Why is it called the “Marlee Float”?
South Carolina started requiring skimmers in January, 2013. Months leading up to that there were several seminars and informational meetings on the new requirements. In December, 2012 my daughter, Marlee, was having a hard time sleeping and asked to sleep with my wife and me. She was tossing and turning, keeping me awake most of the night. As you can imagine I had all sorts of things going through my head. One of them was an idea for a new skimmer. After an hour or so of thinking about it, I got up and sketched out the idea. The result was the skimmer we have today. It was only fitting to name it after my inspiration.
What is a skimmer and why is it needed?
A skimmer, also called a surface drain, is an erosion control device used in sediment basins to increase sediment trapping efficiency. When muddy water enters the basin, the sediment begins to settle to the bottom. When looking at the water column, the cleaner water is towards the surface. Skimmers are designed to release the water from near the surface first and to do so slowly, allowing time for the sediment to settle to the bottom of the pond.
What is different about this skimmer from others?
The primary differences between the Marlee Float and most other skimmers are:
Is this skimmer “approved” for use and if so where?
The device meets all EPA requirements for skimmers/surface drains, as well as requirements for use in all states with surface withdrawl requirements. Neither state has an "approval" process for specific skimmers, but rather they have general requirements and rely upon the project engineer.
We have taken an additional step to have the Marlee Float third party tested and the flow rates verified by a Professional Engineer, so design professionals have assurance that our product functions as published. SCDOT, PADEP & GADOT have approved the use of our skimmer in DOT projects. NCDOT and ALDOT are in the process of testing in multiple locations. The device is being evaluated for use in other states and confirmation of meeting other state requirements will be added as confirmed.
How is this skimmer incorporated into the basin design?
This depends on state or local requirements. Generally states require that the skimmer be sized to drain the basin volume over a specified time frame. For example, South Carolina requires that the sediment basin be drained from near the surface and over a time period of 2-5 days, with 3 days being preferred. A simplified method is to determine the volume of the basin to be drained and then using the average flow rate for each skimmer determine which one(s) meet the required drawdown time range. If a conservative approach is used then this is a generally accepted method for selecting skimmers.
Although skimmers are often referred to as "constant-flow" devices, testing has shown the flow rates actually vary by basin depth. Because the flow rates do vary, a more accurate way to incorporate the device into the design is by inputting the actual discharge rate at given elevations into stormwater modeling software. We provide flow rate data based upon our third party test results for use by engineers when a more precise design is preferred or required. Click here for details.
We have also developed an easy to use design tool for use by engineers that takes into account the actual flow rates of the Marlee Float, as well as basin size and depth.
Your flexible coupling is different from others. Is it flexible enough?
This is a very common question and the answer is YES! The device has been thoroughly tested and as long as it is installed according to manufacturer recommendations the couplings will perform well. Click here for a video of a complete installation that demonstrates the flexibility.
When using a straight line coupling, such as a 3"x3", it is important to not butt the pipes together and to leave +-/2" between the pipes to allow the coupling to flex properly. The flex should be checked during installation by simply lifting the skimmer to confirm it flexes properly.
We are also currently developing and testing a more flexible coupling for use when needed. If you have a specific need for a custom solution, it can be provided.
How long will it last?
HDPE is highly U-V resistant. Although no specific life span is specified for HDPE, we would expect the device to last for a minimum of 10 years and likely much longer. It comes with a one-year warranty.
Because of the long life span, the skimmer can be reused on future projects and because each model of the Marlee Float has a range of flow rates it is adaptable for different size basins.
Can this device be used in a permanent pond?
Because this skimmer is made of UV-resistant materials and has a long life, it is a cost-effective tool for use as a part of the outlet system in permanent basins, both wet and dry. The unique design allows for very low flows while minimizing clogging, making it an excellent alternative to small orifices often needed to meet permanent water quality requirements. Engineers have informed us that use of the Marlee Float in place of a low flow orifice has also saved up to 20% on required pond volumes.
Is it easy to install?
The simple installation can be completed by one person in approximately 5 minutes and is accomplished by installing two Fernco couplings (provided). Detailed cut sheets/installation instructions can be downloaded here. We do suggest use of a cordless drill to aid in tightening the clamps on the Fernco couplings and installing screws through the couplings into the pipe. For the Model 3 the weight is removable for easier handling by unscrewing four wing nuts.
The only part not included is the barrel connecting the skimmer to the outlet structure. The barrel can be PVC for temporary sediment basins but should be HDPE for permanent applications. The barrel length should be a minimum of 1.5, and preferably 2 times, the height of the riser structure.
How does it compare to the Faircloth skimmer and others?
We have compiled a detailed comparison chart that can be found here. The flow rates for the Marlee Float skimmers are similar to the Faircloth skimmer and others, however, there are variations. For example, the Marlee Float 2.5" skimmer is closer in flow rate to the Faircloth 3" than the Marlee Float 3". It is important to compare flow rates, not necessarily size of skimmer or orifice, when comparing brands or looking for an "equal". Because most sediment basins are allowed to drain over a range of time, it is not usually necessary to match flow rates exactly. The Engineer of Record should approve a change from one skimmer brand to another if there are any questions. Our design tool can aid in confirming the appropriate skimmer size.
The engineer specified a different skimmer on the plans, can I use the Marlee Float instead?
Using the comparison chart you can compare the flow rates of the Marlee Float to other brands. Many plans will specify a basin volume and range for draw down time, which allows for easy confirmation of suitable equivalents using the comparison chart or design tool. Ultimately it is up to the Engineer of Record to allow a brand substitution if not specifically allowed on the plans or if questions arise.
If there are any questions as to the suitability of the Marlee Float as an equal to another skimmer we will be glad to assist in verification and coordination with the Engineer of Record and/or local regulatory agency, as needed. You can contact us at firstname.lastname@example.org or 1-855-697-9333.