Multi-Flow drainage systems are your best choice for draining paved
surfaces. They are being used with excellent results along highways,
city streets, runways, and under parking lots.
increase in Multi-Flow usage is part of a larger trend toward more
artificial drainage under paved surfaces due to a more complete understanding
of the relationship between good drainage and pavement life span.
Cities and states are continually seeking to make pavements last longer
in an effort to stretch budgets further.
A case for drainage under or along paved surfaces
dramatically extends the life of pavement. A recent FHWA survey reveals:
Quality of drainage Average
(Reality for most designs) 8
reasons why saturation contributes to premature pavement failure:
bases and subbases quickly soften and lose load capacity.
vehicles move across the surface, a pumping action is triggered
that washes fine particles from the soil creating voids.
cold climates, saturated soils expand when they freeze, causing
Some soils expand when wet, distorting the surface shape.
can permeate the subbase or the base from three different sources
- High water table especially during periods of higher than average
- Water moving laterally resulting from impermeable subsurface
- Water entering from the surface. Paved surfaces are surprisingly
FHWA studies show that water permeates pavement at a surprising
Typical infiltration rates:
33% to 50%
Concrete 50% to 67%
choose Multi-Flow for your pavement drainage?
Whether it is for new construction or addressing an existing problem,
Multi-Flow is a wise choice because 1. tt does a better job, 2. it
is convenient, 3. it will last, and 4. it will save money.
It does a better job –
Illinois DOT research (1991-1994) has concluded panel shaped drain
systems can collect excess water in 60% of the time. Kentucky DOT
studies (1994-1997) have confirmed those findings and have documented
the extended life expectancy and cost savings of well drained pavements.
drainage systems must be able to collect water and transport water.
Multi-Flow excels in both regards:
a water collection system –
Water can enter a Multi-Flow drain more readily because Multi-Flow
has greater surface area than traditional round pipe. The
more drainage product that there is in contact with surrounding
saturated soil, the more quickly drainage can take place.
a water transport system –
Once water has entered Multi-Flow flow channels, it moves
away from the saturated area quickly because the channels
are round and unobstructed, unlike those in other panel shaped
It is convenient –
At least three factors make Multi-Flow a product that engineers,
contractors and public works departments love to work with.
– Because of its panel shape, Multi-Flow can be installed
in a narrow trench. A rock wheel or chain trencher can cut
a narrow trench for installation. The result is less excavated
material to haul away, less backfill to haul in, less time
spent, and of course, less expense. In repair situations,
it also results in less damage to existing pavement.
– Not only are Multi-Flow connectors easy to use, there
are a lot of them. Any configuration that is appropriate for
a given site can be carried out using one or more of the 60
example, airport runways demand exceptional drainage due to heavy
loading, and lack of elevation. Custom manufactured connectors
make it possible to install Multi-Flow in multiple layers adjacent
to the runway, providing unparalleled drainage performance.
Multi-Flow is easily bent making it convenient to work with,
suitable for making tight turns, and easily joined to connectors.
It will last
There are two primary reasons why Multi-Flow systems significantly
outlast other drainage options.
– Multi-Flow is designed to withstand heavy loads. Able
to tolerate loads well in excess of 6,000 psf, Multi-Flow
is not going to collapse due to heavy surface loads in shallow
installations or due to earth weight in deep installations.
The Multi-Flow system includes a heavy effective geotextile
filter. This high quality fabric acts as an excellent secondary
filter, keeping Multi-Flow’s flow channels clean and
open. Clean coarse sand acts as a very effective primary filter.
Due to its shape, Multi-Flow is easily encased in sand, assuring
a long life. When placed in a 4 inch wide trench Multi-Flow
is readily protected in this way. This would be difficult
if not impossible using French drain methodology.
It will save money –
A completed Multi-Flow system typically costs about half as much
as a comparable French drain system. Add to that its longer life
and Multi-Flow begins to look very attractive! Now factor in the
cost of replacing the pavement prematurely and Multi-Flow is a system
you cannot afford to live without.
Sample Projects - Paved Surfaces
Paved Surface Design Assistance
Paved Surface Installation
Paved Surfaces Model Specs