Suchergebnisse

Abstract Agriculture is the main source of nitrogen (N) and phosphorus (P), which are the nutrients accelerating the eutrophication of waters in Finland. Hence, mitigation measures are needed to reduce the nutrient loading from the arable land. Since Finland's accession to the EU in 1995 and the subsequent adaptation to its agri-environmental policy, constructed wetlands (CWs) have been one of the mitigation measures for which farmers may receive agri-environmental subsidies. The aim of this study was to find out how efficiently such CWs are able to retain the loading and how they should be designed and dimensioned in order to optimize their performance. Particular attention was paid to CW hydrology and hydraulics, since the dynamics of the water flowing through a CW is the major factor governing retention. Water quality and flow measurements were made in three CWs located in agricultural watersheds in southern Finland during 1999-2002. Hydraulic properties were examined in 2 of the CWs by simulations with 2-dimensional hydrodynamic and water quality models. According to the calculations of material fluxes, the maximum annual retention was 72% for solid material (TSS), 67% for total P and 40% for total N. The lowest retentions were slightly negative, because the CW with the smallest CW-to-watershed area ratio (0.5% in the Alastaro CW) sometimes acted rather as a source than a sink of nutrients. The highest percent retentions were found in the Hovi CW with the largest CW-to-watershed area ratio (5%). In terms of mass per CW area, the Hovi CW retained 25 kg of total P and 300 kg of total N per one hectare per one year. In the Hovi CW also dissolved reactive P retention was high (49% in situ and 34% in laboratory microcosm experiments), obviously due to high contents and low P saturation of Al and Fe oxides of the CW soil. The basic underlying reason behind the high retentions of both dissolved nutrients and particulate matter in the Hovi CW was the long water residence time coupled with high hydraulic efficiency. In the deep part of the Hovi CW, near-bottom increase of dissolved O2 was found in phase with diurnal temperature changes. The oxygen transport by this kind of convective circulation of CW water inhibited near-bottom anoxia and thus decreased the risk of P desorption. According to the hydrodynamic simulations coupled with simulated tracer tests made for the Hovi CW, a 40% improvement in hydraulic efficiency was achieved by baffles directing the main flow to optimally exploit the CW area. The rectangular, elongated shape of the Alastaro CW also showed fairly high hydraulic efficiency. Hydrodynamic simulations were also coupled with a sediment transport model, which proved to be a useful method in predicting the change of TSS concentrations in CWs. Hourly datasets of inflow and outflow revealed high attenuation of runoff peaks in the well-designed and -dimensioned Hovi CW. The hourly outflow modeled with the reservoir routing method corresponded to the observed with a reasonable accuracy. When carefully designed, painstakingly implemented and wisely located, CWs may – even in cold climate – efficiently contribute to agricultural water pollution control.

Man's activities on the environment often results in pollution and degradation of water bodies. Water bodies must therefore be jealously guided and protected from being polluted, which will affect water quality and availability for desired usage. Causes of water quality impairment are urban and rural storm water runoff, inadequate waste water treatment, nutrient entrophication, atmospheric deposition and acid rain, pollutant in sediments and fish, and nuisance aquatic weed growth and invasive species. Other factors include unhygienic disposal and inadequate treatment of human and livestock wastes, indecent management and treatment of industrial residues, inappropriate agricultural practices and unsafe solid waste discharge. Suggested strategies to combat water quality problems which should form the basis of policy solution for improving water quality include: (i) prevention of pollution; (ii) treatment of polluted water; (iii) safe use of waste water; and (iv) restoration and protection of ecosystem. It is recommended that our water bodies and the environment in general should be protected through appropriate legislation guidelines and public literacy campaign and mass education to sensitize, educate and make the people a fully environmentally literate society. Taking these steps internationally, nationally and locally will mean better water quality for our present society and future generation. DOI:10.5901/ajis.2013.v2n7p69

The land development and increase in urbanization in a watershed affect water quantity and water quality. On one hand, urbanization provokes the adjustment of geomorphic structure of the streams, ultimately raises peak flow rate which causes flood; on the other hand, it diminishes water quality which results in an increase in Total Suspended Solid (TSS). Consequently, sediment accumulation in downstream of urban areas is observed which is not preferred for longer life of dams. In order to overcome the sediment accumulation problem in dams, the amount of TSS in streams and in watersheds should be taken under control. Low Impact Development (LID) is a Best Management Practice (BMP) which may be used for this purpose. It is a land planning and engineering design method which is applied in managing storm water runoff in order to reduce flooding as well as simultaneously improve water quality. LID includes techniques to predict suspended solid loads in surface runoff generated over impervious urban surfaces. In this study, the impact of LID-BMPs on surface runoff and TSS is investigated by employing a calibrated hydrodynamic model for Sazlıdere Watershed which is located in Istanbul, Turkey. For this purpose, a calibrated hydrodynamic model was developed by using Environmental Protection Agency Storm Water Management Model (EPA SWMM). For model calibration and validation, we set up a rain gauge and a flow meter into the field and obtain rainfall and flow rate data. And then, we select several LID types such as retention basins, vegetative swales and permeable pavement and we obtain their influence on peak flow rate and pollutant buildup and washoff for TSS. Consequently, we observe the possible effects of LID on surface runoff and TSS in Sazlıdere Watershed.

AbstractDuring the last decades, a major factor that analysts and policy makers take into account in the assessment of the environment is climate change. This global physical process is expected to cause problems in natural and human environment. Thus, modelling climate change impacts may lead to prevention policies to minimize the degradation of life quality because of lack of water resources in the future. This study implicates Geographical Information System (GIS) and hydrological modelling tools to various scenarios of climate change such as the increase of temperature the decrease of rainfall, or even both of them, to estimate the potential impact of climate change on surface runoff in a typical catchment in Andros Island, Greece. Primary results indicate a proportional runoff decrease in the next 50 years because of global climate changes.

The aim of this thesis is to discuss environmental impacts on river quality. Pollutants from point sources including municipal and industrial sources and from nonpoint sources involving agriculture, urban runoff , mining, silviculture, construction, hydrographic modification and natural sources such as flood can usually cause adverse effects on the environment. These pollutants can be controlled by means of technology and legislation. Wastewater treatment plants can treat wastewater from point sources. Control methods f o r nonpoint source pollution are mainly based on legislation and education. It is more difficult to control the pollution from nonpoint sources than from point sources. The effectiveness of any water quality management plan may be measured in terms of how well the plan accomplishes water quality goals. These goals are usually expressed in the form of wastewater effluent standards or the receiving water quality standards. Water quality models can assist planners in identifying and evaluating possible management programs and in determining which of these best meet the required water quality standards. However, these models should design for both now and future use. The control of technological abuse of the environment, and hence land and river systems, is vital. Aspects of overuse of land f or agriculture, due to population pressures must also be considered.

AbstractSediment deposition and intensified eutrophication of the Miyun Reservoir are directly affecting the water quality in Beijing, China, owing to water pollution issues in the Chaohe River Basin, which contains the main inflow river of the reservoir. This study analysed the runoff, sediment, total nitrogen and total phosphorus load simulation results from three observation stations using the Hydrological Simulation Program–FORTRAN model (Nash efficiency coefficient [NSE] = 0.65–0.8, R2 = 0.62–0.92) and a statistical regression model (R2 = 0.55–0.79). Results indicate that applying these models in combination to basins from which pollution source data are difficult to obtain can fully utilize the advantages of both models. The parameter uncertainty analysis of the model's runoff and pollution‐related parameters is discussed from the basis of the generalized likelihood uncertainty estimation analysis method. Further, using the Mann–Kendall test and the double cumulative curve method, an attribute analysis of climate change and human activities in the basin was carried out. Results show that in the context of global climate change, fundamental ways to achieve the goal of adaptive catchment management include adjusting the land use structure, optimizing the land use mode and carrying out comprehensive management of soil and water loss with vegetation restoration as the main body.

Water protection has long been a cornerstone of EU environmental policy. It is the sector with the most comprehensive coverage in EU environmental regulations (Kallis & Butler 2001). In some European countries such as the Netherlands, France, Sweden and Italy, national and local governments have implemented substantial programmes aimed at combating excessive nutrient loss to watercourses from agricultural, silvicultural and waste treatment activities. It is generally accepted that agricultural operations contribute, in a significant manner, to increased nitrogen and phosphorous loss to water catchments and result in environmentally unacceptable occurrences such as eutrophication and algal blooms. The increase in N and P loading may be dealt with in a number of ways, including a reduction of input or better fertiliser management. However there remains two problems. One is the perseverance of high fertility in the catchment long after regulation or cessation of input and the other is the potential for lower yields as a result of policy change. Water catchment nutrient management is poorly developed in Ireland and runoff nutrient entering watercourses is increasing (Tunney et al 2001). This has a serious and detrimental effect on water quality as well as ecological processes. It has been demonstrated that many trees have the ability to intercept and absorb large volumes of nutrients (Hefting & de Klein 1998). Buffer plantations of, often, willow (Salix spp.) and other species may be established in order to effectively and efficiently intercept surface runoff of nitrate (N) and phosphate (P). In addition, such buffer plantations could themselves produce an annual crop requiring little management and low-priced technology to harvest. Yet, the science behind the application has not been established in Ireland. Hefting, M.M. & de Klein, J.J.M, (1998) Nitrogen removal in buffer strips along a lowland stream in the Netherlands: a pilot study. Environmental Pollution, 102, 521 – 26. Kallis, G. & Butler, D. ...

A variety of good management practices have been recommended to minimize the impact of water runoff from production nurseries. However, studies have not been conducted to gauge which management practices nursery producers are most likely to adopt in response to education and increased government oversight. We surveyed 85 production nurseries in Southern California about their existing practices to limit the impacts of runoff from their facilities. Of these, 65 in Ventura County were resurveyed with the same questionnaire within 2 years. The positive response rate for following good management practices was 65%, compared to 57% in the initial survey. There were significant increases in every category of practices surveyed, and significant changes in the adoption of 38 specific practices. This suggests that nurseries are amenable to adopting management practices within a short time span in areas where there is increased governmental oversight and educational opportunities for growers.

A variety of good management practices have been recommended to minimize the impact of water runoff from production nurseries. However, studies have not been conducted to gauge which management practices nursery producers are most likely to adopt in response to education and increased government oversight. We surveyed 85 production nurseries in Southern California about their existing practices to limit the impacts of runoff from their facilities. Of these, 65 in Ventura County were resurveyed with the same questionnaire within 2 years. The positive response rate for following good management practices was 65%, compared to 57% in the initial survey. There were significant increases in every category of practices surveyed, and significant changes in the adoption of 38 specific practices. This suggests that nurseries are amenable to adopting management practices within a short time span in areas where there is increased governmental oversight and educational opportunities for growers.

Government agencies responsible for monitoring the health of U.S. waterways report that nonpoint-source pollution from agricultural nutrient runoff is one of America's greatest water-quality threats. Federal agencies and states have partnered to develop nutrient-management policies and programs to reduce farm runoff. These efforts are complicated by the fact that policy decisions are made in an environment with limited resources, imperfect scientific knowledge, and diverse interests and understandings. This increases the likelihood that participants in the policy-making process will have different understandings of environmental problems and preferences for addressing them. Thus, there is a critical need for cooperation and collaboration in creating and implementing nutrient-management policies. In particular, it is important for policy makers to work collaboratively with farmers because nutrient-management policy goals cannot be achieved without their support for and full participation in policy programs. I contend that the success of nutrient-management policy efforts can be enhanced by greater knowledge of the cultural models that shape farmers' management beliefs and practices and inform their understandings of themselves and their relationship to the world. By situating policy efforts and proposals within the context of farmers' compelling cultural models, policy makers are more likely to create nutrient-management policy that farmers are willing to support and adopt. This in turn increases the likelihood that environmental goals will be achieved. A key element of this strategy is to successfully link policy ideas and practices with farmers' shared "goal-schemas" and leverage the motivational force associated with them to gain their support. To explore my contention that farmer cultural models play a central role in informing and directing their farm-management decisions, and that knowledge of these models can serve a valuable function in helping policy makers create more effective nutrient-management ...

AbstractThe eighteenth report of the Royal Commission on Environmental Pollution made no reference to any potential environmental impacts resulting from runoff pollution associated with transport activities. This paper identifies the magnitude and extent of pollution associated with discharges from various transport sources and identifies solids, metals, hydrocarbons, herbicides and de‐icing agents as the principal contaminants of environmental concern. The impacts of these pollutants on the receiving water are reviewed. They are primarily associated with highways which have a high traffic density, and herbicides are considered to be the only potential and widespread hazard to groundwaters. Highway and airport runoff are shown to have both acute and chronic effects on biotic diversity and organism mortality rates, although these effects appear to be largely confined to reaches immediately downstream from the discharge outfalls.

Nine runoff containment basins (RCBs), used directly or indirectly for irrigating plants in ornamental plant nurseries, and one adjacent stream were sampled for water quality between Feb. and July 2013 in Maryland (MD), Mississippi (MS), and Virginia (VA). Triplicate water samples were taken monthly. Analysis was done for 18 water quality variables including nitrate-nitrogen (NO3- L-N) and ammonium-nitrogen (NH4+-N), orthophosphate-phosphorus (PO4-P) and total-phosphorus (T-P), potassium, calcium, magnesium, sulfur, aluminum, boron (B), copper (Cu), iron (Fe), manganese, zinc (Zn), pH, total alkalinity (T-Alk), electrical conductivity (EC), and sodium. Additionally, 15 RCBs from 10 nurseries in Alabama (AL), Louisiana (LA), and MS were sampled in 2014 and 2016. Most prevalent correlations (P = 0.01) were between macronutrients, EC, B, Fe, and Zn, but none were prevalent across a majority of RCBs. Water quality parameter values were mostly present at low to preferred levels in all 25 waterways. Macronutrient levels were highest for a RCB that receives fertility from fertigation derived runoff. Water pH ranged from acidic to alkaline (> 8). Results of this study show water quality in RCBs can be suitable for promoting plant health in ornamental plant nurseries, but also shows levels will vary between individual RCBs, therefore demonstrates need to verify water quality from individual water sources. ; USDA National Institute of Food and Agriculture Specialty Crop Research Initiative [2010-51181-21140]; U.S. Department of Agriculture, Agricultural Research Service, Thad Cochran Southern Horticultural Laboratory, Southern Horticultural Research Unit [6404-21430-001-00D]; Virginia Agricultural Experiment Station ; This research was supported in part by the USDA National Institute of Food and Agriculture Specialty Crop Research Initiative (agreement number 2010-51181-21140); the U.S. Department of Agriculture, Agricultural Research Service, Thad Cochran Southern Horticultural Laboratory, Southern Horticultural Research Unit project number 6404-21430-001-00D; and Virginia Agricultural Experiment Station. ; Public domain authored by a U.S. government employee