Session Report Cover Sheet
SESSION CODE: OTHE - 26
Name of Convener(s): JAPAN XERISCAPE DESIGN ASSOCIATION
DATE:
22 - March, 2003
Session Title: Water Conservation and
Efficient Design in Your Garden
Accomodation:1-24-16-6, Josuiminami-cho, Kodaira-shi, Tokyo
JAPAN187-0021
Contact information
in Japan
Contact No.: TEL 042-359-6577
FAX 042-326-6277
Contact E-mail: land_jpn@t3.rim.or.jp
Session Report
SESSION CODE: OTHE - 26
Reporter/Rapporteur: Satomi Matsuzaki
Contact E-mail : land_jpn@t3.rim.or.jp
1. Key Issues

Lack of “water conservation” in landscapes in Japan

Wasting rainwater/storm water (no harvest / utilization at all)

Urban heat island impact

Global drought problem

Global warming effects

Lack of water supply

Water rate hike

Water shortage
2.Actions
To solve above problems, we, JXDA suppose that it is necessary to incorporate the utilization of
rainwater and storm water into all the landscape development, thus, we use the procedure, which is
called “Xeriscape“ or “Water Wise Gardening“, for water conservation and have just started to promote it
in Japan.
Through the session, we showed several practices had been already performing well for water
conservation in landscapes as case studies, and thought about how to use water more efficiently in sites
and what benefits we could get by doing it.
And we decided the action plan finally.
……….Session…………
Title: Introduction
Speaker: Kanehisa Koide, Landscape Architect, ASLA
JXDA Chief Director
Summary
JXDA was founded by me, Kanehisa Koide in 2001 and it has promoted "Xeriscape / Water Wise" action.
Architects, landscape architects, nurserymen, venders, indoor plants producers are involved in this entity
as core members.
Xeriscape is a trial to use water efficiently and consider water more closely in a green space.
Formally, Xeriscape means " water conservation through creative landscaping " and is also called "
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Water Wise Gardening "
For urban planning and residential or multiple facilities' development, it is very important to consider the
relation of plants and water: Plants need water. For the growth of plants, an irrigation which is done with
right way in right time is needed. The reason why it isn't so popular to use irrigation systems at
landscapes in Japan is most of designers don't handle them so well. I think suitable irrigation is needed
for creating a landscape aesthetic and we also have to use all water efficiently in our life to reduce the
amount of using city water. It is significant to know about plants and take Xeriscape procedure which is
easy and available for everyone, to revise the ignorance to the relationship of water and garden. I think
its promote can prevent wasteful water use and pollution of sewage & underground water by mixture of a
pesticide or a chemical fertilizer, and contribute to make water & ecosystem healthy.
The key of its success is to build the partnership among decision-making, technique and design in a
landscape water conservation project and it functions there organically.
I am convinced the issue of water & garden, which is taken as main theme in this session, isn't getting an
imminent problem only for landscape architect in Japan and U.S. but also for everyone in everywhere.
Case study-1
Title: Storm water as a Framework for Regional Gardens
Speaker : William Wenk, FASLA,
Principal, Wenk Associates, Inc., in Denver ,Colorado
Continued rapid urbanization has placed demands on water traditionally used for agriculture. Additionally,
environmental concerns that include destruction of in-stream and riparian habitats, and concern for water
quality have challenged traditional assumptions regarding how additional water supplies can be
developed. Finally, a four-year long drought, and continued shortages as a result of population growth
has required cities in the west to reevaluate contemporary garden design traditions.
The presentation included a brief history of landscape gardening traditions in the West, identified
traditional irrigation practices that could serve as models for a new, more regional garden aesthetic. A
series of projects were presented that illustrated how storm water could be used as a basis for a new
landscape tradition that recognizes the value of urban storm water as a resource.
Projects:
1. Wenk Associates offices. The project demonstrates how an unused driveway and other paved
areas where transformed into a series of small gardens supported by runoff from the buildings roof.
2. Environmental Center of the Rockies. This project illustrates the transformation of a traditional
building landscape and parking area into a series of storm water gardens that retain significant storm
water volumes on a small urban site.
3. Holiday Housing. Planning for a series of storm water gardens in a dense, mixed-use community in
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the city of Boulder, Colorado illustrates how storm water gardens can be incorporated into compact
public and private landscapes.
4. Stapleton Airport New Community. The closure of Stapleton international airport presented at the
opportunity to develop a 4,500 acre mixed-use new community near the center of Denver. The
community is Park and open space system was developed as an integral part of a surface storm water
system.
Projects' Goals:
 Reduction in rainwater or storm water runoff.
 Installation of a "storm water garden ", which mainly includes irrigation systems and water features
supported by storm water.
 The landscape planning incorporated the utilization of storm water developed a new community.
Conclusion:
The presentation concluded with a discussion of a series of issues that placed limitations on the potential
for widespread implementation of storm water garden concepts.
 Cost issues for maintenance. They are still expensive.
 How to connect old drainage systems / techniques and urban systems in a natural city.
 How to divide the storm water from the infiltrated salt water had been used for dissolving snow on the
street. The problems are cost and technique.
Case study-2
Title: Alternative Strategies to Water Reuse, Conservation and Storm Water Runoff in the City of Seattle,
WA. USA.
Speaker: Daniel Winterbottom, Associate Professor,
Department of Landscape Architecture, University of Washington.
The presentation focused on two urban case studies located in Seattle, the largest city in the
northwestern United States.
Projects:
1.Cascade Adopt-a-Park, 1997.
Located in an inner city Seattle neighborhood, the Cascade Adopt-a-Park is located on land owned by
the Seattle Parks Department and maintained by the Cascade community. Completed in May 1997, this
project was designed and built by a landscape architecture class consisting of eighteen students and two
faculty members.
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2. University Heights Park and Community Garden, 2002.
Located in Seattle, University Heights Park and Community Garden, is sited on the grounds of a former
public school, now decommissioned and converted into a community center. The park, situated on land
owned by the Seattle School Department was completed in May 2002, and designed and built by a class
consisting of forty five students and three faculty members.
Projects' Goals:
 Reduction of storm water run-off.
 Water quality.
 Water conservation.
Features of the two projects:
 A rainwater harvesting system.
 A bio-swale infiltration system that conveys and infiltrates the overflow water from the rainwater storage
cistern.
 Benefits of good design solutions.
A gazebo for community gathering, with the plastic lumber flooring serving as the lid to the
cistern below. (Cascade Adopt-a-Park)
The filtration trench which is used to solve a drainage problem, the elimination of off site
storm run-off, but also increases the vehicular parking available on site. (University Heights
Park and Community Garden)
 Pervious pathways.
 Drought tolerant demonstration gardens including:
 Herb garden
 Wildflower garden
 Native salvage garden (Cascade Adopt-a-Park)
 Wetland garden
 Eco Turf (University Heights Park and Community Garden)
 Butterfly garden (University Heights Park and Community Garden)
Summary:The impacts of these projects as replicate models.
Several strategies have been employed to achieve the goals stated previously.
 Low tech. replicable solution of rainwater cisterns:
The former project "Cascade Adopt-a-Park" has an 8,000 gallons underground cistern as a low technical
solution. Once the soil was excavated a rubberized pond liner was laid down on a sand cushion layer to
create a waterproof membrane. To use the system water from the underground cistern is hand pumped
up to a small cistern, providing the needed gravity flow. A garden hose is attached to this second cistern
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and is used to water the gardens. Our building code required that the cistern must be covered, and as
we thought creatively how to resolve capping the underground cistern this became an opportunity, not a
constraint. We decided to create a gazebo, with the plastic lumber flooring serving as the lid to the
cistern below. The provided the community a shady shelter and a place to gather and for special events.
The Parks Department wouldn’t allow a covered roof on the gazebo, as it was believed this would
encourage transients. The solution is a roofing system made of bamboo, which serves as a structure for
a green “vine” roof, providing shade for the daily users but not protection from the rain.
The latter project "University Heights Park and Community Garden" has a 4,000 gallons ground cistern.
It offers a prefabricated, visible solution, providing large quantities of water for irrigation. By exposing the
cisterns, this solution reveals, both physically and visually, the volume of water needed to irrigate this
garden. By using rainwater for irrigation the water costs associated with these gardens is reduced.
 100% reduction in storm water runoff:
By using pervious paving and an infiltration bio-swale, we have achieved a 100% reduction in storm
water runoff leaving the site.
 Multiple habitats are created through drought tolerant gardens:
By developing a series of distinctly different gardens based on their specific water requirements, we
have created a diverse range of habitats.
 Educational Benefits:
The park serves a demonstration model and test site for sustainable practices. Many of the techniques
we used in the Cascade Adopt-a-Park have been reproduced in other projects across the country.
Several local schools also use the park as an outdoor classroom in which science classes are held.
Question: Does the water rot in the cistern? If so, what kind of measure do you prevent it with?
Answer: The water in the cistern should be intercepted from sun. And we should store the filtered water
only. Countermeasures for acid rain go on, however it isn't so serious at this area of United States.
Conclusion:
We have been working to develop small model projects that can be replicated. The impacts of one
project on water conservation are small, but when replicated on many sites can be significant. We are
already seeing a growing interest in adapting these cost-effective strategies in many parts of the United
States. It also can be practiced in Japan and the other place, too. To further our research, we monitor the
completed projects for performance and durability.
Case study-3
Title: The practice of Water Wise Landscape in Japan
-The case of Shimizu-Shirayuri Kindergarten5
Speaker: Kanehisa Koide, ASLA
Chief Director of JXDA
I mentioned the definition of Xeriscape again. Besides, regional climates and microclimates in sites have
very influence on Xeriscape design.
I take a case to explain the other part of Xeriscape design.
Project:
1. Shimizu-Shirayuri Kindergarten in Shimizu, Shizuoka 2002
This is a report from the landscape project with a new school building of a private kindergarten located in
Shimizu (Shimizu and Shizuoka will merge on April 2003. When the project was finished, there was
called Shimizu still. )
I proposed to harvest rainwater from the roof top of the new building and it was accepted by the client,
however, the rainwater conveyance system became a long pipe from the eaves trough of the building to
the underground cistern. Though this was a typical case described the problem "Communication gaps"
laid between architects and landscape architects in Japan, we had a great progress to incorporate the
procedure of water conservation in landscapes. We made the effort the long rainwater conveyance pipe
would be aesthetic as art: We made a creative play tool using the rest of the pipe and planted some
climbers by the pipe at the same time. The client also found to reuse rainwater was very important to
educate children, so, we made the water feature by using rainwater recycle
This project became the good case how decision-making, technique and design in Xeriscape/Water
Wise cooperated together and produced the solution for growing children's creativity using the site.
Project Goal:
Creation of environmental demonstration place of Water Wise garden using the whole kindergarten site.
Features of the project:
 Rainwater harvesting system/rainwater conveyance system.
 Underground rainwater storage cistern.
 Reuse rainwater:
Irrigation for all vegetation and flower beds
Recycling water for stream
 Special filter system installed to exclude dirty granule.
 Water feature "stream" has an educational purpose for kids to think about water.
Asking a question “ Where is your water going? “
Tiny stream for children to play with water
Using stones gathered by children on the seashore
Stimulating the creativity of children
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Our eight process for reducing total water consumption
 Reduce evaporation from the surface of soil
 Raise water retention character of soil
 Raise moisture of soil by earthwork
 Store water runoff from the hard surface
 Invest the expansion of impound facilities
 Irrigate right and efficiently
 Reuse rainwater
 Reduce quantity of water for sewage system
Conclusion:
We would like to emphasize the keyword of “Education and Environment”. In other word, it is extremely
important to educate younger people to have right recognition and future motivation in terms of efficient
water use. By installing model feature of using rainwater efficiently, children and people in the region
will learn how we can utilize it. And we suggest to recognize how water and green bring us wealthy
indeed.
-----Action Plan ------3. Commitments
It is inevitable to establish the partnership among decision-making entities like local governments,
regional communities, public educational system and private companies, and technical specialists of
drainage, soil and civil engineering, and professional designers like landscape architects and architects
in order to materialize water conservation in landscape.
Longer Term Objectives (Goal)

Increase rainwater and storm water storage ratio from 0% to 30% at all landscapes

Reduce the amount of city water and sewage water by 20%

The partnership of decision-making entities, technicians and designers will jointly create the
replicable model as a sustainable design alternative, which is applicable to everyone and
everywhere both functionally and aesthetically.
Tools to Achieve the Objective: Installation of educational demonstration gardens by the partnership.
The garden shows the following solutions:

Introduction of proper irrigation system

Promotion of rainwater harvesting and re-using it.

Selection of drought tolerant plants

Promoting water conservation materials, such as soil or pervious pavement.

The best balance between the sense of water conservation and functional / beautiful garden
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Model garden indicators towards the reduction of water / sewage use
1. Reconstruction of efficient water conservation garden through monitoring water amount use and
sewage use. (For example, re-shaping the existing gardens through the adjustments of plants, soil
and irrigation.)
2. We can specify the plants suitable to each region by closely monitoring the plants during garden
maintenance so that we can create the beautiful landscape without using excessive water.
Short Term Objective (TARGET)

Installing the educational demonstration garden by the partnership at least one for each
prefecture in Japan within next 3 years.

JXDA will strengthen the partnership with global Xeriscape associations to materialize the
transparent information-flow framework where everyone can research and enjoys suitable
information and improve the technology level of Xeriscape within Japan.
4. Recommendations
Japan Xeriscape Design Association (JXDA) proposes that all the landscape developments, from
residential gardens to urban sites, should incorporate the water conservation procedures into its design
process in order to break off water shortage problems both currently and in the future possibly. The water
conservation procedures mean (1) the standardization of right knowledge and technology, which enables
us to use one drop of water more efficiently, (2) the introduction of proper irrigation system, and (3) the
harvest & utilization of the supplemental water, such as rainwater and storm water. We believe the
standardization of these procedures will change our living & environmental space better and sustainable.
It also enables us to pass over the better heritages to the next generation.
Again, we would like to emphasize the keyword of “Education and Environment”. In other word, it is
extremely important to educate younger people to have right recognition and future motivation to solve
water problems. We propose landscape architects should integrate the educational solution in sites
more.
Finally, JXDA proposes many landscape architects or people from landscape universe should be looked
forward to participating the next "the 4th WWF" since we were the only participants from landscape
universe this "the 3rd WWF".
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