What is the measurement unit for precipitation rate (PR) as defined in MWELO?

The measurement unit for precipitation rate (PR) as defined in the Model Water Efficiency Landscape Ordinance (MWELO) is inches per hour. This unit is meaningful for landscape irrigation practices as it allows landscape architects and designers to evaluate how quickly water is deposited onto the soil surface during rainfall or irrigation events. Understanding precipitation rate in inches per hour assists in designing efficient irrigation systems that match the needs of specific landscape types, ensuring that the application of water closely aligns with evapotranspiration rates and minimizes water waste.

Other options such as liters per hour, gallons per minute, and feet per second, while they could theoretically be used to express rates of flow or volume, are not standard for precipitation in the context of landscape architecture and MWELO guidelines. The use of inches per hour provides a standardized, easily interpretable measure that is relevant for calculating irrigation requirements and assessing the effectiveness of water conservation measures.