Cost Effective Dewatering
- By Cameron Green
- Aug 1, 2014
We recently consulted with a client looking to purchase a trash pump he would utilize to manage an ongoing dewatering issue on a specific construction site. He planned to continue to utilize the pump in future dewatering situations throughout his diverse construction company field operations far beyond his present needs as well.
His first questions to us focused on simply how much water he had to deal with. He came with just the right information for use to set out in helping him determine the best pump for his application. He knew the pond acreage which essentially is a measure of the surface area we were going to have to consider. He also had and estimated depth of the lake or pond he was going to have to dewater. Based upon that information our calculations provided us the gallons of water he had to deal with. There are many helpful on-line pond or lake calculators available. We find these sites to be simple and helpful: Pond Volume Calculator or LakeLawnAndPond
With the gallons in hand we were now able to estimate the time to drain his present pond by dividing by gallons per minute discharge capacity of each pump he was considering. Though simply and estimate of the theoretical time it would take him to empty his pond, this calculation gave us a rough order of time investment he would have to figure in manning his pump until the pond was dry. Generally, the lower the GPM and investment level equated to a longer time until dry, while the greater investment and discharge capacity meant a speedier time to drain the pond.
The question was asked if you could leave the pump unmanned and the likely outcome if the pump were to lose prime (or quit pumping water because the suction hose lost back pressure after being removed from the water source) or if the engine were allowed to run out of fuel while pumping. We always frown on these two situations because of the damage that can and will be caused to the pump. There are auto starting and stopping pumps, like Multiquip’s ActivePrime series of pumps that utilize a float system that allows a pump to be remotely operated and turned on and off based upon the water levels of the dewatering area. Though many pump operators may allow their pumps to run out of fuel, our engine manufactures will not endorse this kind of operation. Warranty claims due to such operations will likely be declined.
The operator also had solids content to consider during his pump operations. He was convinced that material of 1-2 inches were likely to be passed through the pump and thus he had easily concluded on the need for a 4-6 inch trash pump which in most cases have no problems handling such materials.
The questions now remained about how he would man the pump during dewatering and if he could justify the price point of a quicker dewatering situation or if he could handle a little more time consuming operation at a more affordable price point.
Given the work hours of his field foreman and superintendents and their availability to man the pumps during the work day, he felt dropping down to the 4 inch pump from 6 inches would be a cost effective solution that still allowed him to dewater at an acceptable rate. He did accommodate for a full day run time though by making sure the trailer mounted pump had a fuel cell that allowed him to run at least a continuous 12 hours. Many of the trailer mounted diesel trash pumps have continuous run times of well over 20 hours thus surpassing most work day hours.
Because of his pond’s capacity, he was looking at over a week’s worth of pumping to totally dewater his pond. For many, this is unacceptable due to the urgency around the work that dewatering may delay or postpone. For some in emergency dewatering situations, the only option is the absolute fastest and largest capacity pumps.
The above narrative is something we walk through on a daily basis with our customers at Absolute Water Pumps. Each contractor, municipality or other organization has their unique situation to consider. At the end of the day we simply enjoy equipping our clients with the most cost effective dewatering solution for their application and budget.
Give us a call at 888-264-2189 or start reviewing our available pumps for your application by clicking here.
