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Open Journal of Applied Sciences, 2017, 7, 213-232

http://www.scirp.org/journal/ojapps

ISSN Online: 2165-3925

ISSN Print: 2165-3917

DOI: 10.4236/ojapps.2017.75019

May 31, 2017

Role of Canal Lining on Groundwater

Fluctuations: A Modeling Simulation Approach

for Jaalwala Distributary, Bahawalnagar

Muhammad Hammad Atique Khan

, Muhammad Usman Saleem

, Sajid Rashid Ahmad

Nasir Ahmad

, Shahid Jamil Sameeni

, Muhammad Akram

, Muhammad Farooq

Institute of Geology, University of the Punjab, Lahore, Pakistan

Collage of Earth and Environmental Sciences, University of the Punjab, Lahore, Pakistan

Irrigation Department, Government of Pakistan, Lahore, Pakistan

Abstract

Jaalwala Distributary

was selected to see the consequences of concrete lining

on the underlying saline groundwater table. Its middle and tail portions were

concrete lined whereas the head portion was still

unlined. Visual MODFLOW

2011.1 was used to simulate the effects of concrete lining on saline groundw

ter in two-

dimensional format. Simulation results showed a gradual rise of

electrical conductivity (EC) up

to 7000 µS/cm and decline in water table depth

to nine feet (2.74 m). It observed negligible in

flows from the distributary

through its western boundary due to formation of a permanent barrier in the

way of seepage of any kind. Results have f

urther predicted that freshwater

layer available beneath the Jaalwala Distributary (before its lining) will fi

nish

ultimately and the below present saline water also move upward to take this

vacated place. Hence it was

concluded to line the canals of saline water areas

from their sides which will not only protect them from erosion but canal w

ter theft as well.

Keywords

Water Balance, Jaalwala Distributary, Saline Water Intrusion,

Hydrostatic Pressure and Interface

1. Introduction

Dependency of our lives on water cannot be overlooked. It not only exists on the

surface of the earth in so many forms but is also present below the lithosphere,

having linkages with each other [1]. Apart from natural activities, groundwater

was also restored artificially by surplus irrigation, seepage from man-built water

How to cite this paper:

Khan,

M.H.A.,

Saleem

, M.U., Ahmad, S.R., Ahmad, N.,

Sameeni

, S.J., Akram, M. and Farooq, M.

(201

7) Role of Canal Lining on Groundwa-

ter Fluctuations: A Modeling Simulation

Approach for Jaalwala Distributary, Bah

walnagar

Open Journal of Applied Sciences

, 213-232.

https:

//doi.org/10.4236/ojapps.2017.75019

Received:

January 2, 2017

Accepted:

May 28, 2017

Published:

May 31, 2017

7 by authors and

Scientific

Research Publishing Inc.

This work is licensed under the Creative

Commons Attribution International

License (CC BY

4.0).

http://creativecommons.org/licenses/by/4.0/

Open Access

M. H. A. Khan et al.

214

ways, and water applied intentionally to supplement it [2]. All the ancient em-

pires were established near or along some perpetual water sources [3]. The total

quantity of water on earth remains the same though it changes from one form to

another. It exists as liquid at room temperature, in gaseous state above its boiling

point and as solid in the form of snow, hail or ice subject to the temperature,

pressure and elevation of that place [4]. Good quality of water found on surface

or beneath this earth collectively constitute to the freshwater resources of this

planet [5].

Canals were human-made channels used for conveying water to irrigate fields

and gardens which navigate on a small or large scale. The history of excavation

of canals goes back to at least three thousand years as can be traced in the foot-

prints of Nineveh and Babul civilizations. Theory of flow of fluids was put for-

ward by Torricelli in 1643. It was the Kennedy who excavated a canal in the In-

do-Pak Subcontinent (in the late 19th century) which carried silt-ridden water in

it [6]. These canals were designed in such a way that the silt flowing in these

channels were unable to damage their sides, wear down their banks or clog them

by being dropped in their middle thus jeopardizing their operations [7].

In order to safeguard a canal against any physical damage streamline its gra-

dient offers resistance against infiltration and transport the allocated amount of

water to reach its ends. Canal lining has an addition advantage in strengthening

the banks of canals, checking the growth of weeds and algae in them and lessen-

ing the seepage losses that caused in the earthen channels [8]. Seepage of water

from the earthen structure of Bari Doab Canal in India was taken as an engi-

neering failure when it started operation in 1859. Many suggestions to curtail

this outflow from the earthen boundaries of this canal were put forward but the

most popular and feasible approach was to line this canal altogether with con-

crete. This was adopted as it minimized the incidents of breaches in the canal

structure and acquisition of additional valuable agricultural land was not in-

volved thereby a saving to the government exchequer [9] [10].

The main purpose behind lining of various main canals, distributaries and

minors in Pakistan is to reduce seepage losses from the initially excavated ear-

then canals along with improving their hydraulic performance, reduction in

their operation costs, stoppage of canal-water theft, and delivery of freshwater

right into the field of the farmers [11].

Materials used for lining the canals must be of sufficient strength and quality

to resist the pressure caused by the flowing water. It also prevents seepage from

canal sides and bed so that the hydraulic structure remains safeguarded [12].

Different materials like bricks, cement or concrete were used for lining the can-

als in Pakistan. These constituents have their own capacities: reduce the quantity

of seepage from their surfaces, decrease the eroding capacity of canal banks from

its water, minimize the chances of breach from the high discharged water, allow

minimal weeds growth along their sides and minimize the cost of their main-

tenance [6] (

Table 1).

The main source of recharge in the Indus Plain was infiltration from the upper

M. H. A. Khan et al.

215

Table 1. Impact of different lining materials used for reducing the rate of seepage [6].

Types of lining material

Initial rate of

seepage

Stabilized rate of

seepage

Cusecs per million square foot

No Material (Earthen/ Unlined) 22.4 10.26

Cement, Lime and Brick Ballast (1:5:12) 1.05 0.125

Cement and Sand (1:3) Mortar sandwiched

between the two

0.507 0.027

4” thick Concrete, Sand and Brick Ballast (1:1:3) 0.367 0.02

4” thick Concrete, Lime, Brick Ballast (5:12:24) 1.223 0.39

land surface where it is either permeable and has ruptures or flaws. After the de-

velopment of canal irrigation in this region the rate of percolation increased ma-

nifolds from these porous surfaces thus making the water come up within a few

feet from the land [13]. Apart from the acts of nature aquifers of the Indus Val-

ley River System (IVRS) were restored artificially by activities like surplus irriga-

tion, seepage from waterways and water applied intentionally to supplement

them [2] [14]. Seepage from unlined channels not only helps recharge the aqui-

fers of the Indus Valley but also was a source of clean and fresh water for all the

dwellers living along such waterways [15].

Before the excavation of canals in the IVRS water table of various aquifers was

quite deep that enjoyed a dynamic balance of inflows and outflows of percolated

water into them. This was disturbed with the addition of a constant source of

seeped fresh water from the earthen canals making the water of canal irrigated

areas rise at an average rate of 1.5 ft. per year thereby making these areas water-

logged by the late 1930 (

Table 1). When this standing water in the fields sub-

sided because of evaporation and less reclamation supplies from the canals the

land was left with a covered surface of accumulated salts. It was believed that

these salts came up to the ground surface along with the rising groundwater un-

til research during 1937 revealed that they were present in the soil which mixed

with the upcoming groundwater and were left on the ground with the subsi-

dence of this water [7].

Salts present in the shallow groundwater zones of the Indus plain moved to-

wards the surface and got deposited there because of high evaporation and less

rainfall. This process was augmented by poor drainage of freshwater which failed

to exert enough pressure from the upper side on this up scaling saline water and

stop its vertical movement towards the ground surface [16]. This rise of ground-

water in the saline water-logged areas not only harmed the quality of soil but al-

so diminished the quantity of yields with an additional disadvantage of damag-

ing the civil structures around it. Deposition of huge mounds of salts along the

water channels in the saline water areas are due to primary salinity whereas sec-

ondary salinity in an area is the outcome of inordinate agricultural practices

prevalent in the local population [17].

M. H. A. Khan et al.

216

Canals in Pakistan were excavated as earthen (unlined) channels which not

only reduce the cost of these projects but have an additional benefit of recharg-

ing the groundwater with its freshwater outflows. In areas having freshwater

aquifers seepage from the flowing canals was accepted by the underlying aquifer

as such and they become part of it however in the saline water zones such seeped

freshwater from the earthen channels is not assimilated in these saline water

aquifers but remain above their upper surface as an independent entity. This

layers of seeped freshwater presses the saline water (

Table 1) downwards be-

cause of difference in their densities and hydrostatic pressure. This layer of

freshwater was not only used by the community for its domestic purposes but is

taken by animals and plants besides irrigating the farm fields. However, lining

these canals hinder the seepage and recharge of groundwater resulting either in

lowering of fresh water or rise of saline water from below. These results in dis-

turbance of water balance of that area forcing the farmers to use both canal and

underground water to cater for their needs [8] [14].

A lens of fresh water was formed below the running unlined canal and above

the underlying saline aquifer which has a distinct interface formed as a result of

variance in their gravities. The width of this freshwater layer formed below the

operational earthen canals decrease with their distance away from these channels

(

Table 1) in small oceanic islands where the thickness of fresh water layer float-

ing above the salty seawater decrease towards the coast [2] [14]

Like all other countries distribution of freshwater was not even in Pakistan. It

was surplus in some places while scanty at others. There was also plenty of water

available in some seasons whereas it is rare in others. The gap between demand

and supply of water as a result of rise in population was more than ten percent in

the beginning of this century (2000) which is likely to go up to three times by

2025 due to non-construction of new reservoirs and hence non-replenishment of

groundwater [4]. Per capita availability of water in 1951 was more than five

thousand cubic meters which has dwindled to thirteen hundred cubic meters

[18].

This groundwater study aims to develop a simulated flow model for the canal

command area (CCA) of Jaalwala Distributary located at Bahawalnagar, Pakis-

tan in a two-dimensional format. It will focus on the reasons behind shrinking

and completely diminishing of freshwater layer below the Jaalwala Distributary.

Details regarding rise of saline water to the natural surface level (NSL) and fluc-

tuations being taking place in the dimensions of the freshwater layer present be-

low the Jaalwala Distributary before and after its concrete lining.

In the following sections study area, methods and methodology, results with

conclusion will explained.

2. Study Area

In order to compare the pros and cons of concrete lining of canals in the saline-

water zone Jaalwala Distributary in district Bahawalnagar province of Punjab

Pakistan was selected. Bahawalnagar district (73.40345˚E, 29.97473˚N) was in

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