Author(s): Diaz Aragon Alejandro; Guangwei Huang
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Keywords: No Keywords
Abstract: The main objective of this study is to evaluate the spatiotemporal changes that Kasumigaura Lake’s discharge to Tone River has had over the past 10 years. The parameters being evaluated are: COD, BOD, Temperature, DO, TN, and TP. Temporal changes were evaluated from the year 2008 to 2015 using the databases from the MLITT (Ministry of Land, Infrastructure, Transportation and Tourism) web page. The river’s transport phenomena were simulated using a box model approach implemented by the EPA’s WASP simulation program. Finally the model was calibrated with the observed data. Nutrient loads discharged to Tone River from Kasumigaura Lake were elucidated, the results show that organic content and TP are compounds of concern, particularly in April and late July, where concentration in the Lake’s discharge are considerably higher than those in the upstream of the river. COD loads incoming from Kasumigaura Lake can have up to 20% the organic content of those in Tone River. TP loads on the other hand can be as high as 11% in spring and late summer. The spatial variation analysis within Kasumigaura Lake showed an increase in the DO in the riverine sections. As for BOD levels decrease mostly in Nishiura Lake and Sotonasakaura Lake. The rivers (Kitatone and Hitachi) transport the organic loads and nutrients almost unchanged as discharged by the lakes. The simulation showed a good degree of accuracy in most of the evaluated EQS. DO and BOD were the values the model was able to predict with a greater degree of precision. Simulated TP values showed behaviors in accordance with the observed values, though they had an important variance.
Year: 2018