187 resultados para River water

em Aquatic Commons


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The objective of this short project progress report is to investigate the possible water quality implications of modern watercress growing practices. Chalk receiving watercourses are usually of high supply, amenity, game fishing and fish farming value. Any headwater pollution load, therefore, needs characterising and quantifying. Two sites of watercress farming were studied in 1986-87 and nutrient levels examined. Different approaches of watercress farmers in Dorset and Hampshire are summarised.

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Using water quality management programs is a necessary and inevitable way for preservation and sustainable use of water resources. One of the important issues in determining the quality of water in rivers is designing effective quality control networks, so that the measured quality variables in these stations are, as far as possible, indicative of overall changes in water quality. One of the methods to achieve this goal is increasing the number of quality monitoring stations and sampling instances. Since this will dramatically increase the annual cost of monitoring, deciding on which stations and parameters are the most important ones, along with increasing the instances of sampling, in a way that shows maximum change in the system under study can affect the future decision-making processes for optimizing the efficacy of extant monitoring network, removing or adding new stations or parameters and decreasing or increasing sampling instances. This end, the efficiency of multivariate statistical procedures was studied in this thesis. Multivariate statistical procedure, with regard to its features, can be used as a practical and useful method in recognizing and analyzing rivers’ pollution and consequently in understanding, reasoning, controlling, and correct decision-making in water quality management. This research was carried out using multivariate statistical techniques for analyzing the quality of water and monitoring the variables affecting its quality in Gharasou river, in Ardabil province in northwest of Iran. During a year, 28 physical and chemical parameters were sampled in 11 stations. The results of these measurements were analyzed by multivariate procedures such as: Cluster Analysis (CA), Principal Component Analysis (PCA), Factor Analysis (FA), and Discriminant Analysis (DA). Based on the findings from cluster analysis, principal component analysis, and factor analysis the stations were divided into three groups of highly polluted (HP), moderately polluted (MP), and less polluted (LP) stations Thus, this study illustrates the usefulness of multivariate statistical techniques for analysis and interpretation of complex data sets, and in water quality assessment, identification of pollution sources/factors and understanding spatial variations in water quality for effective river water quality management. This study also shows the effectiveness of these techniques for getting better information about the water quality and design of monitoring network for effective management of water resources. Therefore, based on the results, Gharasou river water quality monitoring program was developed and presented.

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The aim of this paper is to explore the potential role that quality objectives, particularly when backed by statutory force, may play in the sustainable management of river water quality. Economic valuation techniques are discussed, as well as the theory of "critical natural capital". A brief history of water quality legislation includes the implementation of the National Water Council classification in 1979, and the statutory water quality objectives introduced under the Water Resources Act 1991.

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Because of the widespread concern over increasing nitrate concentrations in river water , the Freshwater Biological Association has undertaken a study to investigate seasonality, nitrate concentrations and loads in the River Frome catchment in relation to land use and compare the results for 1984/86 with data obtained in 1970/71. Information on land use changes and fertiliser applications were obtained both from MAFF and individual farmers. The study concludes that input of nitrogen from rainfall to the River Frome catchment had not significantly changed between 1970/71 and 1984/86.

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This is the Review of discharge consents, River Irwell catchment report produced by the North West Water Authority (NWWA) in 1979. The purpose of this Report is to make recommendations for the revision of consents for discharges within the catchment of the River Irwell, downstream and including the River Medlock in Manchester. This revision has the sole objective of recognising the present effluent and river water quality - proposals for long term river water quality objectives are to be put forward in other Reports. The report identifies the existing situation regarding the legal status of effluent discharges from Authority and non-Authority owned installations within the catchment, details the determinant concentration limits included in existing discharge consents (where appropriate) and proposes the limits to be included in the reviewed consents. The reviewed consents will reflect the quality of effluent achievable by good operation of the existing plant based on 1977 effluent quality data but taking into account any improvements, extensions etc. that have been or are about to be carried out and any known further industrial and/or housing development in the works drainage area.

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This study assessed the physico-chemical quality of River Ogun, Abeokuta, Ogun state, Southwestern Nigeria. Four locations were chosen spatially along the water course to reflect a consideration of all possible human activities that are capable of changing the quality of river water. The water samples were collected monthly for seven consecutive months (December 2011 – June 2012) at the four sampling stations. pH, air temperature (℃), water temperature (℃), conductivity (µs/cm) and total dissolved solids (mg/L) were conducted in-situ with the use of HANNA Combo pH and EC multi meter Hi 98129 and Mercury-in-glass thermometer while dissolved oxygen (mg/L), nitrate (mg/L), phosphate (mg/L), alkalinity (mg/L) and hardness (mg/L) were determined ex-situ using standard methods. Results showed that dissolved oxygen, hydrogen ion concentration, total hardness and nitrate were above the maximum permissible limit of National Administration for Food, Drugs and Control (NAFDAC), Standard Organization of Nigeria (SON), Federal Environmental Protection Agency (FEPA), United States Environmental Protection Agency (USEPA), European Union (EU) and World Health Organization (WHO) for drinking water during certain months of the study period. Results also showed that water temperature and conductivity were within the permissible limits of all the standards excluding FEPA. However, total dissolved solids and alkalinity were within the permissible limits of all the standards. Adejuwon and Adelakun, (2012) also reported similar findings on Rivers Lala, Yobo and Agodo in Ewekoro local government area of Ogun state, Nigeria. Since most of the parameters measured were above the maximum permissible limits of the national and international standards, it can be concluded that the water is unfit for domestic uses, drinking and aquacultural purposes and therefore needs to be treated if it is to be used at all. The low dissolved oxygen values for the first four months was too low i.e. < 5 mg/L. This is most likely as a result of the amount of effluents discharged into the river. To prevent mass extinction of aquatic organisms due to anoxic conditions, proper regulations should be implemented to reduce the organic load the river receives.

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A study was conducted to investigate the survival of five Pseudomonas strains resistant to antibiotics in different types of water. The selected Pseudomonas strains were designated as strain P1 (CT-29), strain P2 (CT-25), strain P3 (CT-36), strain P4 (CT-20) and strain P5 (CT-27) which were only recovered from farmed fishes. Six types of water viz., distilled water, saline water, tap water, deionized water, pond water and river water were used. Among these experimental waters, river water was found to be the most suitable for long-term survival of these strains. Deionized water did not support survival of all these Pseudomonas strains. Pond water, tap water and distilled water were moderately suitable for strain P1 and strain P4. Saline water was also found to be highly suitable for long-term survival in case of the strain P3 and moderately suitable for normal survival of strain P2 and strain P5.

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In this paper, some results of analyzing the hydrographic characteristics of the seawater temperature and salinity are presented. The received results showed that: in dry season, the influence of the Cai river water has is limited in Cai river estuary with the approximate transferable distance from the river mouth to the open sea of about 1 km. The isohaline 32%o could be defined as the separate boundary of the Cai river water; In rainy season, due to the river water discharges are high, the influence of Cai river water could be transferred to the open sea and island areas. The immerge of the Cai river water in the open sea areas in rainy season has changed the vertical structure of salinity and temperature in the northern part of Nhatrang bay. In both seasons, the Cai river water have influenced in the surface water layers 0 - 2m and the water layers deeper than 2m are influenced by the sea waters with the salinity of higher than 32%o.

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Executive Summary: Circulation and Exchange of Florida Bay and South Florida Coastal Waters The coastal ecosystem of South Florida is comprised of distinct marine environments. Circulation of surface waters and exchange processes, which respond to both local and regional forcings, interconnect different coastal environments. In addition, re-circulating current systems within the South Florida coastal ecosystem such as the Tortugas Gyre contribute to retention of locally spawned larvae. Variability in salinity, chlorophyll, and light transmittance occurs on a wide range of temporal and spatial scales, in response to both natural forcing, such as seasonal precipitation and evaporation and interannual “El Niño” climate signals, and anthropogenic forcing, such as water management practices in south Florida. The full time series of surface property maps are posted at www.aoml.noaa.gov/sfp. Regional surface circulation patterns, shown by satellite-tracked surface drifters, respond to large-scale forcing such as wind variability and sea level slopes. Recent patterns include slow flow from near the mouth of the Shark River to the Lower Keys, rapid flow from the Tortugas to the shelf of the Carolinas, and flow from the Tortugas around the Tortugas Gyre and out of the Florida Straits. The Southwest Florida Shelf and the Atlantic side of the Florida Keys coastal zone are directly connected by passages between the islands of the Middle and Lower Keys. Movement of water between these regions depends on a combination of local wind-forced currents and gravitydriven transports through the passages, produced by cross-Key sea level differences on time scales of several days to weeks, which arise because of differences in physical characteristics (shape, orientation, and depth) of the shelf on either side of the Keys. A southeastward mean flow transports water from western Florida Bay, which undergoes large variations in water quality, to the reef tract. Adequate sampling of oceanographic events requires both the capability of near real-time recognition of these events, and the flexibility to rapidly stage targeted field sampling. Capacity to respond to events is increasing, as demonstrated by investigations of the 2002 “blackwater” event and a 2003 entrainment of Mississippi River water to the Tortugas. (PDF contains 364 pages.)

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RIVPACS has been used successfully for biological assessment of river water quality but its potential in forecasting the effects of environmental change has not been investigated. This study has shown that it is possible to simulate faunal changes in response to environmental disturbance, provided that the disturbance directly involves the environmental variables used in RIVPACS predictions. These variables relate to channel shape, discharge and substratum. Many impacts, particularly those associated with pollution, will not affect these variables and therefore RIVPACS cannot simulate the effects of pollution. RIVPACS was sensitive only to major changes in substratum. It was concluded that, because of the static nature of RIVPACS, it cannot respond to the dynamic effects and processes associated with environmental disturbance. Thus RIVPACS, while showing direction of change and indicating sensitive taxa, cannot be used to predict or forecast the effects of environmental impacts.

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This is the report from the Regional Fisheries Advisory Committee meeting, which was held on the 15th February 1979. The report contains the minutes of the last meetings of the Local Fisheries Advisory Committees, information on the long term objectives for inland river water quality, and income and expenditure. The report also includes information on the redeployment of honorary bailiffs, and a private fish farm on the River Wyre. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

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This is the report from the South and West Cumberland Fisheries Advisory Committee meeting, which was held on the 2nd April, 1979. It covers the information on the 1978 water quality survey on the Derwent Estuary and the recommended long term objectives for inland river water quality. Also added is the report by the area fisheries officer on fisheries activities which comments on river conditions and fishing and an update on Holmwrangle hatchery including mortalities due to water quality and gill infections in brown trout. It also looks at pollution incidents on the River Ellen and Ehen, Yearl Weir fish counter and data of monthly salmon and migratory trout catches on rod, line, nets and fixed engines for the 1978 season. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

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Thirty-three groups of geochemically related natural lake and river waters collected from 368 sites scattered over East and West Africa, were investigated to determine correlations between their various ions and the patterns of change in their ionic composition across the African continent. The following nine significant correlations were found to exist in the entire area or in a major part of it: sodium and potassium; sodium and chloride; sodium and sulphate; potassium and ammonium; potassium and chloride; ammonium and nitrate; calcium and magnesium; magnesium and chloride; sulphate and chloride. When compared with the world average composition. The concentration of potassium in these waters was found to be high, that of calcium and nitrate was low. With respect to the area of East Africa only, trends in the pattern of change involving the ionic composition of the lake and river water and the longitude at which the sites were present, were found to exist for the ratio of sodium: conductivity (which showed an increase in the direction of West to East), magnesium: conductivity, and for the sum of calcium and magnesium: phosphate was generally found to increase in East Africa in the direction of west to East.

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Salinity gradient power (SGP) is the energy that can be obtained from the mixing entropy of two solutions with a different salt concentration. River estuary, as a place for mixing salt water and fresh water, has a huge potential of this renewable energy. In this study, this potential in the estuaries of rivers leading to the Persian Gulf and the factors affecting it are analysis and assessment. Since most of the full water rivers are in the Asia, this continent with the potential power of 338GW is a second major source of energy from the salinity gradient power in the world (Wetsus institute, 2009). Persian Gulf, with the proper salinity gradient in its river estuaries, has Particular importance for extraction of this energy. Considering the total river flow into the Persian Gulf, which is approximately equal to 3486 m3/s, the amount of theoretical extractable power from salinity gradient in this region is 5.2GW. Iran, with its numerous rivers along the coast of the Persian Gulf, has a great share of this energy source. For example, with study calculations done on data from three hydrometery stations located on the Arvand River, Khorramshahr Station with releasing 1.91M/ energy which is obtained by combining 1.26m3 river water with 0.74 m3 sea water, is devoted to itself extracting the maximum amount of extractable energy. Considering the average of annual discharge of Arvand River in Khorramshahr hydrometery station, the amount of theoretical extractable power is 955 MW. Another part of parameters that are studied in this research, are the intrusion length of salt water and its flushing time in the estuary that have a significant influence on the salinity gradient power. According to the calculation done in conditions HWS and the average discharge of rivers, the maximum of salinity intrusion length in to the estuary of the river by 41km is related to Arvand River and the lowest with 8km is for Helle River. Also the highest rate of salt water flushing time in the estuary with 9.8 days is related to the Arvand River and the lowest with 3.3 days is for Helle River. Influence of these two parameters on reduces the amount of extractable energy from salinity gradient power as well as can be seen in the estuaries of the rivers studied. For example, at the estuary of the Arvand River in the interval 8.9 days, salinity gradient power decreases 9.2%. But another part of this research focuses on the design of a suitable system for extracting electrical energy from the salinity gradient. So far, five methods have been proposed to convert this energy to electricity that among them, reverse electro-dialysis (RED) method and pressure-retarded osmosis (PRO) method have special importance in practical terms. In theory both techniques generate the same amount of energy from given volumes of sea and river water with specified salinity; in practice the RED technique seems to be more attractive for power generation using sea water and river water. Because it is less necessity of salinity gradient to PRO method. In addition to this, in RED method, it does not need to use turbine to change energy and the electricity generation is started when two solutions are mixed. In this research, the power density and the efficiency of generated energy was assessment by designing a physical method. The physical designed model is an unicellular reverse electro-dialysis battery with nano heterogenic membrane has 20cmx20cm dimension, which produced power density 0.58 W/m2 by using river water (1 g NaCl/lit) and sea water (30 g NaCl/lit) in laboratorial condition. This value was obtained because of nano method used on the membrane of this system and suitable design of the cell which led to increase the yield of the system efficiency 11% more than non nano ones.

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For survey incidence of nephrocalcinosis in rainbow trout fish, during winter 1385, samplings were performed in three fish farm with different water source: river, spring and recirculation system by using well water. In this survey 5 specimens from each 8 groups and in general 120 specimens of this fish were caught by random sampling, and also amounts of O2, CO2, pH and temperature of water were measured. Then blooding and renal tissue sampling performed that renal samples were fixed in 10% buffered formalin and blood samples after separating serum stored in -200C. Renal specimens transferred to pathology laboratory, pathological slides were prepared and stained by hematoxylin & Eosin method. From 120 specimens, 6 cases of fish represent nephrocalcinosis. Pathologic signs include: renal epithelial necrosis, dilated ureters, dense basophilic materials inside the dilated tubules and cast formation in some renal tubules. From 6 cases of nephrocalcinosis, 3 cases (7/5%) were related to recirculation system and 2 (5%) case were related to river water and 1 (2/5%) case was related to spring water. In survey amount of urea, creatinine and Uric acid between different weight groups, distinguished that difference between creatinine middling in different weight groups were significant and also in between healthy and afflicted fish, significant statistical difference were only in creatinine amount between healthy and afflicted fish in each farm. Amounts of O2, pH and temperature of water in three farms were in normal range and only rate of water CO2 in ponds of recirculatory system were very higher (25 mg/lit) than other farms. May be, this reason led to high number of nephrocalcinosis in recirculatory system, than other farms, nemley 7/5% of fish that caught from this farm .This subject is related to the role of CO2 in creating nephrocalcinosis which is descript in references.