So rather than ease water woes and the impact of droughts, the new pan disrupted the traditional land use management system of the Borana tribe in the Yamicha area and led to conflict with herders from other ethnic groups, residents and activists said. "The water pan caused encroachment by other communities, destroying the reserve," which was part of an old grazing rotation system designed to ensure grass availability for local herders even in drought periods, said Abdi Adi, chairman of the Cherad Ward Plan Committee in Isiolo.