

‫ە‬Research Trends and Results

Fully considering the care of thenatural environment at the roadproject concept stageYAMAMOTO Yuichiro, Researcher
INOUE Ryuji, Senior Researcher
SONE Shinri, HeadRoad Environment Division, Environment Department

Research Trends and Results(Key words) Environmental impact assessment technology, road project, animals, plants, ecosystem
1. Background and Purpose
Under the recently revised Environmental Impact
Assessment Law (refer to, Topics: “Proposed
Amendment of Environmental Assessment Law andResponse to the SEA (Strategic Environmental
Assessment)” for an outline of the revision proposal),the Strategic Environmental Assessment (below,“SEA”) which considers care for the environment
from the earliest stage before the project begins, isstipulated. SEA was established in response to theinsistence that it was needed to prevent loss of thenatural environment, and in response to its
codification, early concern for the natural environment
may attract attention in the future.
From the practical perspective, presumably, there
will many restrictions on the study of ways to care forthe environment, because it is predicted that at thestage where the location and scale etc. of a project towhich SEA will be applied (below, “concept stage”) is
decided, the project plan will still be in preliminary
form, and information concerning the local naturalenvironment will be limited.
This research is intended to establish methods ofeffectively and efficiently caring for the naturalenvironment at the road project concept stage.2. Conservation effectiveness according todifferences in route and road structure
—For future discussion which must be consideredat the road project concept stage—
Road projects, as shown by Eco-roads 1) for
example, have included bridges, tunnels, and otherstructures, and initiatives to install facilities allowing
animals to cross roads, in order to select routes which
are in harmony and compatible with nature and tominimize change to the topography and vegetation.
These often permit concrete studies at the stage whereroad structures are designed. To apply SEA, it isnecessary to not only simply speed up the study period,
but to also clarify the study range, conduct surveys
according to the study stage, and search for effective
ways to care for the environment.
In 2010, which was the first year of the project, toprepare for future discussion of “items which must be
considered at the concept stage”, we conducted a basic
case study of the relationship between theeffectiveness of conserving the environment andconstruction costs according to differences in route
location and road structures. Five proposals for theroad studied were hypothesized (Fig. 1), and existing
documents were used to classify the degree to which
each one would change vegetation and divide routes
traveled by animals. The results have shown that theimpact of each would vary according to differences inthe location of route several hundred meters in lengthand selection of the road structure (Table 1), andsuggested that it is possible to obtain various measures
to care for environment.

500m(1) Cutting of䐟ᒣഃษᅵ᱌
mountain side(2)Cutting/embankment䐠ษᅵ䞉┒ᅵ᱌

(3)
Cutting along river䐡ᕝἢ䛔ษᅵ᱌

(4)
Large tunnel䐢㛗኱䝖䞁䝛䝹᱌(5)
Partial bridge䐣୍㒊ᶫᱱ᱌

Figure 1. Hypothetical Proposals
Table1. Conservation Effects of each Proposal andConstruction Cost

Degree of alteration of existingvegetation
Degree of change of growth of valuablespecies and their habitat environments
Degree of division of routes traveled byanimals

(1)
Cutting ofmountainside(2) Cutting/embankment(3) Cutting
along river(4) Large
tunnel(5)Partialbridge‫ڹ‬‫ۑ‬‫۔‬‫ڹ‬‫ۑ‬‫ۑ‬‫ۑ‬‫ڹ‬

‫۔‬Construction cost (rough calculation)

‫ۑ‬
‫۔‬
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‫ڹ‬
N o t e ) ‫ ۔‬, ‫ ۑ‬, ‫ ڹ‬,  b e g i n n i n g wi t h s m a l l e s t d e g r e e o f i m p a c t a n d c o n s t r u c t i o n c o s t s .

3. Contents of future studiesThe following studies are planned in response to theamendment of the law and trends in later discussionsof the amendment of related cabinet orders andministerial orders. Clarification of the range of studies under SEA
based on past cases
Past cases considering environment are analyzed toclassify effective ways to care for environment whichshould be studied according to the stage of the project.(2) Collecting information about the naturalenvironment and studying the evaluation method Effectively implementing SEA depends to a great
extent on the quantity and quality of information
concerning the natural environment of a region.
Survey and research on animals and plants and theadvance of IT are accompanied by the provision ofvarious kinds of information, so methods of using
SEA in a road project and methods of evaluatingconservation effects are studied.
[Reference]
1) A. Kameyama: Eco-roads —creating roads kind tolife—, Soft Science, 1997‫࣭ྥື✲◊ە‬ᡂᯝ