Suspended sediment transport in agricultural drainage ditches on the coastal plain of North Carolina / by Jingyu Wang.
| Author/creator | Wang, Jingyu author. |
| Other author | Lecce, Scott A., degree supervisor. |
| Other author | East Carolina University. Department of Geography. |
| Format | Theses and dissertations |
| Production | 2002. |
| Description | 102 leaves : illustrations, maps (some color) ; 28 cm |
| Supplemental Content | Access via ScholarShip |
| Subjects |
| Summary | The purpose of this thesis was to assess seasonal variations in suspended sediment transport in a small, agricultural watershed on the Coastal Plain of North Carolina. Suspended sediment samples were collected automatically with a pump sampler every 20 minutes during twelve storms at the outlet of the watershed during a 13 month period. The samples were filtered in the lab and suspended sediment concentrations were determined gravimetrically. Hydrographs and hysteresis plots were produced for each storm along with runoff coefficients, rainfall totals and intensities, and sediment yield. Results show that the first major spring storm after the dry dormant winter season in March 2001 had the highest peak sediment concentration of the twelve storms analyzed from March 2001 to March 2002. The storm on August 20 had the highest rainfall intensity, the highest peak discharge, and a very short duration. This storm produced the highest runoff coefficient among the twelve storms. Tropical Storm Allison (June 2001) was the largest storm during the study period, lasting about 72 hours and producing a total rainfall depth of 17.15 cm. Although Tropical Storm Allison produced a high peak discharge and a high runoff coefficient, the peak sediment concentration was not as high as the March storm. Nevertheless, Tropical Storm Allison produced the highest sediment yield of the study period, which suggests that large storms of long duration may be responsible for much of the suspended sediment transport in this watershed. The three largest storms (March 20-22, June 14-17, and August 20) transported about 80% (55.5 Mg) of the measured sediment load during the study period. Even though the March 2001 storm was not particularly intense and did not produce a tremendous amount of runoff, the lack of vegetation on fields and in ditches made it easier to mobilize sediment that had accumulated over the winter. Tropical Storm Allison produced a large amount of intense rainfall with a very long duration. The largest sediment load during this big storm resulted from its large total runoff volume combined with large peak discharge and long duration. The August 20 storm was a very intense storm causing erosion and significant sediment transport even with mature crops on fields and ditches choked with vegetation. Compared to other rivers in eastern North Carolina, this small watershed had a higher sediment yield during the study period than the average annual sediment yield of some larger rivers, and the maximum sediment concentration measured was highest among Coastal Plain rivers. Nevertheless, the sediment yield measured at Littlefield (0.9Mg/ha) was within the range of values reported for other agricultural watersheds on the Coastal Plain of North Carolina. |
| General note | Presented to the faculty of the Department of Geography. |
| General note | Advisor: Scott A. Lecce |
| Dissertation note | M.A. East Carolina University 2002 |
| Bibliography note | Includes bibliographical references (leaves 82-85). |
| Genre/form | Academic theses. |
| Genre/form | Academic theses. |
| Genre/form | Thèses et écrits académiques. |
Availability
| Library | Location | Call Number | Status | Item Actions |
|---|---|---|---|---|
| Joyner | University Archives | ASK AT SPECIAL COLLECTIONS DESK | ✔ Available | Request Material |
| Electronic Resources | Access Content Online | ✔ Available |