Water Pressure and Drain Structures

Water Pressure can generate surprisingly large forces

Water pressure increases 0.433 pounds per square inch with for every foot of depth.

The water pressure can an generate surprisingly large forces on the lower flashboards and the structure in general.    These forces multiply with the width and height of the structure.  

Lower flashboards in a tall structure will experience higher pressure and can be difficult to remove on wide or tall structures.   

A 12-inch flashboard at the bottom of a 10-foot tall, 24-inch wide riser will be pushed toward the structure with 1247 pounds of force!

Rugged and Strong Drain Structures are Important!

Large pipes can generate massive suction forces from the pressure of the water flowing through them

Debris, animals and even people can be sucked through large drain pipes during flooded conditions. The forces increase with larger pipes and deeper water.

A 24-inch diameter pipe running full and submerged under three feet of water will create a suction force of 780 pounds!

We Avoid Recommending Larger Diameter Pipes.

We recommend utilizing spillways to handle flood water — they do not clog or restrain the maximum flow.

We recommend using the smallest pipe possible to level the pond during normal flow conditions.

We rely on 6-inch structures for most of our installations.