Temporal scale-induced uncertainty in load duration curves for instream-dissolved oxygen

Area of Science:

• Environmental science
• Hydrology
• Water quality assessment

Background:

• Dissolved oxygen (DO) is critical for aquatic ecosystems.
• Understanding DO dynamics is essential for effective water resource management.
• Temporal data resolution can significantly impact water quality assessments.

Purpose of the Study:

• To introduce the concept of 'dissolved oxygen reserve'.
• To analyze the effect of temporal resolution on DO reserve duration curves for the Amite River.
• To develop regression equations for simplified water quality monitoring.

Main Methods:

• Hydrological Simulation Program FORTRAN (HSPF) modeling was used to develop DO load duration curves.
• Duration curves were generated using daily, weekly, biweekly, and monthly average data.
• Seasonal analysis and coefficient of variation (CV) were employed to assess temporal scale effects.

Main Results:

• Daily DO data showed higher variability in load estimates compared to biweekly and monthly data.
• A seasonal trend in DO reserve was identified.
• Regression equations were developed to simplify flow and water quality monitoring, reducing associated costs.

Conclusions:

• Temporal resolution significantly influences DO reserve estimations; lower resolutions (e.g., monthly) provide more stable estimates.
• The developed regression models offer a cost-effective approach for near real-time water quality monitoring.
• The study provides valuable insights for managing DO levels in the Amite River and similar systems.