What is a key advantage of using surface-water sources like lakes over river water sources?

Using surface-water sources such as lakes typically provides a key advantage in terms of water quality. Lakes often have a more uniform quality of water compared to rivers. This is largely due to their relatively stable conditions, where water can settle and thus impurities can settle out over time, leading to a more consistent composition.

Additionally, lakes are generally less affected by rapid changes in environmental conditions and can provide a more stable supply of water. In contrast, river water quality may fluctuate significantly due to varying factors such as rainfall, runoff, and upstream activities, which can introduce contaminants or alter the water's physical and chemical properties.

While treatment is often still required for lake water, and there are instances where lakes can be polluted or have issues with algae, the overall uniformity in quality is a distinct benefit that provides a reliable source of water for various uses.