Survey of suspended solids sources and riparian corridor condition for the lower Mahoning River

Abstract

The Mahoning River experiences high turbidity and total suspended solids (TSS) concentrations, particularly during and after rainfall events. The loading of suspended solids to the river, both from runoff and bank erosion, depends partly on the condition of riparian corridor adjacent to the river. Two major goals fo this project were to estimate TSS fluxes in the Lower Mahoning River and to study the riparian corridor condition along the river in Trumbull County. Eighteen sampling sites were chosen from Lowellville to Milton Dam along the river and tributaries. Nine samplings trips were accomplished from January 17 to July 6, 2005. The highest average TSS concentration and flux rates on the Mahoning River were 26.1 mg/L and 40,670 MT/yr, respectively for Lowellville. Among tributaries, Mill Creek had the highest average TSS concentration (19.5 mg/L) and Mosquito Creek had the highest TSS flux/loading (2258MT/yr). Mass balance analysis between Leavittsburg and Lowellville showed net deposition of TSS on the river bed for five sampling dates and net resuspension for three dates. For the trip of May 14, 2005 (after heavy rainfall), the estimated flux was 547,000 kg/d, which was so high that it probably included river bank erosion as well as resuspension of earlier deposited sediment from the river bottom. Two metrics of the Qualitative Habitat Evaluation Index (QHEI) - Riparian Width and Flood Plain Quality - were determined for the lower Mahoing River by analyzing aerial photos for 259 river segments using ArcView GIS software. Most of the segments from Braceville and Weathersfield townships were ranked "Excellent" for the combined score of these two metrics.