Brazos River and Surfside, TX Case Study

All of the variables that were measured at the sample points have been graphed in relation to the points’ distance from the mouth of the Brazos River. Distance v Salinity v Nitrate v Ammonia graph for the bayside data points clearly shows that as the salinity increases, both the ammonia and nitrate concentration increases as well. This graph supports the Explanatory Regression results that suggested that the change in salinity could be explained by the increase in ammonia and nitrate concentrations. Since the Brazos River changes the salinity of the Gulf of Mexico, its water could also increase the ammonia and nitrate concentration.  

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Distance v Salinity v pH v Ammonia graph displays the variables measured on the beachside of the island in relation to the points’ distance from the mouth of the Brazos River. The variables do not relate to each other in any way and support the results of the Explanatory Regression results. Since none of the variables have any correlation with each other, the Brazos River does not impact the beachside as strongly as the bayside.

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Sample Point Data at Surfside, Texas map shows the values of salinity, pH, ammonia and nitrate concentrations measured at each sample point. The bar graphs representing the variables highlights significant jumps in value compared to their neighboring points. Having all of the information represented in one map gives a quick overview of the data. The map shows that the variables measured on the bayside highly vary and change, but the variables on the beachside are similar. Since the bayside has more varied data, the Brazos River changes the variables in this water the most and does not change the beachside water. 

The Bayside Data-Surfside map, Texas map displays the salinity, ammonia and nitrate concentration measured at each sample point on the bayside of the island. The changes and fluctuations in the variables are easily seen since the bars are three-dimensional and larger without the beachside data. Only the variables that have been determined to have a relationship, the salinity, ammonia and nitrate concentrations, were included to highlight changes.

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The results of the Explanatory Regression and the graphs show that salinity has a positive correlation with the ammonia and nitrate concentration on the bayside. Since the Brazos River is responsible for changes in salinity, it could also be responsible for the changes in ammonia and nitrate concentration.

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The Explanatory Regression results and the graphs show that there is no relationship between the measured variables collected on the beachside of the island. There is no significant change in any of the variables as shown in Distance v Salinity v pH v Ammonia graph and it can be concluded that the Brazos River does not change the variables on the beachside. 

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The amount of samples taken and the geographic area that was covered was limited by time and testing supplies. Further studies with unlimited resources would have samples taken along the Brazos River upstream of the mouth to provide more information about the attributes of the river. Further sampling could also be used to pinpoint causes of changes in salinity, pH, ammonia and nitrate concentrations along the river. These sources could then be studied and brought to the attention of officials to implement laws that will reduce human impact on the variables.

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This project would have also benefited from sampling a larger geographic area along the coast would provide more information of how the Brazos River flows interacts with the Gulf of Mexico. Taking samples on Surfside and Matagorda Bay would give insight on both sides of the mouth of the Brazos River. Having more sample points would also increase the area coverage of the project.

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Additional analysis should also be conducted to identify what environmental factors cause the Brazos River to have a larger impact on the bayside than the beachside. Data would need to be collected over the course of several days after significant rainfall upstream from the Brazos River to increase flow into the Gulf of Mexico. Flooding in areas upstream from the mouth of the Brazos are known to lower salinity near the mouth than usual. 

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Current flow mapping would be a crucial element to further investigate the aspects of the Gulf of Mexico that the Brazos River changes. Did the current prevent the Brazos from interacting with the water on the beachside? If it was known that the current was heading south at the time that the data was collected, then it could be said that the Brazos River’s water did not mix with the beachside water. The current map would also inform how the Brazos flows through the bayside and interacts with other bodies of water.