No description available.

No description available.

No description available.

River networks act as a link between components of the terrestrial landscape, such as soils and groundwater, with the atmosphere and oceans, and are now believed to contribute significantly to global budgets of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). The idea of rivers being an inert conduit for carbon and nitrogen to reach the coast has been challenged recently, with considerable processing of carbon and nitrogen occurring in both the water column and bed sediments in the various aquatic components that make up a river network, including lakes, streams, rivers and estuaries. Although understanding of the cycling of carbon and nitrogen has improved markedly in the last 20 years, there is still much uncertainty regarding the production and emission of greenhouse gases (GHGs) linked to this processing across river catchments and few studies have quantified GHG fluxes from source to sea. Therefore this study aimed to a) understand the spatial and temporal saturations and fluxes of GHGs from both the freshwater River Tay catchment (Scotland) and the River Tay estuary, and b) understand what controls the production of GHGs within both a freshwater lake and across multiple sites in the freshwater river using laboratory incubations of sediment. Hotspots of in-stream production and emission were evident both in the freshwater catchment and the estuary, with significant temporal and spatial variability in saturation and emission (density) for CH4, CO2 and N2O. CH4 emission densities, across the freshwater river sites, ranged from 1720 to 15500 μg C m-2 d-1 with a freshwater catchment wide mean of 4640 μg C m-2 d-1, and in general decreased from upland to lowland sites along the main river stem, with notable peaks of emission in a lowland tributary and at the outflow of a lowland loch. This corresponds well with the main drivers of spatial variability which include allochthonous inputs from gas rich soil waters and in-situ production in fine grained organic rich sediments. CH4 production was observed to be higher in the lowland tributaries (R. Isla 4500 μg C m-2 d- 1) compared to main-stem river sites both in the lowland river (129 μg C m-2 d-1) and upland river which displayed an uptake of CH4 (-1210 μg C m-2 d-1). The main driver of spatial variability in CH4 production rates was the quality of the sediment, as production was higher in fine grained sediments rich in carbon compared to sand and gravels with a low carbon content. CH4 production also varied seasonally, with temperature and seasonal variation in sediment quality as the predominant driving factors. CO2 emission densities across the freshwater catchment ranged from 517 to 2550 mg C m-2 d-1 with a catchment mean flux density of 1500 mg C m-2 d-1. Flux densities on the whole increased along the main river stem from upland sites to lowland sites, with higher fluxes in lowland tributaries. Seasonally, CO2 flux density was highest in late summer and autumn and lowest in winter at most sites, highlighting the importance in seasonal environmental controls such as temperature, light, and substrate availability. Production rates in the sediment increased from upland to lowland sites with highest production rates evident in the lowland tributaries, and in autumn sediment samples. N2O emission density also showed considerable spatial and seasonal variation across the catchment with flux densities ranging from 176 to 1850 μg N m-2 d-1 with a mean flux of 780 μg N m-2 d-1. Mean fluxes were highest in the lowland tributaries and lowest in the upland river with sediment experiments finding similar spatial variation in N2O production. On the whole, in-stream N2O production and emission across the freshwater catchment was driven by increases in nutrient concentration (NO3 -, NH4 +) which in turn was related to the proportion of agricultural landuse. The saturation and emission of GHGs also varied substantially both spatially and temporally in the River Tay estuary, with a mean emission density of 2790 μg CH4-C m-2 d-1, 990 mg CO2-C m-2 d-1 and 162 μg N2O-N m-2 d-1. The spatial variability of GHG concentrations and emission densities in the estuary were predominantly controlled by the balance between lateral inputs (from tidal flushing of surrounding intertidal areas), in-situ microbial production/consumption (both in the water column and bed sediments) and physical mixing/loss processes. Although emission densities of CH4, CO2 and N2O appear low compared to the freshwater river, this is because the estuary is emitting large quantities of gas in the middle and outer estuary, for example net annual emission of N2O increased from 84.7 kg N2O-N yr-1 in the upper freshwater section of the estuary to 888 kg N2O-N yr-1 in the middle estuary section, then decreased to 309 kg N2O-N yr-1 in the saltwater lower estuary. Overall, this study has shown that both dissolved and aerial fluxes of GHGs vary markedly both spatially and temporal from source to sea in a temperate river catchment, with hotspots of in-stream production and emission across the river catchment. The catchment (river, lake and estuary) was a smaller source of CO2, CH4 and N2O emission (total emission and by area) compared to other highly polluted aquatic systems both in the UK and globally.

This research report is a completed Catchment Diagnostic Framework (CDF) for the Klip River catchment (Johannesburg) for the period October 1998 to September 1999. The framework consists of a catchment description and a diagnostic index which provide a simple and representative view of the catchment and its characteristics and assist in identifying problem areas. GIS maps, graphs and tables are used to provide a background of the catchment. The Diagnostic Index is based on a set of Indicators that are calculated and then scored according to a rating system allowing for the calculation of an overall value for the catchment. The indicators and description cover resource conditions, socioeconomics, water quantity, water quality and management. Using this CDF it was found that the Klip River catchment is highly altered due to mining, urban, industrial and agricultural development. All of these have impacts on the beneficial use of the Klip River itself and on the downstream users of the Vaal Barrage. / AC 2016

In the water utility sector, traditional asset management focusses on the maintenance and provision of physical assets (infrastructure) that allow water companies to deliver their services, meet their customers’ expectations and achieve their economic objectives. Nevertheless, the serviceability of the sector heavily depends on natural elements (e.g. rain, land). The importance of Natural Capital (i.e. the natural systems and their deriving ecosystem services) has been at the core of policy recommendations which have shaped regulatory changes in the water sector of England and Wales. Water companies are now required to explicitly account for and report their inter-dependencies on the natural environment and adopt systems-oriented approaches in their Asset Management Programmes (AMPs). These reforms will enable the sector to become resilient to the environmental and societal challenges faced at urban and rural contexts. Responding to the regulatory demands, the research introduces a novel and structured approach for integrating natural capital in the asset management portfolio of the water industry. The work is built on a transdisciplinary research framework and demonstrates that a new scale needs to be considered for the implementation of Holistic Asset Management: the water basin or catchment. A Catchment Metabolism modelling schema was created, grounded on the principles of Integrated Catchment Management and ecosystems services. The schema is based on the robust synthesis of concepts, tools and methods from a spectrum of disciplines. These include Industrial Ecology, Water Accounting, Environmental Regional Input-Output Analysis, hydrology, software engineering and functional modelling. Catchment Metabolism introduces a holistic perspective in asset management and expands its scope. The schema enables the conceptualisation, modelling and management of catchments as complex asset systems. It, thus, forms the ground for structured collaboration among experts for integrated water resources planning and decision-making. The schema allows for the design and implementation of catchment-based strategies and the assessment of their environmental performance. An industrial case study for a pilot catchment system (Poole Harbour Catchment) is used to demonstrate the application of the Catchment Metabolism. Alternative strategies for nitrogen pollution mitigation are assessed. The application of winter cover crops across the catchment appears to be the optimum strategy. The case study demonstrates the practical and modular implementation of the schema, reveals its methodological strengths and limitations and evaluates its applicability in the asset management planning and decision-making of the water sector.

The purpose of the study was to investigate possible environmental impacts of a reduced catchment area (~25 %) for Kaunisjärvi lake and Patojoki river due to establishment of a iron ore mine in Kaunisvaara, Pajala municipality. To accomplish this, two methods were used; first a literary study was inducted to establish impacts of reduced inflow to lakes and reduced flow in rivers. Secondly, the state of the waters was determined by collecting background data from the mining company (Northland Resources SA) which included chemical- and biological parameters. The result showed that a reduced inflow can affect a lake by either eutrophication or oligotrophication, depending on the lakes condition and the character of the inflow, which in turn has impacts on the entire food-web. Reduced flow in rivers also has impacts on the entire food-web by increased water temperature, decreased dissolved oxygen levels, decreased inundation (witch effects nutrient and organic material exchange), decreased biodiversity in phytoplankton, benthos and fish and inhibiting migration, studies differed in effects on pH and alkalinity. The result also showed that both Kaunisjärvi and Patojoki are affected by nutrient load and organic matter, which impacts the entire ecosystem of the waters. Possible consequences for Kaunisjärvi and Patojoki of reduced inflow and reduced flow are discussed. The report concluded that the reduced catchment area will have impacts on environmental goals set by EU and also on national level, but that the interest of exploitation weighs higher.

Water is a constantly changing resource by way of the hydrological cycle. It is unevenly distributed and crosses boundaries of all kinds i.e. political, social, cultural and natural. Samoa is a small developing state in the Pacific Region that is facing rapid pressure with its water resource availability. Consequently, access to and use of water resources has created tensions between water resources regulators, water utilities and villages. Therefore, managing and governing of water becomes a challenging process that has to take into account the complexity of both nature and society. With the emergence of the Integrated Water Resources Management (IWRM) framework, a greater social acceptance and importance has been given to catchment scale management and governance. Nowadays, many countries including Samoa, have embraced this appealing concept where catchments are seen as natural units for water governance and management. This study used a social qualitative approach, aimed to investigate the implementation of catchment management and examine local community perceptions of catchment management, using Apia Catchment as case study. It is based on a conceptual framework of the concept of scale i.e. set out in recent debates and ideas in the arena of catchment scale water governance and management. The primary data was collected from community focus groups within two villages of Apia Catchment, and semi-structured interviews with government agencies involved in the Water and Sanitation Sector programmes. The findings revealed a shift in water resources management and governance and a spatial scale mismatch in Apia Catchment management. According to government officials, the catchment approach is a ‘management tool’ adopted to improve the coordination between water users and to promote local ownership of catchment activities amongst individual villages. However, several challenges arose around land ownership, monetary cost, community resistance and issues outside of catchment areas when implementing catchment management. Despite the challenges that government officials encountered and the concerns raised by the communities, catchment scale management is still being adopted in Samoa. With the adoption of catchment management, many individual villages within Apia Catchment are expected to make decisions collectively. However, some local groups have concerns about the use of the term ‘boundary’, the possibility of the government taking over their land and the proposed catchment-based authority taking precedence over pre-existing cultural hierarchy. Overall, this research reveals that catchment management is often viewed or seen by government as a ‘one size fits all’ notion that ignores the range of the socio-ecological realities on the ground. This study shows that in order to design better water resources policies and strategies that are fully applicable and workable for Samoa, it is very important to identify these mismatches in scales (e.g. spatial and administrative) and levels (e.g. national and local). Understanding scales and associated levels is critical to understanding the whole system and can reduce possible consequences of mismatches due to lack of interaction and collaboration between levels and scales. Local villages have expressed their opinions on how to enhance catchment management and this could perhaps be useful for government in terms of implementation. Based on the results, recommendations are made for water resources managers to assess the importance of different levels and their interactions but, more importantly, to consider how local communities perceive catchment management.

Forest disturbance is expanding in rate and extent and is affecting many montane catchments critical to water resources. Western North America is experiencing an epidemic of mountain pine beetle (MPB) that has affected 20 million hectares of forest in Canada and the United states. This epidemic may have long-lasting consequences for coupled cycles of water, energy, and biogeochemicals. While impacts of forest disturbance by fire and harvest have been studied for more than a half-century, insect-driven mortality differs from these events in the timing and accompanying biophysical impacts. In this work, we quantified catchment hydrologic and hydrochemical response to severe MPB infestation in a lodgepole pine ecosystem. Observations were organized laterally in a nested fashion from soil observations to nested headwater catchments. Vertical observations encompassed what is often termed the critical zone, from atmospheric interactions at the top of the forest through the ground surface and the rooting zone to the interface with groundwater. We quantified responses manifest in snowpack, the primary hydrologic input to this montane ecosystem, in water partitioning between vapor flux and streamflow, and in biogeochemical patterns across the landscape. Key findings of this study include 1) Loss of shelter from the atmosphere caused compensatory sublimation of snowpack to offset decreased interception losses after MPB-driven canopy loss; 2) Vaporization at multiple scales increased over time and in comparison to control forest, reducing water available for streamflow; 3) Nitrogen (N) concentrations were elevated in hillslope groundwater, but attenuation in the riparian zone protected streams from major N influx; and 4) headwater streams rapidly attenuated dissolved carbon (C) and N inputs. Collectively these results demonstrate compensatory negative feedbacks which help explain the lack of strong response to streamflow and stream chemistry observed in the recent MPB epidemic.

Forest disturbance is expanding in rate and extent and is affecting many montane catchments critical to water resources. Western North America is experiencing an epidemic of mountain pine beetle (MPB) that has affected 20 million hectares of forest in Canada and the United states. This epidemic may have long-lasting consequences for coupled cycles of water, energy, and biogeochemicals. While impacts of forest disturbance by fire and harvest have been studied for more than a half-century, insect-driven mortality differs from these events in the timing and accompanying biophysical impacts. In this work, we quantified catchment hydrologic and hydrochemical response to severe MPB infestation in a lodgepole pine ecosystem. Observations were organized laterally in a nested fashion from soil observations to nested headwater catchments. Vertical observations encompassed what is often termed the critical zone, from atmospheric interactions at the top of the forest through the ground surface and the rooting zone to the interface with groundwater. We quantified responses manifest in snowpack, the primary hydrologic input to this montane ecosystem, in water partitioning between vapor flux and streamflow, and in biogeochemical patterns across the landscape. Key findings of this study include 1) Loss of shelter from the atmosphere caused compensatory sublimation of snowpack to offset decreased interception losses after MPB-driven canopy loss; 2) Vaporization at multiple scales increased over time and in comparison to control forest, reducing water available for streamflow; 3) Nitrogen (N) concentrations were elevated in hillslope groundwater, but attenuation in the riparian zone protected streams from major N influx; and 4) headwater streams rapidly attenuated dissolved carbon (C) and N inputs. Collectively these results demonstrate compensatory negative feedbacks which help explain the lack of strong response to streamflow and stream chemistry observed in the recent MPB epidemic.