Jongchan Kim earns PhD for research on a framework to improve the water environment of the Nakdong River in South Korea

My PhD research focuses on improving water quality in rivers, specifically by addressing harmful cyanobacterial blooms (called harmful algae blooms, or HABs), which are getting worse due to climate change. I have created a practical plan to efficiently and effectively operate upstream reservoirs to reduce the cyanobacterial blooms in downstream rivers.

For my research, I developed three models: one predicts the occurrence of cyanobacterial blooms at a specific location of a river, another simulates water quality factors in a river, and the third optimizes reservoir operations. I applied this in South Korea's Nakdong River with real data.

The importance of my work is simple and practical: it helps make rivers cleaner and safer without using more water from upstream. By reducing the occurrence of cyanobacterial blooms downstream, my research contributes to healthier ecosystems, safer drinking water, and a better world, especially considering the effects of climate change.

I'll forever cherish the moments when my first and third research papers were accepted for publication. Composing my first research paper was challenging – I had to learn about manuscript organization and content. Nearly two years into my research journey, I wrote my debut paper and I cannot forget the moment when I received the notification of its acceptance.

The experience from the first publication proved invaluable when crafting my second paper. Thankfully, it flowed seamlessly without major obstacles. Then hardship followed as I sought to publish my third research paper. Although I believed the manuscript to be well-crafted, it faced rejection -  this was new experience that left me bewildered. With helpful guidance from my supervisors, I revised the paper and was happy when it was accepted by another journal.

The publication of my first paper and the eventual success of my third stand as indelible milestones in my research journey.

The most challenging aspect of my PhD journey revolved around creating a river water quality model utilizing a River Analysis System known as HEC-RAS for my second research paper. HEC-RAS is primarily used for flow analysis, but I used it for water quality modelling. I used the HEC-RAS manual as a guide, but encountered an unexpected error and had to conduct extensive troubleshooting. Due to this struggle, I contemplated  switching to an alternative water quality modeling system, but I persevered and ultimately resolved the issue, culminating in the successful completion of my research.

Frankly speaking, I have no illusions about any transformative impact of my PhD research on the world. Nonetheless, I aim to provide decision makers and engineers with insights about reservoir operations and their untapped potential beyond their conventional role in managing water quantity. Water reservoirs can be leveraged reservoirs as instruments for enhancing water quality. I aspire to provoke a shift in the prevailing reservoir operation paradigm: I hope that, through innovative reservoir operations, the pressing issue of water quality degradation driven by climate change can be addressed. I believe my research has a significant value in a scientific context.

I have returned to my work at the Korea Water Resources Corporation (K-water), a public entity that  oversees water resources management in South Korea. In my position as senior manager, I am in charge of Official Development Assistance (ODA) projects within the water sector.

Although my current responsibilities do not directly align with my research, I hope to eventually make a substantial contribution to K-water's technological advancements in reservoir operations, a field closely tied to my academic pursuits. I find this endeavor significant, and while it may not be immediate, I am committed to using my expertise toward enhancing K-water's capacity in this area.

K-water financially supported my PhD journey, which started in my early forties at IHE Delft. However, the financial aid was restricted to three years, something that ignited a fierce determination for me to expedite my doctoral pursuit. Three years and four months after embarking on the PhD program, I had fulfilled all degree requirements, finalized my doctoral thesis draft, and returned to South Korea. Five months later, I was awarded my PhD.

In addition to the time pressure, the COVID-19 pandemic also was a challenge as it hindered me and my family from fully enjoying Dutch life. If I could start over, I would not solely concentrate on my research. I would also strive to make meaningful connections, immerse myself in diverse cultures and experience European society while embarking on adventures with my family.

A Framework for Optimal Reservoir Operation to Improve Downstream Aquatic Environment: Application to Nakdong River Basin in South Korea

In the water sector, issues concerning the aquatic environment have been extensively discussed due to climate change. Particularly, water quality problems such as harmful cyanobacterial blooms (CyanoHABs) can be threats to the water environment while harming human health and aquatic ecosystems. This study focused on establishing a practical framework for the optimal operation of upstream reservoirs to address the problem of CyanoHABs in a downstream river. Furthermore, the applicability of this framework was demonstrated using observational data related to the quantity and quality of the upstream reservoirs in the study area, the Nakdong River of South Korea. Methodologically, three models were incorporated: a machine learning model to predict the occurrence of CyanoHABs, a river water quality model to simulate a water quality parameter influencing CyanoHABs, and an optimization model for the joint operation of upstream reservoirs. The research findings can support the decision-making of reservoir operation to create a favorable aquatic environment in a downstream river by reducing the frequency of CyanoHABs downstream. In particular, the framework to be established in this research can be a novelty in terms of efficiency since it can be a solution to the problem of CyanoHABs without using an additional amount of water from an upstream reservoir.