After released by the government in 1869, he devoted himself to promote regional growth; when he became a junior councilor of Tonami Prefecture (soon incorporated into Aomori Prefecture) established by Haihan-chiken (abolition of feudal domains and establishment of prefectures enacted by new government), he exploited Western style pastures in Yachigashira (present Misawa City) for those retainers of the Aizu clan suffering from extreme poverty since the reduction and transfer of Aizu Domain to a wasteland Tonami as Tonami clan (reorganized as Tonami Prefecture and soon incorporated into Aomori Prefecture by Haihan-chiken).
明治2年（1869年）釈放され、斗南に減封移封された後廃藩置県により小参事となった広沢は貧困に苦しんでいた会津藩士のため谷地頭（現在の三沢市）に洋式牧場を開設し地域の発展に尽くした。