The objective of this study was to determine the impacts of irrigation tailwater and sewage lagoon discharge on the water quality of Crowfoot Creek, Alberta, Canada. The monitored irrigation tailwater accounted for more than 55% of the water flow in the basin. With the exception of the early part of the 1997 irrigation season the irrigation tailwater only impacted the phosphate and total phosphorus levels in the creek. High values for all parameters were recorded in the early part of the 1997 irrigation season, due to irrigation source water quality or deposition of contaminants into the irrigation canals during the 1997 spring runoff. The impact of the sewage lagoon effluent on the water quality of the creek was minimal to insignificant. The primary sources of contamination in the watershed are thought to be direct cattle access to the creek, soil erosion and surface runoff.

Agricultural management practices geared towards reducing nutrient leaching are in focus for the research presented in this thesis. Critical measures for reducing diffuse pollution from the agricultural sector depend on decisions of individual farmers. It is useful to take stock of what different stakeholders are actually doing to reduce nutrient leaching and analyze their reasoning before defining a new administrative process. Stakeholder perceptions about potentials and problems concerning management of agricultural practices are analyzed with a systems approach using various analytical methods, and put in relation to the implementation of EC Water Framework Directive in Sweden. The methods used include surveys, focus group interviews, model comparison, sensitivity analyses and analyses of climate change implications. The results indicate a general positive attitude among stakeholders towards the main characteristics of the newly introduced directive. They also reveal that a move towards a pro-active process was perceived as an additional positive factor for the improvement of water quality, where specific activities and measures are carried out according to planning based on local assessments. The respondents pointed out that a national approach would put necessary pressure on local politicians to define environmental objectives and provide resources to fulfil them. The current findings indicate that decision making for farmers is a complex procedure and that the different factors need to be addressed in order to obtain a change in agricultural practices. Consistent legislation that is clear about power and rights is fundamental for cooperation to function when volunteerism and enthusiasm are absent. Environmental and socio-economic conditions change constantly, and administration has to be flexible to be able to adapt. Having access to and being able to use relevant data is only one important factor for stakeholder involvement. To give farmers the opportunity to further develop production towards reduced nutrient losses, appropriate information provided in all the right arenas is crucial.

Thesis (M.S.)--Oregon State University, 2011. / Printout. Includes bibliographical references (leaves 69-74). Also available on the World Wide Web.

Urban expansion of the City of Vancouver has resulted in increased land development of the municipality of Surrey, and more intensive agriculture on the remaining farmland. From 1980 to 1984 five different fish kills in the Serpentine River attributed to low dissolved oxygen were thought to be caused by a combination of agricultural discharges, high autumn water temperatures, as well as rainfall and river flow patterns. In 1985 an experimental instream aeration system was installed in a lower reach of the river in an attempt to provide additional oxygen during the critical autumn period. This study was undertaken to determine the extent of the agricultural drainage discharge problem. Weekly sampling from July to December, 1987, revealed that organic pollutional loading from dairy farms was high. Nutrients loadings in the river supported a heavy algal growth which resulted in an oxygen deficit during autumn algal die-off and decay. Although the flushing of farm ditches normally exerts an additional oxygen demand on the river, this was not observed in 1987 because the major autumn rains began on Oct 30, and lower water temperatures prevented a rapid exertion of the biodegradable oxygen demand. Implementation of source control of farm animal wastes is strongly recommended, along with a program of public education on conservation and management of natural habitat. Harvesting of filamentous algae in the river may eventually prove necessary for successful rehabilitation as diffused river aeration appears to be having a very small effect. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

The objectives of the study were to investigate the sorption and degradation of a glucuronide conjugated natural hormone, 17β-estradio1-3-glucuronide (E2-3G), and its estrogenic metabolites in soil-water systems. Radiolabeled E2-3G was first synthesized in the laboratory. Soil-water batch experiments were then conducted using natural and sterilized topsoil (0-6 cm) and subsoil (18-24 cm) with the radiolabeled E2-3G to investigate the effects of soil organic matter content and microbial activity. The aqueous dissipation of 14C in the batch experiments followed a biphasic pattern with an initial rapid dissipation phase followed by a second slower phase. Significant differences in total aqueous 14C dissipation were observed for the different initial concentrations for both soils, with greater persistence of intact E2-3G at higher initial concentrations. / National Science Foundation [Grant No. 0730492]

No description available.

Thesis (MSc)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: Runoff is generally regarded as one of the most important routes of nonpoint source pesticide pollution in agricultural surface waters. Of major concern is the fact that low, sub-lethal levels of pesticide exposure are responsible for negative ecotoxicological effects, stressing the need for methods capable of identifying problem areas where populations could be at risk. Predicted average losses of three pesticides in tributaries of nine sub-catchments of the Lourens River were calculated through use of a GIS-based runoff model. There was a significant (p < 0.005) positive correlation between the predicted average loss and mean measured concentrations of the insecticides both in water and suspended sediments (R2 between 0.75 and 0.9), indicating that the model could serve as a powerful tool for the risk assessment and management of surface waters in South African orchard areas. Based on field relevant exposure scenanos, the potential effects of azinphos-methyl on macroinvertebrate communities were evaluated in a combined microcosm and field approach. Microcosms were contaminated for 1 h with AZP (control, 0.2; 1,5and 20 ug/L; three replicates each) and acute effects on survival were evaluated 6 days after exposure. The sensitivity or tolerance of 12 core taxa was determined based on their response to the exposure scenarios and compared to field tolerance/sensitivity as was established by a field investigation at a control and contaminated site of the Lourens River. The sensitivity/tolerance of ten of the 12 taxa corresponded to that which was found in the field. Thus microcosm studies employing a field relevant design can be successfully linked to field studies and indicate that transient pesticide contamination affects the aquatic communities of the Lourens River. / AFRIKAANSE OPSOMMING Afloop word oor die algemeen beskou as een van die belangrikste roetes van niepuntbron pestisiedbesoedeling in landbou oppervlakwaters. Die feit dat lae, sub-letale vlakke van pestisiedblootstelling negatiewe ektoksikologiese gevolge kan hê, is van groot belang. Dit beklemtoon die behoefte aan metodes om probleemgebiede te kan identifiseer waar bevolkings aan risiko onderhewig is. 'n GIS-gebaseerde afloopmodel is gebruik om die gemidddelde verlies van drie pestisiede in die sytakke van nege sub-opvangsgebiede van die Lourensrivier te voorspel. Daar was 'n beduidende (p < 0.005) positiewe korrelasie tussen die voorspelde gemiddelde verlies en gemete konsentrasies van insektisiede in beide die water en sediment (R2 between 0.75 and 0.9) fases, wat aandui dat die model as 'n kragtige hulpmiddel vir risikobestuur van oppervlakwaters in Suid Afrikaanse boord-gebiede kan dien. Die potensiële gevolge van azinfos-rnetiel (AZP) op makroinvertebraat gemeenskappe is deur middel van 'n gekombineerde mikrokosmos (wat op veldrelevante blootstellings gebaseer is) en veldbenadering bepaal. Mikrokosmosse is vir 1 h met AZP gekontamineer (kontrole; 1; 0.2; 1; 5 en 20 ~g1L; drie replikate elk), en die akute gevolge op oorlewing is ge-evalueer na ses dae van blootstelling. Die sensitiwiteit of toleransie van 12 sleutel taksa is deur middel van hulle respons op die blootstellingsreeks bepaal, en met hulle veldtoleransie/sensitiwiteit vergelyk wat in 'n veldstudie by 'n kontrole- en gekontamineerde gebied in die Lourensrivier bepaal is. Die sensitiwiteit/toleransie van 10 van die 12 taksa in die mikrokosmos eksperimente het ooreengestem met die wat in die veld gevind is. Mikrokosmosstudies wat op 'n veldrelevante ontwerp gebaseer is, kan dus suksesvol aan veldstudies gekoppel word, en dui aan dat oorgedraagde pestisiedkontaminasie die akwatiese gemeenskap van die Lourensrivier beinvloed.

Phosphorous concentrations exceed water quality guidelines in most of the major rivers in southern Quebec. The problem is particularly acute in the Pike River, which drains into the Missisquoi Bay of Lake Champlain, in southeastern Quebec. Elevated phosphorus concentrations can lead to a reduction in the palatability of drinking water, a decrease in diversity of aquatic life and loss of recreational opportunities. All of these problems have been observed in the Bay. / Two agricultural fields (the Marchand and Gagnon sites) located on the Pike River watershed, in southeastern Quebec were selected and equipped with instrumentation to measure and evaluate the partitioning of phosphorus between surface runoff and subsurface drainage, on a year round basis. The snowmelt event was the dominant surface and subsurface event for the 2000/2001 hydrological year. On the Marchand site surface flow data was incomplete as a result of a failure of the surface runoff flume. On both sites the IF 200 subsurface flow meters failed, which resulted in missing subsurface flow data during certain runoff events. Therefore, the majority of the comparisons made relate to the Gagnon site. / The 2000/2001 hydrological year was unusually dry, which resulted in a limited number of surface and subsurface runoff events. The annual depth of surface runoff for the Gagnon site was 87.5 mm/ha, of which only 0.2mm occurred outside the snowmelt event. The estimated depth of subsurface runoff of the snowmelt event at the Gagnon site based upon a water balance equation was 93.7 mm/ha, or 51.7% of the total volume that occurred on the Gagnon field during the snowmelt event. / The total phosphorus load in surface runoff for the spring snowmelt at the Gagnon site was 166.4 g/ha, whereas the estimated total phosphorus load in subsurface drainage was 98.2 g/ha, or 37.1% of the total load. Subsurface drains can therefore be a significant pathway for phosphorus losses.

The research was undertaken to simulate the surface transport of water and chemicals from a flat agricultural watershed at the Green Belt farm in Ottawa, Ontario, Canada. The GIS database created for the Black Rapid Creek watershed focused on attributes and data necessary to run a non-point source model for surface transport of water and chemicals called AGNPS. The GIS used in the current study was SPANS for the OS/2 warp (version 3) environment. The years of simulation for the study area were 1992 and 1993. The study was carried out on a watershed scale and flow routing from different cells to the outlet of the watershed was simulated with AGNPS under different management practices. The results of the study indicate that input variables of AGNPS model for a flat agricultural watershed, flow direction, precipitation event and topography of the land, affect the surface runoff volume at the outlet considerably. (Abstract shortened by UMI.)

The U.S. government implemented many incentive programs in the 1980s to encourage farmers to reduce agricultural runoff and erosion through the use of best management practices (BMPs). Remote sensing, GIS, and modeling, have been used to determine the effectiveness of BMPs through comparisons of before and after BMP implementation. The Salamonie watershed in Northeastern Indiana was studied for BMP effectiveness. The study addresses how agricultural practices have changed over a twenty nine year period (1975-2003), and how the implementation of BMPs will decrease the amount of sediment and nutrient load to surface waters. Methods reported on include the use of the Soil and Water Assessment Tool (SWAT) watershed model and how different weather data (precipitation and temperature) greatly affects streamflow predictions, as well as the effects of BMP implementation on sediment loads to surface water. The outcomes of this study provide a viable argument of how BMPs implementation positively affects water quality in the watershed region by effectively reducing sediment loads. / Department of Geography