報告書番号

U00071

タイトル（和文）

手賀沼における流動・水質・底質のシミュレーションと底泥からの栄養塩溶出の湖内水質への影響

タイトル（英文）

Simulation of Flow, Water Quality and Sediment and Effect of Nutrient Release from Sediment in Lake Teganuma

概要 （図表や脚注は「報告書全文」に掲載しております）

手賀沼を対象に，流動・水質・底質の年間に亘る時空間変動のシミュレーションを実施した．水質の縦断分布から，有機物は流下方向に増大し，無機物は減少すること，場所によって有機物の季節変化が異なることが認められ，流動・水質のシミュレーションによってこれらの特性が概略再現された．さらに，年間に亘る全リンの物質収支から， 流入負荷量の5割が下流に流出し，5割が湖底に堆積することが確認され，底泥からの溶出フラックスは，静的な条件下では流入負荷量の2割であった．

概要 （英文）

Seasonal and spatial changes in water quality in Lake Teganuma were investigated by using the field data and were simulated by a flow, water and sediment quality models. Chlorophyll-a and COD increased, and inorganic nitrogen, phosphate, total nitrogen and total phosphorus decreased toward downstream direction. Chlorophyll-a increased in summer and decreased in winter, and inorganic nitrogen and phosphate decreased in summer and increased in winter at the observation point of Nedo-shita. These observed variations of nutrients were practically reproduced in the simulation of the flow , water and sediment quality. Furthermore, according to the mass balance, 50 percent of total phosphorus in the inflow load was transported to downstream and the rest of 50 percent was accumulated to the bottom of the lake. Moreover，the results of the simulation suggested that 20 percent of total phosphorus in the inflow load is released from sediment.

報告者

キーワード