Osaka Bay Area metropolitan region exists, the water quality by regulating the amount of inflow loads are being improved. However, an area of sea where closing practices became high over-nutrition in filled land chronically. By the way, Awaji Island of offshore in Osaka Bay and Harimanada has withered laver. Considered the problem of bias in the balance of nutrient cycling in the Bay Area region in addition to the quantitative issues as the cause of this nutrient. In this study, which aims to restore a proper balance of nutrient circulation in the area of Osaka Bay. In the first study, the actual condition and problems of bias and nutrients to build organized in GIS databases. Then, we designed the optimal method for sewage effluent for the purpose of optimizing the balance between nutrient cycling. Finally, we evaluated the effect of forecast measures for the application of numerical analysis. From these findings, in Osaka Bay restore Project have shown that the plan will balance the need for nutrient cycling.