Stream Monitoring

Lab-Developed
Urban Stream
Monitoring System

High-frequency water-quality monitoring
of an urban stream in Seoul, South Korea
using a YSI EXO2 sonde

YSI EXO2 10-min interval Storm-event response

01. Project Overview

Urban catchments rapidly convey stormwater and pollutants to receiving streams through urban drainage networks, particularly during storm events. To capture these dynamic responses at high temporal resolution, a YSI EXO2-based water-quality monitoring system was installed in the upper Dorim catchment near Sindaebang Station, Seoul, South Korea, on March 27, 2026.

Location of the study area: South Korea (left), Seoul (middle), and the YSI EXO2 monitoring site in the upper Dorim catchment (right; 23 km²)

02. Multiparameter Sonde, YSI EXO2

The YSI EXO2 provides continuous in-situ monitoring in urban streams through its modular sensors, built-in data logging, data-transfer functions, and programmable wiper operation, which enables reliable field deployment and long-term data collection.

YSI EXO2 monitoring system: equipment and protective enclosure (left), and in-stream deployment (right)

Measured variables

| Physicochemical |
Temperature, Electrical conductivity, pH, Dissolved oxygen

| Nutrients |
Ammonium nitrogen (NH4+-N), Nitrate nitrogen (NO3--N)

| Algal |
Chlorophyll, Phycocyanin

03. Regular Site Visits and Sensor Maintenance

We conduct regular field visits every two weeks to inspect site conditions, clean the YSI EXO2 sonde, and perform three-point calibration for nutrient sensors. Full sensor calibration is conducted monthly, and the monitoring data are being compared with rainfall records and grab-sample measurements for quality control and storm event-based analysis.

YSI EXO2 installation Regular field visits Study area overview Equipment maintenance, cleaning, and calibration