The Makorokio stream originates in the Tararua Ranges and flows through farmland until is joins the Ohau. The monitoring site is located close to the ranges south of Levin. The predominant land use upstream of this monitoring site is native bush. This site is recognised as a Site of Significance – Aquatic for shortjaw kokopu, lamprey and redfin bully and lies within the Waikawa target catchment for diffuse sourced nutrient management.