File:Solar panels 2.png

File:Solar panels 2.png

Rain falls on the solar panel and runs off to the edge of the panel, where it falls vertically at the dripline to the ground below. From there this water can infiltrate or move along the ground surface toward the next panel. The area beneath the panel consists of pervious soil with well-maintained vegetation. The area between panels includes the gravel road, which is impervious, and may include pervious soil with well-maintained vegetation. Water falling from a panel can infiltrate from the dripline until it encounters the gravel road, where it runs off until crossing the road and discharging to the pervious surface across the road. This water can then infiltrate until the next dripline, where additional water is supplied from the next panel. Note that the gravel road will contribute additional runoff water. Panels can be rotated from the horizontal position. α measures the angle of rotation from the horizontal position. Because the panel rotates, the length Z, which represents the horizontal distance beneath a panel, varies. The average value for Z is given by

\( Z = (COS(α max)H + COS(α min)) / 2 \)

where H is the horizontal length of the panel. Y, which is the length between panels, can vary depending on the angle of panel rotation, so for simplicity of calculations Y should be based on the average value of Z. The pervious portion of Y is calculated as Y minus W, where W is the width of the gravel road.