Modeling sediment and nitrogen export from a rural watershed in eastern Canada using the soil and water assessment tool

Watershed simulation models can be used to assess agricultural nonpoint-source pollution and for environmental planning and improvement projects. However, before application of any process-based watershed model, the model performance and reliability must be tested with measured data. The Soil and Water Assessment Tool version 2005 (SWAT2005) was used to model sediment and nitrogen loads from the Thomas Brook Watershed, which drains a 7.84 km rural landscape in the Annapolis Valley of Nova Scotia, Canada. The Thomas Brook SWAT model was comprised of 28 subbasins and 265 hydrologic response units, most of them containing agricultural land use, which is the main nonpoint nitrogen source in the watershed. Crop rotation schedules were incorporated into the model using field data collected within Agriculture and Agri-Food Canada's Watershed Evaluation of Beneficial Management Practices program. Model calibration (2004-2006) and validation (2007-2008) were performed on a monthly basis using continuous stream flow, sediment, and nitrogen export measurements. Model performance was evaluated using the coefficient of determination, Nash-Sutcliff efficiency (NSE), and percent bias (PBIAS) statistics. Study results show that the model performance was satisfactory (NSE > 0.4; > 0.5) for stream flow, sediment, nitrate-nitrogen, and total nitrogen simulations. Annual corn, barley, and wheat yields were also simulated well, with PBIAS values ranging from 0.3 to 7.2%. This evaluation of SWAT demonstrated that the model has the potential to be used as a decision support tool for agricultural watershed management in Nova Scotia.     

Coastal zone management in wales: The information gaps

In 1994 the Countryside Council for Wales, the government nature conservation and countryside advisor in Wales, published a consultation document on marine and coastal policy, and also commissioned research into the status of coastal zone management (CZM) in the Principality. The research, undertaken by the University of Wales Cardiff, investigated CZM from an international, national (U.K.) and Welsh perspective, concentrating on detailed case studies of three areas (including both urban and rural coasts). Policy makers, managers, practitioners and users from all sectors were included in the study which established current activity, identified problems and reviewe future plans. Interviews and questionnaire returns highlighted vital information gaps at all levels. These ranged fom a lack of basic data (including scientific and technical), to a breakdown in communication both within and between organisations, as well as a policy vacuum in both regional and central government.     

GIS based mapping of land cover changes utilizing multi-temporal remotely sensed image data in Lake Hawassa Watershed,Ethiopia

Classifying multi-temporal image data to produce thematic maps and quantify land cover changes is one of the most common applications of remote sensing. Mapping land cover changes at the regional level is essential for a wide range of applications including land use planning, decision making, land cover database generation, and as a source of information for sustainable management of natural resources. Land cover changes in Lake Hawassa Watershed, Southern Ethiopia, were investigated using Landsat MSS image data of 1973, and Landsat TM images of 1985, 1995, and 2011, covering a period of nearly four decades. Each image was partitioned in a GIS environment, and classified using an unsupervised algorithm followed by a supervised classification method. A hybrid approach was employed in order to reduce spectral confusion due to high variability of land cover. Classification of satellite image data was performed integrating field data, aerial photographs, topographical maps, medium resolution satellite image (SPOT 20 m), and visual image interpretation. The image data were classified into nine land cover types: water, built-up, cropland, woody vegetation, forest, grassland, swamp, bare land, and scrub. The overall accuracy of the LULC maps ranged from 82.5 to 85.0 %. The achieved accuracies were reasonable, and the observed classification errors were attributable to coarse spatial resolution and pixels containing a mixture of cover types. Land cover change statistics were extracted and tabulated using the ERDAS Imagine software. The results indicated an increase in built-up area, cropland, and bare land areas, and a reduction in the six other land cover classes. Predominant land cover is cropland changing from 43.6 % in 1973 to 56.4 % in 2011. A significant portion of land cover was converted into cropland. Woody vegetation and forest cover which occupied 21.0 and 10.3 % in 1973, respectively, diminished to 13.6 and 5.6 % in 2011. The change in water body was very peculiar in that the area of Lake Hawassa increased from 91.9 km² in 1973 to 95.2 km² in 2011, while that of Lake Cheleleka whose area was 11.3 km² in 1973 totally vanished in 2011 and transformed into mud-flat and grass dominated swamp. The “change and no change” analysis revealed that more than one third (548.0 km²) of the total area was exposed to change between 1973 and 2011. This study was useful in identifying the major land cover changes, and the analysis pursued provided a valuable insight into the ongoing changes in the area under investigation.     

Review of biosolids management options and co-incineration of a biosolid-derived fuel

This paper reviews current biosolids management options, and identifies incineration as a promising technology. Incineration is attractive both for volume reduction and energy recovery. Reported emissions from the incineration of biosolids were compared to various regulations to identify the challenges and future direction of biosolids incineration research. Most of the gaseous and metal emissions were lower than existing regulations, or could be met by existing technologies. This paper also presents the results of an experimental study to investigate the potential use of biosolids for co-incineration with wood pellets in a conventional wood pellet stove. Pilot scale combustion tests revealed that co-incineration of 10% biosolids with 90% premium grade wood pellets resulted in successful combustion without any significant degradation of efficiency and emissions.     

Coastal zone management in Wales: The information gaps

In 1994 the Countryside Council for Wales, the government nature conservation and countryside advisor in Wales, published a consultation document on marine and coastal policy, and also commissioned research into the status of coastal zone management (CZM) in the Principality. The research, undertaken by the University of Wales Cardiff, investigated CZM from an international, national (U.K.) and Welsh perspective, concentrating on detailed case studies of three areas (including both urban and rural coasts). Policy makers, managers, practitioners and users from all sectors were included in the study which established current activity, identified problems and reviewe future plans. Interviews and questionnaire returns highlighted vital information gaps at all levels. These ranged fom a lack of basic data (including scientific and technical), to a breakdown in communication both within and between organisations, as well as a policy vacuum in both regional and central government.