In A History of the Hakkas in Taiwan, Huang Jung-luo notes that the Hakka settler Chang Ta-chao had already opened up the northwest part of the Taichung plain by the reign of the emperor Yongzheng (1723-1735), and the Chang family's irrigated fields in Tuwu Chienchun already covered an expanse of 3,000 chia (approximately 2,900 hectares).
黃榮洛在〈客家人的台灣史〉文中寫道，雍正年間，客家人張達朝，早已入墾整個台中大平原的西北部，到乾隆五十年左右，張家所築獨霧揀圳的灌溉面積已有三千甲。