Pothole wetlands are ubiquitous throughout the Prairie Pothole Region and since 1900, 40-70% of potholes in the region have been drained to increase agricultural production. This thesis describes factors influencing spatial and temporal variations in wetland water quality and characteristics of drainage water. Research was conducted at Smith Creek watershed, southeastern Saskatchewan, where there has been controversy over recent renewed efforts to drain wetlands. Following snowmelt in 2009, 67 wetlands were sampled to determine whether spatial variations in wetland water quality were attributable to land cover, permanence classes, and surface drainage characteristics. Wetlands with cropped uplands had greater TP and K than wetlands with wooded and grassed uplands; TP, TDN, and DOC were higher in seasonally than permanently ponded wetlands; and salts were lower in wetlands with wooded uplands compared to wetlands with cropped and grassed uplands. Measurements of water quality of one permanently ponded wetland over a 20 week period in 2008 showed that the wetland acted as a solute trap. Variations in salts and DOC were influenced by hydrological processes such as runoff, evaporation, and shallow groundwater seepage, whereas variations in nitrogen, phosphorus, and bacteria were influenced by biotic, sorption, and hydrological processes. The experimental drainage of this wetland in November 2009 demonstrated that its water quality was an important control of drainage water quality. Further, the wetland ditch acted as a simple conduit, i.e., little solutes loss or gain occurred along it. In spring 2009, water quality along seven ditches and five natural connections that form between wetlands (termed spills) was compared. Concentrations of most solutes were similar, except TDN, DOC, HCO<sub>3</sub><sup>-</sup>, K<sup>+</sup>, and Ca<sup>2+</sup> that were higher in ditches than spills. Minimal changes in water quality along ditches and spills occurred, likely due to the low temperatures occurring in spring that restrict biotic processing and sorption. Notably, because ditches connect wetlands to streams, as opposed to spills that connect adjacent wetlands, ditches have a greater potential to contribute to downstream solute loading. Wetland drainage efficiency and wetland water quality were deemed the factors critical to determining solute exports via ditches. Results of wetland water quality and drainage characteristics can be useful to future modeling exercises and could be used to inform wetland drainage practices and policies.
| Identifer | oai:union.ndltd.org:USASK/oai:usask.ca:etd-04112011-140210 |
| Date | 15 April 2011 |
| Creators | Brunet, Nathalie Nicole |
| Contributors | de Boer, Dirk, Hudson, Jeff, van der Kamp, Garth, Westbrook, Cherie J., Bedard-Haughn, Angela, Pomeroy, John |
| Publisher | University of Saskatchewan |
| Source Sets | University of Saskatchewan Library |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-04112011-140210/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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