Model catchments for testing biosphere assessment models of geological disposal

Yamaguchi, Masaaki; Suzuki, Yuji*; Kabasawa, Satsuki; Kato, Tomoko

JAEA-Data/Code 2024-001, 21 Pages, 2024/03

JAEA-Data-Code-2024-001.pdf:3.45MB
JAEA-Data-Code-2024-001-appendix(CD-ROM).zip:8.0MB

Model catchments have developed for use in testing various assessment models that can consider specific surface environmental conditions such as topography, riverine systems, and land use in the biosphere assessment of HLW geological disposal. The model catchments consist of the topography and riverine system of the catchment area created using existing tools, as well as land use and population distribution, river discharge, sediment flux data set by algorithms from topographical data. Datasets of three types of model watersheds (Types 1 to 3, watershed area: 730 to 770 km) with different topographical characteristics have released as raster data that can be handled by geographic information systems (GIS). Since the model catchments were created virtually reflecting as much as possible the main characteristics of Japan's surface environment, they can be used as a test bed for conducting hydraulic/mass transport analysis to set the GBI and compartment model.

An Evaluation of runoff point considering topography and repository depth changes due to uplift and erosion

Sakamoto, Michihito*; Wakasugi, Keiichiro*; Kabasawa, Satsuki; Yamaguchi, Masaaki

no journal, , 

The topography is affected by long term uplift and erosion, which also causes change of the depth of the repository site. In addition, nuclide migration paths and outflow points on the ground surface change according to the changes in topography and the repository depth. In this study, the topographical transition analysis was performed focusing on the difference in the topographical transition due to the difference in the uplift rate, and the groundwater flow analysis was performed based on that. In addition, nuclide migration paths were evaluated considering the changes in topography and repository depth. As a result, it was indicated that the runoff points from the repository near the ground surface would change according to the uplift rate.

Development of the Topography and repository depth transition analysis tool for coastal areas (TARTAN-II)

Yamaguchi, Masaaki; Kato, Tomoko; Suzuki, Yuji*; Kabasawa, Satsuki; Mihara, Morihiro; Makino, Hitoshi

no journal, , 

The topography and repository depth transition analysis tool developed for inland areas has been expanded to accommodate coastal areas (TARTAN-II), taking into consideration sediment transport from land to ocean, and their spatiotemporal change due to sea-level and climate changes.

Analysis of nuclide migration reflecting changes in topography, repository depth, and groundwater flow due to uplift and erosion

Kabasawa, Satsuki; Sakamoto, Michihito*; Takahashi, Yuta; Yamaguchi, Masaaki

no journal, , 

no abstracts in English

Comparison of actual topography and virtual topography based on topographic change simulation, 1; Comparison of river cross section

Nishiyama, Nariaki; Kawamura, Makoto; Komatsu, Tetsuya; Jia, H.*; Koizumi, Yukiko*; Kabasawa, Satsuki; Nakanishi, Toshimichi*; Umeda, Koji*

no journal, , 

no abstracts in English

Comparison of actual topography and virtual topography based on topographic change simulation regarding topographic changes due to river denudation, 2; Comparison of topographical features

Kawamura, Makoto; Nishiyama, Nariaki; Komatsu, Tetsuya; Jia, H.*; Koizumi, Yukiko*; Kabasawa, Satsuki; Nakanishi, Toshimichi*; Umeda, Koji*

no journal, , 

In geological disposal projects and safety regulations for HLW, one of the challenges in surveying and evaluating technology related to uplift and erosion, which is important in site selection and safety assessment of geological disposal, is that in the distant future, topography mainly due to river undercuts will occur. It is necessary to be able to quantitatively evaluate the changes and effects that these changes have on the underground geological environment. Among the geological environmental conditions, changes in groundwater recharge areas and outflow areas are important when building performance evaluation models because they can change the flow direction of surface water infiltration into the ground or groundwater outflow to the surface. The most reliable way to evaluate recharge and discharge areas is to use actual measured data on precipitation and river flow. However, when dealing with past or future topography, or hypothetical topography generated by simulations of topographical change, actual measurements are not possible, and so technology is required to indirectly estimate the area from topographical information. As one of the research technologies, a method has been developed to measure topographical features using a digital elevation model, calculate runoff volume using statistical analysis techniques, and visualize it as an index. In previous studies, we also attempted to apply this method to three rivers which have different drainage basin areas and uplift rates, and were able to present, to a certain extent quantitatively, results that are consistent with the general understanding that areas where high-altitude divided drainage basins are concentrated are high, meaning that surface water tends to flow more easily. Here, following previous studies, we report an example of applying the same method to a virtual topography created by simulating topographical change, and comparing and examining it with an actual river.