The South Nation watershed is located in Eastern Ontario, Canada and managed under the authority of the South Nation Conservation (SNC). The watershed covers an area of 400,000 hectares with four dominant categories of land-use classes (60% agriculture, 34% forest, 5% mixed urban, and 1% other). Water quality is a great concern for the SNC as many anthropogenic activities generate harmful pollutants (such as heavy metals, nitrogen, phosphorus, and pesticides) that are discharged to the river through surface and groundwater flow. The discharge patterns of these pollutants are mainly driven by land-use distribution within the watershed which has been constantly evolving with urbanization and intensification of agriculture. Major changes in land-uses can potentially offset current SNC efforts to mitigate water pollution. The objective of the current study is to predict land-use series of maps for the South Nation watershed starting from 1991 to 2020. The prediction is carried out using the land-use allocation algorithm of the Dyna-CLUE (Dynamic Conversion of Land-Use and its Effects) model which is implemented for local regions. Dyna-CLUE is a spatially explicit hybrid land-use allocation model that combines estimation and simulation models, and its allocation procedures predict future trends of land-use surface (estimated from historical trends). The binary logistic regression is used to link preferences of land-use classes and potential demographic and geographic driving factors. Expert judgment was used to select a set of spatial driving factors believed to be responsible for changes in land-use distribution in the South Nation watershed. Three different scenarios for future development of the region were considered, with different initial conditions and conversion restrictions. The simulation results were evaluated using visual and statistical validation techniques to assess the performance of the model in generating maps similar to reality. The Dyna-CLUE model was successfully applied to the South Nation watershed. It was observed that the simulated maps generated from the model were in good agreement with the reality maps. This was confirmed through statistical validation via map pair analysis (error matrix) used to assess the overall accuracy of the model predictions. Results showed that the model was sensitive to land-use restrictions. Such type of modeling can be valuable for assessing the land-use changes at the local level, and setting up a decision support system for the South Nation Conservation towards sustainable land-use management in the watershed. Better results are expected to be achieved with more reliable datasets (i.e., accurate classification of land-use types in reality maps). Data availability and quality were the main obstacles that faced this research work. Our work has the merit to be the first application of CLUE model in Eastern Ontario.

The South Nation watershed is located in Eastern Ontario, Canada and managed under the authority of the South Nation Conservation (SNC). The watershed covers an area of 400,000 hectares with four dominant categories of land-use classes (60% agriculture, 34% forest, 5% mixed urban, and 1% other). Water quality is a great concern for the SNC as many anthropogenic activities generate harmful pollutants (such as heavy metals, nitrogen, phosphorus, and pesticides) that are discharged to the river through surface and groundwater flow. The discharge patterns of these pollutants are mainly driven by land-use distribution within the watershed which has been constantly evolving with urbanization and intensification of agriculture. Major changes in land-uses can potentially offset current SNC efforts to mitigate water pollution. The objective of the current study is to predict land-use series of maps for the South Nation watershed starting from 1991 to 2020. The prediction is carried out using the land-use allocation algorithm of the Dyna-CLUE (Dynamic Conversion of Land-Use and its Effects) model which is implemented for local regions. Dyna-CLUE is a spatially explicit hybrid land-use allocation model that combines estimation and simulation models, and its allocation procedures predict future trends of land-use surface (estimated from historical trends). The binary logistic regression is used to link preferences of land-use classes and potential demographic and geographic driving factors. Expert judgment was used to select a set of spatial driving factors believed to be responsible for changes in land-use distribution in the South Nation watershed. Three different scenarios for future development of the region were considered, with different initial conditions and conversion restrictions. The simulation results were evaluated using visual and statistical validation techniques to assess the performance of the model in generating maps similar to reality. The Dyna-CLUE model was successfully applied to the South Nation watershed. It was observed that the simulated maps generated from the model were in good agreement with the reality maps. This was confirmed through statistical validation via map pair analysis (error matrix) used to assess the overall accuracy of the model predictions. Results showed that the model was sensitive to land-use restrictions. Such type of modeling can be valuable for assessing the land-use changes at the local level, and setting up a decision support system for the South Nation Conservation towards sustainable land-use management in the watershed. Better results are expected to be achieved with more reliable datasets (i.e., accurate classification of land-use types in reality maps). Data availability and quality were the main obstacles that faced this research work. Our work has the merit to be the first application of CLUE model in Eastern Ontario.

Aquesta tesi vol contribuir a comprendre millor els sistemes socioecològics i el seu canvi al llarg del temps des d’un punt de vista holístic i relacional. Pretén mostrar que les activitats productives del camp no són necessàriament incompatibles amb la conservació de la biodiversitat, i que algunes d’aquestes activitats, fins i tot en situacions d’integració en economies de mercat, són indispensables per conservar els paisatges culturals que les societats urbanes modernes volen protegir. La tesi es pregunta si la recuperació i l’expansió de la superfície forestal poden tenir un efecte negatiu en l’escolament de les conques i el cabal dels cursos d’aigua, així com en la biodiversitat pròpia d’hàbitats oberts a escala local. També explora la transformació del camp durant el procés d’industrialització i urbanització per recolzar la noció d’una interrelació i hibridació històriques entre el rural i l’urbà, i mostra que l’expansió urbana és el resultat d’intenses lluites polítiques entre diferents grups socials amb una distribució desigual dels costos i els beneficis del canvi socioecològic. La Mediterrània és una regió especialment idònia per als objectius d’aquesta recerca, ja que es considera un ‘hotspot’ de biodiversitat mundial el qual és resultat de la integració entre processos naturals i humans. A més, està fortament amenaçada degut a la gran sensibilitat dels seus ecosistemes envers tots els components del canvi global. La tesi se centra en la Regió Metropolitana de Barcelona, a Catalunya, una de les ciutats més grans de l’Europa mediterrània, i específicament en dos municipis de muntanya baixa de la segona corona metropolitana: Olzinelles, al massís del Montnegre, i Matadepera, al massís de Sant Llorenç del Munt i la serra de l’Obac. La metodologia es basa en una combinació d’elements de la història ambiental, l’ecologia política i la hidrologia forestal amb el coneixement ecològic de la pagesia local. L’anàlisi del sistema productiu d’Olzinelles i les seves arrels històriques (capítol 4) mostra com les diverses pràctiques de gestió dels recursos naturals, incrustades en un marc institucional i una cosmovisió particulars, permetien al sistema socioecològic adaptar-se a les variacions de la demanda externa i al mateix temps mantenir la seva capacitat per proporcionar aliments a la població local. L’abandonament d’aquestes pràctiques durant un procés de modernització a escala nacional i global ha comportat una reducció de les poblacions d’espècies pròpies de camps, pastures i boscos esclarissats. A l’escala de conca (vall d’Olzinelles, capítol 3) es conclou que l’assecament de la riera observat en les darreres dècades s’ha d’atribuir a un període més sec i no pas a la petita aforestació que hi ha tingut lloc. No obstant, en futurs estudis caldria incorporar la variació de la coberta arbòria ja que té un rol important en la intercepció i la partició de la pluja, i en les darreres dècades ha experimentat un fort augment com a resultat de l’abandonament de les pràctiques de gestió forestal. L’anàlisi de Matadepera (capítol 5) mostra com en el procés d’expansió urbana s’enfrontaren diferents visions del futur de diferents grups socials (propietaris de terres i pagesia d’esquerres). El projecte socioecològic de les elits dominants va esdevenir una realitat perquè van ser capaces de controlar recursos vitals com la terra i l’aigua amb l’aniquilació de la dissidència a través de la presó, les execució i la violència psicològica del règim franquista sorgit al final de la Guerra Civil (1939). La construcció discursiva d’una ‘escassetat natural’ va ajudar a construir un consens espontani en relació als impactes negatius de l’arribada de grans quantitats d’aigua procedent del riu Llobregat per a possibilitar la gentrificació del poble. La tesi conclou que una combinació adequada de diferents graus d’hibridació socioecològica en l’anàlisi de la realitat pot ser una bona forma d’entendre les dinàmiques complexes dels canvis en els usos de la terra i de la conservació de la biodiversitat en llocs concrets, i també útil per superar l’estricta separació conceptual i analítica entre societat i natura, camp i ciutat, conservació i desenvolupament, i àrees protegides i no protegides. / This thesis is aimed to better understanding the coupled social-ecological systems and their change over time in a holistic and relational way. It intends to show that productive rural activities are not necessarily incompatible with conservation of biodiversity, and that some of these activities, even when they are quite integrated with market economies, are indispensable to conserve the cultural landscapes that modern urban societies want to protect. This thesis also asks whether forest recoveries have a negative effect on water discharge from the catchments and on the biodiversity from open habitats at a local scale. It also explores the transformation of the countryside during the process of industrialization and urbanization to support the notion of historical interrelatedness and hybridity between the rural and the urban; and shows that suburbanization is the outcome of political struggles between different social groups resulting in uneven distribution of the costs and benefits of socioecological change. The Mediterranean is a particularly illuminating region for the aims of this research since it is considered a hotspot of global biodiversity which itself is a consequence of the integration between natural and human processes, besides being highly threatened because of the particular sensitivity of Mediterranean ecosystems to all drivers of global change. This thesis is focused in the Barcelona Metropolitan Region (Catalonia), one of the largest cities of Mediterranean Europe, more specifically in two mountain municipalities of the outer metropolitan ring: Olzinelles, in Montnegre Mountains, and Matadepera, in Sant Llorenç del Munt Mountains. The methodology combines elements from environmental history, political ecology and forest hydrology with the local ecological knowledge from peasants. The analysis of the productive system of Olzinelles and its historical roots (chapter 4) shows that several management practices, embedded in a particular institutional setting and worldview, allowed the social-ecological system to adapt to the changing external demand while keeping its capacity to supply food to the local community. The abandonment of such practices under a national-to-global process of modernization resulted in a decrease of species from fields, meadows and sparse forests. At the catchment scale (Olzinelles valley, chapter 3) it is concluded that the observed decrease in the water runoff may be attributed to a drier period rather than to the small afforestation experienced in the catchment. However, future studies should incorporate the variation of canopy cover given its potential role in rainfall interception and partitioning processes, and the great increase in canopy cover experienced in the catchment as a result of the abandonment of forest management practices. The analysis of Matadepera (chapter 5) shows that different visions of the future by different social groups (landowners vs. left-wing peasantry) collided in the process of suburbanization. The socioecological project promoted by ruling elites prevailed because they were able to control vital resources like land and water with the annihilation of the dissidence through prison, execution and psychological violence under the new Francoist regime that arose after the end of the Civil War in 1939. The discursive construction of a ‘natural scarcity’ of water helped to achieve spontaneous consent for controversial aspects of bringing water from the Llobregat River to allow the gentrification of the town. The thesis concludes that a suitable combination of different degrees of socioecological hybridity in the analysis may be suitable to understand the complex dynamics of land change and biodiversity conservation in a particular setting, as well as useful to overcome the strict conceptual and analytical separation between society and nature; city and countryside; conservation and development; and protected and non-protected areas.

Globally, stream invertebrate communities have been shown to respond to habitat degradation as a result of land use hanges. The effects of land use changes on stream communities have been well documented in temperate regions, however, their effects in the tropics are relatively unknown, particularly where land use activities can differ markedly (e.g., tea, maize and Eucalyptus plantations). To understand how land use affects tropical highland Nigerian stream communities, I surveyed 55 second and third order streams across four land use categories, ranging from continuous tropical montane forest to intensive crops/pasture. Streams were sampled in the dry season (October to March) for physico-chemical parameters (i.e., temperature, pH, conductivity, turbidity, current velocity, channel morphometry and riparian characteristics) and ecological characteristics (i.e., fine particulate organic matter [FPOM], coarse particulate organic matter [CPOM], algae and benthic invertebrates). Water temperature in all streams was high (up to 25oC) while levels of dissolved oxygen were frequently low (15–79 %). Physico-chemical conditions varied across land uses with continuous forested streams being cooler, with higher dissolved oxygen, larger bed substrate and more stable channels. Similarly, benthic invertebrate communities showed a strong response with the highest taxonomic diversity in forested streams and the lowest in streams within intensive crops (e.g., cabbage crops). Several of the taxa which occurred in forested streams (e.g., the mayflies Heptageniidae and Oligoneuridae and brachyuran crabs) were rare or absent in streams with more intensive land use. In contrast, damselflies and several true bugs (e.g., Notonectidae and Corixidae) were rare in forested streams but more common in other land uses. In order to test land use impacts on stream processes leaf litter decomposition experiments were carried out in nine streams, three in forest, three in tea plantations and three in maize fields. Leaf breakdown rates were slow compared with other reports for tropical streams, however leaves in forested streams broke down significantly faster (on a degree day basis) than in other land uses. This faster break down seemed to be driven by greater shredder densities in forested streams. Significantly lower densities of invertebrates were found in leaf bags incubated in streams draining tea plantation and maize fields than in forest streams. In the same nine streams food web components were sampled and analysed using gut content and stable isotope (N and C) analyses. Stream food webs in continuous forest were more complex than plantation and maize field streams. Stable isotope analysis indicated that primary consumers assimilated a mixture of autochthonous and allochthonous carbon resources, but the proportion varied among sites. Overall, my results suggest that in Nigerian highland tropical streams more intensive land use activities strongly affect the diversity and composition of benthic stream communities and ecosystem function, in similar ways to those reported in temperate streams.

The South Nation watershed is located in Eastern Ontario, Canada and managed under the authority of the South Nation Conservation (SNC). The watershed covers an area of 400,000 hectares with four dominant categories of land-use classes (60% agriculture, 34% forest, 5% mixed urban, and 1% other). Water quality is a great concern for the SNC as many anthropogenic activities generate harmful pollutants (such as heavy metals, nitrogen, phosphorus, and pesticides) that are discharged to the river through surface and groundwater flow. The discharge patterns of these pollutants are mainly driven by land-use distribution within the watershed which has been constantly evolving with urbanization and intensification of agriculture. Major changes in land-uses can potentially offset current SNC efforts to mitigate water pollution. The objective of the current study is to predict land-use series of maps for the South Nation watershed starting from 1991 to 2020. The prediction is carried out using the land-use allocation algorithm of the Dyna-CLUE (Dynamic Conversion of Land-Use and its Effects) model which is implemented for local regions. Dyna-CLUE is a spatially explicit hybrid land-use allocation model that combines estimation and simulation models, and its allocation procedures predict future trends of land-use surface (estimated from historical trends). The binary logistic regression is used to link preferences of land-use classes and potential demographic and geographic driving factors. Expert judgment was used to select a set of spatial driving factors believed to be responsible for changes in land-use distribution in the South Nation watershed. Three different scenarios for future development of the region were considered, with different initial conditions and conversion restrictions. The simulation results were evaluated using visual and statistical validation techniques to assess the performance of the model in generating maps similar to reality. The Dyna-CLUE model was successfully applied to the South Nation watershed. It was observed that the simulated maps generated from the model were in good agreement with the reality maps. This was confirmed through statistical validation via map pair analysis (error matrix) used to assess the overall accuracy of the model predictions. Results showed that the model was sensitive to land-use restrictions. Such type of modeling can be valuable for assessing the land-use changes at the local level, and setting up a decision support system for the South Nation Conservation towards sustainable land-use management in the watershed. Better results are expected to be achieved with more reliable datasets (i.e., accurate classification of land-use types in reality maps). Data availability and quality were the main obstacles that faced this research work. Our work has the merit to be the first application of CLUE model in Eastern Ontario.

The Thornton Well Field, located in an area of dominantly (~80%) agricultural land-use, produces ~50% of the drinking water for the city of Woodstock. Since the mid 1990?s nitrate concentrations in some of the supply wells are above the Maximum Allowable Concentration (MAC) of 10mg-N/L. The source of the nitrate is believed to be from agricultural fertilizing practices. As response to this problem, the County of Oxford purchased 111 hectares of farmland within the capture zone of the Thornton Well Field. This land is rented back to farmers with restrictions placed on the amount of nitrate fertilizer that can be applied in an attempt to sustainably reduce the nitrate concentrations in the ThorntonWell Field below MAC. <br /><br /> The objective of this thesis is to improve the site conceptual hydrogeologic model, both at a spatial scale suitable for numerical analysis through regional groundwater flow modelling (representative distance ~9km) and at a smaller scale (representative distance ~2km) for nitrate transport modelling in the vicinity of the Thornton Well Field and the purchased land. Field investigations aimed to support the site hydrogeologic model involved drilling, geologic logging, and instrumentation of a 72m deep borehole completed to bedrock in the center of the nitrate plume, at the border of the farmland under consideration. The shallow subsurface features encountered during this initial drilling operation were tracked below the farm fields with geophysical tools and additional drilling and core logging throughout the field site. Transient hydraulic head observations in combination with on-site precipitation measurements were used to indicate where a hydraulic connection between ground surface and deeper layers exists, which allow rapid infiltration to occur into a glaciofluvial outwash channel which was identified as one important pathway for nitrate transport to the Thornton Well Field. One receptor at the end of that pathway, the screen of the supply Well 01, was depth-discrete profiled for water inflow and nitrate concentrations to obtain better characteristics of the receptor. <br /><br /> A method was developed to estimate the nitrate mass stored in the unsaturated zone below Parcel B, permitting an estimation of the time frame required for flushing the nitrate out of this zone, and the anticipated effects on nitrate concentrations in the supply wells. The spatial distribution of nitrate concentrations in the unsaturated zone and in the aquifer units was analyzed. It was found that the nitrate concentration within the unsaturated zone below Parcel B is ~16mg-N/L, resulting in a total nitrogen mass of ~20t within that zone. It was shown that significant reductions (~10%) in nitrate concentrations in the supply wells of the Thornton Well Field can be achieved, assuming zero nitrate mass influx into the domain from Parcel B. <br /><br /> A comprehensive data base was developed to organize, manage, and analyze all site measured data for that purpose, and regional hydrogeologic data from the MOE Water Well Record Database. The contents of this database in conjunction with the MOE Water Well Record Database were used to construct a three-dimensional digital representation of the hydrostratigraphic units at a regional and at a local scale. This three-dimensional hydrostratigraphic unit spatial distribution along with surface watershed information and potentiometric surfaces of the various aquifer units will be used to define a suitable spatial domain and associated boundary conditions for future modelling efforts. This hydrostratigraphic model will serve as basis for predicting the effects of agricultural land-use changes within the capture zone of the Thornton Well Field (Parcel B) on the nitrate concentrations in the supply wells of the Thornton Well Field.

This thesis titled "The influence of important local entrepreneurs on changes in landscape use: case study from municipalities Zbraslavice and Bohdaneč" is focused on the evaluation of changes in the use of the countryside after 1990. The search part briefly summarizes the data for the study and evaluation methods of land use changes values of natural capital and ecosystem services. Followed by the physical-geographical characteristics of interest area. In the practical part there are applied acquired theoretical knowledge and practices, evaluating the change of land use of the municipalities Bohdaneč and Zbraslavice in the period 1838-2013 and the change of the volume of natural capital and ecosystem services at the same territory between 1990 and 2013. On the basis of the results are formulated trends that are being discussed with local knowledge, national and global levels. It is also monitored and evaluated the effects of three local businesses to detected changes. It is concluded that the changes in land use area of interest after 1990 are positive and that due to the implementation of business plans, these changes take place much faster and stronger than reported national trends. The text is supplemented adds a number of charts, graphs and thematic maps and the annex. Key words: landscape...

O fenômeno de aquecimento do planeta, conhecido como \"Efeito Estufa\", é um dos fenômenos de degradação ambiental mais alarmante. Países que mais emitem os gases de efeito estufa (GEEs) têm, portanto, sofrido forte pressão internacional para que reduzam tais emissões. No caso do Brasil, grande atenção é voltada à questão do desmatamento, um dos maiores responsáveis pelas emissões de dióxido de carbono. Com isso, o país se comprometeu a reduzir suas emissões entre 36,1% e 38,9% em relação às emissões projetadas para 2020. Para conseguir isso, foi promulgada a Lei nº 12.187, que regula que uma das medidas a serem tomadas é a redução de 80% do desmatamento na Amazônia Legal e de 40% do desmatamento no Cerrado. Assim como o aquecimento global, a produção de alimentos também é um dos maiores desafios do mundo moderno. Mais uma vez, Brasil tem um papel fundamental nesta questão, organizações como a OCDE e a FAO afirmam que o Brasil é o país com maior potencial de aumentar a produção agrícola. Ademais, a importância da produção de alimentos para o Brasil é reforçada pelo fato de que o agronegócio é um setor fundamental da economia brasileira tanto em termos de geração de renda quanto para promoção de divisas. Uma questão importante é como a agropecuária brasileira será impactada diante da redução no desmatamento da Amazônia e do Cerrado. Uma hipótese é que frear o desmatamento resultaria em redução significante na produção agropecuária, maiores preços dos produtos agropecuários e alimentos, e menor geração de renda. O presente trabalho objetiva responder essa questão por analisar os impactos econômicos de uma política restritiva de desmatamento sobre o setor agropecuário e a economia nacional, uma vez que essa discussão é recente e ainda carece de estudos mais abrangentes. Para esse propósito é utilizado o modelo de equilíbrio geral computável EPPA, capaz de considerar as relações entre os diferentes setores da economia e uma ampla gama de distorções de políticas. Os resultados deste estudo apontam que uma política restritiva de desmatamento gera perdas pequenas em termos de PIB, de aproximadamente 0,15% no cenário de política em relação ao cenário de referência. Os impactos sofridos pela produção são modestos, de queda de até 1,9% no setor agrícola, -1,8% na pecuária e -1,5% no setor de alimentos. As exportações do agronegócio, no entanto, reduzem em mais de 3,9%. Um resultado positivo importante é que em torno de 68 milhões de hectares de florestas e cerrados deixam de ser transformados em área agrícola, até 2050. Esses resultados sugerem custos econômicos pouco expressivos diante dos potenciais benefícios de preservação ambiental, e devem-se em grande parte à capacidade de aumento em produtividade das pastagens brasileiras e conversão de áreas de vegetação secundária e subaproveitadas em cultivos agrícolas. / The global warming phenomenon known as the \"Greenhouse Effect\" is one of the most alarming phenomena of environmental degradation. Countries that have been larger emitters of greenhouse gases (GHGs) have therefore received strong international pressure to reduce such emissions. In Brazil, much of the attention is focused on the issue of deforestation, a leading cause of carbon dioxide. As a result, the country has committed to reducing its emissions between 36.1% and 38.9% compared to projected emissions by 2020. In order to accomplish this, Law nº 12.187 was enacted, which regulates that deforestation in the Amazon be reduced by 80% and in the Cerrado (savannah) by 40% by the year 2020. Just as global warming is one of the largest challenges facing the modern world, so is food production. Once again, Brazil has a critical role in this issue, organizations as the OECD and FAO recognize that Brazil is the country with the greatest potential to increase agricultural production. Moreover, the importance of food production to Brazil is enhanced by the fact that agribusiness is a key sector of the Brazilian economy in terms of its contribution to both income generation and for promotion of foreign exchange. The key question is how will Brazil\'s agricultural and livestock sectors be impacted by a reduction in deforestation in the Amazon and Cerrado. One hypothesis is that halting deforestation would imply significantly lower agricultural production, higher prices of agricultural products and food and lower income generation. This study serves to answer this question by analyzing the economic impacts of a restrictive policy of deforestation on the agricultural and livestock sectors and the national economy, a growing topic and concern that has yet to be studied in significant detail. For this purpose, the computable general equilibrium model EPPA is utilized, able to consider the relationships between different economic sectors and a wide range of policy distortions. The results of this study reveal that a restrictive policy of deforestation causes only small losses to GDP, of approximately 0.15% in the policy scenario compared to the baseline scenario. The impacts suffered by the production are modest: -1.9% in agriculture, -1.8% in livestock and -1.5% in the food sector. Agribusiness exports, however, decrease by a higher 3.9%. An important positive result is that around 68 million hectares of forests and savannahs cease to be transformed into agricultural land by 2050. These results suggest little economic costs against the potential benefits of environmental preservation, and are due in large part to the ability to increase pasture productivity in Brazil and conversion of areas of secondary vegetation and underutilized in areas of crops.

Land use changes such as lowering of lakes, draining of wetlands and channelizing of streams have affected the hydrological environment in many catchment areas. Numerous studies report that these changes affect the nutrient retention. The river Svärtaå catchment, near Nyköping is identified as one of the areas in Sweden that transport most phosphorus and nitrogen to the Baltic Sea per unit area. The aim of this study was therefore to analyse to which extent land use changes such as lowering of lakes, draining of wetlands and channelizing of streams have affected the nutrient transport to the Baltic Sea. Land use changes were to a large extent performed between the years 1880 and 1930 inSweden, historical maps from the late 19th century have therefore been studied. An application based on the concept of a Geographical Information System (GIS) has been used in order to compare the district map from late 19th century and the terrain map from today. To address the nutrient transport retention coefficients have been found in the literature and implemented on the changes in water area.  Changes in the hydrological environment reached totally1068 ha,964 hawere decreasing water areas and104 haincreasing water areas. Wet areas totally decreased with 28 % when the historical setting was compared with the contemporary environment. The loss in wet area represents860 ha. Watercourses with riparian zones have decreased with 54 %, bogs with 53 %, wetlands with 43 % and lakes with 13 %. The loss in retained mass regarding phosphorus was, based on calculations involving retention coefficients, 7,18 – 146 tonnes, and regarding nitrogen 37,9 – 941 tonnes. The changes in the catchment are probably connected to measures like lowering of lakes, draining of wetlands and channelizing of streams. The assumed lost retained masses shows to be high compared to the measured output from the catchment. This leads to questioning of the retention coefficients and the vast range between them, as well as questioning of other assumptions in the method. The consequences of the hydrological changes are therefore difficult to evaluate.

The Thornton Well Field, located in an area of dominantly (~80%) agricultural land-use, produces ~50% of the drinking water for the city of Woodstock. Since the mid 1990?s nitrate concentrations in some of the supply wells are above the Maximum Allowable Concentration (MAC) of 10mg-N/L. The source of the nitrate is believed to be from agricultural fertilizing practices. As response to this problem, the County of Oxford purchased 111 hectares of farmland within the capture zone of the Thornton Well Field. This land is rented back to farmers with restrictions placed on the amount of nitrate fertilizer that can be applied in an attempt to sustainably reduce the nitrate concentrations in the ThorntonWell Field below MAC. <br /><br /> The objective of this thesis is to improve the site conceptual hydrogeologic model, both at a spatial scale suitable for numerical analysis through regional groundwater flow modelling (representative distance ~9km) and at a smaller scale (representative distance ~2km) for nitrate transport modelling in the vicinity of the Thornton Well Field and the purchased land. Field investigations aimed to support the site hydrogeologic model involved drilling, geologic logging, and instrumentation of a 72m deep borehole completed to bedrock in the center of the nitrate plume, at the border of the farmland under consideration. The shallow subsurface features encountered during this initial drilling operation were tracked below the farm fields with geophysical tools and additional drilling and core logging throughout the field site. Transient hydraulic head observations in combination with on-site precipitation measurements were used to indicate where a hydraulic connection between ground surface and deeper layers exists, which allow rapid infiltration to occur into a glaciofluvial outwash channel which was identified as one important pathway for nitrate transport to the Thornton Well Field. One receptor at the end of that pathway, the screen of the supply Well 01, was depth-discrete profiled for water inflow and nitrate concentrations to obtain better characteristics of the receptor. <br /><br /> A method was developed to estimate the nitrate mass stored in the unsaturated zone below Parcel B, permitting an estimation of the time frame required for flushing the nitrate out of this zone, and the anticipated effects on nitrate concentrations in the supply wells. The spatial distribution of nitrate concentrations in the unsaturated zone and in the aquifer units was analyzed. It was found that the nitrate concentration within the unsaturated zone below Parcel B is ~16mg-N/L, resulting in a total nitrogen mass of ~20t within that zone. It was shown that significant reductions (~10%) in nitrate concentrations in the supply wells of the Thornton Well Field can be achieved, assuming zero nitrate mass influx into the domain from Parcel B. <br /><br /> A comprehensive data base was developed to organize, manage, and analyze all site measured data for that purpose, and regional hydrogeologic data from the MOE Water Well Record Database. The contents of this database in conjunction with the MOE Water Well Record Database were used to construct a three-dimensional digital representation of the hydrostratigraphic units at a regional and at a local scale. This three-dimensional hydrostratigraphic unit spatial distribution along with surface watershed information and potentiometric surfaces of the various aquifer units will be used to define a suitable spatial domain and associated boundary conditions for future modelling efforts. This hydrostratigraphic model will serve as basis for predicting the effects of agricultural land-use changes within the capture zone of the Thornton Well Field (Parcel B) on the nitrate concentrations in the supply wells of the Thornton Well Field.