The Athabasca River Basin is home to the largest oil sands operations in Canada which is situated in a hydrologically complex region. As oil sands development has progressed, the complexity of disentangling changing hydrologic contributions have only increased with the presence of industrialization. The landscape has been altered through surface and in-situ mining, transportation routes, employee lodging and much more. Understanding the impacts that this continuous development through time has on the hydrological regime of the area will allow modellers to make more informed decisions on model parameters, processes, and interactions. We present an investigation on the impacts the Syncrude oil sands development has had on surface runoff pathways in the Athabasca River Basin around Fort McKay and how to integrate these into hydrologic modelling. This work encompasses an overview of the natural flow pathways prior to the oil sands era as well as throughout the 50 years of development that produced self-contained water storage units such as pit lakes and tailing ponds. The results of changing landcover and hydrologic pathways have been integrated into a WATFLOOD/CHARM model, including the concepts of grid flow direction manipulation and contributing area fractions. This work is part of a larger project aimed at quantifying the impacts of changing land cover on water availability in the Athabasca Oil Sands Region.