LiDAR-based fluvial remote sensing to assess 50–100-year human-driven channel changes at a regional level: The case of the Piedmont Region, Italy

Remote Sensing (RS) technology has recently offered new and promising opportunities to analyze river systems. In this paper, we present a calibration of characteristic Hydraulic Scaling Law (HSL) using a regional database of river geomorphic features. We consistently linked discharge with channel geometry features for estimated Bankfull Channel Depth (eBCD), Active Channel Width (ACW), and Low Flow water Channel Width (LFCW), which are continuously available from RS data along the river course. We then used historical information and external sources of information on channel reaches that were relatively unaffected by human pressure over periods ranging from a few decades to a century (measured in comparable geographical areas) to infer relatively Unaltered HSLs (rUHSLs). Adopting rUHSL validated with available local historical evidence on channel geometry, we were able to assess historical changes in channel geometry consistently over the entire region and within the studied temporal window. The case study was conducted for the Po basin in the Piedmont Region, north‐west Italy. From our analysis, it emerges that regionally 74% of the river network has riverbed incisions exceeding 1 m, while 66% of channels have halved their historical widths with a total of 617 ha of land subtracted from the active channel. LFCW is, on average, wider in Alpine rivers compared with those located in the North Apennines. Although it is currently not possible to measure the accuracy of these estimates, the evidence generated is coherent with available historical information, characteristic hydraulic scaling laws, evidence from relatively unaltered reaches and the available literature on local fluvial systems. This methodology provides robust, novel and quantitative information regarding decadal to secular channel changes that have occurred on a regional scale. This new layer of information enriches our ability to rationally address assessments of large‐scale past and future channel trajectories

From Risk to Opportunity: Climate Change and Flood Policy in Bangladesh

This study identifies current gaps and opportunities of existing flood regulatory frameworks and national climate change strategies of Bangladesh . In so doing, the research develops a framework to reconcile the interest of land, water, and people in order to reduce the vulnerability of extreme flooding and develop strategies for future flood management. The study reveals that the existing flood regulatory framework is only effective for relief and response during times of flooding but has significant gaps and inadequate provisions to increase communities’ adaptive capacity and resilience to deal with future flooding vulnerability under climate change. The flood management system also suffers from a lack of coordination, complex institutional frameworks, and budgetary constraints. The findings of the study also reveal that people’s/communities’ participation is at a very early state in flood-related project formulation and implementation, and they are totally absent at the level of flood management committees. In addition, the study strongly urges introduction of evidence-based flood policy formulation to reconcile the interest of land, water, and people. Working in this way will give people and communities a voice in the decision-making process, ensure the participation of vulnerable people in decision-making around flooding, and take immediate initiatives to fill the existing gaps and weaknesses of flood management system in Bangladesh