Advantages of the Open Levee (Kasumi-Tei), a Traditional Japanese River Technology on the Matsuura River, from an Ecosystem-Based Disaster Risk Reduction Perspective

Large-scale disasters, such as hurricanes, cyclones, tsunamis, and forest fires, have caused considerable damage in recent years. This study investigated two case studies of discontinuous open levees (kasumi-tei), which are a traditional Japanese river technology, on the Matsuura River at the sites of Okawano and Azame-no-se, and evaluated the advantages of these levees from the perspective of ecosystem-based disaster risk reduction (Eco-DRR). These case studies were conducted through literature surveys, flood observations, and oral interviews. The systems in both the cases were flood control systems utilizing ecosystem services. The traditional river technology (the flood plain open levee) served as an effective Eco-DRR in both cases. Additionally, the flood plain levee technology enhanced the ecosystem services at both sites, including not only flood control capabilities, but also other ecosystem services. Furthermore, the open levees offered substantial cost advantages over their alternatives. These results suggest that other traditional Japanese river technologies may also be effective in strengthening Eco-DRR

The Use of Molluscan Fauna as Model Taxon for the Ecological Classification of River Estuaries

River estuaries are important aquatic environments characterized by large environmental gradients in their water quality, riverbed material, and microtopography in the longitudinal and transverse directions. The geography or habitats in river estuaries differ depending on the energy from the tide, waves, and river; therefore, the biota inhabiting river estuaries vary depending on the river estuary type. In view of this, for effective conservation in river estuaries, there is a need for information about potential habitats and biota based on objective data about the river estuary type. The objective of this study thus was to classify river estuaries by their molluscan fauna and physical indicators to reveal the relationship between molluscan fauna and the physical environment. The classification results using physical indicators indicated three types of river estuaries (wave energy-dominated group, tide energy-dominated group, and low tide and wave energy group). This classification result was similar to the classification of molluscan fauna. Therefore, it was suggested that molluscan fauna is extremely useful as a variable representing the river estuary environment. From the comparison between molluscan fauna and the physical environment, some rivers were not classified into the same group in the classification of molluscan fauna, despite them having similar physical environments. Some of these rivers with a molluscan fauna that diverged from expectations had undergone channel modification, which is expected to have caused a shift in this fauna group. These results suggest that this approach could be used to identify rivers that have been degraded by human activities

Evaluation of Pandanus Trees as a Means of Eco-DRR against Storm Surge Wave on Saint Martin’s Island, Bangladesh

Saint Martin’s Island is a tiny island located in Bangladesh that is rich in biodiversity but threatened by many natural disasters, and it is often neglected due to being far from the mainland. Ecosystem-based disaster risk reduction (Eco-DRR) is the most urgently required provision for Bangladesh as it is a very easy and inexpensive way to survive natural adversities. In this study, attempts were made to quantify the capacity of an existing Pandanus forest on Saint Martin’s Island to reduce the storm surge disaster risk. For this, satellite images were processed with ErdasImagine and ArcGIS software, and land use and land cover changes were analyzed to determine the changes related to Pandanus trees over time. Storm surge wave height reduction was analyzed using the Bao regression model equation. The results show that the Pandanus tree population increased almost 3-fold from 2010 to 2021, and that the Pandanus trees can reduce the surge height, which will ultimately preserve 75% of the area of the island (2021). The minimum required patch width for the Pandanus tree belt was identified as 4.53 m. The areas highly vulnerable to flooding were also identified in this study

Longitudinal distribution of sediment composition in the Kita River

In the recent years, river restoration has been carried out in Japan. In those cases, we need some information of sediment movement and geology of river basin relationships because of river management of the basin scale. However, the information of these relationships is still poorly understood. The Kita River runs through the northern part of Miyazaki prefecture, and this river is one of the special research sites of river ecology in Japan. In this research, we investigated the deposited sediment component and geological map in the Kita River basin relationships

Evaluation of Pandanus Trees as a Means of Eco-DRR against Storm Surge Wave on Saint Martin’s Island, Bangladesh

Saint Martin’s Island is a tiny island located in Bangladesh that is rich in biodiversity but threatened by many natural disasters, and it is often neglected due to being far from the mainland. Ecosystem-based disaster risk reduction (Eco-DRR) is the most urgently required provision for Bangladesh as it is a very easy and inexpensive way to survive natural adversities. In this study, attempts were made to quantify the capacity of an existing Pandanus forest on Saint Martin’s Island to reduce the storm surge disaster risk. For this, satellite images were processed with ErdasImagine and ArcGIS software, and land use and land cover changes were analyzed to determine the changes related to Pandanus trees over time. Storm surge wave height reduction was analyzed using the Bao regression model equation. The results show that the Pandanus tree population increased almost 3-fold from 2010 to 2021, and that the Pandanus trees can reduce the surge height, which will ultimately preserve 75% of the area of the island (2021). The minimum required patch width for the Pandanus tree belt was identified as 4.53 m. The areas highly vulnerable to flooding were also identified in this study

河川等の水空間における水の豊かさ,清らかさに関する景観工学的研究

1.緒論 2.都市における水空間の豊かさ 3.景観からみた河川水量 4.人は清流をどのようにとらえるか 5.景観からみた河川水質 6.結論Made available in DSpace on 2012-09-05T02:47:26Z (GMT). No. of bitstreams: 2 shimatani1.pdf: 12068129 bytes, checksum: 7b774eaa2b96bc1c95f70ce741196cff (MD5) shimatani2.pdf: 16197432 bytes, checksum: 1230a53987c3a168ef54bb6872afe38c (MD5) Previous issue date: 1999-03-12主1-参1工学_環境都市_都市環境システ

河川等の水空間における水の豊かさ,清らかさに関する景観工学的研究

1.緒論 2.都市における水空間の豊かさ 3.景観からみた河川水量 4.人は清流をどのようにとらえるか 5.景観からみた河川水質 6.結論主1-参1工学_環境都市_都市環境システ