Fisheries and the Environmental Challenges of the Gorai-Madhumati River System
•
0 likes•1,128 views
By M. Niamul Naser, University of Dhaka Revitalizing the Ganges Coastal Zone Conference 21-23 October 2014, Dhaka, Bangladesh http://waterandfood.org/ganges-conference/
Recommended
Recommended
More Related Content
What's hot
What's hot (20)
Similar to Fisheries and the Environmental Challenges of the Gorai-Madhumati River System
Similar to Fisheries and the Environmental Challenges of the Gorai-Madhumati River System (20)
More from International Water Management Institute (IWMI)
More from International Water Management Institute (IWMI) (20)
Recently uploaded
Recently uploaded (20)
Fisheries and the Environmental Challenges of the Gorai-Madhumati River System
- 1. Conference on Revitalizing the Ganges Coastal Zone October 21-‐23, 2014 M Niamul Naser PhD Professor of Zoology University of Dhaka, Dhaka mnnaser@du.ac.bd Cell. 01711 707217 Fisheries and the Environmental Challenges of the Gorai-‐MadhumaM River System
- 2. Ganges (=Padma) and Gorai River System • River Ganges (Padma) originates from Tibet-‐ India border area as Ganges river ; Passes by many important towns • Gorai is the a tributary of river Padma at KusMa conMnued as MadhumaM, Kacha and Baleswar river. • At the mouth of Bay of Bengal this river is known as Horinghata. • Baleswar is the eastern border of the Sunderban.
- 3. GORAI R 89 Km MADHUMATI R 137 Km BALESWAR R 146 Km
- 4. Why Gorai-‐MadhumaM river system is important? • Gorai-‐MadhumaM (GM)river system supplying freshwater to the Sunderbans Mangrove Forest • The river system is in total 372 km long • Considering Ganges dependent area, GORAI-‐MADHUMATI serving the SWR • GM touches 16 districts of Bangladesh in its course; covering 16,100 km2 area and about 10-‐12 million people. • Agro-‐ecologically the GM river support 8,588 km2 of crop lands
- 5. River Fish Culture Ecosys-‐ tem People NavigaMon Riparian wetland PolluMon Dam/ Barrage Water CC ??
- 6. River systems that led to civilizaHon
- 7. Tagore and Mrinalini Devi, 1883
- 11. Dredging at Gorai (Closer look!!)
- 12. Hardinge Bridge & Gorai Bridge
- 13. Baor along the Gorai R.
- 14. Magura bridge
- 15. Magura channel
- 16. ModhumaM R.
- 17. Kalna Ferry Ghat, Norail-‐BhaMapara
- 18. Fishing at ModhumaH River
- 19. Baleswar R. touches Sunderban RF.
- 20. Close glimpses
- 22. Water Quality of GM river system Gorai river Shamsad et al. 2014 MadhumaM river Present study 2011-‐12 Parameters Pre-‐monsoon Post-‐ monsoon Pre-‐monsoon Post-‐ monsoon Water Depth (m) 1-‐ 1.5 1-‐1.5 2-‐3 3-‐3.5 Temperature (°C) 32-‐ 33.5 19-‐22 31-‐ 33 18-‐ 22 pH 7.6-‐7.9 7.2-‐7.8 7.7-‐ 7.8 7.6-‐7.9 Dissolved Oxygen (mg/L) 5.8-‐7.7 6.0-‐7.6 6.6 6.9 TSS (mg/L) 0.9-‐2.5 0.9-‐3.0 1.2 2.1 EC (µS/cm) 219-‐278 208-‐264 449 334 TDS (mg/l) 140-‐178 133-‐169 -‐ -‐ Hardness (mg/L) as CaCO3 112-‐158 114-‐148 170 188 Salinity Nil Nil Nil Nil Tidal influence None None Presence Presence
- 23. Biodiversity in the catchment area Gorai river AquaHc species: 37 • Cypriniformes 10 • Perciformes 4 • TetraodonHformes 1 • Siluriformes 8 • Beloniformes 1 • Channiformes 2 • Clupeiformes 6 • Synbranchi formes 1 • Decapoda 1 • Molluska 3 • AquaHc mammals 0 MadhumaM river AquaHc species: 65 • Cypriniformes 14 • Perciformes 13 • TetraodonHformes 1 • Siluriformes 15 • Beloniformes 2 • Channiformes 3 • Clupeiformes 6 • Synbranchi formes 1 • Decapoda 3 • Molluska 4 • AquaHc mammals 2
- 24. Migratory fishes
- 26. Exclusive aquaHc animals of MadhumaH River
- 27. Gorai-‐MadhumaM dependent Districts (selected) Fish ProducMon (2010-‐2011) DoF, 2012 0 2000 4000 6000 8000 10000 12000 14000 16000 River Beel Flood plain Pond Semi-‐closed WB Baor Shrimp farm KushMa Magura Narail
- 28. Annual fish Catch in Rivers (mt) (2010-‐2011) 0 50 100 150 200 250 300 350 Major Carps Other Carps Cat fishes Hilsha Prawns Other fishes KushMa Magura Narail
- 29. FINDINGS • The obvious effect of drought is that water area in riverbed decrease in size, the death and decomposiMon of aquaMc plants and animals releases nutrients such as nitrogen and phosphorus into the remaining water resulMng in dense growths of algae • Diurnal changes in oxygen concentraMon which ulMmately threaten all aquaMc biota, especially fish. • Drought decreases water availability and consequently disrupt fish producMon in the river
- 30. FINDINGS • River water scarcity is chronic in Gorai river • Adverse climaMc cycles lead to detrimental environmental condiMons • Drought is characterized by a sequenMal decline in rainfall, surface runoff, soil moisture, groundwater interacMon, and discharge of the rivers • As the drought progresses, floodplain and wetland areas dry, and rivers become confined to low-‐flow channels.
- 31. OTHER THREATS TO THE RIVER OPENION
- 32. River Ecosystem at Low Water Flow Less Oxygen Area Less Oxygen Area
- 33. Padma River Water Flow Afroz & Rahman 2013 Irregular water flow Lowering Trend
- 34. How much dredging can we afford?
- 35. Fish Bana @ Magura
- 37. PerspecMves • Change in cropping pa[ern (Using less water? + nutriHonal and financial security) • Establishment of industry (Sunflower oil, Maize oil mills?) • Moving towards aquaculture (freshwater oxbow lake, ponds and lake) • Ecotourism in Gorai River • Social forestry (save environment, fuel and earn money)
- 38. TAKE HOME MESSEGES CONCLUSION
- 39. Conserving the river system Ecology of the river Structures & Processes: WQ, biodiversity, hydrology, flooding etc Social benefits Goods & Services: Fish, Water supply, NavigaHons etc Valuing River services Markets, recreaHons, non-‐monetary value-‐AstheHc Planning by prioriMzing the river needs a.FuncHonal indicators: biophysical equivalences b.Ecosystem service indicators: socioeconomics equivalence
- 40. Way forward • Establishing water quality standards for river • Monitoring water qualiMes of important river system including Gorai-‐MadhumaM river • Maintenance of ecological water flow • Human health (eg. Arsenic) and aquaMc life protecMon measure • Planning by prioriMzing the river needs
- 41. Thank you all