Development and testing of a bioticindex to assesstheecologicalquality of lakes in Bangladesh

Appendix A. Full description of study sites.

CENTRAL BANGLADESH
Dhanmondi Lake (N 23°44'41.8"; E 90°22'38.3") is the part of Dhaka's history, situated in Dhanmondi residential area, one of the most crowded areas in the middle of Dhaka City. The area was developed in 1956, including the lake, which occupies about 16% of the total area (Chowdhury, 2003b; Khan and Rahman, 2010). This lake has been playing a vital role in maintaining the only drainage system of Dhanmondi and adjacent areas (Chowdhury, 2003b). Part of this lake still functions as a storm-water drain and falls into the Begunbari Khal. Urban expansion in this area during the Pakistan period has changed the natural water system here. The area of the lake is about 176,000 m2(JICA, 1987; Khan and Rahman, 2010) and the lake is fairly uniform in depth, ranging from about 0.5-1.5 m. There is one box culvert in the lake near Sukrabad area, which is the only outlet of the lake. Excess floodwater due to heavy rainfall passes through this outlet. The lake is managed by several authorities looking after its various aspects. In and around Dhanmondi Lake some renovation works were carried out from 1998 to 2001 with a view to making the lake a pollution-free recreation zone (Chowdhury, 2003b). Pollution sources for this lake have been identified as sewage from the hanging toilets of the floating population around the lake, municipal waste water and effluents from adjacent industries, tanneries, hospitals, pathology centres and garbage from restaurants and homes.

Ramna Lake (N 23°44’57’’; E 90°24’89’’) is located inside the Ramna Park, on the west side of the Ramnathana of Dhaka city. The area of the lake is about 35, 000 m2and the depth ranged from 0.69-2.1 m. The present shape of Ramna Park was drawn up in 1952 and the lake was excavated and extended. This lake controls the drainage system of a particular area (Chowdhury, 2003a). Major sources of discharges into the lake were observed as garbage from the Ramna Hotel besides the lake and from floating human population in and around the park area.
Gulshan Lake 1 (N 23°46'43''; E 90°25'12'') and Gulshan Lake 2 (N 23°48'9"; E 90°25'49") lie in the central Dhaka metropolitan area. Gulshan Lake 1 and Gulshan Lake 2 jointly occupied an area of about 850, 000 m2in the city. They are in low-lying land in the Gulshan, Banani and Baridhara residential areas, and were originally ox-bow lakes. They were deepened (about 2-5 m) during the 1970s to provide an environment-friendly landscape. Many drains discharge into both lakes and due to human interference, the depths of the lakes are rapidly decreasing. As a result of years of sewage discharge, effluents and pollutants from factories in the large industrial zone (Tejgaon industrial area) south of the lakes, indiscriminate pollution and illicit dumping, discharges in to the lakes from the slum areas adjacent to the lakes. More recently, due to pollution in city areas, almost all lakes in Dhaka are now severely impacted, and are among the most polluted water bodies in Bangladesh (CWBMP Inception Report, 2003; Islam, 2003; Khan, 2003). According to Islam (2003), these two lakes have been considered to be critically threatened and declared as an Ecologically Critical Area (ECA)-environmental protection zone in 2001. The people of the Gulshan-Baridhara areas were not aware of the status of the lakes and the conditions of both lakes are deteriorating, as it has been used as a waste-dumping ground.
Jahangirnagar University (JU) Lake 1 (N 23°53'02"; E 90°16'07") and JU Lake 2 (N 23°53'14"; E 90°16'28") are close to the JU Registrar building. The area of the JU Lake-1 is about 70, 000 m2 and JU Lake-2 is about 130, 000 m2. Depth of these two lakes ranged from 0.15-1 m. These lakes are important wetlands for wild waterfowl. The migratory birds begin to come here in September every year and stay until March-April. It is reported that about 8,000 to 10,000 birds came to the campus in winter just five years ago, but now the number is only 3,000 to 4,000. Siltation is a major problem for the lakes. The Daily Star (2004) reported that the lakes were leased by the university authorities for commercial fish cultivation that posed threats to the lakes, as fertilisers such as TSP, urea and lime used for fish cultivation were recorded to increase the ratio of nitrogen, phosphorus and decrease dissolved oxygen content in the water. Jahangirnagar University is included in the MadhupurShal tract zone of the 12 ecological zones of the country (Alam and Chowdhury, 2003).

SOUTH-WEST OF BANGLADESH

MarjatBaor(N 23°18'10"; E 89°06'09") is located between Kaliganjupazila (under Kashtobhanga and Rakhalgachi union) and Chaugachaupazila (under Jatrapur, Hakimpur, Patibila and Jagadishpur union) of Jhenaidaha and Jessore districts. This baor is crescent-shaped and the area is about 2,000,000 m2. Depth is ranged from 0.5 to 6 m. The Director General of the Department of Environment (DoE) officially declared MarjatBaor an Ecologically Critical Area (ECA) – an environmental protection zone in 1999 (Alam, 2003; DoF, 2008-09).
BergobindopurBaor(N 23°13'6"; E 89°01'49") is located in Chaugachaupazila of Jessore district. This baor is horse-shoe shaped (Alam, 2003; DoF, 2008-09). Area is about 1,900,000 m2and depth of the lake ranged from 1.5 to 6 m.
KathgoraBaor(N 23 0 16'57.1"; E 88 0 57'06.0") is located in the Maheshpurupazila of Jhenaidaha District. Shaymnagar, Bishwanathpur, Mandarbaria, Kashypur, Shahpur and Porapara are the adjacent villages of this baor. This is a plate-shaped baor (Alam, 2003; DoF, 2008-09). Area is about 1,400,000 m2 and depth of the lake ranged from 1 to 4.5 m.
FatehpurBaor(N 23°22'26"; E 88°54'09") is located in the MaheshpurupazilaofJhenaidaha District. Berermath, Kanaidanga, Ektarpur and Begumpur are the villages adjacent to this baor (Alam, 2003; DoF, 2008-09). Area is about 470,000 m2and depth of the lake ranged from 0.5 to 5 m.
JoydiaBaor(N 23°26'40"; E 88°55'47") is located in the Kotchandpurupazila of Jhenaidaha District. Chaturpur, Baloramnagar, Narayanpur, Joydia, Laxmikundu and Roypur villages are located on the east of this baor and Keshtopur village under Jibannagarupazila of Chuadanga district is located on the west (Alam, 2003; DoF, 2008-09). Area is about 1,800,000 m2and depth of the lake ranged from 3 to 7 m.
BaluharBaor(N 23°24’85’’; E 88°59’14’’) is located in the Kotchandpurupazila of Jhenaidaha District. Baluhar village is on the east of the baor and Ramchandrapur village is on the north. Gobindopur, Rahamatpur, Shingya villages are located on the west of this baor, while Bajrapur village is on the south. Kaliganj-Chuadanga road crosses over the south of the baor. Kagmari village is located in the middle (Alam, 2003; DoF, 2008-09). Area is about 2,800,000 m2and depth of the lake ranged from 1.5 to 5 m.

NORTH-EAST OF BANGLADESH

BaikkaBeel(N 24°21'07"; E 91°42'08") is managed by Baragangina Resource Management Organization (RMO), overseen by Sreemangal Local Government Committee through agreement with the Ministry of Land, Government of Bangladesh. BaikkaBeel in Hail Haor wetlands, near Sreemmangal, was declared as a sanctuary in 2003 to protect the wetland, fish, birds, plants and animals of Hail Haor - one of Bangladesh’s “mother fisheries” and an international “Important Bird Area” (MACH, 2006; Thompson and Colavito, 2007). BaikkaBeel complex includes three khasbeels - Chapra, Magura and Jaduria that retain water year round, together with surrounding marshy areas they form the 1,000,000 m2BaikkaBeel sanctuary. This sanctuary protects 98 fish species and 160 bird species found in the haor. Wetland habitat, including swamp forest, has been restored, and fish yield in the rest of the haor have increased (Alam and Hossain, 2003a). Depth ranged from 0.5 to 3.5 m. Baragangina RMO is responsible for protecting and maintaining the sanctuary. It is advisedand supervised by Sreemangal Local Government Committee, which includesgovernment officers, Union Parishad chairman, and leaders of other RMOs. Management is supported by Ministry of Fisheries and Livestock through an endowment fund. In accordance with the approved sanctuary management plan, Baragangina RMO charges modest visitor fees, which are used for maintaining the sanctuary. The RMO accounts are publicly available and are audited by Upazila officials. (MACH, 2006; Alam and Hossain, 2003a).
HakalukiHaor(N 24°37'56"; E 92°05'14") is located in greater Sylhet; it offers a very different type of marsh wetland ecosystem. It is one of Bangladesh's largest, and one of Asia’s larger, marsh wetland resources. HakalukiHaor itself is a complex of more than 80 interconnecting Beels located in the Maulvi Bazar district. During the dry season, the Beels cover an area of about 4,400 ha, but, during the rainy season, the entire area gets flooded, and the Beels are united as one large lake, or haor, with an area of about 18,000 ha. This makes it the largest haor in Bangladesh (Alam and Hossain, 2003b). Depth of the wetland ranged from 1.5 to 9.5 m. HakalukiHaor is a highly-significant site for a wide variety of waterfowl. It is important for wintering migratory birds. This site has been proposed to be declared a Ramsar site. This has also been declared as Ecologically Critical Area (ECA) in 1999 (Islam, 2003).

Fig S1.Some of the lakes surveyed in this study to develop a biotic index for Bangladeshi lakes.

Fig.S2 Example of human perturbation in Bagladeshi lakes. Gulshan Lake 1 and Gulshan Lake 2 are declared as Ecologically Critical Area in 2001. In spite of bill boardsset by the Department of Environment at the bank of the lake area, these two lakes are used as waste dumping grounds from different slum areas.

References

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Alam, M.S. and Chowdhury, M.H. 2003.Wetlands.In: Banglapedia - national encyclopedia of Bangladesh. (ed. S. Islam, S. Miah, W. Ahmed, A.M. Chowdhury, S.M.M. Rahman, K. Siddiqui, S.M.H.Kabir, A.Kabir, K.M.H.Huq, F.Alam, B.A.Kamal, and S.Akhter). Asiatic Society of Bangladesh.

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