UAV-Deployable Open-Source Sensor Nodes for Spatial and Temporal In Situ Water Quality Monitoring and Mapping

Area of Science:

• Environmental Science
• Sensor Technology
• Aquatic Ecosystems

Background:

• Effective water quality management requires cost-efficient, spatially resolved monitoring.
• Existing methods can be expensive and lack real-time, high-resolution data.
• Protecting aquatic ecosystems necessitates continuous assessment of surface-water conditions.

Purpose of the Study:

• To develop a low-cost, open-source sensor node for unmanned aerial vehicle (UAV) deployment.
• To enable real-time, in situ assessment of key surface water quality parameters.
• To demonstrate the system's capability for spatially resolved water quality mapping.

Main Methods:

• Integration of sensors for pH, turbidity, temperature, and total dissolved solids (TDS).
• Onboard data logging with real-time clock (RTC) synchronization.
• Validation through bench testing and field deployment with Ordinary Kriging interpolation.

Main Results:

• The sensor node, costing approximately USD 200, achieved low validation errors (pH: 1.34%, TDS: 5.23%, temperature: 0.81%).
• Continuous operation for 42 hours was achieved.
• Field deployment successfully mapped spatial gradients in pH (6.0-6.7), turbidity (11-18 NTU), TDS (44-51 ppm), and temperature (22.8-24.6 °C).

Conclusions:

• The open-source, UAV-deployable sensor node offers a cost-effective solution for real-time water quality monitoring.
• The system effectively resolves spatial water quality variations, facilitating detailed mapping.
• This accessible platform supports both community-based and research-driven aquatic ecosystem assessments.