Aug 11, 2010

Issues on Drinking Water Resources in Khulna

Water supply in Khulna relies on groundwater. Groundwater is being depleted in many areas of Bangladesh. In Khulna although arsenic contamination of groundwater is limited, increase of groundwater withdrawals is expected to be difficult from groundwater at the current extent.
Khulna has an enormous excess of surface water in the summer months (July to October) and relative scarcity in the winter months.

A water treatment plant (WTP) of which capacity was 450 m3/d had commissioned in 1921 on the right bank of the Rupsa River where currently KWASA office exists on. The operation of this WTP was pulled out several years ago due to depleting. Consequently current water supply is entirely depends on groundwater.

There are salinity issues in the Southwest region in Bangladesh, attributed to reduced dry season river flows into the area from the Ganges System. During the 1990s dry season, salinity levels in the Khulna area rose, for which one of the likely causes was postulated to be the decrease in dry season surface flow from the Ganges.


The temporary decommissioned surface water treatment plant is located in the same precinct of KWASA’s Office. The system of this plant is as follows;
  1. Raw water is pumped from Bhairab River and pumped up via a rising main to a primary settling pond.  
  2. Water is pumped from the primary settling pond (desilting basin) to two secondary settling/coagulation tanks designed for coagulation and settlement after mixing with a solution of alum. 
  3. Water from the settling tank is lead into a single rapid-sand filter. 
  4. Chlorination of the filtered water takes place by the introduction of bleaching powder in solution (calcium hypochondria). 
  5. The treated water is then passed into underground storage tanks from where it is finally pumped into a steel overhead tank.  
  6. Water from the overhead tank is also used to backwash the filter bed. 
  7. The capacity of the plant is desisted to produce 450 m3/d. 
  8. Before pulling out operation, the plant was operated for only seven months of the year due to salinity.

Production tube wells (PTW) have been constructed since 1962.  Since then they have been demolished and newly constructed constantly. And currently 33 big tube wells (6 inch diameter) and 22 small tube wells (3 inch diameter) have been operated by KWASA.
Table: KWASA’s Production Tube Wells
Big Tube Wells
Small Tube Wells
Sr
Name
Ward
Const. Year
Sr
Name
Ward
Const. Year
1
R & H Baikali
9
1980
1
Habeliloug
26
2008
2
Nirala WF -1
24
1986
2
Khulna Circuit House
21
2002
3
Nirala WF -3
24
1986
3
Ferighat - 3
20
2002
4
Sonadanga -1
17
1987
4
Khalispur Noyabati More
10
2002
5
Arambag
25
1987
5
Mujigunni Well Field - 3
9
2002
6
Tarer Pukur
27
1987
6
Municipal Trank Road
29
2004
7
Zilla School
22
1994
7
Noornagar Mosque
16
2002
8
Hazi Malek College
31
1994
8
Khalispur Durbar Shanghe
10
2002
9
Shaikh Para Bazar -3
20
1994
9
Alia Madrasha
29
2002
10
250 Bed Hospital
16
1995
10
Scout Bhaban
10
2003
11
Noor Nagar Fire Service
16
1995
11
Mistripara Bazar
27
2004
12
Rupsha Kashai Khana
30
1997
12
Khalispur Maternity Hospital
10
2003
13
Sonadanga KCC Park
17
1997
13
Khalispur 12 No. Road
12
2003
14
DC Office
21
1997
14
Boyra Public College Back Side
14
2004
15
Sir Iqbal Road Park
23
2000
15
Sonadanga Sweeper Quarter
17
2004
16
Khalishpur Jheel Pukur
10
2000
16
Front of Sonadanga PS
18
2004
17
Madina Mosque Boyra
16
2000
17
Zilla School Quarter
22
2004
18
Babu Khan Road
29
2001
18
Tootpara Tahalla Hospital
30
2005
19
Nirala KCC Park
24
2001
19
Royer Mahal
14
2006
20
West Baniakhamar Urban
26
2002
20
Toyelea Mosque Khalispur
11
2006
21
Boshpara Grave Yard
25
2002
21
Charerhat Ghat
13
2008
22
Mujgunni Lebutala
9
2002
22
Nazurul Nagar Islamabad
19
2008
23
Mujgunni Battalla (MSP)
9
2003




24
Khalishpur KCC Branch Office (MSP)
10
2003




25
East Baniakhamar Madrasa(MSP)
27
2003




26
KDA Approach Road (MSP)
17
2004




27
Sher E Bangla Road Park (MSP)
26
2004




28
West Toot para Primary School (MSP)
28
2004




29
PTI More (MSP)
23
2004




30
KCC Rest House (MSP)
29
2004




31
Shaikh Para Bazar Mosque MSP)
20
2005




32
Old Gallamari Road (MSP)
25
2005






The average depth of the tube wells is approximately 270 m.  Tube wells are generally equipped with 10 to 13 stage vertical turbine pumps connected to 150mm or 75mm dia rising mains and powered by vertically mounted electric motors. The pump discharges are directly into the distribution systems, where the system pressure varies between zero and several meters.

Currently KWASA has about 10,000 hand tube wells. As of now the handover of KCC asset is still on process and KWASA has no distribution system as-built drawings. Based on the discussions with KWASA engineers it can be assumed that there are approximately 230 km of pipelines with pipe sizes varying from 75mm (3 inches) in diameter to 250 mm (10 inches) in diameter in Khulna. The distribution systems had been progressively developed over the years. Several development agencies, including DPHE, KDA, and HSD, had been responsible for design and installation, and the completed systems had been subsequently handed over to KCC for O&M.  Then those distribution systems have handed over to KWASA. Under the ongoing DPHE/GOB “Crash Programme”, an additional 40 km of distribution pipeline will be laid and subsequently handed over to KWASA for O&M.


There were five elevated water storage tanks with a total capacity of 2,815 m3. Two of them were completely demolished. As to one of them, the tank itself was demolished and only the supporting stand remained.  And another one is defunct and the last one is waiting to be repaired. Consequently, no storage facilities (over head tanks) are being operated. In Khulna, as in other cities with non pressurized system, consumers generally have their own storage tanks (ground tanks) to provide system balancing and storage for the consumer.

Service connections comprise 15, 20, 25 & 50 mm diameter GI pipes connected to the distribution main via a saddle clamp. The service connection normally ends up an underground tank and in some cases, where there is sufficient pressure in the distribution mains, directly into a roof tank. The tanks do not usually have float valves so the tanks overflow when full. The tanks vary in capacity from 400 to 600 litres. The plumbing systems of buildings have service connections comprising 15 mm and 20mm diameter GI pipes. Houses in high income areas are generally fully plumbed. In January 1995, KCC records showed a total of 11,000 service connections of which 10,876 were domestic connections and 124 were commercial and institutional. JICA Study Team has measured flow of 30 samples of recorded connections. The results of this measurement are on the process of compiling.

About 500 street hydrants have been installed, the majority in low pressure areas. The hydrants generally consist of a 20mm diameter GI pipe connected to the distribution main, similar to house connections. Stand pipes have a 20 mm diameter GI pipe encased in concrete. The majority of hydrants appear to be dry during supply hours. Some hydrants have been blanked off and some have broken taps; it was reported that about 200 hydrants are non-operational.

A large number of deep and shallow hand tube wells, fitted with hand pumps, supply water to residents, especially in the northern part of the KCC area. Many private organizations, factories, schools and other educational institutions have their own tube wells because the public supply is so unreliable.
There is no legislation to control the exploitation of groundwater in Khulna. Private tube wells can be sunk without a permit. As water is a valuable and limited resource in Khulna, an inventory of private wells is essential.