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About ground water supply system of Khulna city corporation 2004
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Submitted to:Dr. Subrota Kumar SahaAssistant ProfessorES DisciplineKhulna UniversityKhulna
Submitted by:Group No: 22nd year 2nd termES DisciplineKhulna UniversityKhulna
Date of Submission: 2 October, 2005.
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Acknowledgement
All praise is to the Supreme Being; creator and ruler of the universe, God
whose mercy keep us alive and to pursue our education in Environmental
Science Discipline and to complete the assignment for the fulfillment of the
course Hydrology.
We would like to express our indebt ness to Dr. Subrota Kumar Saha,
Assistant professor, Environmental Science discipline, Khulna University.
For giving this assignment and under his guidance, encouragement, and
helpful suggestion make possible to fulfill this work.
On this auspicious occasion, we would like to grateful acknowledge the
support of the seminar library of Environmental Science discipline.
However, we are responsible for any remaining errors or inadequacies.
October, 2005 Group: 2
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ABSTRACT
Bangladesh, one of the most densely populated countries in the world,
inspite of severe resource, constraints, is trying to provide the basic
amenities like water supply for its population. It also faces massive urban
problems. All the urban areas are remote from planned community
facilities, like water supply, sanitation, sewerage system etc. Absence of
planning and automated technology generates a deplorable present and
future circumstance. Khulna city is an instance of having typical urban
problems particularly the crisis of water. Approximately 25% population
in this area is covered under piped water supply system while in the major
cities it ranges more.
In this study an attempt has been made to analyze the existing water in the
Khulna City Corporation (KCC) area. And to identify its defects and
deficiencies with suggesting possible remedial measures. The analysis of
present and future water demand and supply is also made in KCC area. It
shows that about 30 million gallon water per day is needed again the study
shows that the above 90% people use tube well both shallow and deep for
their drinking purpose.
The water potentiality of this area is especially dependent for the
development of the surface and ground water source. The environmental
concerns related to development of water supply system include depletion
of water resource, impact on agriculture and industry, disposal of waste
water and loss of land.
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CONTENTS
TOPICS PAGE NO
ACKNOWLEDGEMENT 2
ABSTRACT 3
CONTENTS 4-7
INTRODUCTION 8
BACKGROUND OF THE STUDY 9
OBJECTIVE OF THE STUDY 10
EVALUATION OF EXISTING
WATER SUPPLY SYSTEM IN KCC 11
SURFACE WATER SOURCES 11
GROUND WATER SOURCES 12
PRODUCTION SOURCES OF KCC WATER SUPPLY 13
HAND TUBE-WELLS 17
EVALUATION OF TREATMENT SYSTEM 17
STORAGE AND DISTRIBUTION 18
FACTORS RELATING TO THE WATER-
POTENTIALITY 20
REGIONAL SETTING 20
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GEOLOGY OF THE STUDY AREA 21
STRATIGRAPHY 21
LITHO LOGY 22
STRUCTURE 23
GEOMORPHOLOGY 23
HYDROMETEOROLOGY 23
RAINFALL DISTRIBUTIONS 24
RELATIVE HUMIDITY 27
WIND SPEED 28
BRIGHT SUNSHINE HOURS 28
EVAPORATION AND EVAPOTRANSPIRATION 29
HYDROGEOLOGY 30
DRAINAGE PATTERN 30
AQUIFER PROPERTIES AND HYDROGRAPHS-
AQUIFER PROPERTIES 31
HYDROGRAPHS 31
NATURAL RECHARGE 33
DEVELOPMENT OPTIONS FOR WATER SOURCES 35
DEVELOPMENT OF GROUND WATER RESOURCES 36
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DEVELOPMENT OF SURFACE WATER 38
DEVELOPMENT STRATEGY FOR SURFACE AND-
GROUND WATER SOURCE 39
33
ENVIRONMENTAL ISSUES 40
SUMMARY 42
CONCLUSION 44
RECOMMENDATIONS 45
REFERENCE: 46
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INTRODUCTION
Lack of safe water is more prominent in the third world countries. In
Bangladesh, like many developing countries, there is a great demand for safe
water. Water is available in country apparently almost everywhere but
availability of safe water is the prime question. Now, Khulna city faces the
same problem. Khulna is the third largest city and second seaport in
Bangladesh. It is situated in southwestern part of Bangladesh along the
Bhairab and Rupsha rivers. These rivers are affected by tidal conditions and
contaminated by various industries and municipal untreated waste disposal.
As a result, surface water is not frequently used for various purposes. Ground
water is available in and around Khulna city from the shallow and deep
aquifers, Withdrawn of ground water by well is the primary source of water
for KCC water supply system.
The KCC water supply system is primarily based on small groups of
production tube wells and one surface water treatment plant. There are only
five overhead tanks in the city but two are not active. The total system has
been developed over many years and has been constructed using relatively
small diameter pipes. Water Works Department of KCC currently recovers its
operating costs through the holding tax, connection fees for new services and
a flat monthly charge based on the size of service connection.
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BACKGROUND OF THE STUDY
Throughout history water has been considered a natural resource critical to
human survival and human history can generally be considered to be water-
centered. Human survival and welfare generally depend on regular
availability and control of water. The people of developed countries has
easily access to the pure and sufficient water usages where the paradox of
community water supply in developing countries is that everyone has access
to water supply, but in fact many people do not. They may have access to
water but only at a large walking distance, in too little volume or poor quality.
A lot of effort is made in the world to change this situation, but have we been
effective and this situation really- changing?
In 1981, KCC was able to provide 5 million gallons of water in a day. But it is
not enough to serve the urban population because the total demand was 15
million gallons (Islam, 1984). In the year 1991 water supply capacity rose to 8
million gallons but demand rose even higher and KCC was able to supply only
34% of the total demand (KDA, 1997). At present the total demand of water is
about thirty million gallons but the supply of water is half of this by which only
30% people are served (KCC, 2001). About 90% of the total populations of the
KCC area collect their drinking water from shallow and deep tube wells instead
of network water supply system from KCC (KCC, 1997). On the other hand, the
water supply management of KCC is not systematic and having limited
expansion capabilities which requires designing, constructing and managing to
face future challenges.
As a common characteristic of the urban areas of Bangladesh, accessibility to
the suitable quantity and quality of water is a major problem in KCC. Unplanned
and improper withdrawn of water is the main causes of the shortage of water.
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These shortages become more acute when pumps are installed haphazardly. In
some of the cases the supply system suffers a gross water loss from old pipes,
poor system control and excessive consumer wastage. Sometimes, the
consumers suffer frustration because of inadequate storage capacity of the
system and the intermittent supply.
OBJECTIVE OF THE STUDY
This study has intended with the followings objectives:
To evaluate the existing water supply facilities in Khulna City
Corporation area.
To evaluate the existing usage pattern of water and analyzing the water
supply and demand situation in KCC.
To ascertain the sustainable sources of ground water for the area.
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EVALUATION OF EXISTING WATER SUPPLY SYSTEM IN KCC
Oceans and seas are the main source of water but they are not potable.
Fresh liquid water sources from land surface and in the ground constitute
only 1 % of the total water on earth. In Bangladesh, safe water for drinking
and other needs is available in surface water of rivers, canals, ponds,
reservoirs and lakes and ground water in shallow and deep aquifers; ground
water is the most important source of water supply in our country rather than
surface water and for the salinity the water supply system of KCC is mainly
dependent on the ground water.
In Khulna city, the quality of drinking water is apparently a more serious
issue than the, supply water. The primary source of water supply in KCC
area is mainly from the ground water extracted through production and hand
tube wells. The secondary source of water supply is surface water extracted
from rivers, ponds and wells etc.
SURFACE WATER SOURCES:
Every year vast quantity of surface water from the Ganges and its
distributaries flows through two-river system in and around Khulna city, viz.
Rupsha and Bhairab for 6 months. Beyond this period i.e. in the dry season
the river water flow is reduced and affected by saline water intrusion from
the sea. Dakatia Beel has also been included as a source of surface water
supply. There are other numerous ponds which are used as surface water
sources in KCC area. The existing ponds in KCC area is shown in the Figure
1.
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Fig 1: Location of ponds of KCC
GROUND WATER SOURCES:
Ground water in and around Khulna is available in both shallow and deep
aquifers. The shallow aquifers are extended towards north of Khulna town
and well developed in the west of Dumuria thana. The depth of shallow
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Scale1:25,000
aquifers varies from 0~100 m. Phultala and Rupsha areas have a good
potential for abstracting shallow ground water with acceptable iron content.
The Jessore-Khulna-Bagerhat ridge running almost parallel to the river
Bhairab and having a maximum width of 6 km, has hydrological relationship
with the adjacent depressed lands known as Dakatia Beel.
The deep aquifers are generally present below 150-300m. Water from
deep aquifers is almost pure and safe for drinking purpose and less
vulnerable to pollution from industrial waste and spillage. The contents of
iron and manganese are within permissible limits of WHO or Bangladesh
standard Investigations suggest that untapped ground water supplies are
available from around Khulna city, particularly Dumuria area.
PRODUCTION SOURCES OF KCC WATER SUPPLY
There are currently 43 production wells in operation. Total installed
capacity of the wells is in excess of 35,000 m3/ day but the yield to the
system is considered significantly less because of operating condition. Most
of the wells with some few exceptions in shallow aquifer are 150mm
diameter deep tube wells at an average depth of 275meters. Service is
intermittent as the pumps are operated for a maximum of 13 hrs in a day
divided into two shifts. These service periods are frequently interrupted,
which reflects reduced supply and level of service to the consumers. An
inventory of production wells was undertaken in 1994 which resulted that
there is a need for consideration of either rehabilitation or replacement of
worst performing wells in KCC. Production wells in KCC area are indicated
in Table 1 and drinking water production tube wells are indicated in fig 2.
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Serial no Location of well
Well no.
Year installed
Total depth (m)
Pump capacity m3/hour
1. Khalispur-1 1 1963 85 682. Khalispur-3 3 1973 238 683. Gollamari 10 1981 276 1364. DPHE/Rupsha-1 16 1982 201 685. R&D Compound 18 1982 253 686. Azam khan comm.college 19 1983 276 327. Circuit house 22 1983 198 688. Feri ghat-2 23 1983 256 689. Bagmara 24 1983 265 6810. Pollimangal 25 1984 262 6811. Khalispur pourashava 26 1984 226 6812. Taltala city college 27 1984 210 6813. DPHE/Rupsha-2 28 1985 197 4514. Hadis Park 29 1986 210 6815. Khalispur-5 30 1987 247 6816. Islamabad comm. Center 31 1987 270 6817. Sheikh para-2 32 1988 169 6818. Tutpara well field-1 33 1987 201 6819. KDA Nirala-1 34 1987 251 6820. KDA Nirala-2 35 1987 232 6821. KDA Nirala-3 36 1988 253 6822. Tutpara well field-2 37 1988 198 10223. Tutpara well field-3 38 1986 274 7024. Mujganni well field-1 39 1986 290 7025. Mujganni well field-2 40 1986 253 7026. Mujganni well field-3 41 1987 281 6827. Sisu park-2 42 1988 234 7028. Shonadanga 43 1987 283 6829. Arambag 45 1987 286 7030. Tarerpukur-2 46 1994 250 6831. Municipal tank road 47 1994 281 6832. Khalispur sewerage 47 1994 268 6833. Khalispur TV center 48 1994 254 6834. DPHE/Rupsha-3 49 1994 212 6835. Nurnagar 50 1994 245 6836. Zilla high school 51 1995 245 7037. Islamabad comm. Center 52 1995 274 7038. East Baniakhamar 53 1995 285 13039. Feri ghat 54 1994 323 7040. Khalispur (near club) 55 1995 266 6841. Alia Madrasa compound 56 1994 282 6842. Mosselman para 57 1994 214 6843. Sonadanga near police fari 58 1994 245 68
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Table 1: KCC Production tube wellsSource: KCC (2000)
Fig 2: Location of the drinking water production tube-wells and Selected holds in the KCC area.
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HAND TUBE-WELLS
The KCC statistical current information shows that KCC have 5650
hand tube wells of which 3800 are shallow and the remaining 1850 are deep
tube well. The yields of these tube wells were estimated by Haskonning 1981
as 3.3 m3/day for the shallow wells and 6.6 m3/day for the deep tube wells
estimates with this consultant concerns. The Table: 2 reflect the total picture
of tube wells.
Table 2: KCC Hand Tube wells
Descrition No. of wells Capacity (m3 /day)
Deep Tube well 1850 6.6Shallow Tube well 3800 3.3
Total 5650Source: KCC (2000)
It can be observed from the accompanying table that more than 4% of
both shallow and deep tube wells of KCC are not working. The status of
shallow and deep tube wells is shown in Table 3.
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Table 3: Status of Tube wells
Ward No.
Deep Tube wells Shallow Tube wells
Working Not workingWorking Not working
1 5 256 22 3 254 13 3 332 14 39 72 15 3 190 26 3 246 27 3 173 48 7 164 99 61 7 2
10 30 1 128 511 3 1 153 412 14 1 131 413 3 134 314 84 8 315 25 61 1016 82 13 -17 76 30 318 57 3 4 -19 43 7 21 420 57 5 35 821 42 3 68 1222 76 4 66 823 47 2 64 124 71 4 33 825 52 1 16 126 46 2 22 l27 57 57 45 528 56 1 29 229 44 21 4
30 643 45
14
31 83 7 2 4Total 1239 53 2761 128
Source: WWD, 2000
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EVALUATION OF TREATMENT SYSTEMThere is one surface water treatment plant. In 1921, it was founded in the old
city opposite the KCC office In this plant, raw water is pumped from the river
of Bhairab and delivered via rising main to a primary settling pond. Water is
pumped from the settling pond to two secondary settling tanks designed for
coagulation and settlement after mixing with a solution of own. The capacity
of each settling tank is such that a two hour sedimentation time is allowed.
Water from the settling tanks is then loaded into a single rapid sand filter
where the present filtration rate is 34 m3/hr. The treated water is then passed
underground storage tank. The water is finally pumped into a steel overhead
tank which is now in poor condition; water from the overhead tank is also
used to backwash the filter bed.
The treatment works operate for only seven months of a year, due to
salinity in the river during the dry season. The treatment plant is normally
operated for an average of 8 hrs per day and produces treated water of about
450m3/day. This amount is less than the yield of one newly installed
production well. Again, the production tube-wells are away from the
treatment system.
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STORAGE AND DISTRIBUTION
Storage Facilities Reservoirs
There are five elevated water storage tanks with a total capacity of
2815 m 3 but now three are running. The location of tanks is shown in
Figure 3 and Table 4 shows the inventory of existing overhead storage
tanks in KCC area.
Table 4: Inventory of Existing Overhead Tanks
SL. No. Location
Height of tank fromGL(m)
Maximumwater
level(m)
Storagecapacity(m3)
Material ofconstruction
1 Water Works 15.2 19.2 91 Steel
2 Ferry ghat 23 27.4 909 R.C.
3 H&S New colony 18.3 22.0 680 R.C.
4H&S Khalispur lal
hospital18.3 22.6 455 R.C.
5 DPHE 26.2 28.7 680 R.C.
Total 2815
Source: KCC (2001)
The main sources of water supply in KCC area are ground water. Above 90
percent usage water is extracted from the ground with the help of production
tube-wells, deep and shallow tube-wells and other private tube-wells. There
are only one surface water treatment plant which generates 450 m 3 /day and
43 production tube-wells. Besides, there are five overhead tanks and 262 km
of distribution lines.
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Over head tankPump houseRail wayHigh wayWard boundaryRiver
FACTORS RELATING TO THE WATER POTENTIALITY:
The occurrence movement and storage of ground water are governed by the
Litho logy, geological structure, thickness and depth of occurrence of
different geological formation along with the tectonic activities prevailing in
the area. The ultimate source of most dissolved ions in water is the mineral
assemblage in rocks near the land surface. The purity of crystal -size of
minerals, the rock texture and porosity, the regional structure, the degree of
fissuring and a good number of other factors might influence the composition
of water passing over and through the rock (Hem, 1970).An understanding of
Landscape and its formation is essential for the demarcation of catchments
boundaries, assessment of surface and subsurface water resource and the
planning of water development projects for irrigation development. All these
are relates with geology of that area. Hence the important role of geology in
assessing the hydrology and hydrochemistry of an area cannot be over
emphasized.
REGIONAL SETTING
Khulna city is located on the banks of the Rupsha and Bhairab rivers. It is
in the south west part of Bangladesh with it’s location on the axis of
jessore-mongla port, the second largest seaport of the country.
Geographically, khulna lies between 22o 49/ north latitude and 89o 34/ east
longitude and it’s elevation is 7 feet avove MSL. Khulna is bounded by the
Bhairab and Fultala thana, on the east by the Rupsha river, on the south by
the Rupsha river and on the west Dumuria thana. Figure shows the location
of the Khulna city in context of Bangladesh and Khulna district.The Study
area is mainly covered by the Ganges deltaic deposits and paludal deposits of
Quaternary age (ALAM, et. al., 1990). The deltaic deposits comprise of tidal
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FIG 3: Location of Pump House and Over Head Tanks
deltaic deposits, deltaic silt deposits and mangrove swamp deposits. The
southern part of the study area is low lying area, whereas the land level of
northern part is comparatively higher. The major portion of the area lies
between five and seven feet (1.5 and 2.1 meters) above the average sea level.
The northern part of the city is above the normal flood level. But the areas
lying at south east and west area usually inundated during the rainy season.
GEOLOGY OF THE STUDY AREA
Khulna is situated in the delta region and delta is divided into moribund delta,
central delta, basin immature delta, mature delta and active delta. Khulna is in
the immature delta. It is possible that subsidence has played a major part in
depressing this area There are many evidences of it, such as large ruins in the
heart of the swampy estuarine areas such as at Shekertek and Bedkashi
(Fawcus,1927), and presence of human artifacts and tree stumps, buried in the
alluvium many feet below the level of the sea. Hunter (1875) recorded the
presence of large tree trucks buried in the ground at Khulna town, indicating
subsidence of 6m.
STRATIGRAPHY
The Study area is covered by Holocene river alluvium comprising deltaic, terrace
meander, inter stream and swamp deposits. These Sediments continue to
accumulate from detritus deposits by the main river, particularly on the flood
plain of the Meghna. Tidal deltaic deposits are light to greenish gray,
weathering to yellowish gray, silt to clayey silt with lenses of very fine sand
along active and abandoned stream channels including crevasse splays, and
contain some brackish water deposits. Deltaic silts are light gray to gray, fine
sandy to clayey silt. Mangrove swamp deposits are found in the southern
margin of the study area. These are dark gray to black silt and clay deposited
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in the active tidal zone which is dominated by woody organic rich mangrove
swamps. Marshy clay and peat deposits occur in the central, northeastern and
northwestern side of the study area. They are gray and black herbaceous peat
and yellowish grey silt. There is no specific evidence of wells in the Study area
because of there general similarity in Litho logy to Holocene sediments and
lack of fossil evidence although the Sediments become progressively older
with depth.
LITHO LOGY:
The litho logy of the various sediments referred to above varies from clay,
through silt, to fine, medium and occasionally coarse sand The geometry of
individual Sedimentary units is inevitably complex and there is a general lake
of horizontal continuity on a local scale. Also, there is an upward finding of the
sequence, while the degree of sorting decreases with depth. Table 5 Show an
arbitrary subdivision of subsurface strata of the study area based on litho logy
and electrical-log.
Table 5: Stratigraphic Succession in Khulna (ALAM, et.a1.,1990)
Age Study area Lithology Thickness
Quaternary Khulna Clay, silty clay with occasional very
fine sand and traces of micas
13-65 m
Silt, silty sand, sandy clay, very fine to
fine sand, fine to medium sand
18-92m
Caly, silty clay, fine sandy clay 31-188m
Silty clay, fine to medium sand, 10-165m
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medium sand, some course sand
Peat is located in the deltaic pale is known from Kala Mouja in the Khulna
district (Ahmad, 1969, 7aher, 19G2): This peat bed has a thickness ranging
from some few centimeters to about 3.5m. This type of peat is highly humified
and its dark brown color indicates advanced decomposition of the organic
matter.
STRUCTURE
Major regional Structural feature of the Bengal Basin have been investigated
as part of oil/gas and mineral exploration, and various troughs, saddles and
faults can be identified within it. However there are no apparent major
structures within the Pleistocene to Holocene sediments of project area, such
as faults and folds, which would be hydrologic ally significant.
GEOMORPHOLOGY
Geomorphologic ally, the study area lays in the Ganges tidal flood plains.
In the Khulna all the soils are developed in alluvial sediments laid down by
the river Ganges. Most of the soils are seasonally shallowly flooded, grey to
dark gray in color with variable amount of brown and yellow mottling and
are silt to clayey in texture (SRDl, 1973) of Bangladesh.
HYDROMETEOROLOGY
The climatic condition of an area can be evaluated through analyzing the
climatic and hydrologic data. The climate and hydrologic data include
rainfall, temperature, humidity, atmospheric pressure, sunshine , wind
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speed, evaporation, transpiration, etc. among which the rainfall,
evaporation, transpiration component have a direct role in the hydrologic
balance and they are relevant to the hydrologic cycle of an area . The
climatic condition of an area has much influence on quality of water not
only in amount and kind, but also in the annual regime of water quality
fluctuation (SANTOS 1972). Hassan (1992) constructed the following path
of hydrologic cycle for South part (Khulna, Jessore ) of Bangladesh (Figure
4}and possibly it is the best fitted in Bangladesh.
Figure 4: Hydrological cycle for Bangladesh after (Hassan,1992)
Explanation: R= Rainfall, R-0= Runoff, E= Evaporation, T= Transpiration, I= Infiltration, PC= Percolation, EF= effluent, INF = Influent, O-F = out flow, Cp = Ca pillory Pressure and Sp = Seepage
RAINFALL DISTRIBUTIONS
Rainfall is an important component of hydrologic cycle. It is also the input
component of the hydrodynamic System of an area. Both the surface water
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and groundwater of an area could be derived from this component alone.
Less rain create imbalance in the hydrologic budget of an area while heavy
rains produce flush flood causing damage to humidity i.e. agricultural
products and others. Thus a long term rainfall distribution statistics through
out the year is very important for the local agro climatic condition which will
help in making the agricultural planning of an area (Hassan,1994).
Khulna receives an average rainfall of about 1800mm. The main source of
rainfall is the southwestern monsoon. Nearly 81 per cent of total rainfall
occurs during June-October. During March-May some rainfall also occurs due
to Nor'wester effect. Winter is the dry period with little or nearly no rainfall.
However, during the months of December and January little rainfall is
recorded. The monthly rainfall variation in Khulna city is shown in the Figure
3.2. (Environmental Maps and Work Book for Khulna City, Bangladesh)
Figure: 5 Monthly Rainfall (in mm) in the year of 2000 (Meteorology Department)
The mean annual rainfall is 1692mm at Khulna. The mean monthly rainfall
varies from 2mmto 341 mm. Other seasonal rainfall distributions on Khulna
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monthly rainfall in mm
0100200300400
month
rain
fall
in
mm
rain
are represented in the Table6. About 90%of its mean rainfall in Khulna was
received in May-October (monsoon period) and rest 10% of rainfalls was
received in November April (Non monsoon period).
MonthRainfall(mm)
Temperature(oC) RelativeHumidity( %)
Brightsunshine (hr) Maximum Minimum
January 2 26.25 11.6 73.63 212.6February 40 28.65 15.55 70.9 220.03
March 19.5 31.35 20.15 71.57 272.25
April 75.5 34.85 24.2 75.7 204.5
May 194 34.7 24.8 80.56 183.4
June 286 31.9 25.7 90.15 113.05
July 341 31.95 25.85 88.57 142.55
August 241 33.1 26.3 85 172.2
September 271.5 32.8 24.9 87.65 159.5
October 206 32.9 24.85 88.68 196
November 15.5 30.7 20.85 83.09 205.3
December 2 25.55 13.65 80.57 213.65
The recorded minimum mean monthly rainfall was in the month of
December which is 0.12mm (0.12%of total rainfall) and the maximum mean
monthly rainfall was in the month of July which is 341mm(20.14%of total
rainfall)About 80% of rainfalls were received in annually within the
Monsoon period(June to October) in Khulna . Considering the rainfall
intensity, it is seen that over 250mm/month of rainfall were received in the
May-October months of the year and this duration may be termed as wet
month. The rest months of the year may be considered as non monsoon in
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Table 6: the monthly average climatic data in climatic in Khulna region
Source: Meteorological department, 1997-2001
which less than 30 mm/month of rainfall were received from November to
April.
RELATIVE HUMIDITY
Relative humidity is inversely proportional to the temperature. Higher the
temperature lesser will be the relative humidity of the atmosphere. The
region has high relative humidity. In Khulna area the mean monthly relative
humidity varies from 90.15Qune) % to 70.90% (February) and the mean
annual is 81.35%. Tab le 6 gives the mean monthly relative humidity in
percent of Khulna and Figure 6. shows the monthly relative humidity
variation and Figure: 7 the relationship between relative, humidity and
temperature of Khulna.
Fig 6: Monthly Variation of Relative humidity (%) in Khulna
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relative humidity
020406080
100
januar
y
mar
chm
ay july
sept
embe
r
nove
mbe
r
relativehumidity
Y=0.331X -0.5402R2=0.3315
0 20 40 60 80 100Relative humidity (%)
Fig 7: Correlation between Temperature (0C) and relative humidity (0C) in Khulna
WIND SPEED:
Wind speed data at the meteorological office is reported as an average for
the day in Knots for the predominant wind direction of at 10m height. The
records indicate a significant variation in the mean wind speed across the
region. The monthly distribution of the wind speed also varies.
BRIGHT SUNSHINE HOURS
Bright sunshine is the important parameter in controlling the climatic
condition of an area. The air pressure of an area depends on the bright
sunshine and thus it control the wind blow(Direction and speed), evaporation
rate etc .The mean monthly bright sunshine in Khulna varies from 113.05
hours to 272.25hours in June and March respectively. The mean monthly
bright sunshine in Khulna is given in the T'able6, and the monthly brightly
sunshine variation is shown in the figure 8.
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Figure 8: Variation of monthly bright sunshine (hrs) in Khulna
The Study area experiences a wide variation in the distribution of sunshine
hours, ranging from a mean annual minimum of 5.2 hours of to a maximum
of 7.0 hours. As would be expected the sunshine hours in the monsoon from
June to September are much lower than during the rest of the year where in
excess of 8.5 hours of sunshine are not uncommon.
EVAPORATION AND EVAPOTRANSPIRATION
The evaporation and transpiration data along the rainfall are required to study
the hydrologic balance of an area. Evaporation is depended upon the
temperature condition of the atmosphere and it is directly proportional to the
temperature i.e., higher the temperature greater the evaporation. The estimated
mean maximum evaporation in Khulna area was 4.33mm/d (April), and the
mean annual evaporation was 2-mm/d. The Khulna area, the mean monthly
evapotranspiration varies from 2.67 mm/d (January to 5.12mm/d (April) and
the mean annual is 3.49mm/d.
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HYDROGEOLOGY
Hydrogeology is the Study of geological factors relating to the earth's
Water. The traditional Studies in hydrogeology focused on either the
mathematical treatment of flow through porous media or on a general
geological description of the distribution of rock formation in which ground
water occurs. Therefore the optimum development and management of
groundwater resource for mitigation human requirements must be
dependent on the proper investigation of the water bearing formations on an
area and its properties and characteristics (Bowen, 1986).
DRAINAGE PATTERN
The Study area is mainly drained by the Bhairab, Rupsha, and Pasur river
and numerous minor tidal; streams. These (Bhairab, Rupsha, and Pasur) are
actually a same river course but have different names in different locations
during their courses and gradually found their way by a Southerly route to
the Bay of Bengal. The Bhairab River, the most important river of the Study
area, enters the Study Area from the north near Phultala and flows in a
south easterly course at the northern part of Khulna district. It then passes to
the south, discharging a great part of its water into the Rupsha or Pasur,
while the main channel runs to the Southeast part Fakirhat and Bagerhat and
joins the Madhumatiat Kachua near Khullna. Bhairab is joined by the
Atharabanki which covers the surplus Water of the Madhumati into the
Bhairab.
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AQUIFER PROPERTIES AND HYDROGRAPHS AQUIFER PROPERTIES
Aquifer parameter data for the Study area are relatively Sparse. Based on
Pump test Data the aquifer properties of the upper aquifer namely
transmissivity of Khulna city area is 3900m` and the Storage co-efficient is
2.O× 103. Based on litho logy the Specific yield of upper aquifer is
16.60%.
Table7: Aquifer properties of The Upper aquifer of the study area:
Location Derived from
Litho logy
Derived from pumping test
Specific yield in
%
Transmissivity
in m2/day
Storage co
efficient×10 -3
Khulna 16.60 3900 2.0
Source: HASSAN, 1992 GWC, BWDBI 1985 &1986
HYDROGRAPHS:
Ground water observation wells monitored by BWDB and other
organizations concerned with ground water development show a pattern
which is characteristics of other alluvial areas in Bangladesh.
The characteristics Hydrographs pattern is:
A variation in ground water levels corresponding to the wet and dry Season;
Lowest water levels at the end of the dry Season in April/May;
A rapid rise following the onset of the rain, to field capacity (aquifer -
full condition) in the wet Season;
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A dry Season recession, to complete the cycle.
In many cases the lowest recorded water level during April, when the onset
of the rain was usually late. Hydrographs over a longer period often show a
general trend of increasing maximum depth of ground water. As a result of
increased pumping for irrigation. However, aquifer-full conditions are
always established during the wet season so it is also a process of storage
manipulation to increase recharge and is there fore a beneficial effect.
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NATURAL RECHARGE
In the contest of the alluvial aquifer of Bangladesh, the usual method of
evaluation of available ground water resources is based on a calculation of
recharge. Recharge is the process by which water infiltrates during the wet
season and restores in the groundwater levels to field capacity. It is usually
expressed as a depth of water per unit area, or as a seasonally available
volume. The groundwater System in the Study Area is considered to be in
hydrodynamic equilibrium condition, that is, the annual discharge is
approximately equal to the annual recharge. Recharge exceeds the discharge
during the monsoon period and the ground water rises but during the dry
season recharge is considerably less than discharge and then the ground water
levels decline. The Area under study, the primary source of natural research are
taken to be direct infiltration of rainfall and flood waters during monsoon,
other potential sources such as ground water inflows are considered to be
negligible(UNDP,1982: MPO/Harza, 1986). This water infiltrates. and fills the
unsaturated zone created by the dry season groundwater level recession. The
following component and processes are involved in recharge and discharge
mechanism of the ground water System of the study area as well as Bangladesh
(I-IASSAN, 1992).
Recharge (R) . Input
Components Processes
Rainwater Runoff, infiltration and percolation
Floodwater Runoff, infiltration and percolation
- 34 -
River water Infiltration and percolation
Seepage water Infiltration and percolation
Discharge (D) : out put
Components Processes
Artificial flow By using different types of tube ells.
Natural Flow By Steam flow activity (to river ponds and canal etc)
Capillary rise By differential atmospheric pressure
Evapotranspiration By heat, temperature and light.
In Bangladesh , about 26% of the total annual groundwater recharge is being
lost by discharging into cannels, streams and rivers before the start of the
irrigation season in the month of November (KARIM, 1982) The runoff has
been estimated as 20°'o to 40°'0 of the excess(P-PF) rain fall (UNUP,
1982).Considering the topographic configuration of the study area it may be
assume as minimum of 20% runoff of the excess rainfall that is equivalent to
138.53 mm/anam.
The estimated annul ground water recharge of the study area is about 196.2
million cubic meter, it can be considered as actual ground watrer research of
the study area. The available ground water recharge within this period can be
calculated by 26% deducted from the annual ground water recharge that is
equivalent to 145.18 million cubic meter of the area.
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DEVELOPMENT OPTIONS FOR WATER SOURCES
General Considerations for Water Resource Development
To develop the KCC water supply system we should keep in mind the same thinking because it is not apart from the horrific water deficit. We should stress the need for striking a balance between use of ground water and surface water.
Identification of potential ground and surface water sources for future
water supply of KCC is very essential and the evaluation is based on
the following criteria:
• Reliability and quality
• Sustainability
• Finance and economy
• Implementation consideration
• Environmental impact
• Institutional aspects
The following broad options are considered:
i) Development of ground water resources as a sole source of supply.
ii) Development of surface water resources as a sole source of supply.
iii) Development of a combination of surface and ground water resources
(conjunctive use).
- 36 -
Since the supply of water from the existing hand tube-well/production tube-
well is likely to go down, additional sources of ground water and new
potential well fields made to be explored immediately. New sources of water
resources also include availability of surface water from rivers in and around
Khulna city. Beel as a natural reservoir of surface rainwater, need
investigation to explore the possibility as a source of supply of potable water.
Surface water from natural rivers also needs evaluation as new and additional
sources of water. The ponds and lakes should be conserved as a surface water
source for KCC area.
DEVELOPMENT OF GROUND WATER RESOURCES
Ground water in and around Khulna is available in both shallow and deep
aquifers. The shallow aquifers are extended towards north of Khulna town
and well developed in the west of Dumuria Upazilla and the deep aquifers
are generally present below 150 to 300 m. The deep aquifer has been
intensively exploited by production wells of KCC and to some extent by
industrial well and private hand tubewells.
Ground water supplies are available from the following sources within
reasonable distance from Khulna city which are shown in Figure 9.
(i) Khulna city area
The previous modeling study monitoring data suggest that a continuous
abstraction of 59000m;/d of fresh water could be maintained for decades.
However, at present the shallow aquifer is only a reasonable source in the - 37 -
northern half of the city. The shallow aquifer has been developed by a few
production wells, numerous hand tubewells and many private motorized
tubeweils.
Fig 9: Potential ground water sources in and around Khulna city
(ii) Rupsha area
- 38 -
There are shallow ground water resources in this area. This area is expected
to grow rapidly after construction of the proposed Rupsha Bridge over the
Rupsha river. Therefore, the ground water resource can be developed in the
future for the local needs.
(iii) Dumuria area
Both deep and shallow ground water are available in central Dumuria. At
present shallow tube-wells are used for irrigation purpose, which indicate,
that there is a very high productive shallow aquifer in the west of Dumuria.
This source has probably highest potential ground water resources around
Khulna city (MSP, 1997).
(iv) Khalishpur-Phultsia area
Both deep and shallow aquifers are available in the same area within a strip
of a few kilometers wide from the northern part of Khutna city to Ahultala
and beyond towards Jessore. The shallow aquifer runs almost parallel to the
river Bhairab and on either side of the Khulna-Jessore road. The water
quality in both aquifers is good. The transmission distance and pipe lines to
augment city water distribution system will be less and so the development
of ground water resources (both deep and shallow) in the area will be most
economic option for meeting the city demand. Short and medium term needs
of the city can be met by developing new wells in the area.
DEVELOPMENT OF SURFACE WATER
Surface water from the Ganges and its tributaries flows through the rivers
Rupsha and Bhairab for six months. In the dry season the river water flow is
reduced and affected by saline water intrusion from the sea. Besides, Dakatia
Beef can be developed as a potential surface water sources for the KCC.
- 39 -
The delivery of fresh water from the river and surface water can be made
through the following methods:
i) By constructing a barrage at a location where saline water intrusion can be
checked. But it involves high cost for construction, operation and
maintenance;
ii) By developing a regional water supply system through potential
surface water resources; utilization of surface water stored in natural
depression / water bodies.
The Mayur river from Gallamri to Rayermahal has been developed as
water based recreational open space. This can also serve as a water
reservoir to meet the daily water consumption needs of the city dwellers.
This will necessitate to re-excavation of and protection of the rivers
supported by a treatment plant. The supply from this reservoir can be
linked with city water supply network.
DEVELOPMENT STRATEGY FOR SURFACE AND GROUND WATER SOURCES
It is considered that the general strategy for further sources development
should follow the principles summarized below:
(i) Short term (0 to 5 years)
• Continuation of use ground water from the deep aquifer in and around
Khulna;
• Development of new well fields for extracting water from the aquifers
north of Khulna in Khalishpur and Phultala area;
• Monitoring and evaluation of the impact of ground water development and
increasing abstraction.
(ii) Medium term (6 to 15 years)
- 40 -
• increased with drawl from the shallow and / or deep aquifers;
• Further development of new wells fields for extracting water from
the aquifers north of Khulna in Khalishpur and Phultala area;
• Continued monitoring and evaluation of the impact of ground water
development and increasing abstraction.
(iii) Long term (over 1.5 years)
• Further exploitation of available ground water resources in and around
Khulna;
• Continued monitoring and evaluation of the impact of ground water
development and increasing abstraction;
• Construction of a surface water abstraction and treatment plant for.
conjunctive use with ground water abstraction if or when required by the
inability of the ground water sources to meet the demands.
ENVIRONMENTAL ISSUES
Overview
The rehabilitation and expansion of the Khulna city water supply system
raises a number of environmental concerns which will be addressed at the
design stage. Though Bangladesh is continually threatened with inundation
and water is to be seen everywhere,
it is no longer a limitless resource which can be squandered. A combination
of increased water demand for agriculture, industry and domestic use, the
contamination of many sources by pollution, and decreased dry season supply
due to upstream diversion in India, has made water into a limited resource to
be husbanded and used efficiency.
- 41 -
The planned expansion of the capacity of the public supply system represents
both a significant increases in per capita demand and coverage of the
population. This results not only a major increases in demand in available
water sources but is likely to lead to a major increase in the releases of
polluted waste water.
System losses represent a tremendous wastage of valuable natural resources
which can not be afforded by Bangladesh. Therefore, the reduction of water
losses to an acceptable level is a critical mitigation measure required to make
the project sustainable, economic and environmentally acceptable.
The environmentally concerns related to the expansion of the Khulna Water
Supply therefore cover the following areas:
- Depletion of water resources;
- Impacts on competing water users (i.e. agriculture and industry) - disposal
of waste water; and
- Other impacts, including loss of land and resettlement for locating reservoir
and other water supply facilities.
The critical mitigation measure is water conservation, including the reduction
of system losses and wastages.
There are alternative sources include:
i) ground water,
ii) Surface water and
- 42 -
ii) Conjunctive use of ground water during the dry season and surface
water during the rainy season. The ground water withdrawal involves
the use of both shallow and deep aquifers.
Shallow aquifers are found to be fully recharged during the rainy season, and
the major concerns with the shallow aquifer are the possibilities of salt water
intrusion and contamination of the aquifer by effluent released at the surface
or to leach pits. The major concern with the deep aquifer is that withdrawals
should not exceed die safe yields of the aquifer. To be environmentally
sound, the impacts of water withdrawal on the aquifer should be carefully
monitored over the short term to determine the impacts of sustained
abstraction.
The use of surface water as a year-round source would involve the
construction of barrages, reservoirs, and water treatment plants. These
require the allocation of significant land areas which will diverted from other
productive uses such as agriculture, will interfere with natural river system,
and are likely to require the resettlement and the finding of alternatives
livelihood for a number of families. They therefore have the potential for
significant negative impacts.
Conjunctive water use, which involves the use of sweet water from the
Bhairab river during the rainy season and ground water during the dry season
when the Bhairab is saline, would significant reduce demands on ground
water aquifers. The allocation of areas for treatment plants and reservoirs
would be needed but such areas would be significantly less than required for
the year round use of surface water option. The conjunctive water use option
is therefore considered to be the most appropriate in the long-term to
maintain a sustainable water supply for Khulna with minimum negative
impacts.
Conservation
- 43 -
The existing water system in Khulna is extremely wasteful in term of water
losses. From an environmentally point of view, reducing wastages is a
critical issue, and environmentally acceptable option should be based on an
effective water conservation program.
Wastewater
Increasing water supplies will result in greater discharges of wastewater
which could significantly contribute to the contamination of surface and
ground water. Of greatest concern is the potential for contamination of the
shallow aquifer under the city. This could cause in a public health risk
leading to the need for water treatment or the possible abandonment of the
affected aquifer as a water source, resulting in increased demands of the deep
aquifers. To minimize the risks of contamination, an appropriate sewerage
system for collection and disposal of sludge and wastewater should be
seriously considered in conjunction with any major water system expansion
programme.
SUMMARY
To develop water supply system, there is need an identification of potential
ground and surface water sources in and around Khulna city and to develop
the collection system i.e. most of the existing wells should be tested. Besides,
the treatment and distribution system can be developed with the help of
proper technology. Again, there is need some policies to maintain the water
supply system i.e. incorporation of GIS and water policy etc.
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CONCLUSION:
Khulna is having a tropical monsoon climate characterized by high
temperature heave rainfall, often excessive humidity and fairly marked
seasonal variations. The mean annual 1997 to 2001 rain fall is 1692.5 mm
about 90% of the annual rainfall were received from May to October. The
minimum is observed in the months of January and December (0.12%) and
the maximum in the month of July (20.14%).The mean maximum
temperature in Khulna in the month of April (34.85 oC) and the minimum in
the month of January (11.6 oC). The mean relative humidity of Khulna is
81.35% and the mean monthly sunshine in Khulna is 191.2525 hours.
For the development and management of water resource of the study area, A
detailed climatologically, hydrological, and hydro-geological and hydro-
chemical subsurface mapping is necessary to be considered. The tropical
monsoonal climate characterized by relatively high temperature, heavy
rainfall, excessive humidity etc is suitable for the ground water potentiality.
- 45 -
RECOMMENDATIONS
From the study it becomes clear that the water potentiality of KCC area is
depend upon ground water source, surface water source and a surface water
treatment plant. But this is not sufficient for the KCC area people. So this is
very important to develop water system of KCC area. Here some points are
giving for developing water System for Khulna City Corporation area.
Establish new water well and water reservoirs.
Proper use of water resources.
Rain water harvesting.
Waste water treatment.
Proper use of surface water.
Less ground water withdrawal.
All storage tanks should be properly managed.
Development of water supply system.
Special attention should be given to ensure that service connections
don’t have any linkage.
Storage tank should be fitted with suitable taps to avoid the possibility
of loss of water.
And overall rising of social consciousness.
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REFERENCE:
1. Nazim Uddin, M., 2002, “A Study on water supply system of
Khulna City.” Environmental Science Discipline,
KhulnaUniversity, Khulna. (Thesis Paper).
2. Sultana Nasrin, 2003. “Physico-chemical and
Microbiological Aspects of Drinking water- A Case Study on
Khulna City Corporation, Khulna, Bangladesh”.
Environmental Science Discipline, Khulna University,
Khulna. (Thesis Paper).
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