The Lower Old Red Sandstones in northeast Scotland form an aquifer suitable for groundwater development. A groundwater abstraction scheme was proposed for augmenting water supplies to local villages. A production borehole was drilled into the sandstones which has a design yield of 2420 m3 day-1. However, the scheme was abandoned because of concerns that the abstraction would reduce flows in a nearby stream which is important for salmonids. This study demonstrates the potential value of using a stream-aquifer numerical model (MODFLOW) in an environmental risk assessment for the scheme. Results indicate that the proposed abstraction would not cause streamflows to fall to a level where flow compensation will be needed to maintain salmonid habitats.