Irricad

I'm a bit confused about the travel time, specifically the MAXIMUM LATERAL TRAVEL TIME. I would like to better understand how this time is calculated, as it seems to be greatly overestimated. For example, a lateral drip line that is only 50 meters long, at level, results in times exceeding 20 minutes, which is not accurate because we conduct field tests and this value does not occur. It seems that it adds up all the lateral lines. Could it be something like that?

The “Maximum Lateral Travel Time” noted in the Zone Summary report is the travel time just for the longest lateral in the zone, from the start of the lateral to the end of the lateral. You will also see this value in the Zone Travel Time Report “Lateral” column when you locate the longest lateral.

The theoretical travel times are calculated on the velocity in each segment of the lateral and these are added together for the total lateral travel time. For low-flow emitters such as dripline the travel time to the last emitter, when the flow is the smallest, can take longer than people think.

It is difficult to comment on your example without knowing more details.

I have drawn an example of a 50m length of dripline with 1.1lph emitters at 0.6m spacing with an internal diameter of 13.9mm. The total lateral travel time is 1491 seconds (24.85 minutes).
The velocity between the 2nd to last and the last emitter is only 0.002m/s and therefore it takes 300 seconds (5 minutes) to travel the last 0.6m distance. The time taken between the 3rd-to-last and 2nd-to-last emitters, with a velocity of 0.004m/s, is 150 seconds (2.5 minutes). Each of the 83 segments' time adds up to 24.86 minutes.

If you still have a concern about the results in your design please provide more details about the emitter and spacing in your dripline.

The IRRICAD Team