抄録：底泥置換覆砂工法の現地実証実験

底泥置換覆砂工法の現地実証実験
諏訪湖実証実験

大谷英夫・小林峯男・松木田正義・上野成三・勝井秀博・岡田和夫・友井宏・丸山邦男・岡田美穂・駒井篤

水質改善対策である浚渫や覆砂には，浚渫土の処理場，砂の入手先などの問題があるため，新技術の開発が望まれている。底泥置換覆砂工法は、底泥下の砂をジェット水流により浮上させ底泥を覆砂する新技術である．開発の課題は，砂の浮上量，覆砂範囲とも覆砂工法として十分で，湖底が生物にとって望ましい環境に改善されることである．諏訪湖実証実験の結果，本工法は好気性環境を提供し，底質改善効果も持続することが示された．

キーワード：

底泥浄化，水質浄化，浚渫工，覆砂工，諏訪湖

Field experiment of a new type of sand capping method by sand-upwelling system
Field experiment In lake suwa

Hideo Ohtani, Mineo Kobayashi, Masayoshi Matsukida, Seizo Ueno, HIdehiro katsui, Kazuo Okada, Hiroshi Tomoi, Kunio Maruyama, Miho Okada and Atsushi Komai

As a water quality purification measure for areas such as lakes, a sand covering method was developed. This method involves welling up clean sand from below contaminated sludge by using a water jet. The disposal of sludge and the acquirement of pure sand are not necessary. Besides, the ecosystem will hardly be disturbed by this method.
This method was carried out in Lake Suwa and six months after finishing the works, the following results were obtained.
The thickness of the sand covering layer and the aerobic environment were maintained. Also, many Limnodius appeared in the sand covering area.

keywords:

sediment quality purification, water quality purification, dredging, sand covering works, lake suwa