THE IMPACT OF DREDGING IN THE PASHUR RIVER ON AGRICULTURAL LAND AND ECOSYSTEM ASSESSMENT ( Funded by Water Keeper)

Introduction

The World Heritage Committee of the United Nations for Educational, Scientific and Cultural Organization (UNESCO) prepared and submitted a report concerning the Sundarbans World Heritage Property, Bangladesh to the government on November 28, 2016, according to the Decision 39 COM 7B.8. This was the first document that showed the importance of occasional dredging in the Pashur River in Mongla. The Pashur is a tidal river, and its siltation rate is high. As such, to ensure navigability, occasional dredging is essential. This occasional dredging does not only help to maintain the navigability of the Pashur channel; rather it ensures a sufficient volume of water to maintain the ecosystem including biodiversity in and around the Sundarbans. Without dredging the river would have been silted up with high detriment to the mangrove ecosystems. According to the report, the area has less fertile and minimum agricultural land and the dredged material of Mongla Port to Rampal Power Plant will be disposed of in the low laying area of acquired land by Bangladesh Power Development Board. The total area of low land is 1834 acres. Up to 2016, 485 acres have been developed and the remaining area is to be used for disposing of the dredged material. The disposed of the dredged material will be protected by an earthen dyke/ embankment to prevent the spill of dredged material into the river. As far as dredging of the outer bar is concerned, the dredged material was to be disposed of in deep-sea during ebb tide only along the south-east side of fairway buoy, where present water depth is around 28 m from CD, and which is far away from Swatch of No Ground.

Unfortunately, these resolutions mandated by UNESCO was not followed to date. Presently, the GoB has planned to dredge the Pashur river from Mongla port to the Rampal project site which is around 4 km river distance from the Sundarbans Reserve Forest (SRF) and around 80 km River distance from the World Heritage Site (WHS). Although the EIA presented for this dredging project was in favor of the operational and maintenance of the Rampal Coal Power Plant, in reality, this is degrading the local environmental and ecological landscape. The environmentalists say that it is a signal that the operation of a power plant so close to the forest would inflict damage on it. According to the ECNEC meeting, the Pashur river is being dredged at a depth of 8.5 meters so that large ships can sail into it. The biodiversity of the Pashur river snaking past the mangrove forest is threatened by vessels that dump oil into its water. Most importantly, the soils extracted from the Pashur river are being dumped on the nearby agricultural fields which are threatening the already less fertile agricultural lands. Field-based observations, consultation with local people, and representatives of the local government ensured that the agricultural lands are not being preserved from dumping of this dredged soil. However, the policy says no agricultural land is tampered/damaged, might be dumped plan-wise in shallow places in the river upon technical considerations, connection khals (channels) are not disconnected, etc.; and the best way of management to fillin up low land (following Conservation Act 2000) or pile in government-owned khas (wasteland). Unfortunately, these policies are not in place and the dredged soils from the Pashur River are being indiscriminately dumped on the nearby agricultural lands which may threaten the e, ecological, livelihood, biodiversity, and aquatic life options of the whole area.

British Standard (1991), Abul-Azm and Rakha (2002), Bogers and Gardner (2004), England and Burgess-Gamble (2015), Gob et al. (2005), Jonge et al. (2012), Cai et al. (2012), Freedman and Stauffer (2013) studied on the dredging related activities, deposition of dredged soil, impacts, policies, etc. in different countries. Institute of Water Modeling (2015) studied the feasibility study on the capital dredging in the Pashur river from Mongla Port to Rampal Power Plant.

From the above literature review and initial observation, it is evident that abandoning the dredged soil on these agricultural lands leads to a myriad of environmental problems. Against this backdrop, it is necessary to assess the effects of river‐dredged sediments on nearby agricultural soil health and related physico-chemical changes. More specifically, assessment should be on the following elements (not exclusive) of the nearby agricultural lands that are being affected by dumped soils extracted from the Pashur River:

1.     E1. Ecology and Biodiversity

a.      Loss of habitat and degradation of habitat quality of endangered life forms, such as animals, insects, birds, and trees.

b.     Change in the local food chain and ecological biology.

a.      Land reclamation using fill material from offshore sources.

c.      Prevention of re-colonization of the sites by native life forms and species.

2.     Soil Fertility of the Agricultural Lands

a.      Change in degree of change in soil compaction and composition.

b.     Extreme acidification and heavy metal pollution.

c.      Evidential information on the decrease in soil pH, Ca, and Mg.

d.     Evidential information on the decrease in the levels of soil Mn, Cu, Fe, Zn, and Si.

3.     3. Local Livelihood

b.     Loss of land and house of local people.

c.      Migration to other areas due to infertile lands.

4.     4. Aquatic Life

a.      Impact on increase/decrease in fish number and species.

no such data are available on the impact of dumping dredged soil on the agricultural lands, ecosystems, and also the impact of dredged soil on the surrounding human inhabitants.

Under these circumstances, it has become imperative to institute an investigation on the impacts of dredged soil on the agricultural lands, ecosystem, and surrounding inhabitants; especially (i) loss of habitat and degradation of habitat quality of endangered life forms, such as animals, insects, birds, and trees; (ii) change in the local food chain and ecological biology; (iii) land reclamation using fill material from offshore sources; (iv) soil fertility of the agricultural lands, (v) change in the degree of soil compaction, composition, and physico-chemical conditions; (vi) loss of land and house of local people; (vii) migration of villagers to other areas due to infertile lands, etc.

• Research Project