"Spatial Composition of Waterfront Environment
in Residential Areas of Hino City--Analysis of Residential Areas
Utilizing Canals
from the Viewpoint of Landscapes"
Faculty of Architecture, Department of Engineering, Hosei University
(Laboratory of Katsumi Nagase)
Shinji Kubota and Yasuhiro Nakayama
Purpose of Study: We aim to find the key for future community improvement
of residential areas using irrigation canals, by analyzing composition
of surrounding environment of irrigation canals in Hino and clarifying
relationship between canals and various elements, based on landscape
pictures, distribution maps of elements relating to canals, cross-section
diagrams, etc.
Method of Analysis: We made distribution maps of materials used for
irrigation canals, vegetation, types of rails, location of the canals,
etc. Based on those maps, we clarified characteristics and relationship
between canals and surrounding environment. Furthermore, we drew cross-section
diagrams of canals flowing within residential areas, including their
width, depth, and materials. We also drew an oblique line indicating
the area from where a canal can be seen by measuring distances to surrounding
houses and their heights. By considering how irrigation channel networks
relate to surrounding buildings, we made evaluation lists of space
composition.
Results: We found several characteristics by the research of each
irrigation canal within the city from upstream thorough downstream.
Firstly, "approach
from a house to a canal". In view of road ratio of both sides
of canals, the left side facing toward downstream is high. Most of
irrigation canals flow from west to east. Therefore, the left bank
is north and right bank is south. From the roads on the left bank,
one can approach houses facing south, without a bridge. We also researched
on houses with bridges, and on which side of banks adjoining parallel
roads are located. As a result, many of such roads are located on the
right side (south). Therefore if a house is on the left bank and the
road is on the right bank, the waterway and road are located in the
south of the house. In other words, the general concept, "large
south front space is to be provided to a house, in order to distance
shade under north oblique line" is considered to be applied.
Environmental Elements Distribution Map (［Distribution
Maps of Environmental Elements by Canal
水路別環境要素分布図.pdf］
analyzing ratios of environmental elements of each canal, and Sample Distribution
Map (［Distribution Map of Samples 見本分布図.pdf］)
clarified the followings: for example, Mokojima Irrigation Channel has rich vegetation,
while Arai Irrigation Channel has large stone revetment area.
The ratio of buildings along irrigation canals occupies about 50% of buildings
within Hino city at present. The ratio of farmland makes up from 30 to 40 percent.
Regarding materials of revetment, concrete is over 60 percent.
Guard rails and net fences make up 60 percent of rails along canals.
Vegetation configures 30 percent of the city.
Construction of Houses in the Surrounding Environment
When comparing the right and left banks, more buildings are built on the left
bank, while more farmland, forests, and vacant lots are found on the right bank.
Because the left bank is on the north side and the right bank is on the south
side, houses tend to be constructed on the left bank, and farmlands are kept
on the right bank, which might be related to sunshine. For example, when a house
is constructed without enough depth and with a canal or road on the south side,
shade can be avoided because of the space on the south side. However, it cannot
be applied to the housing complex.
Canals-From the Cross-Section Diagrams of Residential Areas
We analyzed the cross-section diagrams of waterways (Evaluation of Cross-section
Picture ［Evaluation of Cross Section
Pictures
断面写真の評価の説明.pdf］) : from the viewpoint
of
closeness to water, deep canals, canals with high rails, private use of water
space, and revetment preventing
water view, have given disadvantages. At the same time, we could find some cases
where those issues could be resolved. For a deep canal, a walkway was constructed
along the canal, or on lower ground from the road level, or plant shrubberies
were provided; for safer canals, rails were demolished or lower rails were built.
Bridges linking houses were built with wide intervals on the canal. Sidewalks
were built for safe walk and view of water. "Step-back revetment" also
improves closeness to water.
From Concrete Upright Revetment to Natural Revetment
The distribution map shows that concrete revetment is over 60% regarding the
canals where water flows. Although upright revetment has fulfilled useful functions,
it is not good for landscape. It is required to remake concrete revetment to
stone or earthen dikes after getting a budget. The areas adjoining to roads with
a lot of traffic and attracting public attentions should be preferentially improved.
From Covered River to Open River
In the area where houses can be approached from bridges, canals have declined
in importance because bridges prevent the view of water. The landscape of such
residential area where water has reduced its value should be reconsidered.
In the process of making distribution maps, we noticed that rivers within the
city have many covered areas. The one fifth of total length of irrigation canals
is covered or hidden by bridges. In the future, such covered river should be
opened. Firstly the river with a side road can be easily renovated by removing
the cover of the river.
Evaluation List (Merits and Demerits of Canals and Residential Areas)
Points to be considered as demerits:
・The only role of a canal is the place where water flows
・High percentage of concrete revetment
・Rails that does not harmonize surrounding landscape are built for safety reasons.
・Canals decline their importance because bridges to houses hide water
Points to be considered as merits:
General points:
・Farmlands are retained even if they are small, and canals and open spaces are
utilized.
Partial points:
・The canal along the road to station gives affluence.
・Stone or earth revetment is built for areas attracting attentions of pedestrians
・Some houses are fenced by vegetation
Future Irrigation Canals
Revetment
・From the viewpoint of landscape, concrete revetment should be reconstructed
into natural revetment
Rails
・Rails which do not fit landscape should be demolished; instead, rails covered
with vegetation and wooden rails should be built
・Rails within residential areas should be changed to rails covered with vegetation
Relationship between Canals and Residential Areas
・To keep the view of canals from houses, visible area under oblique line should
be enlarged by constructing slope revetment
・Generally, a window is not provided on the north side because of sunshine. However,
if a canal is located on the north side of a house, a window on the side should
be recommended for attracting interests for canals.
Perspective from Planning
・Old landscapes such as washing place were lost. They should be restored in the
places such as where morning markets are held, in consideration of closeness
to water.
・Biotopes should be constructed in elementary schools, junior high schools and
residential areas. By introducing small nature into the city, places for daily
environmental education should be provided
・Quiet places should be prepared where various sounds of streams can be heard
・For spots near headwater, it is recommended that wasabi or watercress would
be planted for vitalization by foods and works. In the edge of residential areas,
it is recommended to provide a border line by water. Various landscapes should
be produced such as parks with closeness to water, aiming to prepare usable waterfronts
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[Distribution
Maps of Environmental Elements by Canal] |
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[Distribution
Map of Samples] |
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[Evaluation
of Cross Section Pictures] |
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