What metric is a key predictor of watershed health?

What metric is a key predictor of watershed health?

• A. Impervious cover percentage
• B. Vegetation index
• C. Percent forest cover
• D. Slope

Answer: (A)

Impervious cover percentage is a strong predictor of watershed health because it directly measures how much of the land surface blocks infiltration. When a watershed has more impervious surfaces like roads and buildings, rainfall becomes surface runoff instead of seeping into the soil to recharge groundwater. This runoff transports pollutants, increases erosion and sedimentation, and causes rapid shifts in stream flow, all of which undermine water quality and habitat in the watershed. While vegetation, forest cover, and slope influence hydrology and habitat, they don’t capture the same consistent signal of urban runoff intensity across different landscapes as impervious cover does.

Impervious cover percentage is a strong predictor of watershed health because it directly measures how much of the land surface blocks infiltration. When a watershed has more impervious surfaces like roads and buildings, rainfall becomes surface runoff instead of seeping into the soil to recharge groundwater. This runoff transports pollutants, increases erosion and sedimentation, and causes rapid shifts in stream flow, all of which undermine water quality and habitat in the watershed. While vegetation, forest cover, and slope influence hydrology and habitat, they don’t capture the same consistent signal of urban runoff intensity across different landscapes as impervious cover does.