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The Aggression of Human Activities on Chalanbeel a Threat on Wetland Environment: Study on Natore - Rajshahi Region of Bangladesh

M M Rahman
PhD fellow
Institute of Environmental Science, University of Rajshahi.

M R Rahman
Institute of Environmental Science, University of Rajshahi, Rajshahi-6205, Bangladesh

M Asaduzzaman
Executive Director. Bangladesh Science Foundation, Dhaka, Bangladesh.

Abstract/ Executive Summary:

The Chalanbeel is the main wetland of Northwestern region of Bangladesh. It is not only the source of water but also one of the main sources of occupation for thousands of people. It supplies fresh water as well as abundant of aquatic resources. This wetland is the large source of native fishes. It plays a vital role to keep the environment of the surrounding vast region balanced. It makes the land fertile, alluvial and alive for whole the year round. It is also a large reservoir of biological diversity of this region. Recently the aggression of man on this great beel increases in such a rate that the overall environment of this wetland fall in a crisis. It is going to loss its tradition and pride of her resources. Specially the aggression of settlement and road construction along the wetland hampered the natural characteristics. Reach it and an investigation was conducted to study the overall condition of the wetland. The observation indicates horror news for both the environment and its inhabitant of the surrounding area. Soils under lower Natore- Rajshahi region of Bangladesh with a view to evaluate the agricultural potentiality, environmental condition and their management options. The studied wetlands were nutritionally very productive. It is believed that the soils of this area became enriched by siltation during flooding. Soil textural condition is very much appropriate for rice production in these basin floodplains. The content of nitrogen and boron is low. Probably, the denitrification process leads to the loss of nitrogen in these soils; other nutrients seem to be in balanced condition for the successful growth of deep water aman and boro rice. High yielding boro rice got preference over broadcast aman and aus as major rice crops in the area. Availability of irrigation water in the dry periods and deep inundation level in the monsoon may be the main cause of such cropping pattern. Recently a problem is found that is the gradual decreasing of crop production in these areas. Both soil fertility and water table deterioration is noticed as the main causes of this alarming news for North Bengal. As this area is consider as the rice production zone of Northern region of Bangladesh. Over pumping of water during dry season is also a cause to deteriorate the environmental balanced of this wetland. For the betterment of grater environment of this area it is essential to take necessary step to stop all kind of human aggression on wetland. Public awareness should increase about the matter.

Keywords: Aggression, Chalanbeel, Wetland, Environment.

Location: Singra, Grudashpur and Boraigram upazila of Natore district, Chatmohar upazila of Pabna district, Tarash, Roygonj and Ullapara upazila of Sirajganj district and Ahasanganj and Manda Upazila of Noagaon district.

Start Date:

End Date:

Program Area: Risk Management in Agriculture

Non-commodity: Impact

Objectives:

The main objectives of this study are to (i) find out the causes responsible for loss of environment of wetland, Chalan beel (ii) Assess the importance of Chalan beel in economical and environmental context (iii) Indicates the threats of wetland occurred due to human aggression (iv) Provide proper recommendations to protect the natural environment of Chalan beel.

Methodology:

LOCATION OF STUDY AREA Chalan Beel is an extensive lowland area in the old Brahmaputra and lower Atrai basin. It is located between 24.35 to 24.700 north latitude and 89.10 to 89.350 east longitudes. It covers an area belonging to Singra, Grudashpur and Boraigram upazila of Natore district, Chatmohar upazila of Pabna district, Tarash, Roygonj and Ullapara upazila of Sirajganj district and Ahasanganj and Manda Upazila of Noagaon district. It consists of a series of beels connected to one another by various channels to form a continuous water body during the rainy season. The materials of the surface area are of recent to sub-recent age. According to an estimate of Brammer (1968), the age of these soils may be around 200 years. The lithology of the recent and sub recent alluvia dominated by silt and clay sized particles (Brammer, 1971). The main rivers in the study area are the Atrai, the Tista and the Jumuna and the courses of these rivers appear to be nearly stable. About 90% of the area is affected by seasonal flooding. Depth and duration of the flooding vary with topographical position and are mainly controlled by the rainy season water levels of the main rivers and their tributaries. Four extensive use of wetland by the men is hampered the natural condition of the study area. Specially the over pumping of water for irrigation in winter season for Robi cultivation makes the area imbalance in many respects. Due to over pumping of ground water the water table in the study area reached down. Study found the water table of this belt reached about 3 meters down during March to May. The aquifer loss its required water due to over pumping by shallow and deep tube well. It is found by pilot survey report on the concern area that 13 thousand shallow and 23 hundred deep tube well settled here for irrigation purpose. Singra series is located at 240 21/ 49//N to 240 42/ 22/ N and 880 02/ E to 80 880 24/ E in the medium highland phase. It is seasonally shallowly flooded, poorly drained soils developed in mixed textured alluvium occupying in the gently sloping ridges. They have mixed grey and dark brown, friable, silt loam to loam subsoil with strong to moderate sub-angular blocky structure and patchy to continuous grey cutans on ped faces. Boraigram series is located at 240 10/ N to 240 22/ N and 880 01/ E to 880 18/ E in the slope of basin. It is poorly drained, seasonally deeply flooded soils developed in the basins and basin margins of old Brahmaputra floodplain. They have a grey to dark grey, clay sub soil usually with strong prismatic and angular blocky structure and continuous grey or dark grey cutans along the ped faces. Atgharia series is located at 240 07/ to 240 66/ N and 880 15/ E to 880 26/ E in the nearly level basin sites. It comprises seasonally very deeply flooded, very poorly drained, moderately fine textured soils developed in the Tista valley of the Atrai basin. They have a dark grey to very dark grey, mottled brown, silty clay loam sub soil. Tarash series is located at 240 20/ N to 240 340 N and 880 08/ E to 880 33/ E (Banglapedia- 2003) in the basin depressions. It comprises seasonally very deeply flooded, very poorly drained soils developed in fine textured alluvium on the Buri Tista valley of the Atrai basins. They have a very dark grey, silty clay to clay. A horizon with common brown mottles overlying a silt loam to silty clay loam oxidized substratum. Soil samples were collected and air dried, grinded and screened through sieve. The samples were analyzed for pH, organic matter, N, P, K, Ca, Mg, S, B, Cu, Zn, Fe and Mn. The extraction procedure and interpretation of soil samples were made as Agro-Services International methodology and pH (H₂O) of soils was determined at a soil-water ratio 1:2.5 using a pye pH meter. The organic carbon content of soils was determined volumetrically by wet oxidation method as described by Jackson (1996). The total nitrogen in soils was determined by Kjeldahl’s method as described by Jackson (1996). Available phosphorous was determined by Olsen method (Jackson, 1962). Ammonium acetate extract was prepared and the exchangeable Ca, Mg, K were determined from the extracts (Black, 1965). Soil physical attributes were assessed in the field using standard field methodology (FAO, 1977).

Source of Information: J. Sci. Foundation, 8(1&2): 151-159, June-December 2010 ISSN 1728-7855

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Achievement/Findings:

This study provides an overview of the current resources and fisheries status of the Chalan beel, which reveals not a good message for man and environment. The study also identifies the scope of opportunities to evolve existing fisheries management strategies, focusing on fish biodiversity conservation. This largest, most important watershed in the North Central Bangladesh, and covers an area of about 375 km2 during the monsoon season is now in threat. The watershed serves about 5 million people, predominantly through fisheries and agricultural activities. Although considerably degraded over time, Chalan beel still supports a diverse ichthyofauna of major importance to the local economy and people's livelihoods. The Chalan beel area incorporates 21 rivers and 93 smaller seasonal beels of varying size. Most of the rivers and beels are at risk of 156 partial or total degradation, as a result of agricultural encroachment, siltation and other anthropogenic activities. During the study, 83% of the rivers, and 68% of the beels in the lean season, shrunk to 0-5% of their maximum (monsoon) water-spread area during the dry season (i.e. critical levels for survival of many fish species). A fish catch survey was carried out in the main fishing season (July to December) over two successive years in the three most important catchments areas; namely, the Gumani, Baral and Katagang Rivers. The study results indicate at least 19 fish species once considered abundant can now be classified as threatened, with a possibility of local extinction. In 2005-2006, the annual fish production in Chalan beel was 12 217 tons, being less than half of the production observed in 1982. The stakeholders identified several major causes they thought were directly responsible for the continued decrease in fish production and biodiversity of the beel area. Several management strategies were suggested by the same stakeholders, and the findings are discussed in the context of overall developments in the Chalan beel fisheries related to habitat and biodiversity management. Study focused mainly on causes responsible for the loss of natural environment of the wetland and found human aggression as the prime factor responsible for it.

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