dc.description.abstract | Developing Nations are always in a constant struggle to achieve subsistence both, governments and citizens dream about reaching economical development to offer to the present generation better life standards and to the future generations, better opportunities. In this quest for well being human practices at all scales, from artisanal fishery to Nationwide Policies, Plans and Strategies explodes any available natural resources to achieve that goal and must of the times there is no awareness on how affects the environment and natural equilibrium. The Gulf of Fonseca is one of the most dynamic spots on Central America, shared by three countries; El Salvador, Honduras and Nicaragua is scenario of constant land use changes, increase of urban developments, establishment of aquaculture industries at big scale, industrial fishery, logistics and marine transport. All these activities generate direct and indirect impacts to this estuarine ecosystem an undeniable fact is that pollution is already present in this marine ecosystem. Understanding how this ecosystem works is a key element to know how to preserve them from pollutants agents, to know how to identify, treat and prevent a major environmental impact. The approach of this thesis is the use of Remote Sensing as a tool to identify how contaminants behave in spatial distribution as well as time variations. This study has two major aims, the first one is to investigate spatial patterns in selected water quality indicators (Turbidity and Total Suspended Solids), by using Landsat 7 ETM+ and in situ measurements, the second aim is to determine temporal variations patterns in order to identify whether or not there is a factor that progressively affect to the environment or a permanent impact. To analyze spatial patterns based on previous studies a linear regression statistical model was performed, our results shows that Turbidity and Total Suspended Solids are correlated with the combination of Band 3 and 4 from the Landsat 7 ETM+, with a correlation coefficient of 0.73 for Turbidity and 0.74 for suspended solids. The second aim was to perform a Temporal Analysis within a time observation period of 7 years, from 2004 to 2010, for this a process of normalization was performed for apply the founded relationships to the rest of the years. Variations of the rainy season and dry season where considered for each year seasonal, also variation of rainy season through every consecutive year was observed, as well as dry season behavior. Conclusions on this study lead us to believe that mapping Turbidity Patterns and Suspended Solids concentrations is feasible, by the use of a moderate resolution satellite and in situ measurements. Through the seasonal change analysis we can conclude that the most predominant factors on variations of these patterns are change of seasons, during the dry season we can find the highest pollution levels in the Bay of San Bernardo and the Bay of La Union, this is also product of anthropogenic activities such as shrimp aquaculture and municipal waste water discharges to the Gulf. Another important conclusion is that there is no evidence of a progressive behavior on pollution by turbidity or suspended solids through the 7 years of observation, which means that the dredging works during the development of the port of La Union at El Salvador has no permanent impact on the turbidity and suspended solids patterns.
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