• Share
  • Email
  • Embed
  • Like
  • Save
  • Private Content
G4- Assessment of the impact of anticipated external drivers of change on water resources of the coastal zone
 

G4- Assessment of the impact of anticipated external drivers of change on water resources of the coastal zone

on

  • 317 views

by: Dr. Zahir Haque Khan & Team

by: Dr. Zahir Haque Khan & Team
Presented at the GBDC Reflection Workshop,November 2013

Statistics

Views

Total Views
317
Views on SlideShare
307
Embed Views
10

Actions

Likes
0
Downloads
4
Comments
0

2 Embeds 10

http://wle.localhost 9
http://unjobs.org 1

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

CC Attribution License

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

    G4- Assessment of the impact of anticipated external drivers of change on water resources of the coastal zone G4- Assessment of the impact of anticipated external drivers of change on water resources of the coastal zone Presentation Transcript

    • Ganges Basin Development Challenge G4: Assessment of the Impact of Anticipated External Drivers of Change on Water Resources of the Coastal Zone
    • Outcome Logic Model Project outputs Existing condition: • Data on WL, Flow, Salinity •Digital Elevation Model • Freshwater & salinity zoning map • Drainage Conditions and Inundation maps of polders • External drivers • Scenarios Future condition: Outcome Logic Model • Climate change projections • Population projection • Landuse change projection OUTCOMES Change in KAS Change in Practice/ behavior Planning Commission, minis Farmers and fishers of polder 3, 30 and 43/2F tries of water resources, Encouraged to Awareness building environment & participate in discussions Knowledge enhancement forests, agriculture to contribute in planning and fisheries in Bangladesh – Researchers of G1, G2, G3 & other ongoing projects Scaling up Acquiring data, information & Use of data & information knowledge Extrapolation Domain, Understanding of the Understanding external drivers, scenarios and their effects new database, Planning of cropping system LGI, BWDB, WARPO, LGED, DOF and NGOs Acquiring new information & knowledge Understanding the benefits of using new information and improved plan for proper drainage and irrigation Use in Improving planning, design and implementation • Freshwater & salinity zoning map • Drainage Conditions and Inundation maps of polders • Improved Drainage plan of the three polders Ministry of Water Resources, Planning Commission Understanding of effects of external drivers Motivated and encouraged to use the new information Assimilation of new knowledge and information in project planning and approval and policy change effects of external drivers & anticipated change of water resources and the benefits of adaptation measures will encourage these policymakers to be motivated to formulate new policies. Impact Improved and resilient water infrastructure and operation Improved Polder management for maximizing crop & fish production
    • Study Area Polder-30 Medium Salinity Polder-43/2F Low Salinity Polder-3 High Salinity Coastal Zone of the Ganges Basin in Bangladesh
    • Date Mar-2014 Jan-2014 Nov-2013 Sep-2013 Jul-2013 Kharif-1 May-2013 Mar-2013 Jan-2013 Nov-2012 Sep-2012 Jul-2012 May-2012 0.5 Mar-2012 Rabi Jan-2012 11-May 1-Apr 2.0 Nov-2011 12.0 Sep-2011 Jul-2011 21-Feb 12-Jan Salinity (ppt) 0.0 May-2011 POLDER-43/2f Date 3-Dec 8.0 Mar-2011 24-Oct 14-Sep 5-Aug Salinity (ppt) 24.0 Polder 43-2f (Station-2 (In Side),Para River) Data:Temporal variation of Salinity 20.0 16.0 Polder 43-2f (Paira River) 2 PPT 4.0 1.5 1.0 Kharif-2 0.0
    • Temporal variation of Salinity Salinity at Kazibacha River Kharif-1 2 PPT 19 Jun 2012 POLDER-30 8 Feb 2012 Rabi Kharif-2
    • 12.0 8.0 4.0 0.0 Apr-2012 Date 2 PPT Aug-2013 Jun-2013 Apr-2013 14 Sep 2012 Feb-2013 Kharif-1 Dec-2012 Oct-2012 Aug-2012 Jun-2012 Rabi Feb-2012 Dec-2011 Oct-2011 Aug-2011 Jun-2011 16.0 17 Dec 2011 20.0 Apr-2011 POLDER-3 Salinity (ppt) Data:Temporal variation of Salinity 24.0 Polder 3 (Ichamoti River) Kharif-2
    • Spatial and Seasonal Variation of Salinity in the Coastal Ganges in Bangladesh May, 2012 Base Year: 2012 BARISAL KHULNA Fresh and Brackish water zone
    • Output: External Drivers of Change
    • External Drivers and Future Scenarios Scenario Generation Workshop Final List of Key External Drivers and Their Ranking Combination Scenarios
    • Scenario: Effect of Transboundary flow and Climate Change Upstream Boundaries (Q, Sal = 0pt) Minimum and maximum flow in Gorai in dredged condition Trans-boundary flow Best case scenario: maximum flow since GWT worst case scenario: minimum flow since GWT Ganges Basin Climate change: A1B condition (Precipitation, Temperature and Sea level rise) Scenario : 2050 Downstream Boundaries (WL, Sal) + Sea Level Rise
    • Scenario: Transboundary Flow, Land-Use Change and Climate Change Upstream Boundaries (Q, Sal = 0pt) Minimum and maximum flow in Gorai in dredged condition Trans-boundary flow Best case scenario: maximum flow since GWT Land-use change Ganges Basin Climate change: A1B and A2 condition (Precipitation, Temperature and Sea level rise) Scenario : 2030 and 2050 Downstream Boundaries (WL, Sal) + Sea Level Rise
    • Scenarios: Effect of Multiple Drivers on Water Resources Upstream Boundaries (Q, Sal = 0pt) Minimum flow in Gorai in dredged condition Trans-boundary flow (worst case scenario: minimum flow since GWT) Population growth: water extraction from the river system Ganges Basin Land-use change Climate change: A1B condition (Precipitation, Temperature and Sea level rise) Scenario : 2030 Downstream Boundaries (WL, Sal) + Sea Level Rise
    • Scenario: Population Growth Upstream Boundaries (Q, Sal = 0pt) Maximum flow in Gorai in dredged condition Trans-boundary flow (best case scenario: maximum flow since GWT) Population growth: water extraction from the river system Land-use change Ganges Basin Climate change: A1B condition (Precipitation, Temperature and Sea level rise) Scenario : 2030 Downstream Boundaries (WL, Sal) + Sea Level Rise
    • Scenario: Infrastructure Development Upstream Boundaries (Q, Sal = 0pt) Minimum flow in Gorai in dredged condition Population growth: water extraction from the river system Trans-boundary flow (best case scenario: maximum flow since GWT Land-use change Change in water management practices Water infrastructure development Ganges Basin Change in water governance and institutions (including policy change) Climate change: A1B condition (Precipitation, Temperature & Sea level rise) Scenario : 2030 Downstream Boundaries (WL, Sal) + Sea Level Rise
    • Transboundary Flow Transboundary Flow
    • GWT Farakka Barage Effect of Transboundary Flow on Salinity Salinity in the south-west zone is very much dependent on upstream freshwater flow Salinity variation with upstream freshwater flow during dry season (Salinity Data Source: BWDB) Ganges Water Treaty is very important for salinity control in the south-west zone of Bangladesh Salinity variation with upstream freshwater flow during dry season (Salinity Data Source: IWM)
    • Effect of Transboundary Flow :South-west Zone of Bangladesh May, Base condition with maximum Transboundary flow under Ganges Treaty
    • Effect of Transboundary Flow :South-west Zone of Bangladesh May, Base condition with minimum Transboundary flow under Ganges Treaty
    • Effect of Climate Change and Transboundary Flow: South-west Zone May, 2030 climate change (A1B) with minimum Transboundary flow under Ganges Treaty
    • Effect of Infrastructure Development: Ganges Barrage May, 2030 Climate change (A1B) with Ganges Barrage
    • Effect of Drivers: Trans-boundary flow, Climate Change and Ganges Barrage
    • Effect of Drivers: Trans-boundary flow, Climate Change and Ganges Barrage
    • Effect of Drivers: Trans-boundary flow, Climate Change and Ganges Barrage
    • Effect of Drivers: Trans-boundary flow, Climate Change and Ganges Barrage
    • Effect of Drivers: Trans-boundary flow, Climate Change and Ganges Barrage Decrease of Freshwater and mild brackishwater area (0-2ppt): Transboundary flow: 1100 sq. km Climate Change: 800 sq. km
    • Drainage Condition Khals within polders vary greatly in size, can store fresh water during the dry season, but often heavily silted up (some no longer exist), blocked… 26
    • Drainage Performance of Polders at Present and Future 3 day Depth-Duration Map Flood type Area (sqkm) % of Area Flood Free 25.48 40 F0 (0 - 30 cm) 21.01 33 F1 (30 - 90 cm) 13.42 20 F2 (90 - 180 cm) 4.32 7
    • Drainage Performance of Polders at Present and Future 3 day Depth-Duration Map (Scenario_2030) Flood type Area (sqkm) % of Area Flood Free 21.97 34 F0 (0 - 30 cm) 22.24 34 F1 (30 - 90 cm) 15.26 24 F2 (90 - 180 cm) 5.03 8
    • Drainage Performance of Polders at Present and Future 3 day Depth-Duration Map (Scenario_2050) Flood type Area (sqkm) % of Area Flood Free 16.41 25 F1 (30 - 90 cm) 27.86 43 F2 (90 - 180 cm) Flood type 21 F0 (0 - 30 cm) 2030 13.54 6.70 11 2050 (Change from present condition) (Change from present condition) Flood Free -6 % -19 % F0 (0 - 30 cm) 1 % -8 F1 (30 - 90 cm) 4 % 23 % F2 (90 - 180 cm) 1 % 4 % %
    • Drainage Improvement Measures • Dredging and Re-excavation of rivers and khals • Additional drainage structure
    • Drainage Improvement Measures 25 Year Flood Event : A1B Scenario; 2030 Inundated Area = 68%
    • Drainage Improvement Measures 25 Year Flood Event : A1B Scenario; 2030 With improvement measures
    • Polder-30: Case Study- Maitbhanga Village Discussion with local people of Maitvanga about drainage Drainage canal has been silted up and the bottom level has been same as the surrounding land Drainage canal blocked by human intervention The high depth of water in Aman field of Maitvanga beel UP road crosses the canal without any culvert blocking cross-drainage
    • 2 1.5 Considerations for Sub-polderization:  Land level 1 0.5 0 0 2000 4000 Distance (m) 2 1.5 1 0.5 0 -0.5 0 2000 4000 Distance (m) Land Level (mPWD) Land Level (mPWD) Land Level (mPWD) Polder-30: Subpoldering and Community based Water Management 2 1.5 1 0.5 0 -0.5 0 2000 4000 Distance (m)
    • Polder-30: Subpoldering and Community based Water Management Considerations for Sub-polderization:  Land level  Canal system
    • Polder-30: Subpoldering and Community based Water Management Considerations for Sub-polderization:  Land level  Canal system  Tidal characteristics of the peripheral rivers
    • Polder-30: Subpoldering and Community based Water Management Considerations for Sub-polderization:  Land level  Canal system  Tidal characteristics of the peripheral rivers  Road network
    • Polder-30: Subpoldering and Community based Water Management Sub-polder Considerations for Sub-polderization:  Land level  Canal system  Tidal characteristics of the peripheral rivers  Road network
    • Polder-30: Subpoldering and Community based Water Management Sub-polder Community based water management Unit/ Block Considerations for Sub-polderization:  Land level  Canal system  Tidal characteristics of the peripheral rivers  Road network Benefits of Sub-polderization:  Better water management, i.e., drainage and flushing of irrigation water  Conflict management between high and low land  Involvement of local community in water management  Easy and timely maintenance over the years for subpolders  High depth of water in aman field reduce production; thus proper drainage will enhance crop yield
    • Sub-polderization : Community Participation in Water Management and Governance Water Management Organization (WMO) Community Based Water management Unit/Block Water management Group (WMG) Sub-polder Water management Association (WMA) Polder Water management Federation (WMF)
    • Solutions for Drainage Congestion in Polder-30 Message:  New paradigm shift in water management: Sub-polderization and community based water management Outscaling Opprotunity:  Blue Gold  Costal Embankment Improvement Project (CEIP)
    • Polder-30: Opportunity for Gravity Drainage Kazibacha river Area (Percent) Maximum water level 2.4 m 0 4 Average water level 1.3 m 40 60 80 100 Area-Elevation curve 3.5 Land level (mPWD) Minimum water level 0.0 m 20 3 2.5 2 1.5 1 0.5 0 0 Lower-Shalta river 10 20 30 40 50 60 Area (sqkm) Level (mPWD) Area below % Average water level 1.0 m Digital Elevation Model 0.60 1.00 1.20 1.60 1.80 2.00 15 61 80 95 98 99
    • Area Elevation curve (Polder Polder-43/2F: Opportunity for Gravity Drainage 43/2F) 45 100 40 35 80 Area (Sq Km) 30 25 60 20 Level (mPWD) 1.0 1.2 1.4 1.8 2.0 15 10 5 Area below (%) 9 23 52 92 98 40 20 0 0 0 Kharif-1 Avg WL 1.00m PWD 0.5 1 1.5 2 2.5 Elevation (mPWD) Kharif-2 Avg WL 1.20m PWD 3 Rabi 3.5 Avg WL 0.80m PWD 4 Area (Percent) Tidal window above 1.40 mPWD
    • Polder-3: Water Management (Drainage and Flushing)
    • Polder-3: Water Management (Drainage and Flushing)
    • Polder-3: Water Management (Drainage and Flushing)  Land use has beenchanged over the years  Shrimp culture has been introduced  Huge number (133 pipes and 27 private regulators) of informal structures have been built for flushing brackish water into the polder  Present drainage system needs to be revisited to meet the demand of flushing brackish water  18 new formal structures and improved canal system can meet the demand of flushing brackish water Benefits:  If properly managed, brackish water can be considered as a resource, can be used for highincome aquaculture  Opportunity for crop diversification
    • Trans-Boundary and Food issues By IWMI
    • Key Messages  There is abundant fresh water for irrigation in much of Barisal Division throughout the dry season. The water will remain suitable for irrigation all over the year in the changing climate in 2030.  Polder 30:Storage of freshwater in improved internal drainage canals can meet irrigation demand of boro rice for 20% area of cultivable land  In high saline areas, brackish water can be considered as a resource that, if properly managed, can be used for high-income aquaculture. In polder-3, existing huge number of informal pipes (133 Nos) and structures (27 Nos) can be replaced by a smaller number of formal structures (18) and improved canal system.
    • Key Messages  G4 used hydrological, hydrodynamic, salinity and storm-surge models to assess the impacts of the external drivers of change on the water resources in the Ganges dependent coastal area in Bangladesh  To predict future climate, population growth and land-use scenario G4 used model results (PRECIS, SDSM and SWAT) provided by partner organizations: IWFM-BUET and IWMI
    • Closure Plan Way Forward to the Project Closure: Effectiveness of sub-polders Land-use change projections in the study area Storm surge risk assessment in the thee selected polders (Polder-3, 30 & 43/2F) Out scaling of the research results: Workshop presentation in coordination with G5 Institution based workshop: with BWDB, LGED, DAE and DoF Policy brief on drainage management and water availability in present and future scenario
    • Closure Plan Description of Activities Storm surge modelling for selected 3 polders Land-use projection Assessment of the effect of Land-use and Population growth of Sub-polder in Polder-30 Water management Outscaling Policy Brief Drainage Management Water Availability Transboundary flow Infrastructure Development Final Closure Report 2013 2014 Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    • THANK YOU