"mgd" stands for "million gallons per day," a unit of measurement commonly used to quantify the flow rate of water or wastewater. It is often used in the context of water treatment facilities, municipal water supply systems, and environmental studies to assess water usage and availability. This measurement helps engineers and planners understand how much water is being consumed or treated daily. For example, a city might report its water supply in mgd to monitor usage trends and ensure sustainable management of its water resources.