A new approach for designing a hypolimnetic oxygenation system to improve the water quality in tropical reservoirs

In order to improve water quality retrievals of multi-spectral image accurately, this paper puts forward a method for water quality remote retrieva based on support vector regression with parameters optimized by genetic algorithm. The method uses SPOT-5A data and the water quality field data, chose four representative water quality parameters, support vector regression are trained and tested, the parameters of support vector regression are optimized by genetic algorithms. The result of experiment shows that the method has more accuracy than the routine method. It provides a new approach for remote sensing monitoring of environment.

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Coping with Water Quality Problems due to Hypolimnetic Anoxia in Central Ontario Lakes

Water Quality Research Journal ◽

10.2166/wqrj.1997.025 ◽

1997 ◽

Vol 32 (2) ◽

pp. 391-405 ◽

Cited By ~ 8

Author(s):

Gertrud Nürnberg

Keyword(s):

Water Quality ◽

Binding Capacity ◽

Oxygen Depletion ◽

Eutrophic Lakes ◽

Niagara Escarpment ◽

Softwater Lakes ◽

Phosphorus Accumulation ◽

Hypolimnetic Oxygenation ◽

Quantitative Manner ◽

Water Outflow

Abstract Many lakes experience oxygen depletion in their hypolimnia during summer or winter stratification. This study investigates the remedial actions that are available to combat the harmful effects of hypolimnetic anoxia in three types of Central Ontario lakes with different trophic states. In more eutrophic lakes, e.g., Lake Wilcox, southern Ontario, much phosphorus accumulates in the hypolimnion during anoxia and represents ca. 60% of the annual P budget. To diminish the detrimental effects of such a high internal phosphorus load, withdrawal of the hypolimnetic waters, together with damming of the surface water outflow, has been suggested. In oligo- to mesotrophic Chesley Lake, on the Niagara Escarpment, phosphorus accumulation in the hypolimnion is only slight and metals with a binding capacity for phosphorus are available. Here a hypolimnetic oxygenation has been suggested to alleviate the stress on fish and also to prevent further P release from the sediments. Lakes in the District of Muskoka are softwater lakes because of their location on the Canadian Shield. Although the geochemistry of the catchment typically renders these lakes nutrient poor and oligotrophic, long-term development on their shores has led to phosphorus accumulation in the sediments that is released under anoxic conditions in some lakes. To prevent the deterioration of the water quality in these lakes, water quality models to manage and control future development in its watersheds, as those of the district municipality, should include anoxia and internal P recycling in a quantitative manner.

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Influence of the use and the land cover of the catchment in the water quality of the semiarid tropical reservoirs

Journal of Hyperspectral Remote Sensing ◽

10.29150/jhrs.v7.7.p389-398 ◽

2018 ◽

Vol 7 (7) ◽

pp. 389

Author(s):

Herika Cavalcante ◽

Patrícia Silva Cruz ◽

Leandro Gomes Viana ◽

Daniely De Lucena Silva ◽

José Etham De Lucena Barbosa

Keyword(s):

Water Quality ◽

Supervised Classification ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Landsat 8 ◽

Dissolved Phosphorus ◽

Sparse Vegetation ◽

Tropical Reservoirs

The aim of this study was to evaluate some parameters of water quality of semiarid reservoirs under different uses and occupation of the catchment’s soil. For this, the reservoirs Acauã and Boqueirão, belonging to the Paraíba do Norte river watershed and Middle and Upper course sub catchments, respectively, were studied. For this, water samples were collected in August, September and October 2016. From these samples, total and dissolved phosphorus, nitrate, nitrite, ammonia, chlorophyll, dissolved and suspended solids were analyzed. In addition, images of the Landsat 8 satellite were acquired for the calculation of the Normalized Difference Vegetation Index (NDVI), and for the supervised classification of the use and occupation of the sub catchments. Thus, it was observed that, in general, the Acauã reservoir presented values of phosphorus and nitrogen and solids larger than the Boqueirão reservoir, due to the greater urban area, even though it had a smaller total area of the basin. Both reservoirs presented low vegetation rates and high areas of sparse vegetation and exposed soil, increasing the propensity to soil erosion and the transport of nutrients from the basin to the reservoirs, making water quality worse or impossible.

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