Small headwater streams provide ecosystem services and support critical habitat required to maintain freshwater biodiversity. Human activities often impact these streams with more than half of all river systems in the world being heavily affected. One strategy frequently utilized for stream restoration is floodplain reconnection through engineered stream aggradation, which reduces stream power, increases sediment deposition, enhances stream habitat complexity, and facilitates hyporheic exchange of stream water. It is theorized that these changes to the stream hydrogeomorphology alter nutrient cycling and create important rearing habitat for salmonids. However, few studies have critically evaluated the ecosystem effects of floodplain reconnection using controlled and replicated ecosystem-level experiments, thus limiting the inferential value of study findings. To investigate the impacts of floodplain reconnection we used a before-after-impact-control (BACI) design to conduct a study in a small creek in Southern England. We collected periphyton and stream insects in a restored and unrestored reach before and after the completion of a restoration construction. Diatom communities showed an increase in the relative abundance of organically bound nitrogen tolerant-taxa in the restored reach one-year post-restoration. Stream insect communities showed an increase in the relative abundance of detritivores and predators. Our results suggest an increase in the availability of organically bound nitrogen and an increase organic material trapping due to the restoration. Our results support hypothesized habitat and nutrient changes in the restored stream reach due to the floodplain reconnection.