1) The document discusses the hydrology of Manipur and Nagaland states in northeast India, including their geology, groundwater availability and quality, and challenges. 2) In Manipur, groundwater is found under thin clay layers underlain by tertiary rock and supplied by confined and unconfined aquifers. In Nagaland, groundwater comes from semi-confined and unconfined aquifers in alluvial deposits and tertiary rock. 3) Key challenges faced include water scarcity due to variable rainfall, overexploitation of groundwater lowering water tables, and lack of irrigation infrastructure limiting food sustainability. Mitigation strategies proposed are adopting efficient water management techniques and artificial groundwater recharging

1. Hydrology of
Manipur and
Nagaland
By Rohan Roy
UG III Roll : 13

2. Introduction to general geology and hydrogeology
Manipur and Nagaland both are north eastern states of India. Being
neighbouring state they have some common linkage in their geology. So we
need to know the geology before giving a jump into those aquifers.
Manipur: The total area of this state is 22,327 sq km as per the latest report.
The state is mainly associated with hilly region which comprises of hills,
valley, intermontane valley and alluvial plane. The main river channels are
Meghna and Chindwin river and their branch rivers.
The Manipur valley is underlined by thin clay layers which is underlain by
tertiary rock group. The groundwater requirement is fulfilled by underlying
confined and unconfined aquifer. But as there is a thin clay or silty layer
distributed at maximum area the shallow water well is not fruitful. But the
deep water well have high potential of water discharge due to the presence
of deep confined aquifer which is made by tertiary sandstone.

3. Ground water availability and quality
The groundwater availability is dependent on the type of aquifer present in that particular area,
whether it is confined, unconfined or leaky aquifer. What is the constituent material of those
aquifers, the specific yield and specific retention of those aquifers? So we come across some
interesting points that we should consider at the time of analysis.
Now let's have a look on the groundwater availability of Manipur.
Manipur: The groundwater is found under the water table in shallow water condition where the
water table is found 22.35 metre below the ground level at pre monsoon period and it is upto 11.92
metre below the ground level at the time of post monsoon periods. The deeper groundwater is found
at the northern part of the state at the foothill region. The deeper groundwater is found at semi
confined to confined aquifer where the piezometric head is found at 20 mbgl and so on. The water
level fluctuation is high due to the clayey and silty behavior of aquifer.

4. Here I used a small district of Manipur, Chandel, to describe
the average ground water quality of Manipur. Though the
quality of groundwater can change from place to place on
large scale to very small local scale but, I want to highlight
some important researched places of Manipur, and Chandel is
one of them.

5. From the Piper’s trilinear diagram we can find
out the major elements in groundwater at
Chandel district. The dominance of major
cations and anions in the order of
Na+K > Ca2+ > Mg2+ type and
Cl− > HCO3− > SO42− > NO3− type, respectively.
The figure also reveals the majority of
geochemical facies at that sample are
dominated by Na+–Ca2+–Mg2+–Cl−–HCO3−–
SO42−-type of water, followed by Na+–Ca2+–
K+–Cl−–HCO3− type of water.

6. Suitability of irrigation water quality was
evaluated using water quality parameters
such as EC, TDS and irrigation water
quality indices such as sodium percentage
( Na%), sodium absorption ratio (SAR) and
wilcox diagram. Here is the wilcox
diagram of that sample area.
Here the maximum samples fall into the
space C2-S1 which suggest low sodium
absorption ratio and slight salinity hazard.
That means the water has partially good
quality and this water can be used for
household work and irrigation after doing
some treatment to reduce its salinity.

7. Challenges Mitigations
Water scarcity is a major problem in manipur.
Extremely variable rainfall pattern affect the
groundwater recharge.
The best way to approach these problems is to adopt
innovative and futuristic management techniques -
minimum use of water, recycling and reusing wastewater
for industrial uses and ensuring a higher degree of
efficiency in the management of water use in irrigation.
Some other measures would be the adoption of the latest
technologies for recharging of the groundwater level by
means of artificial aquifer recharging.
Water comes from rivers, streams, and lakes (surface
water) and water held under the ground in aquifers
(groundwater). The government is responsible for the
strategic management of the State’s freshwater resources.
This involves:
* setting water policy
* determining how available water is allocated to water
users
* monitoring the quantity and quality of water extractions
* monitoring the ecological health of our aquatic
ecosystems.
* developing statutory water sharing plans
Overexploitation of groundwater increase the
deterioration of groundwater quality. The water table of
densely populated area is lowering day by day.
Making of not well planned dam disrupted the water
flow through the river, results in a loss of wildlife and
forest in that area.
As it is a hilly region the huge runoff is very common,
which results the mixing of fertilized water from
agriculture and household’s fowl water with the river.
Urbanisation is a major problem of groundwater
recharge which is gradually increasing in coming years.

8. Nagaland: The total area is about 16,579 sq km with 8 district. The hilly
strip is trending east to south west and with assam plane at its northern
side. The deep aquifers are thinly bedded and 300 metre deep. The
specific yield at Dhansiri and Dupitila is low to very low because of finer
sediments in aquifer. The saturated water zone is 30 to 70 metres within
the depth of 300 metres and the deep water wells which are 250 metres
deep have maximum specific yield of 20-30 m3/hr (Tipam sandstone act as
a good aquifer) . Soils have been derived from tertiary group of rock and
red clay predominate. The state is underlined by the unconsolidated to
semi consolidated alluvial deposits. But there are many fracture zones
prevail in the consolidated to semi consolidated basements. The water
quality of this area is good. We will further discuss it later.
Introduction to general geology and
hydrogeology

9. Nagaland: The main groundwater source of Nagaland are semi confined and unconfined aquifers. The
unconfined aquifers are used for shallow wells which is mainly alluvial deposits or the tertiary group of
rock. The aquifers thickness is 15 to 20 metres and vary from place to place.
The deep water aquifers are semi confined in nature. In unconfined aquifer the water level is in one
metre to 10 mbgl and confined aquifer the piezometric level ranges from 10.24 mbgl to less than 1 mbgl.
1. Mean annual rainfall: 1536 mm.
2. Total surface water resources: 25,465,344,000 m³.
3. The annual average groundwater recharge: 818 mm.
4. Surface water recharge to groundwater: 13,561,622,000 m³
Ground water availability and quality

11. Challenges Mitigation process
Villages in Nagaland are located on the hilltops and their population
has been increasing since their establishment. Once sufficient, the
existing locally available water resources are unable to meet
existing water demand in the villages for drinking and sanitation
purposes, now.
Steps have been taken,
To ensure conservation, protection, safeguard restoration and rejuvenation of
water resources in the state of Nagaland their utilization has to be optimise.
To ensure fulfilment of basic right to water of present and future generations.
Access to water for drinking and other domestic needs is an
emerging challenge in many urban areas, towns and villages in the
state. The potential for inter-village water transfer with the payment
for ecosystem services mechanism needs exploration.
Maintenance of water quality at prevailing standards and reduction of water
resources' pollution by urban sewage and industrial effluents
Encouraging efforts to create infrastructure for water supplies in urban and rural
areas and raise the level of reliability of water supplies by water resource
exploitation.
Lack of irrigation infrastructure is critical to ensure food
sustainability in the state.
Development of planned infrastructure to maintain the good quality water for
irrigation purpose.
Due to a wide temporal and spatial variation in availability of water,
likely to exacerbate due to a number of variable factors including
climate change impacts resulting in incidences of water related
disasters.
Control the illegal exploitation of groundwater, give a restriction on using heavy
duty pump and groundwater must be exploited under the supervision of
government to limit wastage of water.
Groundwater issues:
The groundwater of this region is slightly alkaline to neutral. EC and TDS is very less that indicates soft water.
Other elements are also within the permissible limit for drinking, agriculture as standard set by BIS. Till now no
chemical pollution has been detected but at the shallow areas the iron content is more than its permissible
limit. So before drinking the water someone should boil and filter it.

12. ● References:
● http://cgwb.gov.in/District_Profile/Nagaland/Dimapur.pdf
● http://cgwb.gov.in/District_Profile/Manipur/Imphal%20East.pdf
● https://link.springer.com/article/10.1007/s13201-020-01208-0
● https://npcb.nagaland.gov.in/water-monitoring/
● http://www.nagalanduniv.ndl.iitkgp.ac.in/bitstream/handle/1234567/142/T00127.pdf?sequenc
e=1&isAllowed=y
● https://phed.nagaland.gov.in/assets/nagaland-state-water-policy-20162.pdf
● http://e-
pao.net/epSubPageExtractor.asp?src=education.Science_and_Technology.Problems_and_p
rospect_of_ground_water_management_in_Manipur_By_L_Sherjit

13. Thank
You.