wells in river beds. In addition, many responses also include construction of village ponds,
construction of irrigation tanks and provision of water by the tankers, which is just another
form of groundwater extraction. All of these are supply-side mechanisms and do not always
involve scientific approaches. Planning at village level by preserving the recharge zones of
ground water becomes an integral part of resolving the crises of water scarcity in the
country.
Perennial streams flow because groundwater remains above the streambed / riverbed
throughout the year. If the aquifer is in a healthy condition, then only is one able to see the
perennial streams. Base flow is the water-contribution of an aquifer to streams and rivers.
Stream flow, therefore, depends upon the status of base flows to stream and rivers.
Arguably, the most important factor regarding the fate of aquatic life in surface water is the
amount of sustainable flow in the channel, often determined by such base flows. Since
groundwater temperatures are nearly uniform year-round, groundwater discharge also
provides a measure of temperature stability in surface water. This ecological consideration
becomes a must when we try to study anything about the biodiversity richness around a
plateau such as Barazan plateau.

5. 2
Location, geomorphology and drainage of the area:
Barazan plateau is located in Pernem block of North Goa district in northern-most Goa,
along the Maharashtra border. Plateau encompasses six villages of Varconda, Casarvanem,
Chandel, Mopa, Uguem and Amberem in Goa and Netarde village in Maharashtra. The
residents of these villages (total number of over 7000 persons), especially those living in
settlements on the slopes of the plateau besides the streams originating from the springs
above, are dependent on the springs for their drinking and domestic water needs. This
spring water is also use for cattle rearing and irrigation of large plantations as well as the
paddy fields below.
Google earth image of Barazan plateau and villages around plateau with 10km buffer
These villages also receive piped water from the 10 MLD treatment plant at Chandel, which
lifts water from Kalne river for treatment and distribution. However, the dependency on
the springs remains high even today, since the water is released only for limited durations
(about an hour or two), and because the villagers prefer the spring water for drinking and
cooking, and also because the significant water supply is needed for irrigation and cattle
rearing. It can be said that Barazan plateau is acting as a water tower for surrounding
ecosystems and villages.
The land surrounding the proposed airport site is predominantly forest-land. The northern
and eastern side of the proposed site is reserve forest area, whereas the western side is
cultivated land within the surrounding villages. More than half of the land of plateau is
covered with scrub and scrub forest. Average annual rainfall of the area is 2932 mm.
Regional morphology of the study area comprises plateau at the center, which gives way to
highly undulating terrain as one moves away towards the rivers. The Digital Elevation
Model (DEM) below shows topography of the land in the study area. Highest elevation of

6. 3
the study area is 185 m and the lowest surface elevation is 4m above mean sea level,
implying an overall gradient of 181 m over a straight distance of 4 km, a slope of 0.0452.
The study area is mostly rural and is occupied by agricultural fields with thin soil
thicknesses.
Northwestern part of study area is drained by Terekhol river system and southeastern part
by Chapora and Kalna river systems and there tributary streams. Rivers flow in the
southwesterly direction, following the slope of the area. River and most of the streams are
perennial because most of the springs that are feeding these streams are perennial. Many
first order streams and two second order streams flowing westward are there over the
proposed airport site.

7. 4

8. 5
Geology of the area:
The geology of the area is dominated by laterite (Cenozoic in geological age), which is
underlain by meta-basalt (Archaean to lower Proterozoic in geological age) and a volcanic
intrusions in the form of a dyke. Laterite rock is rich in iron and aluminium and is
commonly considered to have formed in hot and wet tropical areas. Laterites are formed
through the residual weathering of an original rock such as basalt or granite. Soils formed
from laterite are called lateritic soils, also rich in iron and aluminium. Nearly all laterites
are of rusty-red coloration, because of high iron oxide content. They develop by intensive
and long-lasting weathering of the underlying parent rock. Tropical weathering
(laterization) is a prolonged process of chemical weathering which produces a wide variety
in the thickness, grade, chemistry and ore mineralogy of the resulting rocks and soils.
Laterites, in large regions of western Maharashtra and northern part of Goa are formed
from the leaching of parent meta-basalt rock; which leaves the more insoluble ions,
predominantly iron and aluminium. The mechanism of leaching involves acid dissolving the
host mineral lattice, followed by hydrolysis and precipitation of insoluble oxides and
sulphates of iron, aluminium and silica under the high temperature conditions of a humid
sub-tropical monsoon climate. An essential feature for the formation of laterite is the
repetition of wet and dry seasons. Rocks are leached by percolating rain water during the
wet season; the resulting solution containing the leached ions is brought to the surface by
capillary action during the dry season. These ions form soluble salt compounds which dry
on the surface; these salts are washed away during the next wet season. Laterite formation
is favoured in low topographical reliefs of gentle crests and plateaus which prevents
erosion of the surface cover. The reaction zone where rocks are in contact with water from
the lowest to highest water table is progressively depleted of the easily leached ions of
sodium, potassium, calcium and magnesium. A solution of these ions can have the correct
pH to preferentially dissolve silicon oxide rather than the aluminium oxides and iron
oxides.
Meta-basalt is the rock which formed due to metamorphism of basaltic rock during
Archaean to lower Proterozoic ages. Metamorphism is the change of geologic texture
(distinct arrangement of minerals) and recrystallisation of the minerals in pre-existing
rocks in solid phase. The change occurs primarily due to heat, pressure, and the
introduction of chemically active fluids.
A dyke, in geology, is a type of later, vertical rock emplacement between older layers of
rock. Technically, it is any geologic body, which cuts across: flat wall rock structures, such
as bedding (sedimentary rock) or massive rock formations that are usually igneous in
origin. In this area, dyke rock is basalt formed during upper Cretaceous to lower Eocene
ages.

9. 6
ACWADAM’s fieldwork (Barazan Plateau and its slope towards the south-eastern half)
included the area that is entirely underlain by thick and firm mass of laterites with small
patches of meta-basalts in-between; these patches were too small to be called ‘mappable’
and hence are not shown as isolated polygons in the map below. Meta-basalt units are hard
and highly jointed. Laterites that were observed in the field are porous and permeable as
compared to the meta-basalts. One NW-SE trending dyke (of ?meta-basalt) is also marked
by on the eastern slope of the plateau. Almost all the springs (numbering 12) are observed
at the contact between laterites and underlying Meta-basalts.
Overlay of Geology on Google earth imagery of the area

10. 7
Hydrogeology of the area:
A ‘spring’ is the point or area of emergence of groundwater onto the surface of the earth.
The emergence of groundwater on the surface in the form of springs around Barazan
plateau is mainly controlled by the lithological sequence of the area and the water bearing
laterite aquifers above. Laterites observed on and around plateau are thick, porous and
hence they are having considerable water holding and transmission capacity. These
laterites are underlain by the impervious meta-basalt. Due to its porous nature, the laterite
aquifer recharges rapidly with the monsoon rains and the water table recedes slowly from
this laterite mass. Hence, laterites not only act as the storage zones for aquifers feeding
springs, but their tops act as recharge zones for the aquifers that support such springs.
Laterite allows water to slowly percolate and, after reaching the impervious meta-basalt
and the dyke (laterally), it emerges on the ground in the form of contact springs. During
ACWADAM’s visit in the month of July, though the regional water-table of the area was
deep - about 10 meters below ground (155 m above mean sea level) - there was clear
evidence of a perched water table in portions observed at the top of plateau at a height of
about 170m. Such a perched aquifer system had also resulted in seeps and springs forming
a lake. This perched aquifer have formed a unique ecosystem, supporting the rarest of
forms of floral and faunal diversity and also traditionally used for irrigation of paddy fields
through a channel cut in the harder portions of the laterite rock, allowing water from the
lake to flow into the paddy fields on the plateau surface to the south of the lake. This lake is
a large water body which is dry only after March.
All the springs studied by ACWADAM were perennial with discharge ranging from 10
liters/minutes to about 100s of liters/minutes even in the dry season. This system of
springs constitutes a sustainable source of water to the villagers living in and around this
locality. This spring water flows down the slope, some portion of it seeps down into joints
and fracture of the Meta-basaltic flows and adding to the recharge of the regional aquifers
in the plains. These springs occur in areas with high topography, above village settlements
and hence, they are essentially gravity-fed systems with no energy inputs while already
constituting economically viable and ecologically sustainable sources of water for domestic
and livelihood needs.

11. 8
Overlay of Springs on Google earth imagery of the area

12. 9
Post monsoon cumulative discharge was found to be about 6000 liters/minutes. As this
study will proceed further we will try to measure actual pre-monsoon discharge of the
springs. While considering the local setup and geology of the area one can estimate the pre
monsoon cumulative discharge to the tune of 2500 liters/minutes. Based on this
assumption average year-round cumulative discharge can be taken as 4250 liters/minutes.
Normalised over a year, this amounts to more than 2.2 million cubic metres of water every
year. This figure reflects the fact that Barazan plateau is playing the pivoted role in local
hydrology of the area by recharging about 2233800m3 of water year-round. Considering a
catchment area of about 15 km2, this is equivalent to about 150 mm of water, not a small
quantity of fairly pristine, natural water supply.
The slow percolation of water through laterites filters the water and ensures a steady
supply of pure water year-round, long after the end of the monsoon. As a result
groundwater quality was found to be good. This was in stark contrast to the quality of
surface water, which was found to be deteriorated in terms of TDS, hardness, chlorides,
sulfates and presence of coliforms around the plateau.
Source: EIA for the proposed greenfield international airport at Mopa, Goa; prepaired by Engineers India Limited
Due to thin soil cover and highly rugged topography, in spite of heavy rainfall, the drainage
system tends to be lean during the summer months. Likewise, due to steep hydraulic
gradient and highly permeable phreatic aquifers, the dynamic ground water resource also
gets depleted, quickly rendering scarcity even for drinking water during summer months.
Therefore, there is need for augmenting recharge in the region.
Now-a-days it is seen that many infra structural projects including proposed greenfield
international airport project at Mopa is coming in this area. Such large-scale infrastructure

13. 10
footprints are likely to disturb the recharge zones for the aquifer system feeding the
natural springs of Barazan plateau. Such disturbances will significantly affect the laterite
aquifer feeding the spring system, thereby imperiling the integrity and safety of the natural
public drinking water sources. Either which way, it is important to recognize the recharge
zones for springs as well as the spring source areas themselves and ensure that these are
protected from various activities and interventions. Spring areas should be protected from
tree cutting, over grazing, and construction for the sustainability of springs.
Physical changes in the land morphology, land-use, land-cover and modification of drainage
networks in the catchment areas may hamper recharge that will affect the springs of the
area in terms of magnitude and seasonality of discharge and often lead to their complete
disappearance. Given that nearly 150 mm of water is discharged through this spring
system. Any changes to its recharge zones and aquifer storage is will not only hamper
spring discharges but may have negative impacts on the flow of streams and rivers and
will, in the longer run pose a severe threat to the related ecology downstream and also to
the livelihoods of downstream populations.

14. 11
BIBLIOGRAPHY
ACWADAM, 2014. Hydrogeology of the Kirunde springs. Submitted to GRAMPARI
ACWADAM (2009) Kulkarni, H., Badarayani, U. and Upasani, D. (eds) “Groundwater
management –typology of challenges, opportunities and approaches.” Arghyam-ACWADAM
publ. ACWA H-09-2.Compilation of papers from the Groundwater Conference, Pune, May 2009.
Bryan , K (1919) classification of springs. Jour. Geo. v. 27, pp. 522-561.
Buono, J., Thomas.R.(year unknown). Lateritic springs: A vital threatened resource along
the Western Ghats.
Central Ground Water Board (CGWB).(2013). Groundwater information booklet, North Goa
district, Goa state.
Chow, V. T., Maidment, D. R. and Mays, L. W. (1964) Handbook of Applied Hydrology.
McGraw-Hill, NewYork.
Driscoll, F. G. (1986) Groundwater and wells, 2 edition. Johnson division, Minnesota, 1108p.
Engineers India Limited.(2015). Environmental Impact Assesment for the proposed
greenfield international airport at Mopa, Goa.
Fetter, C. W. (1980) Applied Hydrogeology. Charles E. Merrill Publishing Company, 488p.
Freeze, R. A. and Cherry, J. A. (1979) Groundwater. Prentice Hall Inc., Engelwood Cliffs, New
Jersey, 604p.
Kulkarni, H. (1998) Watershed Development and Management - a movement seeking
inputs in Earth sciences. Jour. Geol. Soc. India, v52(2), pp.239-241.
Kulkarni, H., Vijay Shankar, P.S (2009). “Groundwater: Towards an Aquifer Management
Framework”,Economic and Political Weekly, Mumbai, February 7.
Kresic, N and Bonacci, O. 2010.Groundwater Hydrology of Springs, Chp.4; p129-162.
Kresic, N. 2010. Groundwater Hydrology of Springs, Chp.2; p31-83.
Kresic, N. 2010.Groundwater Hydrology of Springs, Chp.5; p165-226.

15. 12
Negi, G. C. S and Joshi, v. (2002) Drinking Water Issues and Development of Spring
Sanctuaries in a Mountain Watershed in the Indian Himalaya. Moun. Res. Dev. v. 22, no. 1,
pp. 29-31.
Oliver, Cliff D., H.C. Sheth. (2008): The High Deccan duricrusts of India and their
significance for the ‘laterite’ issue. Journal of Earth System Science, Volume 117, Issue 5, pp
537-551.
Vashisht, A. K. and Sharma, H. C. (2007) Study on hydrological behaviour of a natural
spring. Curr. Sci. v. 93,no. 6, pp. 837-840.
Weight, W. D. and Sonderreger, J. L., (2001) Manual of Applied Field Hydrogeology.
McGraw-Hill, 608p.
Wisler, C. O. and Brater, B. F. (1959), Hydrology. Wiley, New York, 408p.

16. 13
Glossary – some explanation of concepts and meaning of terms
1. Aquifer: It is a water-saturated rock or rock-material (sand, silt, gravel) formation
that has capacity to store groundwater and transmit it to wells and springs.
2. Basalt: It is an igneous rock formed from the cooling of lava of basalt composition.
The lava is extruded at the surface through volcanic eruption through cones and/or
fissures on the surface of the earth.
3. Base flow: It is the part of stream flow that has been discharged from aquifers (into
the stream). In other words it is the ‘contribution’ of groundwater to streams and
rivers. Hence, in monsoonal climate regions, the water that one observes in streams
during the dry season is usually base flow.
4. Contact spring: Springs that are emerging at places where relatively permeable
rocks overlie rocks of rocks of low permeability.
5. Depression spring: Springs emerging at topographic lows where water table
intersects the ground surface.
6. Discharge: loss of water from an aquifer through springs or pumping out
groundwater
7. Hydrogeology: It is the science of ‘groundwater’
8. Karst spring: Water moving through cavities and openings developed in rocks to
form a spring.
9. Metamorphism: Process of metamorphic rock formation due to changes in physical
and chemical conditions, pressure and heat.
10. Perched aquifer: Locally saturated portion of the subsurface strata is referred to as a
perched aquifer.
11. Permeability: Also referred to as ‘hydraulic conductivity’, it is the property of rocks
or soils to allow the flow or movement of fluids (including water) through their pore
space.
12. Recharge: addition of infiltrated water to an aquifer

17. 14
13. Recharge zone: Recharge zones are the areas from where rainfall (or any other
natural precipitation) that infiltrates the ground surface leading to an addition to
the groundwater storage.
14. Spring: Point of groundwater discharge.
15. Total Dissolved Solids: It is the total amount of minerals, salts and metals dissolved
in a given volume of water, expressed either as milligrammes/litre (mg/l) or parts
per million (ppm).
16. Water table: The water table is the upper surface of an unconfined aquifer,
representing the uppermost surface of the zone of ‘water saturation’. The water
table is usually visible in shallow wells.

18. 15
Salient photographs:
Thick and firm mass of Laterites on the plateau Jointed meta-basalts observed in patches
Depression spring behaving like a Karst spring due to
high weathering in laterites
Springfed stream; villagers are depended on such
streams for their day to day needs

19. 16
Well on the plateau showing Deep water-table Perched water-table on the plateau that forms a
unique ecosystem

20. 17
Spring inventory sheet of mapped springs on and around Barazan plateau