The replica dam that we created was made actually out of wood that had either a single 1 inch hole drilled into the center, or two half inch holes that were the same distance from the center to let some of the water through similar to a hydroelectric dam. The hole was big enough as to not let the water drain above of the dam. However, there was a bit of water that found its way underneath the dam by saturating through the soil. This raises question because things must be done to prevent this because it would weaken the area underneath the dam.
2 .5" holes: Time to fill 2.5 gallons: 2:40.9 seconds
Flow Rate: 0.01554 Gal/sec
1 1" hole: Time to fill 2.5 gallons : 2:54.5 seconds
Flow Rate: 0.01433 Gal/sec
2 .5" holes: Time to fill 2.5 gallons: 2:40.9 seconds
Flow Rate: 0.01554 Gal/sec
1 1" hole: Time to fill 2.5 gallons : 2:54.5 seconds
Flow Rate: 0.01433 Gal/sec