Doctor of Philosophy (PhD), Ohio University, 2016, Civil Engineering (Engineering and Technology)

Sedimentation is one of the important factors affecting stream channel stability. The estimation of sediment supply, assessment of channel stability, and potential influencing factors are of interest in this study. A proposed model was developed by the integration of Revised Universal Soil Loss Equation (RUSLE) model and Watershed Assessment of River Stability and Sediment Supply (WARSSS), aiming to estimate the sediment load and evaluate the channel stability of a man-made channel. The proposed model was applied to the channelized Hocking River near Athens, Ohio. It was estimated that the annual gross erosion from the watershed was 728,733,738 kg, 97% of which was from the surface erosion, while only 3% resulted from streambank erosion. The total sediment yield in the channelized Hocking River was indirectly estimated by the addition of suspended sediments and bedload sediments, which were directly measured in the channel. The total annual sediment yield was 80,991,718 kg, in which 98% was estimated from suspended sediments and 2% from bedload sediments. This resulted in a sediment delivery ratio of 11%, which was consistent with those of the watersheds having similar size in the studied region. The total sediment transport capacity was estimated by the proposed model to be 17,161,761 kg/yr. Compared with the total sediment yield of 80,991,718 kg, 21% of which was transported by the river flow. The majority of sediments deposited in the channel due to the insufficient transport capacity. The amount of sediment accumulated was indirectly verified by the annual dredging project conducted by the Hocking Conservancy District (HCD). The channel stability of the Hocking River near Athens, Ohio was assessed by the characteristics of soil erosion for each monitored reach. Based on the four categories of stability determinations, most of the studied reaches were unstable in the lateral direction and all the reaches had excess deposition except one of the downstream r (open full item for complete abstract)

Committee: Tiao Chang (Advisor); Wei Lin (Committee Member); Kurt Rhoads (Committee Member); Teruhisa Masada (Committee Member); Deborah McAvoy (Committee Member) Subjects: Civil Engineering; Water Resource Management

Master of Science (MS), Ohio University, 2012, Civil Engineering (Engineering and Technology)

The primary objective of this research was to study sedimentation and erosion in the Tappan Lake Watershed. A bathymetric survey performed in 1998 by the United States Army Corps of Engineers had identified the lake as having a sedimentation rate five times greater than other lakes located in the region. Erosion and sedimentation were studied by using data from a 2011 bathymetric survey, the Revised Universal Soil Loss Equation (RUSLE), and a Geographical Information System. The conclusion of the study was that Tappan Lake does not have a sedimentation or erosion problem. Secondary objectives of the study were to evaluate the effects of Digital Elevation Model (DEM) resolution on the terrain related variables of RUSLE, L and S factors. Comparisons of RUSLE results were made using 3-, 9-, and 27- meter DEMS which showed that estimated erosion potential decreases as DEM resolution increases. The results also demonstrated that DEMs with resolutions greater than nine meters are not appropriate for calculating terrain characteristics, as they are incapable of clearly defining areas where overland flow accumulates or where deposition should occur.

Committee: Tiao Chang (Advisor) Subjects: Engineering; Geography; Geology

Master of Science (MS), Ohio University, 2012, Civil Engineering (Engineering and Technology)

This project utilized a Geographic Information System to model soil erosion potential in the Muskingum Watershed using the Revised Universal Soil Loss Equation (RUSLE). The project had three objectives; identify erosion “hotspots” in the Muskingum Watershed, test the applicability of RUSLE in large drainage basins such as the Muskingum Watershed, and study the erosion potential of ten subwatersheds within the Muskingum Watershed. The average erosion potential for the Muskingum Watershed was 0.290 kg/m2/year, and the average erosion potentials for the sub-watersheds ranged from 0.197 kg/m2/year to 0.804 kg/m2/year. The hotspot erosion value for the Muskingum Watershed was 1.286 kg/m2/year.

Committee: Tiao Chang (Advisor) Subjects: Civil Engineering

Master of Science (MS), Ohio University, 2012, Civil Engineering (Engineering and Technology)

The purpose of this thesis was to investigate the sediment transport capacity of the Hocking River in the 9-km long channelized reach between White's Mill and the State Route 50 Bridge, located on the eastern side of Athens, Ohio. Sediment transport capacity was determined using Hydrologic Engineering Centers River Analysis System (HEC-RAS) 4.1 and was compared to inflowing sediment rates to determine overall channel efficiency. Sediment transport efficiency as well as RUSLE sediment delivery ratio analysis indicate the channel has insufficient sediment transport capacity during average and below average flow conditions. Approximately, 1/8th of the channel has efficient sediment transport capacity during flood conditions. The threshold sediment delivery rate that would allow for sufficient transport was determined for the average flow and 1998 flood condition, based on erosion potential estimated by the Revised Universal Soil Loss Equation. Threshold sediment delivery rates indicate that sediment accumulates during average or low flow conditions, when the channel has insufficient sediment transport capacity. A fraction of the accumulated sediment is then removed during flood events, when the channel has more than sufficient capacity.

Committee: Tiao Chang PhD (Advisor); Gregory Springer PhD (Committee Member); Deborah McAvoy PhD (Committee Member); Guy Riefler PhD (Committee Member) Subjects: Civil Engineering

Master of Science (MS), Ohio University, 2012, Civil Engineering (Engineering and Technology)

The objective of this study is to determine the relationship between soil erosion and sedimentation within Wills Creek, Senecaville Lake, and Salt Fork watersheds of Ohio. Both Senecaville Lake and Salt Fork Lake watersheds are entirely located within the watershed of Wills Creek Lake. Experimental results using the Revised Universal Soil Loss Equation and a sediment delivery equation in conjunction with Geographic Information Systems are compared to sedimentation reports prepared by the United States Army Corps of Engineers. Results of this comparison show that the type of land cover has the highest impact on the amount of soil erosion, specifically the lands associated with cultivated crops. Furthermore, the sediment yield of a watershed is not accurately calculated based on average annual sedimentation and present RUSLE erosion potential.

Committee: Tiao Chang PhD (Advisor); Teruhisa Masada PhD (Committee Member); Lloyd Herman PhD (Committee Member); James Dyer PhD (Committee Member) Subjects: Civil Engineering