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Methyl bromide (CH3Br) and methyl chloride (CH3Cl) are two halocarbons that are unique in that they play a significant role in stratospheric ozone destruction, and are mainly produced by natural systems. The current average tropospheric mixing ratios are 7.9 pptv CH3Br and 550 pptv CH3Cl (WMO, 2007). Although CH3Br and CH3Cl are present in such low concentrations, their atmospheric life times are sufficiently long that they can be transported to the stratosphere via the tropical tropopause at the equator. This process takes approximately six months.

Övergödning är ett allvarligt miljöproblem, som bland annat orsakar omfattande blomningar av alger och blågrönbakterier. I söt- och brackvatten är fosfor ofta det mest begränsande näringsämnet för dessa organismer, varför en minskning av fosfortillförseln är nödvändig för att nå förbättringar. I Sverige beräknas jordbruket bidra med 44 % av fosforbelastningen till Egentliga Östersjön, och olika åtgärder för att minska fosforförlusterna från jordbruksmark tillämpas runtom i Sverige. Våtmarker anläggs ofta för att fånga näringsämnen och partiklar från jordbruksmark innan de läcker ut i vattendrag och slutligen i Östersjön. Tidigare utvärderingar av anlagda våtmarker i Sverige har visat på en varierande och relativt låg fastläggning av fosfor. Osäkerheten kring dessa utvärderingar är dock ganska hög, och bottnar i kunskapsluckor både vad gäller processer för fastläggning och transport av fosfor från mindre jordbruksområden. I denna avhandling utreds därför hur anlagda våtmarker fungerar som fällor för jordpartiklar och partikelbunden fosfor i områden med höga fosforförluster. Sju anlagda våtmarker i jordbruksområden med mycket lerjordar studerades, och mängden fosfor och partiklar som fastlades på botten varierade mycket mellan olika våtmarker (13-108 ton partiklar/ha/yr och 11-175 kg fosfor/ha/yr). De faktorer i området uppströms som var kopplade till fosforfastläggning var lutningen i området, markens lerhalt och innehåll av växttillgänglig fosfor samt områdets djurtäthet. Resultat från fyra våtmarker visade på en hög resuspension (partiklar från botten virvlas tillbaka upp i vattnet), men en del av de uppvirvlade partiklarna kom troligtvis från erosion från våtmarkernas sidor och inte från det material som fastlades på botten. Man såg även indikationer på resuspension från vattenprover tagna i utloppet av en annan våtmark. Där var partikelbunden fosfor klart dominerande, vilket kan ha varit en konsekvens av resuspension från botten. Variationerna av fosforkoncentrationer vid in- och utlopp i sju anlagda våtmarker studerades, för att kritiskt kunna granska tidigare retentionsskattningar. Det var stora variationer i sambanden mellan vattenflöde och fosforkoncentrationer mellan de olika våtmarkerna. De faktorer som påverkade sambandet mellan flöde och koncentration var 1) om det var varm eller kall årstid (d v s sommar eller vinter), 2) om det var högt eller lågt vattenflöde, samt 3) om inflödet bestod av ett dräneringsrör eller ett öppet dike/åfåra. I våtmarker med öppet dike som inflöde var flödes-koncentrationssambandet av totalfosfor negativt vid låga flöden och positivt vid höga flöden. De olika sambanden visar hur viktig sättet att provta vatten är, då inkommande mängd fosfor både kan över- och underskattas om man inte är medveten om sådana variationer. Vid automatisk provtagning styrd av flödesmätningen sker detta ofta i utloppet, men eftersom vattnet har en viss uppehållstid i våtmarken (speciellt sommartid) kan retentionsberäkningen påverkas av att all provtagningen styrs av flödet i utloppet.     För att identifiera vilka områden som bidrar med mest näring och partiklar valdes ett stort område dominerat av jordbruksmark ut – för att undersöka hur man skulle kunna bedöma var anlagda våtmarker skulle kunna göra mest nytta. Området delades in i tio mindre områden, och vattenprover samlades in från diken och åfåror. Resultaten visade på stora skillnader i fosfordynamik mellan olika delområden med olika jordtyper, trots att de hade liknande markanvändning. Det fanns ofta en koppling mellan höga fosforkoncentrationer i vattnet och en hög andel lerjordar i området. För partiklar fanns det en tendens till samband mellan höga koncentrationer och hög andel vinterbar mark. En anlagd våtmark skulle antagligen ha högst effekt om den placerades nedströms områden som är känsliga för erosion – områden med hög andel lerjordar eller med hög andel vinterbar mark. / Eutrophication is one of the more serious current environmental problems, causing algal blooms and anoxic bottoms. In fresh and brackish water, phosphorus (P) is often the most limiting nutrient, and various mitigating strategies are used to reduce the load of P to sensitive recipients. In the agricultural sector, this includes both on-field measures (e.g. managing P inputs) and measures at the field edge (e.g. buffer zones and constructed wetlands). Previous evaluations of constructed wetlands (CWs) in Sweden have indicated a variable and relatively low P retention. However, the uncertainties in the estimates are large, and related to an incomplete knowledge about both retention processes and factors determining the P load from agricultural land. Hence, the overall aim of this thesis was to investigate possible reasons for the variation in wetland P retention estimates, and to assess the P retention in wetlands located in agricultural areas where losses are expected to be high. When comparing seven CWs located downstream small catchments with predominantly arable land, the particle and P net accumulation varied considerably (13-108 t particles ha-1 yr-1 and 11-175 kg P ha-1 yr-1, respectively). Catchment factors that were statistically correlated with accumulation of particles and P in the CWs were the slope of the arable land, the P content of the top soil, the animal density (expressed as livestock units per arable land) and the percentage clay in the topsoils. In four of the wetlands, resuspension was studied using sediment traps and plates. The results showed that up to 87 % of the settled material was resuspended, and indicated that erosion of the wetland sides and bottom probably contributed a substantial part of the trapped particles. In order to critically evaluate existing retention data from earlier investigations, the temporal dynamics of P concentrations and P retention in seven CWs were evaluated. The relationships between water flow and concentration (from grab sampling) varied, and depended on the season (warm or cold period of the year), water flow (high or low) and the inlet type (drainage pipe or open ditch). In CWs that received water through an open ditch, flow-concentration relationships were negative during low flow periods but positive during high flow periods. These differences in flow-concentration relationship have implications for water sampling, since P loads can be both over- and underestimated with grab or automatic sampling guided by clock-time. Also composite automatic sampling, regulated from the water flow at the outlet, can lead to errors in transport calculations since the same ‘water parcel’ is not measured at in and out (difference depending on how long the water retention time is in the CW). This may have an effect on estimates of P retention in both past, present and future investigations of constructed wetlands. Finally, a synoptic sampling approach with ten sampling points was used in an agriculturally dominated catchment area (160 km2) to identify differences in nutrient transport dynamics and areas with the highest losses. Spatial differences in P concentrations were strongly correlated with some of the catchment factors, for instance with soil type, and particle concentrations were weakly correlated to agricultural practices associated with bare soils during winter. This supports the practice to focus P mitigation measures – such as constructed wetlands – to erosion sensitive areas.

A research report submitted to the Faculty of Science, University of the Witwatersrand in partial fulfillment of the requirements for the degree of Masters (MSc. by Course work and Research Report) 30th September, 2015 / Acid Mine Drainage (AMD) refers to the seepage or runoff of acidic water from abandoned mines into the surrounding environment. Acid mine drainage is considered a serious long term environmental threat associated with mining. This study was conducted on the Varkenslaagte canal or stream which flows from north to south within the AngloGold Ashanti West Wits gold mining operation, 75 km west of Johannesburg, and receives AMD from tailings storage facilities (TSFs) located on both the northern aspect and the western aspect of the catchment. On the Varkenslaagte, 17 reed beds were planted between 1-12-2011 and 12-9-2012, in a series of shallow excavated depressions. This study was conducted in 2013 and 2014, and aimed to ascertain: (i) whether there is any temporal difference (autumn – end of the rainy season, versus winter – mid-dry season, for 2013 and 2014 combined) in selected fresh-water quality parameters and concentrations of AMD contaminants in the flowing waters in the engineered reed beds; - this was observed, as higher concentrations were recorded in winter than in autumn, for some of the selected water quality parameters, in both survey years; (ii) to determine if vertical changes exist in the elements down the sediment profile from the surface to a depth of approximately half a metre; - conspicuous vertical changes were not evident; and also; (iii) to provide a baseline for monitoring the post clean-up state of the upper Varkenslaagte, and conclude whether the reed bed system is retaining AMD contaminants (major ions, trace and major elements). Chemical variations in water and sediment samples were measured in situ in April/May 2013 and July 2014, and water samples and sediment cores collected for laboratory analyses. Water samples were collected from three points (inflow, middle and outflow) at each of 15 reed beds (RBs, numbered RB 1 -15) in receipt of AMD from two directions (downstream and laterally from TSFs on the northern and western aspects). Ion Chromatography was used to detect chloride (Cl-) and sulphate (SO42-), Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) were used to identify major and trace elements; iron (Fe), magnesium (Mg), manganese (Mn), potassium (K), cobalt (Co), nickel (Ni), lead (Pb), copper (Cu) and zinc (Zn) in the water samples whereas X-Ray Fluorescence (XRF) analysis for elements was conducted on surface sediments (0-2cm; additional analyses of sediment core samples at depths 2-5 cm, 5-10 cm, 10-20 cm and 20 -30 cm were analyzed but were not considered further). The water in the reed beds was moderately acidic to within the target range. It ranged from pH 5.17 to 6.51 in April, 2014 (approaching the end of the wet season) (P < 0.05) (P = 0.0001) to slightly higher values of pH 5.45 to 6.82 in July, 2014 (mid-dry season) (P = 0.0053). Marginal acidity is above pH 6. A pH of 6.5 – 7.5 is within the target water quality range (TWQR) on the Highveld. High electrical conductivity (EC) values were found, ranging from 3500 – 4600 μs/cm in April and 2600 – 5500 μs/cm in July, though EC values can be higher on much of the South African gold mining Highveld. Lateral influx of AMD from the western TSFs was visually observed into two of the southernmost Varkenslaagte stream reed beds (at RBs13 and 15) during both April and July sampling. In 2014, the Varkenslaagte was still flowing from reed bed to reed bed, although very slowly, similar to 2013. Chloride, sulphate and metal concentrations were high relative to target water quality ranges in most of the reed beds in during April and July, 2014. Although higher concentrations in the sediment suggest that the reed beds are effective in capturing and retaining contaminants in sediment and root mass, the concentrations in the water in reed beds 1-15 still exceeded the target water quality ranges for aquatic ecosystems in South Africa (DWAF, 1996) and the World Health Organization (WHO) guidelines for drinking water quality (WHO, 2004). However use of the water from the Varkenslaagte by humans and livestock is prohibited by the Department of Water and Environmental Affairs, and the National Nuclear Regulator. The bar charts comparing 2013 and 2014 selected water quality data showed that during winter/drier periods with no rains, the rate of evaporation exceeded dilution; this was observed by the slightly lower pH values recorded across the reed beds in July, 2013 and 2014, in comparison with the slight higher pH values recorded across the reed beds in May, 2013 and April, 2014. The bar charts also showed that the highest EC was recorded in the winter of 2014. It was also observed from the principal component analyses (PCAs) that EC, sulphate and pH, in combination with Mg and Fe, were responsible for most of the variation in the water quality data for the two survey years, 2013 and 2014. Following the findings from this study, it is recommended that monitoring of the site should also address whether the reed beds and other control measures that have been put in place (riparian woodlands and windmill pumps) will be adequate to control the lateral seepage from the Western TSFs at some of the southernmost reed beds.

A dissertation is submitted as MSc research project in partial fulfilment of the requirements for the degree of Master of Science in the School of Geography, Archaeology and Environmental Studies. July 2016. / A major cause of environmental problems, in the vicinity of mine tailings in and around Johannesburg, is Acid Mine Drainage (AMD). In most research, engineered wetlands are used to ameliorate AMD with the use of vegetation to remove or extract heavy metals from the soil (i.e. phytoremediation). Phytoremediation has been defined as a technology that uses plants to extract or immobilize contaminants in soils and waters (Torresdey, 2007). The aim of this study was to assess and quantify the mass pool size of contaminants (macronutrients, micronutrients, non-essential trace elements) within and between a subset of paddocks from various compartments including sediments, aboveground biomass (shoots –stems and leaves), and belowground biomass (roots and rhizomes) of the two wetland plant species present (P. australis and S. corymbosus ). Analyses were done on the wetland paddocks in situ and ex situ applying different methods, water sample metal cations were analysed by ICP-MS and the major anion analysis by chromatography and Ion Chromatography (IC). The sediment and plant samples were subject to X-Ray fluorescence (XRF) analyses of major elements and trace elements. Although analysis was undertaken for numerous trace and metal elements, only a few macronutrients, micronutrients, and non-essential elements with significant importance to the West Wits Mining Operation were selected for this study. The stream water test strips yielded poor results for this extremely contaminated plume receiving environment this suggests that in this system they are not a useful substitute for conventional laboratory analyses. Of the elements tested, only S showed significant differences in concentrations in plants between paddocks, with the highest concentrations and mass in the downstream paddocks ww6 and ww7. These paddocks also had the greatest masses of S in sediments, and water concentrations were also highest in paddocks ww4, ww6 and ww7. P. australis accumulated highest elemental mass than S. corymbosus, with the highest Zn mass of 93%. P. australis accumulated double the mass of U, Cu, Cl, Ca. In both plants, the roots consistently had highest elemental concentration with sequence often as follows roots> shoots> rhizomes. Sediment element mass accumulation of most tested elements significantly increased with depth, except for Zn and U, which decreased with depth. There are few significant differences in the mass distribution of the elements analysed between paddocks, which is assumed to reflect either the heterogeneity in the underlying sediments following construction of the wetlands, or lateral inputs into the system as seepage from other TSFs. Key words: AMD, Wetland, Varkenslaagte Canal, West Wits Mining Operation, metals, sediment, S. corymbosus, P. australis, ICP-MS, XRF. / LG2017

A research report submitted in partial fulfilment of the requirements for a Masters Degree in Environmental Sciences, School of Animal, Plant and Environmental Sciences. University of the Witwatersrand. Johannesburg, 2016. / Wetland ecosystems cover approximately 6% of the Earth’s surface area and provide important ecosystems goods and services for the sustenance of human livelihoods. According to the Millennium Ecosystems Assessment, wetlands’ ecosystems goods and services cover the provisioning, regulating, support of biodiversity, and wider community cultural values. However, wetland ecosystems are threatened by human interference in combination with effects of climate change, both of which might compromise the functionality of these socio-ecological systems. The study used a combination of observations, interviews and remote sensing combined with GIS to investigate evidence of change and the possible effects on the Blesbokspruit wetland’s natural integrity, and thus availability of ecosystem goods and services in the wetland. Documented spatial changes in land uses were analysed to determine the extent to which land use and cover changes have affected the natural capital (i.e. ecosystem goods and services) for people. The interaction of local people with the wetland was assessed in order to establish how they use the wetland as a livelihood support system. The study found that people from the surrounding communities both in the upper (Putfontein) and lower catchments (Marievale) are interacting with the wetland in different ways. The provisioning services from the Blesbokspruit wetland to the surrounding communities include water used for both domestic and agricultural activities. Both subsistence and commercial farming are taking place along the wetland (crop farming and livestock rearing). The wetland is therefore providing a safety net to disadvantaged households who are able to supplement their food. The wetland is also able to regulate climate change (carbon sequestration and flood attenuation) and water quality due to the presence of vegetation. The wetland also supports high biodiversity (flora and fauna) such as within the Marievale Bird sanctuary. Recreational services of the wetland come from the scenic views noted at both Marievale (picnic spots) and Putfontein (evidenced by children playing and swimming). The integrity of the wetland is primarily threatened by population increase and urbanisation. Remote sensing analyses of land use/land cover patterns between 1998 and 2015 indicate that major changes of the wetland have been due to human encroachment. Subsistence agriculture in the wetland has increased, which fuels damage to the wetland. Direct observation and interviews with female farmers showed that they compete for plot size which is proportional to the respect one farmer earns in the community. Water quality of the wetland seemed to be compromised by industrial activities and use of fertilisers by farmers. Unlike the pristine upper part of the wetland at Putfontein, eutrophication downstream was evidenced by polluted water, algal blooms and change of water colour at Marievale – all suggesting loss of natural benefits such as high quality water. Despite the observed threats, it is concluded that the Blesbokspruit wetland ecosystem goods and services play a significant role in supporting the well-being and livelihoods of surrounding poor communities. It is suggested that activities threatening the wetland’s integrity may be managed effectively through community-based approaches for natural resource management. There is a need for all stakeholders to be equipped with proper conservation knowledge for them to appreciate the indirect (e.g. climate regulation and water quality control) as well as direct (agricultural and water provisioning) benefits of Blesbokspruit wetland. A better understanding of this socio-ecological system would benefit from comprehensive research on hydrological dynamics associated with agricultural practices within the catchment, and the development of an integrated model of natural resources management with a strong social component. / LG2017

A área de estudo da presente pesquisa compreende a bacia hidrográfica do rio dos Sinos localizada entre as coordenadas de 50º 10 e 51º 20 de longitude oeste e entre 29º 15 e 30º 00 de latitude sul, atingindo municípios da Região Metropolitana de Porto Alegre - RMPA e da chamada Serra Gaúcha. O objetivo do trabalho foi o de estudar as terras inundáveis da área especificada a partir de parâmetros geomorfológicos contextualizando-as dentro de uma concepção sistêmica da paisagem, adotando como recorte espacial a bacia hidrográfica. Buscou-se contribuir nas questões relativas às variadas nomenclaturas, definições e no método de estudo dessas áreas. Na escala da bacia analisaram-se a litologia e a pedologia a partir de mapas já presentes na literatura. Elaborou-se mapeamento geomorfológico na escala 1:100000, perfis transversais e longitudinais e análise de dados pluviométricos que serviram como base para a definição das imagens mais apropriadas para a delimitação do limite superior aproximado das terras inundáveis. Em escala de detalhe, 1: 10000 mapearam-se os lagos naturais, bem como aqueles com origem antropogênica, foi também possível refinar o limite das terras inundáveis estudadas. Por meio da elaboração dos mapas de uso nos limites e entorno das terras inundáveis foi possível uma visão do estado atual de conservação destas áreas. A metodologia operacional compreendeu o uso de técnicas do Sistema de Informações Geográficas e do Sensoriamento Remoto. A metodologia teórica metodológica foi embasada em Ab Saber (1969) que propôs três níveis básicos de pesquisa em geomorfologia, Ross (1992) com a proposta de taxonomia do relevo e Bertalanffy (1975) a partir da Teoria Geral dos Sistemas - TGS. No que se referem aos resultados na escala da bacia temos como principais formações litológicas: derrames basálticos e depósitos sedimentares, ambos pertencentes à Morfoestrutura da Bacia Sedimentar do Paraná e depósitos cenozóicos do Terciário e do Quaternário. As morfoesculturas resultantes compreendem áreas de planaltos, planícies e depressões relativas. Os basaltos de formação mais ácida formaram planaltos tabulares, os basaltos de constituição intermediária e básica formaram morros que variam entre 150 e 750 metros de altitude aproximadamente. Nos depósitos da formação Botucatu e Rosário do Sul predominam as colinas e morros de baixa altitude. As planícies flúvio - coluvionares e fluviais estão restritas aos depósitos do Quaternário e do Terciário respectivamente. Os solos localizados nas terras inundáveis foram o chernossolo háplico órtico no trecho médio e superior da bacia e o planossolo háplico eutrófico no trecho inferior. A partir da análise dos dados pluviométricos, que compreendeu o intervalo entre 1999 e 2008, constatou-se que as imagens mais apropriadas para a delimitação do limite superior aproximado das terras inundáveis seria a de outubro de 2005, porém utilizou-se a imagem de setembro de 2005, pelo fato desta, e não da outra, estar disponível. O mês de setembro foi antecedido pelo segundo mês com maior índice pluviométrico para 2005, assim, não houve grande prejuízo na utilização desta imagem. Dos seis mapas elaborados referentes ao aspecto natural das terras inundáveis constatou-se a incidência de lagos em todas as áreas, excluindo apenas o caso do mapa do trecho um jusante onde não há sinal de divagação de canal e alta taxa de alteração dos aspectos naturais. A maioria dos lagos se formaram naturalmente a partir do estrangulamento e abandono de meandro, há também lagos de origem antropogênica. A existência ou não de lagos definiu nomenclatura mais específica das terras inundáveis como fluvias ou flúviolacustres. A partir dos mapas das principais alterações antrópicas contatou-se que no trecho médio e de montante predomina a utilização agrícola. Nas áreas do trecho dois e três de jusante há maior incidência de vegetação natural, porém, de forma insuficiente, a ocupação urbana neste trecho se apresenta na maioria das vezes de forma concentrada. Constatou-se que nas áreas mais a jusante as terras inundáveis são maiores do que nas áreas mais a montante, o que pode ser explicado, entre outros fatores, pela influência do relevo na configuração espacial destas áreas. Acredita-se que a partir dos esforços aqui realizados que tiveram por base pressupostos conceituais e aplicados da Geomorfologia, foi possível melhor compreender as terras inundáveis, para a área de estudo e de forma geral independentemente de fatores de localização ou espaciais. / The study area of this research comprises the Bells river basin located between the coordinates 50 º 10 \'and 50 º 20\' west longitude and between 29 º 15 \'and 30 º 00\' south latitude, reaching municipalities in the metropolitan area of Porto Alegre - RMPA and in the area of the called Serra Gaúcha. The aim of this work was to study the floodable lands in the specified area through geomorphological parameters, contextualizing these areas in a systemic approach of the landscape - the river basin. The methodology comprised, in a basin scale, geological and pedological analysis based on existing maps in the literature, 1:100000 scale geomorphological mapping, analysis of rainfall data that was the basis for defining the most appropriate images for the delineation of the approximate superior boundary of floodable lands. Scale of detail 1: 10000, water bodies placed in the defined areas, as well as major changes from land use, were mapped. High-resolution images were used in order to refine the floodable land boundaries, and these images served as well for paleochannels, land use and anthropogenic lakes mapping. The operational methodology included the use of techniques of Geographic Information System and Remote Sensing. The theoretical methodology was based on Ab\'Saber (1969) who proposed three basic levels of research in geomorphology, Ross (1992) with the proposed taxonomy of relief and Bertalanffy (1975) from the General Systems Theory - TGS. With regard to the results on the basin scale, we have as main lithological formations: basalt flows and sedimentary deposits, both belonging to morphostructural of Paraná Sedimentary Basin, and Tertiary and Quaternary Cenozoic deposits. The forms of relief are related to these structures, the more acidic basalts form tabular plateaus, the basalts of intermediate and basic constitution formed hills ranging between 150 and 750 altitude meters approximately, in the Botucatu and Rosário do Sul deposits predominate the hills and low altitude mountains, the fluvial-colluvial and fluvial plains are restricted to Quaternary and Tertiary deposits respectively. The soils from floodable lands form Mollisol in the middle and superior section of the basin and Haplic Eutrophic Planosol in the lower part. The driest months are January, February and March, and the wettest are October, May and June in the period between 1999 and 2008. We can find, from the six generated maps, that the incidence of lakes is higher in the lower section in the cases that have not lost their natural characteristics due to human action. Most of the lakes are formed naturally from the meander stranglehold, and there are lakes of anthropogenic origin. Differences in relation to water bodies have defined more specific classification of land as fluvial or fluvial-lacustrial. We can find, from the six generated maps concerning the natural aspects of wetlands, that there is incidence of lakes in all areas, excluding only the case of the section 1 downstream, where there isnt any case of meandering and theres high rate of anthropogenic action. Most of the lakes are formed naturally from the meander stranglehold, and there are lakes of anthropogenic origin. Differences in relation to water bodies have defined more specific classification of land as fluvial or fluvial-lacustrial. From the maps of the major anthropogenic changes it was found that in the middle and higher river sections the land is used for agriculture predominantly. In the areas corresponding to sections two and three, downstream, there is a higher incidence of natural vegetation, however its still insufficiently. The urban settlement is most often concentrated. It was found that in further downstream areas the wetlands are bigger than in the upstream areas: this phenomenom can be explained by the shape of relief in the adjacent areas and even by the study of areas beyond the boundary of floodable land. Finally, we conclude that a kind of approach, as addopted in this research (which was based on geomorphological analysis), opens up possibilities for classification and better understanding of floodable lands the phenomenon studied.

<p>Lakes and wetlands cover a large portion of the earth’s surface and play a crucial role in hydrology. They provide permanent and temporary storage for water within the landscape allowing for greater infiltration and evaporation along with a reduction in peak flooding events. Lakes and wetlands also provide many other non-hydrological benefits such as their ability to improve water quality and provide wildlife and fisheries habitat. Despite their known benefits, wetland destruction has been a prominent issue for many years. This study quantifies the hydrologic effects of lakes and wetlands by introducing a parametrization method for hydrologic model simulations in the North American Land Data Assimilation System (NLDAS) domain. Lake profiles were created based on the geospatial lake depth-area relationship through interpolation of known lake depths and areas throughout the domain. Wetlands were parametrized based on topographic wetness index (TWI) calculated using high-resolution DEM imagery. Wetland profiles were created using a binning technique along with the DEM and land use classifications. The Variable Infiltration Capacity (VIC) macroscale hydrologic grid-based model and its associated lake and wetland algorithm were used to quantify the effects of lakes and wetlands on streamflow. Profiles were generated for every corresponding VIC grid cell in the NLDAS domain, but for this study two watersheds, the Buttahatchee River in Mississippi and the Black River in North Carolina, were selected to test the parametrization and quantify the impact of lakes and wetlands on watershed hydrology. The Buttahatchee River watershed contains 6.6% lakes and wetlands, which were predominantly clustered near the stream channel, and the Black River watershed contained 19.2% lakes and wetlands which were spread out across the entirety of the watershed. Simulated daily streamflow with and without the lake and wetland algorithm activated was used to evaluate impacts on flood frequency as well as components of the water balance. Flood magnitude decreased due to the presence of lakes and wetlands. This decrease was 5.8% and 29.6% for a 10-year return period flood for the Buttahatchee River and the Black River sites, respectively. Mean annual flowrate decreased significantly as a result of lakes and wetlands indicating storage of water in the lakes and wetlands allowed for a greater degree of evapotranspiration. There were 1.6% and 10.9% decreases in average streamflow rates as well as corresponding 0.3% and 4.1% increases in annual evapotranspiration in the Buttahatchee River and Black River watersheds, respectively. While lakes and wetlands reduce peak flood events and decrease average streamflow rates through increased storage and evapotranspiration, the magnitude of these impacts varies based on the quantity and distribution of lakes and wetlands in the watershed as well as the climate and vegetation present. </p>

Geographically isolated wetlands (GIWs) within the southeastern U.S. Coastal Plain have been increasingly recognized for their importance in providing ecosystem services. These wetlands serve as valuable foraging and breeding habitat for wetland-dependent species, including wading birds. I quantified wading bird presence in GIWs in southwestern Georgia and determined the relative importance of factors influencing their use of these wetlands. I also examined the diet of a nesting colony of Little Blue Herons; a species experiencing population declines throughout most of the Southeast. I found that wetland-specific parameters were important factors in predicting wading bird use of GIWs, and wading birds utilized agricultural and natural wetlands differently depending on hydrological seasonality. Little Blue Herons were primarily consuming large anurans and anuran larvae, which are characteristic of agriculturally modified wetlands. The seasonal process of receding water levels in GIWs and subsequent concentration of / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Made available in DSpace on 2015-03-05T16:20:41Z (GMT). No. of bitstreams: 0 Previous issue date: 27 / Universidade do Vale do Rio dos Sinos / As áreas úmidas estão entre os ecossistemas mais produtivos de nosso planeta com enorme importância ecológica, econômica e cultural para a humanidade. As áreas úmidas variam em tamanho, desde muito pequenas, a vastas áreas, entretanto todas são importantes para o estabelecimento de plantas raras ou endêmicas. A relação entre área e diversidade de espécies tem sido investigada por vários pesquisadores e numerosos estudos e experimentos têm desenvolvido teorias relacionando estes atributos. Entretanto a informação sobre a relação entre área e diversidade de espécies em áreas úmidas ainda é escassa. Os inventários de áreas úmidas são usados como primeiro estágio para programas de conservação, determinando os valores econômicos das áreas úmidas e originando critérios para o uso desses recursos. O objetivo deste trabalho foi inventariar as áreas úmidas do município de São Leopoldo, analisar a diversidade de macrófitas e macroinvertebrados e elaborar critérios para a conservação desses sistemas. O inventário de á / Wetlands are the most productive ecosystems around the world, with enormous ecological, economic and cultural importance for humanity. The wetlands vary in size, from small to vast areas, however, they are all important to the establishment of rare or endemic plants. The relationship between area and diversity of species has been investigated by biologists, and numerous studies and experiments have developed general theories about this relationship. However, the information about the relationship between species diversity and area in wetlands is still scarce. The inventories of wetland are used in the first stage of the conservation programs, determining the economic value of the wetlands and creating criteria for the use of these resources. The main goals of this study were to inventory the wetlands of the São Leopoldo region, to analyze the diversity of macrophytes and macroinvertebrates in wetland of the São Leopoldo and to establish criteria for the conservation programs in wetlands. The inventory of we