One key measure of river health is Total Dissolved Solids (TDS). Basically, TDS measures how many dissolved minerals, salts, and organic matter are in the water. High TDS can harm ecosystems and affect water use.
The scientists found that:
(1) TDS spikes often happened in rainy months (Aug–Oct), linked to runoff from farms and urban areas.
(2) Forests & wetlands helped stabilize water quality (buffering TDS), while developed/barren lands worsened it.
(3) Temperature played a big role in TDS levels; warmer temps often meant higher TDS.
(4) Midstream sections of the river (Warren County) showed the most concern for elevated TDS.
What this means:
(1) Natural land cover = healthier water.
(2) Agriculture & urban runoff = higher risk for poor water quality.
Source: Salas, E.A.L., Kumaran, S.S., Bennett, R. et al. Integration of Google Earth Engine, Sentinel-2 images, and machine learning for temporal mapping of total dissolved solids in river systems. Sci Rep 15, 27555 (2025). https://doi.org/10.1038/s41598-025-12548-9