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Highlights: [•] Estimates net organic and ammoniacal N content of manure in Canada. [•] Distinct differences among Ecoregions in the proportions of organic versus ammoniacal N. [•] Several best management practices (BMP) evaluated using recent costing information. [•] Relatively low-cost BMPs could save 1.6×107 kgNH3 for an estimated cost of $13M. [ABSTRACT FROM AUTHOR]

In recent years, riparian buffers have become known as one of the most effective best management practices for nonpoint-source pollution. However, establishment of riparian buffer systems with respect to plant species and their position in the buffer zone has not been investigated due to lack of efficient evaluation methods for the analysis of water quality improvement with established riparian buffers. To solve this problem, the SWAT-REMM prototype version was developed by researchers in Canada. In the SWAT-REMM prototype version, many riparian-related input parameters are not directly read from the local input data. Thus, a SWAT-REMM enhancement was developed by improving three major limitations of the prototype version of SWAT-REMM: (1) riparian buffers at designated reaches in the watersheds, (2) riparian buffers using local soil properties at the riparian buffer zone along reaches, and (3) multiple weather stations in a larger-scale watershed. The enhanced SWAT-REMM version was applied to the Bonggok watershed in Korea. This study investigated riparian buffers with different widths (10 m, 5 m, and 1 m) along the slope. Total nitrogen reduction ranged from 14.8% to 54.0% in each catchment for 10 m widths. Total nitrogen reduction ranged from 6.9% to 31.6% in each catchment for 1 m widths. The reduction efficiency was not simply proportional to the width of buffers. This study evaluated the enhanced SWAT-REMM simulation of water quality improvement. Based on this research, the enhanced SWAT-REMM can be used to evaluate water quality improvement by riparian buffers at various watersheds worldwide using local data. In particular, simulation of riparian buffers at user-designated reaches in a watershed enables simulation of riparian buffers in watersheds experiencing frequent flooding where no riparian buffers can be established. It is expected that the enhanced SWAT-REMM can be used to determine economical and environmentally optimum riparian buffer scenarios. [ABSTRACT FROM AUTHOR]

The article discusses the accumulation and persistence of trace elements within materials used in agriculture. While some of these elements are added to animal feeds, others are present in micronutrient fertilizers. Phosphatic fertilizers may have trace element levels that are inadvertently elevated due to the source rock used in their manufacture. A study is conducted that estimates future concentrations of these elements for agricultural land in Canada. Knowledge of this data would allow for the development of best management practices to mitigate the trend. Elements assessed include arsenic, cadmium, and zinc, with inputs from fertilizers, manures, and municipal biosolids.

This paper examines suspended sediment concentration and stream discharge during freshet in three small sub-boreal forest streams (<1.5 m in width) in the central interior of British Columbia for 1 year prior to (1996) and for 5 years following forest harvesting (1997-2001). Harvesting prescriptions in a 20-m strip beside one stream required complete removal of merchantable timber (>15 cm diameter at breast height (DBH) for pine and >20 cm for spruce), while all stems <30 cm DBH were retained beside a second stream. A third stream remained unharvested as a control. The two riparian treatments were prescribed to test the efficacy of current British Columbia legislation that allows for varying amounts of riparian retention as best management practices for the management of windthrow. Both treated watersheds were clear-cut harvested (approximately 55% removal) in January 1997, and in the following year, temporary access roads were deactivated, including two stream crossings in the low-retention watershed. An increase in peak snowmelt and total freshet discharge was first noted in the second spring following harvest in both treatments and remained above predicted in all subsequent years. Suspended sediment also increased during freshet following harvest but returned to levels at or below preharvest predictions within 3 years or less in the high-retention watershed. [ABSTRACT FROM AUTHOR]

The article reports on the Mexican Decision Support (MEDS) project, a national effort proposed by the National Council of Science and Technology of Mexico to prioritize water resources research on watersheds in Mexico. Mexico's MEDS is similar to the Conservation Effects Assessment Project (CEAP) of the United States and to the Watershed Evaluation of Beneficial Management Practices (WEBs) project of Canada. It aims to develop a quantitative measurement for recognizing watershed problems among farmers. It would include watersheds with a process or regional problem and located within natural protected areas of the National Commission for Knowledge and Protection of the Biodiversity.