A recent increase in concerns about algal bloom has resulted in greater demand for a more systematic and scientific measures such as a water quality forecasting system and an algae alert system. In addition, the collaborative R&D among associated institutions, including the National Institute of Environmental Research hasis been carried out since from 2013 to figure out the entire algal bloom process, from the growth mechanism study to the monitoring and removal technologies. Currently water quality is monitored at a certain point of river and it could give only limited information. To overcome the limitations, multi-dimensional water quality monitoring will be tested for different water depth and river cross-section.
Massive algal growth can hinder water use, such as by lowering filtration performance at drinking water treatment plants (DWTPs). Some blue-green algae, which mainly occur in summer, produce toxins and odorous substances that may undermine the safety of drinking water.
The algae alert system was firstly implemented in 1998 at four lakes used as major water supply sources. The system was extended to the lakes susceptible to algal bloom. After 2006, five intake stations at downstream Han River established the system and it is in place at 22 lakes as of the end of 2013.
The algae alert system issues advisories, warnings, and notices on outbreaks based on chlorophyll-a concentration and blue-green algae count as shown in <Table 3-1>. In the past 10 years (2004-2013), algae alerts for lakes were issued for a total of 1,878 days (1,628 days of advisories, 250 days of warnings), allowing timely countermeasures such as strengthening DWTPs operation.
For the rivers used as water sources, the application of an algae alert system was recently reviewed. And it is being tested at three weir segments of Nakdong River from February 2013.
The water quality forecasting system is operated at 16 weir segments to ensure the safety of water-friendly activities and protect aquatic ecosystems. The system uses IT-based numerical modeling techniques based on pollution source, river flow, and meteorological data to predict water temperatures, chlorophyll-a concentration, and other water quality information on a weekly basis. The information is notified to associated institutions in advance.
If the system predicts the algal growth requiring water quality control, the water quality control level is announced and appropriate actions are taken. The water quality control level consists of four stages - Attention, Caution, Warning, and Severe - depending on chlorophyll-a concentration, duration and blue-green algae count.
The water quality forecast system was implemented in 2012. By 2013, the water quality control levels were announced 146 times at eight weir segments of the Nakdong River, 96 times for three weir segments of the Geum River, and 170 times for two weir segments of the Yeongsan River.And appropriate actions were taken according to the each stage.
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Last modified : 2017-12-12 08:38
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