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Orthophosphate removal from wastewater in a subsurface-flow constructed wetland (SFCW) was studied during the fall of 1995. The SFCW consisted of a cell with an impervious liner, filled with 1.27 to 3.81 cm river rock and planted with common reeds (Phragmites australis) and soft-stem bulrushes (Scirpus validus). Municipal wastewater was pumped through the wetland and comparisons were made between inlet and outlet orthophosphate concentrations. Comparisons were also made at locations within the cell. A mean orthophosphate reduction of 62% with a range of 91% to 32% was observed for the duration of the study. An ANOVA test showed a significant reduction of orthophosphate in the wetland cell during the study. A regression analysis indicated that inlet wastewater temperatures played a significant role in orthophosphate removal, while outlet wastewater and ambient air temperature were not a significant factor.Keywords: Subsurface-Flow Constructed Wetlands, Orthophosphate, Municipal Wastewater, Water Chemistry, Nutrients. / Department of Natural Resources and Environmental Management

The Maputaland Coastal Plain is situated in north-eastern KwaZulu-Natal Province, South Africa. The Maputaland Coastal Plain and underlying aquifer are two separate but inter-linked entities. This area with high permeable cover sands, low relief and regional geology that slopes towards the Indian Ocean, hosts a variety of important wetlands in South Africa (e.g. 66% of the recorded peatlands). The wetlands overlie and in some cases also connect to the underlying regional water-table. The apparent distribution of wetlands varies in response to periods of water surplus or drought, and over the long-term has been reduced by resource (e.g. agriculture, forestry) and infrastructure (e.g. urbanisation) development. Accurate wetland mapping and delineation in this environment is problematic due to the ephemeral nature of wetlands and extensive land-use change. Furthermore the deep aeolian derived sandy soils often lacks soil wetness indicators in the soil profile. It is postulated that the aquifer is the source of water to rivers, springs, lakes and wetlands (and vice versa). However, the role of groundwater in the sustainability of hydro-ecological systems is unclear. Consequently this research attempted to determine spatial and temporal changes in the distribution of these wetlands, their susceptibility to human development, understand the landscape processes and characterise and classify the different wetland types. An underlying assumption of the hydrogeomorphic wetland classification concept in South Africa is that wetlands belonging to the same hydrogeomorphic unit share common features in terms of environmental drivers and processes. Given the above, the objectives of this thesis relating to the north-eastern corner of the Maputaland Coastal Plain are to: 1) Map the distribution of wetlands and their relation to other land-use; 2) Characterise the landscape processes shaping the dynamics of wetland type and their distribution; 3) Classify wetlands by applying hydrogeomorphic wetland classification system. This study used Landsat TM and ETM imagery acquired for 1992 and 2008 (dry) and Landsat ETM for 2000 (wet) along with ancillary data. Wetland type characteristics were described using terrain unit position in the landscape, SRTM DEM, land surveyor elevation measurements along with long-term rainfall records, in situ water-table levels with soil analysis and geology and vegetation descriptions. A conceptual model was used to account for the available data, and output from a hydrology model was used to support the interpretation of wetland distribution and function. Wetlands in the study area include permanent wetlands (swamp forests and reed/sedge wetlands), but the majority of sedge/moist grassland wetlands are temporary systems. The wetland distribution reflects the rainfall distribution and groundwater discharge in lower lying areas. The weathering of the Kosi Bay Formation is a key factor in wetland formation. Because of an increase in clay content with depth, the pore-space and hydraulic conductivity are reduced which causes water to impede on this layer. The nature of the aquifer and regional geology that slope towards the east along with extreme rainfall events in wet and dry periods are contributing drivers of wetland and open water distribution. In 2008 (a dry year) the smaller wetland extent (7%) could primarily identify “permanent” groundwater-fed wetland systems, whereas for the wet year (2000) with larger wetland extent (18%) both “temporary” and “permanent” wetlands were indicated. Comparison between both dry years (1992 and 2008) indicates an 11% decrease in wetland (sedge/moist grassland) and a 7% increase in grassland distribution over time. Some areas that appear to be grassland in the dry years were actually temporary wetland, based on the larger wetland extent (16%) in 2000. The 2008 Landsat TM dataset classification for the entire Maputaland Coastal Plain gave an overall 80% mapping accuracy. Landscape settings identified on this coastal aquifer dominated by dune formations consist of 3 types: plain (upland and lowland), slope and valley floor. Although the wetland character is related to regional and local hydrogeology as well as climate affecting the temporal and spatial variability of the wetlands this research confirms that the patterns and wetland form and function are predominantly shaped by the hydrogeomorphic setting and not the rainfall distribution. The following wetland types were identified: permanent wetlands such as peat swamp forests, peat reed and sedge fens; temporary wetland systems such as perched depressions, and sedge/moist grasslands. The Hydrogeomorphic wetland classification system was applied using a semi-automated method that was 81% accurate. The following hydrogeomorphic units could be identified: one floodplain, i.e., Siyadla River Floodplain, channelled valley-bottoms, unchannelled valley-bottoms, depressions on modal slope values <1%, seepage wetlands on modal slope values 1-2%. However, evaluation of the hydrogeomorphic classification application results suggests that the “flat” hydrogeomorphic class be revised. It did not fit meaningfully on the upland plain area. This research finding concludes wetland function does depend on landscape setting and wetland function is not truly captured by the hydrogeomorphic type classification. Not all depression on the coastal plain function the same way and three types of depressions occurs and function differently, i.e., perched depression with no link to the regional water-table vs. depressions that are linked with the regional water-table on plain, slope and valley floor landscape settings. Overall, this research study made a useful contribution in characterising and classifying wetland type and distribution for a high priority wetland conservation area in South Africa. Applying similar methods to the broader Maputaland Coastal Plain will particularly benefit from the research findings. The importance of using imagery acquired in wet and dry periods as well as summer and winter for a more comprehensive wetland inventory of the study area, is stressed. To manage the effects of climate variability and development pressure, informed land-use planning and rehabilitation strategies are required based on landscape analysis and interpretation.

This experiment manipulated water levels in boreal marshes within the Saskatchewan River Delta, a 9500 km2 region in northern Canada. Water levels in three wetland cells were lowered in a partial drawdown by a mean of 0.32 m. Water clarity, nutrient concentrations, and periphyton nutrient limitation were measured over the summer preceding and the summer following manipulation. The water levels of three adjacent control wetlands were not manipulated. Lowering wetland water levels reduced the wind velocity necessary to resuspend bottom sediments, which led to increases in turbidity, dissolved organic carbon, and concentrations of organic and inorganic nitrogen and phosphorus. Prior to drawdown, wetland periphyton communities were limited by nitrogen or co-limited by nitrogen and phosphorus. The input of nutrients from the sediment resulted in a shift from nutrient deficiency to nutrient sufficiency. Periphyton and phytoplankton production increased in response to the nutrient input. Increased turbidity, nutrient concentrations, and algal production were correlated with depth, rather than being inherent to the drawdown condition. Other water level manipulation studies have found that a reflood after a period of total drawdown caused a pulse of nutrients leaching from decomposing litter. This work suggests that these changes may not require complete drying out of sediments, or the input of large amounts of litter from drowned annual mudflat species, but rather can occur when depths are shallow enough that sediments are more frequently resuspended by wind. These findings have implications for future management of these marshes for waterfowl and muskrat production.

ABSTRACT The modern day City of Winnipeg is situated on the poorly drained floor of pro-glacial Lake Agassiz, one of the flattest regions on earth. Within the area now bounded by the Perimeter Highway sixteen major streams and at least twenty small coulees once emptied into the Àssiniboine and Red Rivers. Behind the levees of these rivers large areas of marsh existed providing detention storage of surface waters. The overflow from these wetlands fed many of the streams. The first settlers in the region mimicked the natural drainage regime by damming the waters of the streams to drive grist mills. Later agricultural settlers, occupying the uninhabited but marginally drained lands behind the levees began to drain the wetlands. During the explosive growth period of the City (1880-1910) the drainage regime was radically altered and an expensive and inadequate conduit system was substituted in it's place. Serious flooding episodes have occurred from the first alterations up to the present day. In an attempt to solve the flooding problems, overcome the expense of conduit systems and add amenity, a series of stormwater retention ponds was introduced by private developers in 1965. Functually these impoundments imitate the original hydraulic relationship between the ponds, wetlands and streams of the native landscape. Approximately on hundred years after the elimination of the natural drainage regime, Plan Winnipeg 1981 calls for the preservation of all natural watercourses in recognition of their high value for storm drainage and recreational amenity. Of the original thirty-six streams and coulees only nine exist today. All wetland storage areas have been eliminated. This practicum traces the historical progression of land drainage in the City of Winnipeg, summarizes the design criteria for future urban stormwater management, and outlines the present condition and rehabilitation of the historic water features.

Wetland value is threatened by invasive plant species such as Reed Canarygrass (Phalaris arundinacea). Hence the research objectives of this project were to determine if reed canarygrass abundance has an effect on plant species diversity and assess the effectiveness of novel treatments on reed canarygrass control in a constructed wetland. Four treatments (mowing, herbicide, mowing plus herbicide, and a control) followed by broadcast seeding were applied to regulate growth of reed canarygrass. Principal components analysis, biodiversity measures, and ANOVA were used to identify community composition, quantify biodiversity values and identify treatment differences respectively. Results indicated differences in species composition between east and west blocks of the study site, reed canarygrass abundance appears to keep plant species diversity low, indigenous species were rare, and reed canarygrass was resistant to treatments.The results of this study are not surprising considering there is little evidence that treatments for reed canarygrass control are effective.

The ecological implications of altering the hydrologic regime, or hydroperiod, of a wetland system include major changes to both ecosystem structure and function. Wetland systems are generally sinks of nutrients such as phosphorus, nitrogen and carbon, which are important to water quality. Changes in the hydroperiod such as the inundation or drainage of a wetland system alter wetland function and may switch the system from functioning as a nutrient sink to a source. In this study, I explored the effects from the introduction of a seasonal inundation regime to the Begbie Lake wetland system. Begbie Lake is hydrologically connected to the Sooke Lake reservoir, the main drinking water supply for Greater Victoria, British Columbia. In 2002, the dam on the Sooke Lake reservoir was raised by 6 m, which led to the seasonal inundation of the Begbie Lake wetland system in 2005 and 2006. In 2005, the Begbie Lake wetland system was inundated for 57 days, from April through May. In 2006, the wetland was inundated for 123 days, from January through May. The seasonal inundation resulted in the release of phosphorus, nitrogen and carbon from the wetland system into Begbie Lake and the Sooke Lake reservoir. Nutrients such as phosphorus and nitrogen are especially important in drinking water reservoirs, where increases in concentrations often lead to increased algal biomass and possibly a shift toward cyanobacteria-dominated phytoplankton communities. Organic carbon in source water is correlated with disinfection by-product production during treatment, increases in bacterial biomass within distribution systems, and decreases in the efficacy of water treatment. The response to inundation of the wetland system, in terms of the release of key water quality nutrients into Begbie Lake was assessed. Water chemistry data collected from 2005 and 2006 were compared to pre-inundation baseline data (2003 and 2004) over the growing season. Phosphorus, nitrogen and organic carbon concentrations above the flooded wetland soils increased significantly during the inundation periods. Following drawdown, the total phosphorus concentration in Begbie Lake increased signi cantly. Total nitrogen and total organic carbon concentrations in Begbie Lake did not increase over this same period; the microbial mineralization and reduction of nitrogen and organic carbon, as well as the export of these nutrients into the Sooke Lake reservoir, are proposed as in uencing the observations. The inundation of the Begbie Lake wetland system also resulted in the export of large amounts of nitrogen and organic carbon to the Sooke Lake reservoir. The increase in the duration and extent of inundation in 2006 resulted in higher contributions from the Begbie Lake wetland system. The export of nitrogen increased from 3.8 kg in 2005 to 4.4 kg in 2006. Carbon export increased from 77.7 kg in 2005 to 171.1 kg in 2006. The export of high amounts of phosphorus were not observed during the study. While phosphorus concentrations increased above wetland soils, the data suggest that much of the phosphorus remained cycling within Begbie Lake.

This study investigates surface water and groundwater interactions in a wetland/peatland region surrounding Fort McMurray, Alberta. This work measured local meteorology, water table variation, and isotope and geochemistry concentrations over a two year period. Results from vertical water budget calculations showed episodic runoff events ranging between 0 and 38 mm/yr. Groundwater evaluations showed limited groundwater gradients with mean hydraulic conductivities of 1.01*10-5 cms-1 (NE7) and 1.78 * 10-5 cms-1 (SM8). Overall, groundwater flux estimates were variable and heterogeneous across the catchments areas. Isotopic composition showed mixing between winter precipitation, groundwater and surface water, with groundwater representing the average input signature. This study showed that runoff events were largely associated with spring freshet and significant summer storm events. / Graduate

Warming over the past century has been greatest in high-latitudes over land and a number of environmental indicators suggest that the Arctic climate system is in the process of a major transition. Given the magnitude of observed and projected changes in the Arctic, it is essential that a better understanding of the characteristics of the Arctic climate system be achieved. In this work, I report on modifications to the UVic Earth System Climate model to allow it to represent regions of perennially-frozen ground, or permafrost. I examine the model’s representation of the Arctic climate during the 20th Century and show that it capably represents the distribution and thermal state of permafrost in the present-day climate system. I use Representative Concentration Pathways to examine a range of possible future permafrost states to the year 2500. A suite of sensitivity experiments is used to better understand controls on permafrost. I demonstrate the potential for radical environmental changes in the Arctic over the 21st Century including continued warming, enhanced precipitation and a reduction of between 29 and 54 % of the present-day permafrost area by 2100. Model projections show that widespread loss of high-latitude wetlands may accompany the loss of near surface permafrost. / Graduate

The Brazilian Pantanal, a continuous tropical wetland located in the center of South America, has been recognized as one of the largest and most important wetland ecosystems globally. The Pantanal exhibits a high biodiversity of flora and fauna species, and many threatened habitats. The spatial distribution of these habitats influence the distribution, abundance and interactions of animal species, and the change or destruction of habitat may cause alteration of key biological processes. The Pantanal may be divided into several distinct subregions based on geology and hydrology: flooding in these subregions is distinctly seasonal, but the timing, amplitude and duration of inundation vary considerably as a result of both the delayed release of floodwaters and regional rainfall patterns. Given the ecological importance of the Pantanal wetland ecosystem, the primary goal of this research was to utilize a dual season set of L-band (ALOS/PALSAR) and C-band (RADARSAT-2 and ENVISAT/ASAR) imagery, a comprehensive set of ground reference data, and a hierarchical object-oriented approach. This primary goal was achieved through two main research tasks. The first task was to define the diverse habitats of the Lower Nhecolândia subregion of the Pantanal at both a fine spatial resolution (12.5 m), and a relatively medium spatial resolution (50 m), thus evaluating the accuracy of the differing spatial resolutions for land cover classification of the highly spatially heterogeneous subregion. The second task was to define on a regional scale, using the 50 m spatial resolution imagery, the wetland habitats of each of the hydrological subregions of the Pantanal, thereby producing a final product covering the entire Pantanal ecosystem. The final classification maps of the Lower Nhecolândia subregion resulted in overall accuracies of 83% and 72% for the 12.5 m and 50 m spatial resolutions, respectively, and defined seven land cover classes. In general, the highest degree of confusion for both fine and medium resolution classifications related to issues of 1) scale of habitats, for instance, capões, cordilheiras, and lakes, in relation to spatial resolution of the imagery, and 2) issues relating to variable flooding patterns in the subregion, and 3) arbitrary class membership rules. The 50 m spatial resolution classification of the entire Pantanal wetland resulted in an overall accuracy of 80%, and defined ten land cover classes. Given the analysis of the comparison of fine and relatively medium spatial resolution classifications of the Lower Nhecolândia subregion, I conclude that significant improvements in accuracy can be achieved with the finer spatial resolution dataset, particularly in subregions with high spatial heterogeneity in land cover. The produced habitat spatial distribution maps will provide vital information for determining refuge zones for terrestrial species, connectivity of aquatic habitats during the dry season, and crucial baseline data to aid in monitoring changes in the region, as well as to help define conservation strategies for habitat in this critically important wetland. / Graduate / 0366 / tevans@uvic.ca