2006.4-2007.3 Yearbook of NILIM
Research Summary


Coastal and Marine Department

Reference Number Y070802
Title Wetland Restoration Project for Urban Area
Start-End Date 2003.4-2008.3
Division Marine Environment Division
Author Head, Keita@FURUKAWA
Senior Researcher, Tomonari@OKADA
Researcher, Osamu@Hayakawa
Summary After a new government initiative in 2001, a big push began to promote environmental restoration in Japanese coastal zones. Tokyo bay and Osaka bay was facilitated with a bay restoration action plan in 2003 and 2004 respectively, which is one of dense populated bay in eastern and western part of Japan. These plans were a part of an urban restoration action leaded by cabinet of Japan. Both action plans included menu of coastal ecosystem restoration by restoring wetland environment. Thus, experimental facilities to invent new techniques for habitat creation were implemented in both Osaka Bay and Tokyo Bay. In Osaka bay, a 5ha constructed tidal flat was set as a practical experiment site. To enhance the suitability as benthos habitat, different type of sediment, structural objects, and water pools were set on the flat bed. To stabilize the bottom topography, different type of wave control systems were implemented. As a result, small scale of structure and measures are not effective to control stability of topography. The more large scale phenomenon was dominant at the area. On the contrary, the countermeasures were very effective to enhance the suitability as benthos habitat. In Tokyo bay, two 4m x 10m pools with 0.5m depth were set on the terrace of sea wall. This pool can be act as a nursery for juvenile fish. Only one month after construction, more than hundreds of fish larvae were observed. Outline of the habitat creation techniques and its results will be presented at the presentation.