Katsuhide YOKOYAMA

Professor:Katsuhide YOKOYAMA

Research Interests

The major research areas we have been conducting in our laboratory are sediment transport and morphodynamics in river systems (stream, reservoir, river channel, and estuary). River is the artery which connects the headwaters to the sea, a lake or another river. However, manmade cross-structures such as dams and estuary weirs disrupt the natural flow of water and sediments, thereby affecting the ecosystem and geomorphology of the aquatic environment. Hence we aim to build a healthy relationship between the nature and human beings by promoting the following research themes:

  1. Study on erosion and sediment production processes in watershed
  2. Improvement of water quality by controlling of water current in a large reservoir
  3. Saltwater mixing, suspended sediment transport, phytoplankton process and morphodynamics in an estuary
  4. Restoration and protection of salt marsh, estuary and tidal flat in the coast damaged by a tsunami

We are working to elucidate the aquatic environment through in-situ observations and hydraulic experiments in combination with numerical simulations. In addition, we are developing new equipment which is necessary for the filed observation.

Titles of master theses and doctoral dissertations

20151.Upwelling behaviour of warm surface water released in the bottom of a reservoir by a pump system
2.Relationship between expansion of the city to the steep slope and sediment disaster
3.The relationship between dissolved organic carbon quality and land use in three rivers flowing into the Kesennuma Bay
4.Hydrodynamic flow and phytoplankton transport in a narrow channel of the Kesennuma Bay
20141.* Spatio-temporal variation of estuarine mixing, suspended sediment, and phytoplankton in a highly turbid estuary
2.Field measurement of tidal discharge and sediment transport at the bifurcating point of a multi-branched estuary
3.Transport of radiocaesium depending on the particle size of suspended sediment during flood discharge
20131.Impact of tsunami disaster on bottom sediments of the Kesennuma Bay
2.Movement of surface water transferred to the bottom of the Ogouchi reservoir
3.Development of three dimensional simulation model on saltwater movement in a multi-branched estuary

*: Doctoral dissertation

Titles of bachelor theses

20151.Study on the mass transport of Kesennuma Bay by three-dimensional hydrodynamic simulation model
Nutrient balance in a salt marshes that have been created by the Great East Japan Earthquake
2.Monitoring of the wind distribution, and estimation method of wind speed and wind direction on a reservoir
3.Spatio-temporal variation of the dissolved iron concentration in river water that flows into Kesennuma Bay
20141.Estimation of nutrient load in the Malisbog-Imbang River based on field measurement and runoff model
2.Three dimensional hydrodynamic analysis of salt water intrusion at the bifurcating point of a multi-branched estuary
3.Relationship between euphotic depth and diffusion depth of the plume transferred by pump system in a reservoir
20131.Distribution of dissolved organic matter in the sediment pore water of the Kesennuma Bay
2.Field measurement on the movement of the plume released from a pump system in the Ogouchi Reservoir
3.Water budget analysis in a narrow channel of the Kesennuma Bay by using ADCP