Footnote
(Note 1) Eco-DRR: ecosystem-based disaster risk reduction
(Note 2) K-Cowork Greening® is sustainable greening that connects various stakeholders. It enables the reduction of maintenance and management costs through the collaborative efforts of multiple companies and organizations, and the production and sale of high value-added products using the products harvested there. In addition, by selling products created through the involvement of multiple companies and organizations, a wide range of people, including purchasers, can be involved in the greening activities, which is expected to have the effect of connecting various stakeholders in the community.
(Note 3) "Yato" refers to a valley created by the erosion of rainwater and spring water on a hillside. It is a landform consisting of wetlands, springs, waterways, rice paddies/other agricultural land, and reservoirs, and they are surrounded with hillsides and forested areas from three sides (both sides and behind).
（Yokohama City, Kanagawa Prefecture web page）
Promoting Green Infrastructure
KAJIMA CORPORATION
| Publication date | Jun 9, 2022 (Posted on Jun 27, 2022) |
|---|---|
| Sector | Life of Citizenry and Urban Life / Natural Disasters / Coastal Areas |
Company Overview
Since its establishment in 1840, KAJIMA CORPORATION has been contributing to the creation of a safe, secure, and comfortable society through its construction business by developing social infrastructure such as railways and dams, and by creating places for people to live and work, including offices, commercial and residential facilities. The company provides communities and customers within and outside of Japan with the highest standard of urban spaces, buildings and infrastructure by deploying its capabilities of pre-planning, development, design and engineering, in the upstream part of the construction value chain to downstream maintenance and management.
Climate Change Impacts
Green infrastructure is defined as actively utilizing the diverse functions of the natural environment to improve the attractiveness and livability of a region and to obtain diverse benefits such as disaster prevention and disaster mitigation, and in Japan, its promotion was included in the National Spatial Strategy approved by the Cabinet in 2015. Earlier, the National Biodiversity Strategy of Japan 2012-2020 and the Fundamental Plan for National Resilience also presented the concept of disaster prevention and mitigation utilizing natural ecosystems (Eco-DRR,Note 1). With the rapid progression of population decline, declining birthrates, and aging populations, there is a need for approaches to solve complex social, environmental, and economic issues, and green infrastructure is expected to be a method that provides comprehensive solutions to various problems due to its versatility.
Adaptation Initiatives
We provide comprehensive one-stop services for urban development utilizing green infrastructure, from on-site surveys to operations, and offers advanced technological capabilities and networks (Fig. 1).
As examples, "rooftop farms," "rooftop paddy fields," and "Okujyo Harappa® (green roof)" are examples of greening that uses building rooftops in urban areas. The following is the description of them:
- Rooftop farm: Since it is expected to attract many visitors and users, it can contribute to increasing customers and raising the profile, and if a café or a restaurant is opened, it is possible to serve freshly picked crops from the rooftop farm. We are also developing K-Cowork Greening® (Note 2), in which pop and sweet potatoes are grown, processed into beer and shochu, and sold to secure funds for activities as community-wide greening activity in collaboration with the surrounding community. From the planning stage, in addition to considering the necessary hardware, we provide organizational structure plans for operation, hands-on learning program proposals, and maintenance and management plans (Fig. 2 and 3).
- Rooftop paddy field: In addition to revitalizing the agricultural landscape and making effective use of the rooftop space as a place for communication among participants in rice cultivation, it can also improve the thermal environment of the building and make effective use of rainwater (Fig. 3).
- Okujyo Harappa® (green roof): A new rooftop greening design utilizing the grassy areas (such as vacant lots in urban areas,) which have been decreasing in recent years, and maintaining them by the participation of the residents using nearby vegetation and everyday waste materials. Compared to the conventional rooftop greening designs that use tall trees and shrubs with automatic irrigation systems installed, this new rooftop greening design is environmentally friendly, low-cost, and lightweight. Since seeds are collected from the surrounding area to restore the grass unique to the region, it can create new grass on urban rooftops that matches the characteristics of each region and contribute to the preservation of biodiversity (Fig. 4).
Rain Gardens (rainwater infiltration green belts) are permeable planting spaces that temporarily store rainwater during rainfall and allow it to infiltrate underground over time. In addition to reducing the load on the sewage system, it has the effect of purifying water and enhancing groundwater recharge. It is also effective as a countermeasure for heat island effects by improving the thermal environment through evapotranspiration. Since the amount of collected water and infiltration differs depending on each site, materials and plantings are selected to suit the site, and designs are implemented to harmonize with civil engineering structures and buildings.
Effects / Expected Benefits
The main building of Kyoto Yaoichi, which features specialty food stores focusing on vegetables, has developed a full-scale farm on its third-floor rooftop using soil from Tamba, Kyoto. The rooftop greening is expected to reduce building temperatures and prevent deterioration by blocking direct sunlight, and because it is located right in front of the restaurant on the same floor, visitors can see how seasonal vegetables are grown. This is an advanced example of not only reducing environmental impact but also creating added value by attracting visitors and promoting agriculture (Fig. 2).
Totsuka Ward in Yokohama City, Kanagawa Prefecture, designed a rooftop paddy field, lawn, garden and a biotope on the 8th floor rooftop for the construction of a central facility for municipal administration. The project recreated “yato (vally)” (Note 3) the original landscape of Totsuka Ward that remains in the vicinity of the project site, and the farming that took place in the area. After construction, we coordinated a workshop for nearby elementary school students to experience rice cultivation including planting, harvesting, rice cake pounding, and shimenawa (sacred straw ropes) making, thereby utilizing the unused rooftop space to create added value for community interaction, education, health, and improved profitability (Fig. 3).
