Effective phosphorous reduction by a riparian plant buffer zone enhanced with a limestone-based barrier

•A limestone-based barrier showed average long-term P-PO4 and DP removal effectiveness of 12.4% and 13.0%, respectively.•Removal effectiveness increased with influent concentration.•Maximal P-PO4 and DP reduction was 2.04 and 3.59 mg P/L, respectively.•Schoenoplectus lacustris and Glyceria maxima were the plants most effective at P and N accumulation.•Biomass harvesting from the buffer zone (171 m2) removed 5.8 kg P and 40 kg N.