| Title |
Simple Material Budget Modeling for the Paldang Reservoir in the Spring Season |
| DOI |
https://doi.org/10.15681/KSWE.2017.33.6.696 |
| Keywords |
Eutrophication; Material budget modeling; Paldang; Phosphorous; River-type reservoir; Water quality |
| Abstract |
Simple material budget models were developed to predict the spring season (March~May) water quality for a river-type reservoir Paldang, in the Republic of Korea. These models are available at mixed water bodies whose light intensity is negligible at the bottom. The calculated data from the models fit quite well with field data collected for 30 years, from 1988 to 2017. The apparent settling velocity of total phosphorus was estimated to be 110 m d-1. The critical hydraulic load that determines the usability of phosphorus for algal production appeared to be about 2.0 m d-1. When a hydraulic load was larger than the critical value, the concentrations of chlorophyll α (Chl.α), chemical oxygen demand (COD), and 5-day biochemical oxygen demand BOD in the reservoir water became insensitive to internal algal reactions. The model analysis showed that the allochthonous COD continued to increase while the allochthonous BOD slightly decreased after 1999. The decrease of allochthonous BOD is due to the expansion of sewage and wastewater treatment plants in the watershed. The increase of allochthonous COD seems to result from the increase in anthropogenic non-point sources as well as the increase in the discharge of natural organic matters due to climate change. Organic matter of algal origin continued to increase until the mid-2000s, but recently it has decreased as the phosphorus concentration has decreased. The COD and BOD of algal origin increased from 35% and 30% during 1988~1994 to 43% and 42% during 2000~2010, respectively, and then decreased to 25% and 29% during 2011~2017. |