Earthworking activities have the potential to accelerate soil erosion through vegetation clearance and soil compaction processes. The eroded sediment can have many detrimental effects on receiving aquatic environments, and thus its discharge is controlled under the Resource Management Act, 1991. Two chemically dosed sediment retentions ponds at the SH20 extension project in Mount Roskill, Auckland were investigated, and the impact of the discharge of one of these ponds on a receiving waterbody was assessed using the Stream Ecological Valuation (SEV) method. Rainfall and suspended solid data was collected for a nine month period between November 2006 and August 2007, although sampling did not commence at one of the ponds until March 2007. Two SEV samples were undertaken within the receiving waterbody; one in November 2006 and the other in November 2007 to assess environmental changes resulting from the sediment retention pond discharge. The suspended solids results measured within the sediment retention ponds during this study were much lower than those reported by other studies on earthwork sites. This is believed to be due to the effective implementation of sediment and erosion control measures onsite. The Somerset Road pond was very effective at removing suspended solids throughout the sampling period, with the majority of suspended solid removal occurring in the forebay as it typically did not become full enough to overflow into the main pond. When the forebay was full of water, the PAC dosing system resulted in large reductions in suspended solid levels over a short horizontal distance within the forebay. A smaller amount of suspended solid reduction was achieved in the main pond, predominately through dilution, with the major function of the main pond being additional storage capacity for runoff. Discharge from the Somerset Road Pond was not continuous due to low water levels in the main pond. However, when discharge did occur, the suspended solids levels were very low compared with other studies investigating sediment retention pond discharge. The Richardson Road pond was less effective at removing suspended solids due to the flow regime within the forebay. There were two runoff channels entering the forebay, as well as a continual flow of groundwater. Only one of the runoff channels was directly dosed with PAC, and as the water level in the forebay was typically at, or just below, the level spreader at all times, there was a decreased potential for the PAC to become evenly distributed through the forebay and achieve dosing of all runoff. Furthermore, the main pond discharged continuously during the study period, resulting in reduced residence times of runoff within the pond system. Nonetheless, the discharge from the main pond was much lower than other studies, implying suspended solid reduction was being achieved. The SEV method indicated that the receiving environment was already degraded due to modifications to the riparian vegetation, increased dissolved oxygen demand, and moderate bank erosion. This was reflected in the macroinvertebrate population, with only pollution tolerant taxa being collected, thus limiting the use of macroinvertebrates as an assessment tool in this study. However, the SEV method, which assesses a wide range of ecological functions, implied that very little environmental change occurred as a result of the sediment retention pond discharge. A small increase in deposited sediment was observed on the stream bed, however indications are that deposited sediment is rapidly washed away once earthworks are completed. Thus this deposited sediment may not have a permanent impact within the receiving environment.

A avaliação da largura de florestas ribeirinhas para a retenção de sedimentos inclui as seguintes hipóteses: 1. A presença da Floresta Ribeirinha é eficiente na retenção de sedimentos em áreas cultivadas por cana-de-açúcar; 2. Diferentes larguras de Florestas Ribeirinhas apresentam diferentes eficiências para essa função e, 3. As larguras de florestas ribeirinhas para a retenção de sedimentos variam de acordo com as características da microbacia. Para testar essas hipóteses, foi utilizada a técnica do 137Cs em áreas agrícolas cultivadas por cana-de-açúcar e em Áreas de Preservação Permanente de Iracemápolis, incluindo um fragmento Florestal Ribeirinho Remanescente, uma Área Restaurada com espécies nativas e uma área de Cerradão em Orindiúva. Essa técnica foi aplicada concomitantemente com o programa de interface EDI (Erosion Database Interface) que associa o modelo WEPP (Water Erosion Prediction Project), e SIG (Sistema de Informações Geográficas) para calcular erosão e deposição tanto para a escala das transeções quanto para as microbacias. Para complementar o estudo, as análises morfológicas do perfil do solo serviram para dar suporte à aplicação do modelo WEPP. A análise fitossociológica destacou-se como importante ferramenta para verificar a heterogeneidade das condições da vegetação. Todas as metodologias mostraram que a Floresta Ribeirinha foi eficiente para este papel, pois a deposição ocorreu somente na Floresta e a erosão foi predominante na cana-de-açúcar. A largura de 30 m de faixa ciliar apresentou 10% de eficiência para a retenção de sedimentos nas microbacias de Iracemápolis e 63% de eficiência para a microbacia do rio Turvo. As larguras de Florestas ribeirinhas de 46m, 56 m e 34 m foram as que permitiram uma produção aceitável de sedimentos de acordo com as condições atuais nas três microbacias de estudo (Wtsy). A modelagem utilizando a interface EDI mostrou que as larguras das florestas ribeirinhas para a retenção de sedimentos devem ser analisadas considerando as características da microbacia, como o comprimento de rampa, a - 6 - declividade, o tipo de solo. A heterogeneidade dos parâmetros fitossociológicos entre as transeções com relação à diversidade, densidade, área basal total indica que a análise da largura da Floresta Ribeirinha deve considerar o posicionamento dos fragmentos de floresta na paisagem, o estado de degradação ambiental da Floresta, a largura total do fragmento, a disposição dos elementos na paisagem, o tipo de solo, o histórico de ocupação das terras. / The main hypotheses of the present study regarding the evaluation of the efficiency of riparian forest to sediment retention were: 1. Riparian Forest is an efficient system for sediment retention in watersheds; 2. Different Riparian Forests widths present different efficiencies for this function and, 3. Widths of riparian forests to sediment retention vary according to watershed characteristics. Erosion prediction methods were applied in sugarcane crop areas in Iracemápolis, SP, where a natural Riparian Forest and a Reforested area were selected for the study, and in Orindiúva, SP, were a Savana vegetation (Cerrados) was studied. The interface program EDI (Erosion Database Interface) that links WEPP model (Water Erosion Prediction Project), to GIS (Geographical Information System) was used to evaluate erosion and sediment deposition in the watersheds. Morphological analyses of soil profiles was used as a tool to help in the evaluation of WEPP model deposition estimates. Phytossociologycal studies were important to characterize the heterogeneity of the riparian vegetation. All the methodologies showed that Riparian Forests was efficient for sediment retention. Sediment deposition was observed only in the riparian ecosystem while in the cultivated land the erosion process was predominant. 30m of riparian vegetation strip showed a capacity to retain 10% of the total amount of sediments produced in Iracemapolis watershed and 63% of the total amount in the Rio Turvo watershed. The riparian width of 46m, 56 m and 34 m produced acceptable sediment retention averages considering the current management. Riparian forest width for sediment retention evaluation should consider the watershed characteristics, as shape, slope, soil, kind of soil use and vegetation, historical management analysis, and the environmental conditions of the landscape.

A avaliação da largura de florestas ribeirinhas para a retenção de sedimentos inclui as seguintes hipóteses: 1. A presença da Floresta Ribeirinha é eficiente na retenção de sedimentos em áreas cultivadas por cana-de-açúcar; 2. Diferentes larguras de Florestas Ribeirinhas apresentam diferentes eficiências para essa função e, 3. As larguras de florestas ribeirinhas para a retenção de sedimentos variam de acordo com as características da microbacia. Para testar essas hipóteses, foi utilizada a técnica do 137Cs em áreas agrícolas cultivadas por cana-de-açúcar e em Áreas de Preservação Permanente de Iracemápolis, incluindo um fragmento Florestal Ribeirinho Remanescente, uma Área Restaurada com espécies nativas e uma área de Cerradão em Orindiúva. Essa técnica foi aplicada concomitantemente com o programa de interface EDI (Erosion Database Interface) que associa o modelo WEPP (Water Erosion Prediction Project), e SIG (Sistema de Informações Geográficas) para calcular erosão e deposição tanto para a escala das transeções quanto para as microbacias. Para complementar o estudo, as análises morfológicas do perfil do solo serviram para dar suporte à aplicação do modelo WEPP. A análise fitossociológica destacou-se como importante ferramenta para verificar a heterogeneidade das condições da vegetação. Todas as metodologias mostraram que a Floresta Ribeirinha foi eficiente para este papel, pois a deposição ocorreu somente na Floresta e a erosão foi predominante na cana-de-açúcar. A largura de 30 m de faixa ciliar apresentou 10% de eficiência para a retenção de sedimentos nas microbacias de Iracemápolis e 63% de eficiência para a microbacia do rio Turvo. As larguras de Florestas ribeirinhas de 46m, 56 m e 34 m foram as que permitiram uma produção aceitável de sedimentos de acordo com as condições atuais nas três microbacias de estudo (Wtsy). A modelagem utilizando a interface EDI mostrou que as larguras das florestas ribeirinhas para a retenção de sedimentos devem ser analisadas considerando as características da microbacia, como o comprimento de rampa, a - 6 - declividade, o tipo de solo. A heterogeneidade dos parâmetros fitossociológicos entre as transeções com relação à diversidade, densidade, área basal total indica que a análise da largura da Floresta Ribeirinha deve considerar o posicionamento dos fragmentos de floresta na paisagem, o estado de degradação ambiental da Floresta, a largura total do fragmento, a disposição dos elementos na paisagem, o tipo de solo, o histórico de ocupação das terras. / The main hypotheses of the present study regarding the evaluation of the efficiency of riparian forest to sediment retention were: 1. Riparian Forest is an efficient system for sediment retention in watersheds; 2. Different Riparian Forests widths present different efficiencies for this function and, 3. Widths of riparian forests to sediment retention vary according to watershed characteristics. Erosion prediction methods were applied in sugarcane crop areas in Iracemápolis, SP, where a natural Riparian Forest and a Reforested area were selected for the study, and in Orindiúva, SP, were a Savana vegetation (Cerrados) was studied. The interface program EDI (Erosion Database Interface) that links WEPP model (Water Erosion Prediction Project), to GIS (Geographical Information System) was used to evaluate erosion and sediment deposition in the watersheds. Morphological analyses of soil profiles was used as a tool to help in the evaluation of WEPP model deposition estimates. Phytossociologycal studies were important to characterize the heterogeneity of the riparian vegetation. All the methodologies showed that Riparian Forests was efficient for sediment retention. Sediment deposition was observed only in the riparian ecosystem while in the cultivated land the erosion process was predominant. 30m of riparian vegetation strip showed a capacity to retain 10% of the total amount of sediments produced in Iracemapolis watershed and 63% of the total amount in the Rio Turvo watershed. The riparian width of 46m, 56 m and 34 m produced acceptable sediment retention averages considering the current management. Riparian forest width for sediment retention evaluation should consider the watershed characteristics, as shape, slope, soil, kind of soil use and vegetation, historical management analysis, and the environmental conditions of the landscape.

Doctoral thesis abstract Assessment of climate change impacts on selected ecosystem services in the Czech Republic: Application of land use scenarios MSc Eliška Lorencová Climate and land use change are recognized as the greatest global environmental problems. Both considerably impact delivery of crucial ecosystem services, such as carbon sequestration, water flow regulation, erosion control, and food and fibre production. By combining future projections of ALARM scenarios (for years 2020, 2050 and 2080) with modelling of ecosystem services, the study aims to evaluate climate change impact on selected ecosystem services (carbon storage and sequestration, erosion control and sediment retention) in the Czech Republic. This study provides quantitative as well as spatially explicit analysis of the impacts on selected ecosystem services in the Czech Republic. Performed ecosystem service assessment indicates that spatial distribution of provision of ecosystem services, such as carbon storage and sequestration, sediment retention reflects the projected future land use changes. In case of carbon sequestration, SEDG scenario shows the lowest carbon sequestration rates accounting for 37,029.6 Gg C within the period 2000-2080. Stable vegetation cover is one of the factors that play important role in amount of sediment...

Doctoral thesis abstract Assessment of climate change impacts on selected ecosystem services in the Czech Republic: Application of land use scenarios MSc Eliška Lorencová Climate and land use change are recognized as the greatest global environmental problems. Both considerably impact delivery of crucial ecosystem services, such as carbon sequestration, water flow regulation, erosion control, and food and fibre production. By combining future projections of ALARM scenarios (for years 2020, 2050 and 2080) with modelling of ecosystem services, the study aims to evaluate climate change impact on selected ecosystem services (carbon storage and sequestration, erosion control and sediment retention) in the Czech Republic. This study provides quantitative as well as spatially explicit analysis of the impacts on selected ecosystem services in the Czech Republic. Performed ecosystem service assessment indicates that spatial distribution of provision of ecosystem services, such as carbon storage and sequestration, sediment retention reflects the projected future land use changes. In case of carbon sequestration, SEDG scenario shows the lowest carbon sequestration rates accounting for 37,029.6 Gg C within the period 2000-2080. Stable vegetation cover is one of the factors that play important role in amount of sediment...