A forested first-order catchment in western Amazonia was monitored for 2 years to determine the chemical fingerprints of precipitation, throughfall, overland flow, pipe flow, soil water, groundwater, and streamflow. We used five tracers (hydrogen, calcium, magnesium, potassium, and silica) to distinguish “fast” flow paths mainly influenced by the biological subsystem from “slow” flow paths in the geochemical subsystem. The former comprise throughfall, overland flow, and pipe flow and are characterized by a high potassium/silica ratio; the latter are represented by soil water and groundwater, which have a low potassium/silica ratio. Soil water and groundwater differ with respect to calcium and magnesium. The groundwater-controlled streamflow chemistry is strongly modified by contributions from fast flow paths during precipitation events. The high potassium/silica ratio of these flow paths suggests that the storm flow response at La Cuenca is dominated by event water.

Antimicrobials administered to livestock can be excreted up to 80% in the feces and urine. Liquid swine manure from confined animal feeding operations is generally retained in lagoon storage until it is applied as a nutrient source to cropland. Thus, the applied manure becomes a possible source of antimicrobials to aquatic ecosystems. Veterinary antimicrobials have been detected in surface and ground waters in Canada, the United States and Europe, however, their environmental fate is not well known. Lincomycin and spectinomycin are two antimicrobials administered as a mixture to swine in the prairie region of Canada for the prevention of post-weaning diarrhea. In order to assess the potential for contamination of prairie wetlands, concentrations of both antimicrobials were monitored in the liquid manure from the nursery area of a commercial-scale barn during a 5-week study, and their persistence during simulated manure storage investigated. The potential for transport of lincomycin and spectinomycin to surface waters via surface runoff and to leach to groundwater was also assessed. This was achieved by monitoring manure-amended soil, simulated rainfall runoff, snow melt runoff and groundwater over a two-year period at two study sites in Saskatchewan, Canada following fall application of liquid swine manure from two commercial barns to crop and pasture land. Liquid chromatography coupled with tandem mass spectrometry was used to quantitate these antimicrobials in all matrix extracts. <p>In the nursery area of a commercial-scale barn, concentrations of lincomycin and spectinomycin in the cumulating liquid manure at the end of the study were equivalent to 32 and 3.0%, respectively, of doses administered in the feed. In a laboratory study, using fortified liquid manure, concentrations of both antimicrobials showed a rapid initial decrease during simulated lagoon storage, followed by a slower dissipation over a period of 5 months. The average time required for 50% dissipation of lincomycin was greater than one year (365 d) and was approximately 90 d for spectinomycin. <p>Lincomycin concentrations in soil (46.3 to 117 µg kg-1) collected immediately after fall manure application, decreased to non-detectable levels by mid-summer the following year. Lincomycin was present in simulated rainfall runoff (0.1 to 2.7 µg L-1) immediately after manure application with similar concentrations present in snow meltrunoff the following spring. Concentrations in groundwater were generally <0.005 µg L-1. Spectinomycin was not detected in the manure applied at the study sites nor in soil, runoff water or groundwater samples. This study confirms that some antimicrobials, including lincomycin, may be present in lagoon manure. Thus, the management practice of utilizing livestock manure from confined animal feeding operations as a plant nutrient source on cropland may result in antimicrobial transport to surface and ground waters.

Saskatchewan producers traditionally overwinter their cattle in pens in the yard. The practice of winter feeding of cattle directly in the field is increasing in popularity leading to concerns about increased nutrients being deposited in soil and potentially lost in runoff water and to ground water. In 2008/2009 an experiment was conducted to observe the effect of in-field winter feeding of cows on the nutrients in spring snowmelt run-off. Approximately 100 cattle were baled grazed on a Russian wild ryegrass pasture at a stocking rate of 2240 cow-days ha-1 for 88 d during the winter at the Western Beef Development Center at Lanigan, SK. The spring 2009 ponded water was sampled from four basins in the control (no cattle were present) and four basins in the winter feeding treatment from the end of March to mid-April. Ground water samples from two piezometers in the control and two in the winter feeding area were gathered from the start of runoff until the middle of summer. Soil samples (0-10 cm) were collected in the fall 2008 before winter feeding and again in the spring 2009 after winter feeding on both the control and treated areas to examine the influence of winter feeding on soil nutrients. Orthophosphate-P and ammonium-N concentrations were elevated to levels up to 19.9 mg PO4-P L-1 and 102.3 mg NH4-N L-1 respectively in run-off from the winter feed treatment basins compared to the controls (2.1 mg PO4-P L-1 and 1.72 mg NH4-N L-1). Nitrate-N concentrations in snowmelt run-off water were similar from the winter-fed areas (0.008 mg NO3-N L-1 to 0.739 mg NO3-N L-1) and the control (0.001 mg NO3-N L-1 to 1.046 mg NO3-N L-1). This is explained by lack of sufficient time and temperature for organic N, urea and ammonium in the urine and fecal matter to convert to nitrate. In the ground water there was a slight increase in nutrient ion concentration in the winter feed basins compared to the control. Soil sampled in the spring from the winter feeding site had higher soluble nitrate, ammonium and phosphorus compared to the control. The soluble and exchangeable forms of phosphorus in the soil were lower compared to the fall soil samples for the control and winter feeding site, possibly due to immobilization by plant and microbial uptake in the spring. Caution should be used when selecting sites for in-field winter feeding system so the run-off water does not reach sensitive water bodies.

The presence of nutrients in snowmelt runoff from agricultural watersheds has been reported by previous studies. However, no study has answered the most important question what areas of the watershed contribute nutrients to snowmelt runoff? or addressed the factors that control snowmelt runoff water quality. This study was designed to (1) find the areas that contribute nutrient to snowmelt runoff (termed as critical source areas, CSA), and (2) understand the source and transport factors that control the snowmelt runoff water quality in the Canadian prairies. The findings of this study will provide vital information to understand snowmelt runoff water quality and for sustainable management of soil nutrients and snowmelt runoff water quality in the Canadian prairies. <p>Source and transport factors and snowmelt runoff water quality were studied for two years on shoulder, backslope and footslope landform segments. The distribution of fall soil nutrients in the top 5 cm soil layer (available soil P [ASP], nitrate [NO3-] and ammonium [NH4+]), snow depth, snow water equivalent (SWE), snowmelt runoff and snowmelt runoff water quality (total P [TP], total dissolved P [TDP], NO3-N and sediment) were studied using closed and open plots placed on each landform segment. The influence of source and transport factors was evaluated in relation to snowmelt runoff water quality. <p>The ASP had a distribution pattern of backslope < shoulder < footslope in 2003 before manure application (bma) and shoulder = backslope = footslope in 2004. The NO3- distributed as shoulder = backslope = footslope in 2003 (bma) and shoulder < backslope < footslope in 2004. However, NH4+ had a stable distribution of shoulder = backslope < footslope in 2003 bma and in 2004. The pre-melt SWE increased in the down slope direction having the lowest in the shoulder and backslope and the highest in the footslope in 2005. The average daily snowmelt runoff from 1 m2 plots did not vary between the shoulder and the backslope. Infiltration was dominant in 2004 while runoff was dominant in 2005. Of the three landform segments, the shoulder was the greatest contributor of runoff to the depression. The backslope contributed the least. <p>Hog manure injection did not seem to influence snowmelt runoff water quality. Most nutrients and sediments were from the land surface. Analysis revealed that fall soil nutrient concentrations were not a dominant factor controlling the nutrients in the snowmelt runoff in this site. However, snowmelt runoff volume controlled snowmelt runoff water quality. Snowmelt runoff water quality did not vary between the landform segments. However, as a result of the dominance of shoulder in this landscape, the total transport of nutrients and sediment was the highest from shoulder. Where landform characteristics are similar to the study watershed, it may be argued that all landform segments are CSA. Runoff volume is the most influential factor in determining the importance of CSA and controlling the snowmelt runoff water quality.

This study presents an unsteady-state hydraulic model analysis of hurricane storm surge and rainfall-runoff interactions in the Clear Creek Watershed, a basin draining into Galveston Bay and vulnerable to flooding from both intense local rainfalls and storm surge. Storm surge and rainfall-runoff have historically been modeled separately, and thus the linkage and interactions between the two during a hurricane are not completely understood. This study simulates the two processes simultaneously by using storm surge stage hydrographs as boundary conditions in the Hydrologic Engineering Center’s – River Analysis System (HEC-RAS) hydraulic model. Storm surge hydrographs for a severe hurricane were generated in the Advanced Circulation Model for Oceanic, Coastal, and Estuarine Waters (ADCIRC) model to predict the flooding that could be caused by a worst-case scenario. Using this scenario, zones have been identified to represent areas in the Clear Creek Watershed vulnerable to flooding from storm surge, rainfall, or both.

The presence of nutrients in snowmelt runoff from agricultural watersheds has been reported by previous studies. However, no study has answered the most important question what areas of the watershed contribute nutrients to snowmelt runoff? or addressed the factors that control snowmelt runoff water quality. This study was designed to (1) find the areas that contribute nutrient to snowmelt runoff (termed as critical source areas, CSA), and (2) understand the source and transport factors that control the snowmelt runoff water quality in the Canadian prairies. The findings of this study will provide vital information to understand snowmelt runoff water quality and for sustainable management of soil nutrients and snowmelt runoff water quality in the Canadian prairies. <p>Source and transport factors and snowmelt runoff water quality were studied for two years on shoulder, backslope and footslope landform segments. The distribution of fall soil nutrients in the top 5 cm soil layer (available soil P [ASP], nitrate [NO3-] and ammonium [NH4+]), snow depth, snow water equivalent (SWE), snowmelt runoff and snowmelt runoff water quality (total P [TP], total dissolved P [TDP], NO3-N and sediment) were studied using closed and open plots placed on each landform segment. The influence of source and transport factors was evaluated in relation to snowmelt runoff water quality. <p>The ASP had a distribution pattern of backslope < shoulder < footslope in 2003 before manure application (bma) and shoulder = backslope = footslope in 2004. The NO3- distributed as shoulder = backslope = footslope in 2003 (bma) and shoulder < backslope < footslope in 2004. However, NH4+ had a stable distribution of shoulder = backslope < footslope in 2003 bma and in 2004. The pre-melt SWE increased in the down slope direction having the lowest in the shoulder and backslope and the highest in the footslope in 2005. The average daily snowmelt runoff from 1 m2 plots did not vary between the shoulder and the backslope. Infiltration was dominant in 2004 while runoff was dominant in 2005. Of the three landform segments, the shoulder was the greatest contributor of runoff to the depression. The backslope contributed the least. <p>Hog manure injection did not seem to influence snowmelt runoff water quality. Most nutrients and sediments were from the land surface. Analysis revealed that fall soil nutrient concentrations were not a dominant factor controlling the nutrients in the snowmelt runoff in this site. However, snowmelt runoff volume controlled snowmelt runoff water quality. Snowmelt runoff water quality did not vary between the landform segments. However, as a result of the dominance of shoulder in this landscape, the total transport of nutrients and sediment was the highest from shoulder. Where landform characteristics are similar to the study watershed, it may be argued that all landform segments are CSA. Runoff volume is the most influential factor in determining the importance of CSA and controlling the snowmelt runoff water quality.

Antimicrobials administered to livestock can be excreted up to 80% in the feces and urine. Liquid swine manure from confined animal feeding operations is generally retained in lagoon storage until it is applied as a nutrient source to cropland. Thus, the applied manure becomes a possible source of antimicrobials to aquatic ecosystems. Veterinary antimicrobials have been detected in surface and ground waters in Canada, the United States and Europe, however, their environmental fate is not well known. Lincomycin and spectinomycin are two antimicrobials administered as a mixture to swine in the prairie region of Canada for the prevention of post-weaning diarrhea. In order to assess the potential for contamination of prairie wetlands, concentrations of both antimicrobials were monitored in the liquid manure from the nursery area of a commercial-scale barn during a 5-week study, and their persistence during simulated manure storage investigated. The potential for transport of lincomycin and spectinomycin to surface waters via surface runoff and to leach to groundwater was also assessed. This was achieved by monitoring manure-amended soil, simulated rainfall runoff, snow melt runoff and groundwater over a two-year period at two study sites in Saskatchewan, Canada following fall application of liquid swine manure from two commercial barns to crop and pasture land. Liquid chromatography coupled with tandem mass spectrometry was used to quantitate these antimicrobials in all matrix extracts. <p>In the nursery area of a commercial-scale barn, concentrations of lincomycin and spectinomycin in the cumulating liquid manure at the end of the study were equivalent to 32 and 3.0%, respectively, of doses administered in the feed. In a laboratory study, using fortified liquid manure, concentrations of both antimicrobials showed a rapid initial decrease during simulated lagoon storage, followed by a slower dissipation over a period of 5 months. The average time required for 50% dissipation of lincomycin was greater than one year (365 d) and was approximately 90 d for spectinomycin. <p>Lincomycin concentrations in soil (46.3 to 117 µg kg-1) collected immediately after fall manure application, decreased to non-detectable levels by mid-summer the following year. Lincomycin was present in simulated rainfall runoff (0.1 to 2.7 µg L-1) immediately after manure application with similar concentrations present in snow meltrunoff the following spring. Concentrations in groundwater were generally <0.005 µg L-1. Spectinomycin was not detected in the manure applied at the study sites nor in soil, runoff water or groundwater samples. This study confirms that some antimicrobials, including lincomycin, may be present in lagoon manure. Thus, the management practice of utilizing livestock manure from confined animal feeding operations as a plant nutrient source on cropland may result in antimicrobial transport to surface and ground waters.

Saskatchewan producers traditionally overwinter their cattle in pens in the yard. The practice of winter feeding of cattle directly in the field is increasing in popularity leading to concerns about increased nutrients being deposited in soil and potentially lost in runoff water and to ground water. In 2008/2009 an experiment was conducted to observe the effect of in-field winter feeding of cows on the nutrients in spring snowmelt run-off. Approximately 100 cattle were baled grazed on a Russian wild ryegrass pasture at a stocking rate of 2240 cow-days ha-1 for 88 d during the winter at the Western Beef Development Center at Lanigan, SK. The spring 2009 ponded water was sampled from four basins in the control (no cattle were present) and four basins in the winter feeding treatment from the end of March to mid-April. Ground water samples from two piezometers in the control and two in the winter feeding area were gathered from the start of runoff until the middle of summer. Soil samples (0-10 cm) were collected in the fall 2008 before winter feeding and again in the spring 2009 after winter feeding on both the control and treated areas to examine the influence of winter feeding on soil nutrients. Orthophosphate-P and ammonium-N concentrations were elevated to levels up to 19.9 mg PO4-P L-1 and 102.3 mg NH4-N L-1 respectively in run-off from the winter feed treatment basins compared to the controls (2.1 mg PO4-P L-1 and 1.72 mg NH4-N L-1). Nitrate-N concentrations in snowmelt run-off water were similar from the winter-fed areas (0.008 mg NO3-N L-1 to 0.739 mg NO3-N L-1) and the control (0.001 mg NO3-N L-1 to 1.046 mg NO3-N L-1). This is explained by lack of sufficient time and temperature for organic N, urea and ammonium in the urine and fecal matter to convert to nitrate. In the ground water there was a slight increase in nutrient ion concentration in the winter feed basins compared to the control. Soil sampled in the spring from the winter feeding site had higher soluble nitrate, ammonium and phosphorus compared to the control. The soluble and exchangeable forms of phosphorus in the soil were lower compared to the fall soil samples for the control and winter feeding site, possibly due to immobilization by plant and microbial uptake in the spring. Caution should be used when selecting sites for in-field winter feeding system so the run-off water does not reach sensitive water bodies.

Eight agricultural catchments in south Sweden were investigated for factors that may affect phosphorus (P) load and retention in the downstream situated wetlands (WL). P load is known to affect retention, and is determined by hydrological and geographical catchment characteristics. The wetlands were small (0.02-0.88%) in relation to their catchments (CA) and varied in design. Net sedimentation and P retention was determined with sedimentation plates during one year. The variables that best explained differences in particles and TP retention were the hydraulic load (q), TP load and the wetland length to width ratio. Contrary to expectations there was no correlation between factors that could be associated with erosion (i.e. slope and soil clay content) and retention of neither particles nor TP. Generally, the highest amounts of settled particles and P were found close to the wetland inlets, but soil disturbance (i.e. tillage) and high q increased the settling distance. It was likely that the smallest clay particles were too unaggregated to settle within these wetlands. Factors not included, such as wetland vegetation and bioturbation may have a large impact on P retention and this should be further investigated. The study also points to the difficulties in scaling down geological and P loss data from a regional to a local scale, as there can be large local deviations from the regional standard values. An easy method for identification of local “hotspots” for P losses should be of value for planning the location of future wetlands.

Runoff from road construction and maintenance sites is responsible for erosion and deposition of sediments in the receiving water bodies. In addition to soil particles from erosion, runoff also transports other pollutants such as rubber, toxic metals, automobile fluids, car exhausts (which settle with the rain), pesticides, fertilizers, and other debris. Compost has been used effectively as a valuable soil amendment to aid plant growth. Berms (mounds) of compost placed at the top or bottom of steep slopes can be used to slow the velocity of water and provide additional protection for receiving waters. However, a downside of the application of composted organic material is the potential degradation of runoff water quality. Overloading with nitrogen and phosphorus causes eutrophication, which reduces the suitability of waterways for beneficial uses. A field testing of the berms coupled with a laboratory analysis of the testing water will provide a basis for the impact of the compost berms on the runoff water quality. The study of the impact of compost on the runoff water quality was investigated. The objective of this study was to evaluate the performance of berms made from various materials such as dairy manure compost, yard waste compost and composted bio-solids mixed with wood chips in a ratio of 50:50 on the runoff water quality, as well as, the sediment removal efficiencies. Field tests were performed on the berms to simulate conventional rainfall runoff and the tested water was collected as time-weighted samples and analyzed in the laboratory. Several variables were investigated during this study. Results of this investigation demonstrated that the effectiveness of this application was hampered by the structural instability of the berm. A 100% failure rate was observed in the berms tested. Optimum performance was observed in yard waste compost berms, which introduced the least amount of contaminants into the water. However, some masking effect could be present due to berm failures. In fact, the actual sediment removal by the berms could not be determined. The study of compost filter berms showed some evidence of the existence of first flush effect.