The water turbidity is the measure of water transparency. Water turbidity is used to assess the water quality.
It is a fundamental variable as it allows to analyse drinking water. According to the WHO (World Health Organization), drinking water should have a turbidity of less than 5 NTU (Nephelometric Turbidity Units). Also, water turbidity is an important variable when studying water ecosystems. Indeed, turbidity decreases the amount of light going through the water and thus affects a large range of metabolic and biogeochemical processes. For instance, turbidity decreases the photosynthetic activity, thus contributing to the decrease of oxygen concentration in the water.
Water turbidity can be measured from water samples or remote sensed using satellite/airborne sensors.