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The formation of benches in agricultural channels in Ohio

Jayakaran, Anand D
http://rave.ohiolink.edu/etdc/view?acc_num=osu1149002547

Abstract Details

2006, Doctor of Philosophy, Ohio State University, Food, Agricultural, and Biological Engineering.
The development of depositional features in low gradient agricultural channels in Ohio were investigated. These depositional features are perceived to hinder the transport of floodwaters from an agricultural field. The periodic removal of these features is both financially expensive and ecologically deleterious. Three aspects of the formation of these features, termed benches, were investigated: the factors that contribute to their formation; the particle size composition; and the depositional and scour processes that contribute to bench development. Based on a geomorphic and hydrologic analysis it was found that benches develop due to vertical and lateral accretion and are associated with channel forming discharges. It was found that like many natural streams, bankfull channel dimensions were related to the drainage area. However, the establishment and/or stability of benches, that served as the floodplain for the bankfull channel, was also a function of the original ditch geometry and in particular the width of the constructed ditch. Bench materials were studied by extracting soil cores from stable benches at 18 sites in Ohio; bed materials were also measured at these sites. It was found that benches develop similarly to floodplains of larger riparian systems. The finest particles were obtained from samples in the upper half of the sampled benches, and corresponded to the zones with the highest silt/clay content and least dispersion in particle size. The coarsest samples were obtained from the layer just below the elevation of the channel bed, corresponding to the region with the highest gravel content and greatest dispersion of particle sizes. The coarse fraction of bed material was related to the elevation at which the dominant bench formed. Simulations of depositional and scour processes in a recently cleaned out channel, were performed using a 2-dimensional numerical model (CCHE2D). The model was calibrated using data measured on an instrumented stable channel. An analysis of some measured storm events are presented, and an annual sediment yield from that watershed was estimated. Model simulations showed that the greatest rates of bench development occurred when sediment concentrations were high, while better results were obtained for pulsed inflows than for steady inflows.
Andy Ward (Advisor)
259 p.
Benches; floodplains; bankfull features; Agricultural channels; Sediment transport; two dimensional modeling; CCHE2D

Recommended Citations

Citations

  • Jayakaran, A. D. (2006). The formation of benches in agricultural channels in Ohio [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1149002547

    APA Style (7th edition)

  • Jayakaran, Anand. The formation of benches in agricultural channels in Ohio. 2006. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1149002547.

    MLA Style (8th edition)

  • Jayakaran, Anand. "The formation of benches in agricultural channels in Ohio." Doctoral dissertation, Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=osu1149002547

    Chicago Manual of Style (17th edition)

osu1149002547
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© 2006, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.