|Team member Manual George manually takes a water level reading (photo courtesy of Dr. Khan).|
The two most sensitive geophysical processes that exacerbate coastal vulnerability in Bangladesh are sea level rise and land motion (uplift/subsidence). However, our understanding of current and projected patterns of these factors remains incomplete. This incomplete knowledge is a key hurdle to converting our scientific understanding to actionable knowledge. Thus, improved understanding of sea level rise and land motion patterns is critical for improving long-term adaptation policy against coastal vulnerability in Bangladesh. In addition, understanding of the intra-seasonal dynamics of sea level in the estuarine regions is also critical for improved forecasting of the recession phase of an upstream flood wave that drains into the Bay of Bengal. Given the current gaps in science and application needs for the sustainable development of Bangladesh, this project will implement a satellite data-based integrative modeling framework that will operate in a porous manner with a recently funded NSF Belmont-G8 project awarded to U.S.-based University of Washington (UW). This NSF project is titled: Bangladesh Delta: Assessment of the causes of sea level rise hazards and integrated development of predictive modeling towards mitigation and adaptation (BAND-AID
). The project will build on a long-standing capacity building agenda for Bangladesh established by UW and the Institute of Water Modeling (IWM, http:// www.iwmbd.org
) since 2006. Under the leadership of PI Zahirul Haque Khan of IWM’s Division of Coast, Ports and Estuary (CPE), the project will study sea-level rise and land motion in coastal Bangladesh at select sites by combining satellite geodetic data within-situ GPS/tidal measurements. The integration of satellite data (gravimetry, altimetry and interferometry) will be the first of its kind in Bangladesh for revealing accurate snap shots on current rates of sea level rise and land uplift/subsidence in the coastal regions. In addition, an improved monitoring of downstream boundary condition on water levels with water level sensors in the Meghna estuary will lead to enhancement of flood forecasting skill from 8-day to 12-14-day lead times. The key scientific question that motivates this project is: How cost-effectively and sustainably can IWM improve the understanding of coastal vulnerability and flood forecasting skill in Bangladesh using a satellite data integrative modeling framework without the need for external support?
The involvement of IWM-Bangladesh as the lead institute in this NSF-USAID PEER initiative is of utmost importance given the existential role of sea level rise on Bangladesh. The NSF-Belmont Forum 13-nation consortium, of which UW is a collaborating U.S. institute, does not include Bangladesh as a participating nation. This means that the participation of IWM in the NSF BAND-AID
project has up to now been in-kind only, despite the critical role of IWM in addressing an existential issue for Bangladesh. Award of a PEER grant to IWM will ensure the rapid realization of several developmental impacts for Bangladesh. These impacts pertain to food security, climate change, water security, and improved water management. The specific developmental impacts expected from this PEER project are as follows. First, through planned human resource training of key IWM-CPE staff by Belmont G-8 institutions on the state of the art satellite gravimetry, altimetry, interferometry and in-situ GPS sensor recording, IWM will become (from 2017) an independent user and trainer of this emerging satellite technology for cost-effective monitoring of sea level rise and land motion for the Government of Bangladesh. Second, through intra-seasonal (daily) monitoring of water level in Meghna river estuary, the currently successful 8-day satellite altimeter-based flood forecasting system built by UW in collaboration with IWM (see http://apps.iwmbd.com/satfor
) will improve to 12-14 days of warning by 2016. This will consequently improve pro-active flood disaster management for Bangladesh Government in 2017. It will allow more resilient agricultural planning at the micro-economic level through immediate dissemination of forecasts on affordable mobile platforms (cell-phones) that have already been built by UW (see http://climate.cae.tntech.edu
) to farmers for early harvesting or delayed sowing of crops. Third, completion of this project will make IWM a role model institution for adoption and training of emerging satellite technology for hazards assessment/mitigation in the region. This consequently will position IWM and Bangladesh as a regional trainer hub for other South Asian stakeholder agencies with a significant reduction in future training costs for USAID.
Summary of Recent Activities
|IWM senior professionals visit Sandwip Island ||IWM researchers discussing storm surge model development|
(photos courtesy of Dr. Zahirul Khan)
In the final months of their project during the third quarter of 2017, Dr. Khan and his colleagues have been focusing on application of their upgraded and updated storm surge model for assessing coastal vulnerabilities. Although all of Bangladesh is at risk for tropical cyclones, the islands in the Bay of Bengal are the most vulnerable, as their elevation is very low compared with the coastal area of the country. The researchers selected Sandwip and Hatiya islands as the focus areas for their assessment of the vulnerability effects of cyclonic storm surge using the storm surge model. Using the model, they took the conditions occurring during and after the devastating 1991 cyclone and simulated the effects of climate change conditions to protect future impacts through 2050. To avoid the destructive damages from future cyclones, mangrove afforestation may be an effective solution. IWM professionals have visited Hatiya recently to observe the existing mangrove species and speak with local residents to learn about the functions of the mangroves during cyclones. Based on local opinion, IWM researchers made an extensive survey (available mangrove species, spacing between trees, root and trunk information, etc.) to develop resistance parameters and gain a better understanding of the role of the presence of mangroves in the mathematical model. In model, mangroves are presented as a roughness parameter affecting the foreshore of the islands. Further details will be included in future reports and publications.
While in Hatiya, the IWM had the chance to identify vulnerabilities and observe the physical damages caused by Cyclone Mora in May 2017. During this field visit, they also observed the GPS that had been installed by the NSF-funded BandAID team for tide and land motion observation. August 7-11, 2017, four IWM researchers also visited the Observatoire Midi Pyrénées in Toulouse, France, to attend a training program on the monitoring of land subsidence and sea level rise. With the project end date approaching on November 30, 2017, Dr. Khan and his team are spending the final weeks carrying out additional assessments of coastal vulnerability and risk exposure, as well as applying their model to simulate the potential impacts of various climate change scenarios.