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Sareeha Nadarajah W. M. H. Kelum Wijenayake Upali S. Amarasinghe 《Lakes & Reservoirs: Research and Management》2019,24(3):287-298
Many reservoirs provide multiple benefits to people around the world, in addition to primary uses such as irrigation. Thus, reservoir management should address their multiple uses. The water quality of ten irrigation reservoirs in Sri Lanka was examined in the present study with the objective of better understanding the effects of hydrological regimes on reservoir water quality and trophic state. Basic limnological parameters pertinent to the nutrient loads to, and trophic state of, the reservoirs were collected from June 2013 to February 2016. The sampling period was arbitrarily divided into two periods of approximately similar duration (period 1 = June 2013–September 2014; period 2 = October 2014–February 2016) to investigate whether or not there was a seasonal variation in the water quality parameters. Although temporal and spatial variations were observed, most water quality parameters were within the levels acceptable for drinking water standards. The 10 reservoirs were also ordinated by principal component analysis (PCA) on the basis of the water quality parameters of the two sampling periods in a two‐dimensional score plot. Reservoirs in the first principal component (PC1) axis were represented by negative scores attributable to the dissolved oxygen concentration and pH and, to a lesser extent, by electrical conductivity and chlorophyll‐a concentration. Positive scores in PC1 were represented by reservoirs with a score loading attributable to alkalinity, nitrate concentration, Secchi depth, temperature and seston weight and, to a lesser extent, from the total phosphorus concentration. There was a significant negative correlation of PC1 scores with relative reservoir water‐level fluctuation (RRLF; the ratio of mean reservoir water‐level amplitude to mean reservoir depth). Furthermore, Carlson's trophic index also were influenced by RRLF, although not by hydraulic retention time (HRT), indicating allochthonous nutrient inputs into the irrigation reservoirs were mainly governed by RRLF, but not by HRT. Thus, the results of the present study provide useful insights into achieving desirable reservoir water quality through the manipulation of the hydrological regime. 相似文献
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Observations of the presence or density of individuals in specific habitats are often used to develop predictive models of preferential habitat use and habitat suitability curves. However, most studies only use day‐time observations to model habitat associations. In this paper, we present day and night observations of habitat use by two abundant species of freshwater shrimp, Atya lanipes and Xiphocaris elongata, in a tropical montane stream. At night, the number of shrimp observed was an order of magnitude greater than during the day. Habitat preferences of Atya changed, with more individuals using low velocity edge sites at night. Xiphocaris were not readily visible during the day, but were very abundant at night. Our results suggest that habitat models cannot be based only on day‐time observations. Because the level of nocturnal activity is not known for most species of fish and invertebrates, studies of habitat preferences should include both day and night observations. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
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Christina W.C. Branco Betina Kozlowsky-Suzuki Izidro F. Sousa-Filho Alcides W.S. Guarino Rinaldo J. Rocha 《Lakes & Reservoirs: Research and Management》2009,14(3):175-191
Ribeirão das Lajes Reservoir was constructed in 1905 for energy production, and is now used as a domestic water supply for about 1 million people. The reservoir was considered as being general monomictic, exhibiting water column mixing in the winter. Water column mixing, however, did not occur in the deepest parts of the reservoir in the warm year of 2005. Nevertheless, the long stratification period leads to an anoxic, nutrient-rich hypolimnion that exhibits poor water quality in the deepest part. The meteorological events of cold front passages in the reservoir region were not able to disrupt the water column stability, or affect its water quality for domestic supply. Maintenance of thermal stratification over most of the year was likely because of the low influence of wind, long water retention time, and the input of cold water from the tributary and from rain directly draining into the metalimnion. 相似文献
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John W. Faithful and Dilwyn J. Griffiths 《Lakes & Reservoirs: Research and Management》2000,5(4):231-247
The first flood event following a prolonged dry period is described for an impoundment, Lake Dalrymple, in tropical north‐eastern Australia. The event, in January 1996, generated substantial flow in the two main inflow sources: the Burdekin River from the north and the Suttor River from the south. Flow through the Burdekin River peaked early and then subsided to a lower level, but flow through the Suttor River persisted at a moderate level for over 15 days after the initial inflow. An extensive water quality survey was conducted on 16 January 1996 (seven days after the initial dam overflow) to determine the nature of the inflows originating from the two major subcatchments feeding the reservoir as they entered and passed through the impoundment. The inflow comprising waters of high turbidity and low conductivity occupied the mid‐column region along the two major inflow channels through the impoundment to the dam wall. The suspended particulate material in the form of silt and clay sized particles remained in suspension as the flow passed through the reservoir, due in part to the low ionic strength of the inflow and the relative densities of the inflowing and receiving waters. For both river sources, more than 50% of the total nitrogen and almost all of the total phosphorus were bound to the suspended particulate matter. Much of this was exported in the flow over the spillway. The highly turbid nature of the inflow resulted in strong attenuation of down‐welling photosynthetically active radiation (up to maximum attenuation values of 12.24 m–1 in the reservoir where the euphotic depth was only 0.38 m). The irradiance reflectance and the scattering coefficient were considerably higher than any reported for other Australian inland waters. Concentrations of viable chlorophyll a in the surface waters were very low (maximum value 3.4 μg L–1) because of the highly turbid conditions and extensive dilution by the inflow. The results of this study provide an example of the significant impact a large inflow of turbid, low conductance water can have on a large reservoir in the arid tropics following a prolonged dry period. During inflow events such as the one described in this paper, the reservoir becomes riverine in nature, and large amounts of suspended particulate matter and associated nutrients are transported through the reservoir. 相似文献
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A team of specialists normally carries out the task of locating reservoir sites based on general guidelines, technical knowledge and experience. Consequently, the procedures used are not based on a defined criteria in addition to being time consuming and expensive. Furthermore, the failure of a number of dams and the increase in environmental awareness will require the inclusion ofenvironmental and social factors in the processes besides economy. In this study, a criteria was developed and implementedto locate potential sites for reservoirs in the Langkawi Island, Malaysia based on all relevant factors including: topography, geology, hydrology, land use/cover types and settlements. A satellite imagery and digitized geological and elevation maps were utilized to generate the necessary data layers for the developed criteria. Then IDRISI, a raster based GIS was employed to implement the criteria using the Boolean and the Weighted Linear Combination (WLC) methods. The Boolean method produced five reservoir sites with the 70 Mld water capacity, two of which corresponded well with a field-based study. Whilst theproposed site with the 90 Mld water capacity did not correspond with the field based study. The WLC method produced five sites with the 70 Mld water capacity, three of which matched those of the field study. Whilst for the 90 Mld water requirement, two potential sites were produced and both have matched those of thefield study. The outcomes indicated that the developed criteria were sensitive to physical, environmental and economical settingson the Langkawi Island. Furthermore, GIS and remote sensing can be useful tools for generating, manipulating and handling relevant data layers and ultimately providing management optionsfor decision makers. 相似文献
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Gustavious P. Williams Oliver Obregon E. James Nelson Woodruff Miller M. Brett Borup Caleb Buahin 《Lakes & Reservoirs: Research and Management》2014,19(4):293-305
This study compared the sensitivity of water quality in tropical Aguamilpa Reservoir, as represented by normalized algae mass and dissolved oxygen, to selected projected changes from global climate change and development. The sensitivity of reservoir stratification as an indicator of reservoir sensitivity also was analysed. Model simulations indicated the reservoir was more sensitive to changes during the warm‐dry season than at other times. Both indexes (normalized algal mass and dissolved oxygen mass) were more sensitive to changes in air temperature (climate change) and nitrogen loading (development) than to changes in flow. The sensitivity to air temperature was similar to, but generally less than, the sensitivity to nutrient inflow. At the bounding values for change (3 °C for temperature; 50% increase in nitrogen loading), the algae mass sensitivities were 0.15 mg L?1 per 3 °C and 0.2 mg L?1 per 50% nitrogen load increase, and the dissolved oxygen mass sensitivities were 0.7 mg L?1 per 3 °C and 2.0 mg L?1 per 50% load increase. Changes in air temperature and nitrogen loadings affect the reservoir in different ways, air temperature mostly changing the timing of the algal growth with little change in peak values, while nutrient loadings change the peak values with little change in the timing. While the sensitivities are similar, the total algal mass change is significantly larger for nitrogen loading, compared to air temperature changes. These results imply global climate change effects can be partially mitigated by implementing management measures in the surrounding watersheds to minimize nutrient inflows, especially nitrogen in the case of Aguamilpa Reservoir. 相似文献
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Susperregui Anne‐Sophie Gratiot Nicolas Esteves Michel Prat Christian 《Lakes & Reservoirs: Research and Management》2009,14(1):31-39
This study represents the first limnological assessment of Cointzio Reservoir (Michoacán, Mexico). A full three‐dimensional scan of temperature, conductivity and turbidity was done for the reservoir during two field surveys at the end of the 2005 rainy season (December 2005), and before the beginning of the next season (May 2006). These parameters also were measured continuously during the 2006 rainy season. Analysis of data within the context of local climate trends at a multidecadal scale indicates the reservoir can amplify seasonal features because of its morphometric properties. Between June to December, the reservoir behaved as a fluvial system, exhibiting a rapid, efficient mixing of the water column. Between January to May, the reservoir developed substantial stratification, and exhibited typical lacustrine characteristics. These alternate phases of fluvial and lacustrine regimes, associated with a high water turbidity throughout the year (Secchi depth of ≈0.2 m) contributes to stress on this aquatic ecosystem. 相似文献
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Alessandra Delazari‐Barroso Gilberto Fonseca Barroso Vera Lúcia De Moraes Huszar Sandra Maria Feliciano De Oliveira e Azevedo 《Lakes & Reservoirs: Research and Management》2009,14(4):269-278
The water‐mixing regime, light availability, nutrient limitation and trophic state were evaluated for the Duas Bocas Reservoir (DBR; Espírito Santo State, southeastern Brazil), a small (0.51 km2), shallow (zmax < 10 m) water supply reservoir located in a conservation area. Monthly water sampling was conducted for the lacustrine zone (zmax = 10 m) next to the water withdrawal tower, during one hydrological cycle (October 2002 to September 2003). Water samples were taken at four depths in this area, including subsurface, Secchi depth, euphotic/aphotic boundary and near the bottom of the lake. The variability of the reservoir’s limnological features defined two periods. Period 1, comprised of the summer months (October to April), was characterized by strong thermal stratification, nutrient limitation in the mixing layer, a metalimnetic biomass maximum and anoxia and high nutrient concentrations in the hypolimnion. Period 2, comprised of the winter months (May to September), was characterized by overturn events during which the phytoplankton population experienced light limitation. The observed water‐mixing regime was characteristic of warm monomictic system, presenting atelomixis, the incomplete vertical mixing of stratified water masses. The average total phosphorus and chlorophyll‐a concentrations suggested a meso‐eutrophic water system. The nutrient concentrations exhibited nitrogen and phosphorus limitation, suggesting that nutrients, rather than light, limit or regulate the phytoplankton biomass in the DBR for most of the year. 相似文献
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O. D. Ansa-Asare & Kwadwo Ansong Asante 《Lakes & Reservoirs: Research and Management》1998,3(3-4):205-217
The nutrient status of Weija and Kpong reservoirs, southeast Ghana, was assessed by determining seasonal indices and interannual changes. The nutrient levels were found to be higher in Weija Reservoir. However, ammonia did not follow that pattern. Seasonal distribution of nutrients also showed higher levels in Weija than in Kpong. Seasonal variation showed higher levels of nitrates in the rainy season at Weija than at Kpong; however, data from Kpong Reservoir involved considerable experimental error. The monthly trend of nitrates showed a unique pattern in the months of March and May, the main ploughing periods for farming in the Weija catchment area when most fertilizer is applied. In general, over a 5-year period, there were no trends in nutrient levels. However, for sulfates there was a gradual decrease in spatial distribution from 1993 to 1997. The seasonal distribution for sulfate increased slightly. Seasonal trends as well as a seasonal index were determined and in all cases Weija showed higher levels than Kpong derived from land-based fertilizers on the reservoir. On average, there was a higher seasonal index in the rainy season than in the dry season. However, the phosphate index in January at both Weija and Kpong was high. The seasonal index for both Weija and Kpong was high in the rainy season and low in the dry season. However, the phosphate index in January at both Weija and Kpong was high. The high nitrate index in March was due to rain in the latter part of that month. Ammonia–nitrogen in November also showed high levels; November was just after the rainy season so some influence from rain persisted. 相似文献
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Khan Kamal Uddin Ahmed John B. Hambrey Sanzidur Rahman 《Lakes & Reservoirs: Research and Management》2001,6(1):85-94
Interannual variation in yield per species from a freshwater reservoir in Bangladesh was analysed by using long‐term landing data. Each species was categorized according to characteristics in interannual yield variation. The characteristics were defined with respect to size of the interannual variation in terms of absolute and relative variation around the mean yield and long‐term trends in catch levels. Annual variation was directly (t18 = 7.84; P < 0.01) related to the yield and can serve as a good indication of the status of the fishery when catches are low. The target fish, Indian major carps (IMC) Labeo rohita, Labeo calbasu, Catla catla and Cirrhinus mrigala, showed large variation in annual yield. This might have occurred because of variation in annual recruitment. Illegal use of gears is mostly related to variation in year class strength, and is assumed to be the most important source of change of stock variation. An increase in catch rate was recorded for Corica soborna. Such a stable combination may only be possible for a certain period without a long‐term trend. Trends in the yield rate of the major fish category for three decades reveal a sharp decline in the catch of IMC. In contrast, small clupeid‐like C. soborna have the highest yield rate. Fishing gears can play a crucial role in this fishery. Fisheries managers must always be alert when issuing fishing licenses and on the control on gears. The conclusion is that the IMC fishery of Kaptai Reservoir is an overexploited fish stock. In this fishery, the same gears are usually employed indiscriminately for different species and size classes. To stabilize the fishery, the existing policy needs to be strengthened and more effectively implemented. Also, some fishing gears and traps need to be restricted. An effective stock protection policy is suggested. Further study on catch size of individual species is essential prior to the development and implementation of any management scheme. 相似文献
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Leigh Stitz Susan Kinnear Larelle Fabbro 《Lakes & Reservoirs: Research and Management》2013,18(2):179-196
Cylindrospermopsis is a cyanobacterial species of global concern, due to its ability to produce potent toxins and its near‐cosmopolitan distribution. To date, both management and research efforts for Cylindrospermopsis have focused on riverine settings. By contrast, off‐stream storages are inadequately studied, particularly in terms of population dynamics and toxin profiles, how these are linked with the riverine systems that seed them, and what management options are best for optimizing water quality. This is a critical gap, given that storages are key off‐take points for many water users, including for livestock watering and industrial supply. This study examined the relationship between a riverine and an off‐stream environment, with respect to the development of toxic Cylindrospermopsis blooms in central Queensland. It discusses the role of an aeration system in preventing or delaying bloom development and explores the implications of intake depth with respect to population (cell density) and toxicity. Along the impounded river, the study sites featured warm, stratified conditions and an anoxic hypolimnion. By contrast, the off‐stream storage dam lacked stratification, due to the constant aeration provided by a hypolimnetic bubbler. Cylindrospermopsis raciborskii blooms appeared in both environments, with peak cellular concentrations detected in the subsurface waters. The dynamics of the toxin profiles differed, however, with the riverine concentrations being mostly epilimnetic, whereas the dam featured toxin distributed throughout the water column. Concentrations of both cylindrospermopsin (CYN) and deoxy‐cylindrospermopsin (deoxy‐CYN) were lower in the dam, compared with the riverine sites. A one‐month lag period was evident before C. raciborskii cells appeared in the dam following their observation in the river samples, and a similar period elapsed before the dam populations reached their peak concentrations. These data are invaluable in considering the best management options for off‐stream sites that experience seeding from riverine populations, particularly for toxin producers such as Cylindrospermopsis. 相似文献
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Louis-B. Jugnia D. Debroas J-C. Romagoux J. Dévaux 《Lakes & Reservoirs: Research and Management》2004,9(2):109-117
We examined the impacts of remediation activities aimed at improving the water quality of hypereutrophic Villerest Reservoir, in which Microcystis aeruginosa dominated during the summer. We also compared nutrients and chlorophyll a data from this study with the results of a previous study on the reservoir. Between the two studies, the nitrogen and phosphorus loads into the reservoir from the main tributary decreased by 70% and 80%, respectively. Within the reservoir, the quantities of ammonia‐nitrogen were similar in the two studies, and the total nitrogen was significantly higher in this study compared to the initial study. Both the phosphate‐phosphorus and total phosphorus concentrations decreased significantly between the two studies. However, the statistically significant decrease in phosphate‐phosphorus and total phosphorus did not always lead to a significant decrease in chlorophyll a concentrations. The nitrogen/phosphorus mass ratio during the present study remained well above five, the critical value below which summer blooms of Microcystis aeruginosa were observed in Villerest Reservoir. These study results indicated that the remediation activities being used to improve the water quality of Villerest Reservoir were off to a good start. 相似文献
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J. G. Rangel‐Peraza O. Obregon J. Nelson G. P. Williams J. de Anda F. González‐Farías J. Miller 《Lakes & Reservoirs: Research and Management》2012,17(2):119-129
The dynamics of water temperature, dissolved oxygen and total dissolved solids concentrations in Aguamilpa Reservoir was analysed by considering horizontal and water column variations. The reservoir model, CE‐QUAL‐W2, was used to simulate the temporal variations calibrated with data gathered every 2 months from June 2008 to June 2009. Temperature depth profiles indicated a typical asymmetry of reservoirs exhibiting a large stratification in the lower part near the dam. Dissolved oxygen concentration profiles exhibited some degree of anoxia in the bottom water during the rainy season (May through October). This is most likely due to decomposition vegetation and organic matter via soil erosion and run‐off from the basin accumulating at the bottom of the reservoir. The reservoir stratification is clearly seasonal, occurring during the rainy season, especially in the lowest reservoir zones. The CE‐QUAL‐W2 model results provided a comprehensive understanding of the temporal behaviour of the study variables during the modelling study period. Application of this water quality model is directed to water resource managers to help them better understand the dynamics of physico‐chemical processes, and how they vary temporally and spatially in the reservoir, and to propose the best management practices for preserving or improving the water quality of the system. 相似文献
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Zati Sharip Ahmad T. A. Zaki Mohd. A. H. M. Shapai Saim Suratman Ahmad J. Shaaban 《Lakes & Reservoirs: Research and Management》2014,19(2):130-141
The present study was undertaken to evaluate and verify the water quality status and trophic state of 15 major lakes and reservoirs in Malaysia. The lake water quality assessments were based on the National Water Quality Index (NWQI), while the trophic state assessments were based on Carlson's Trophic State Index (TSI). The findings of this water quality assessment, based on data collected between September and October 2012, indicated that a majority of the lakes were classified as Class II (Clean) waters suitable for recreational use. The results of the trophic state assessments, however, indicated that all of the lakes were eutrophic, meaning they were nutrient‐rich, they could experience algae blooms or macrophyte problems, and they were likely to exhibit poor water quality. Sustainable management measures and strategies are suggested to address the eutrophication problems of Malaysian lakes and reservoirs, with the national responses on lake and reservoir management also being discussed. 相似文献