How is the "Minutes without Runoff" calculated in an irrigation system?

The calculation of "Minutes without Runoff" is based on the infiltration capacity of the soil and the rate at which water is being applied to the landscape. Option A states that Minutes are calculated as (Infiltration Rate * 60) / Precipitation Rate. This formulation is appropriate because it takes into account the rate at which water can be absorbed by the soil (infiltration rate) compared to the rate at which water is being applied (precipitation rate).

When irrigation occurs, if the precipitation rate exceeds the infiltration rate, the excess water cannot be absorbed quickly enough, resulting in runoff. Therefore, understanding how long the soil can continue to absorb water without overflowing into runoff is crucial for effective irrigation management. By multiplying the infiltration rate by 60, you're converting the rate from an hourly basis to minutes, which allows for more precise scheduling of irrigation events and helps prevent water wastage.

Other options do not accurately reflect the relationship needed to determine the duration before runoff occurs. They incorporate factors like soil type, water demand, and pressure rate that don’t directly inform the duration of runoff. Hence, option A provides the correct method to calculate "Minutes without Runoff" effectively.