Contribution to realization of sustainable and vibrant society(11) Development of river channel management technology thatsatisfies both flood control and environmental sustainability
Research period: FY2016-2021
Program leader: Director of Water Environment Research Group

Research Summary

Large rivers (sections administered by the Ministry of Land, Infrastructure and Transport)
Achievement Goals (1)Achievement Goals (2)Water area

landscape diversity

Terrestrial area
scale

Landscapedivision

Wide area terrain
LandscapeSandbar
Bare land

Low water

Flood channelMeadow

PHABSIM by spawningenvironmental
evaluation model[before mid-term]

Field dealing
mainly in riverengineering

ForestCommunity cluster
DetailPlant
community
Plant
species

Field dealing
mainly inbiology

Develop methods for prediction andevaluation for various aspect ofdischarge capacity and biodiversity
using the concept of community
cluster located in the middle of thelandscape and community

spatial pattern of hot spot

R&D Program

Development of techniques for extracting the district of high diversity
from surface data for the river topography, vegetation and ﬂood
frequency

Develop response prediction
technology of habitat/
spawning environment of ﬁshusing the river bed
topography/sediment

Utilization of prior data
- Census for waterside- River channel physicalenvironment data
Implementation of
the ﬁeld survey
Study for methods ofevaluating theriverbed terrain withinhome range of ﬁshAchievement Goals (3)Currently: The decision of shape about excavating river channel iscontinuing on each ﬁeld by trial and error.

Ae.g.) A : lowering of riverbed B : formation of slope
C : shape of ship bottom

Prediction
evaluation

CB

Ensure the discharge
Conservation ofcapacity
spawning ﬂoor
Conservation of plants
Maintenance of river channel

Feedback
Not only ensure the discharge capacity but also develop river channel excavation technology to contribute to conservation and restoration of
the diversity of plants, good ﬁsh habitat/spawning environment in the land. Also develop technology for subsequent maintenance methods.

Small and medium-sized streams (sections administered by municipality)
Achievement Goals (2)Achievement Goals (3)Quantitative assessment for river channel iscarried out from both aspects of ﬂood
control and environment

Qualitative assessment for landscapeformation and conservation area including
the hinterland

Development plan (goal)
Acquisition of the current
river channel
Modiﬁcation of terrain for thecurrent river channel (modiﬁcationof the planned river channel)

Calculation of ﬂow

Improvement ofdesign processes
and tools

Water level vertical check
Judgement of necessity forbank protection+
Habitat of living organisms
determined based on thephysical environment

Using the existing ﬂow regime
calculation tool iRIC

Water system such as rivers and lakes is an important foundationof biodiversity and its loss has continued. In the future we need toset the management objectives of the specific river environment.
The urgent tasks are recovery of biodiversity from the losses andmaintenance of good conditions. On the other hand, a hugeincrease of risks resulting from water disasters are also expected.
So, it is necessary to promote the river management by taking
disaster prevention/mitigation and the natural environment as anintegral part while clarifying management objectives.
This research consists of the following three segments for the
purpose of development of planning, design, maintenancetechnology for river channels based on a set of conservation/formation area of the river environment.
(1)	Development of space management technology with a

16 PUBLIC WORKS RESEARCH INSTITUTE 2016

River channel
planning and design
process (draft)

Organizing prior knowledge

Trial of riveradministrators andriver engineers

Extraction ofproblems

Goal is implementation in the ﬁeld
working on improvement

focus on the river landscape, biological growth and habitat.
(2)	Development of response/prediction techniques forvegetation and fish towards for human alteration such as ariver channel excavation(3)	Development of river channel excavation technologythat satisfies flood control and environment as well as
maintenance technology
Through these, we aim to satisfy both flood control andenvironment and propose river channel planning/design foreasy maintenance and maintenance/management techniques
to maintain the river environment in good condition. Research
results will be reflected in basic guidelines and technical standards
to disseminated to the sites.