type of area is often located behind a house, at the base of a
slope, where excess run-off is directed to a lawn area that's nearly
level. Other times, the wet area might be along property lines where
two adjoining lots were graded separately. Whatever the case may be,
the goal is always the same: move water away from the soggy area.
Once the decision is made to install a french drain, the next step
is determining where to end the french drain, and where to send the water. In
most situations, the best place to channel the water is toward the
front street curb, if you're on the high side of the street, but this presents
other potential problems.
WHERE TO THE CHANNEL WATER
>> TO THE CURB: Piping
storm water to the curb, and dumping it into the street, is often
done with downspout connections in new building plans, especially when they can't be
tied-in to existing storm sewers. Most storm sewer systems have been
engineered for set flow rates, and it's usually difficult to get
permission to tie-in to an existing storm sewer, even though this is
the ideal solution.
The biggest problem with water dumped over the
curb, is it ices-up in northern areas with a winter
season. In freezing weather, the steady flow of underground water can create large
"ice flows" along the curb, that create a sliding hazard to pedestrians and
vehicles. In summer, water flow along a curb can create algae, as
well as a favorable environment for mosquitoes.
connecting to a storm sewer requires advance permission from your
local municipality. Therefore, if you must send water to the
curb area, check applicable local laws and ordinances first.
French drain we saw in our travels...
It was installed at the top of a slope
to intercept water runoff from above.
Water flow was piped to the curb.
>> INTO A DOWNSPOUT: Tying
your french drain into an existing downspout is another solution.
This is often done when no other solution exists. The biggest
downside to this type of arrangement is that you are sending water
back toward the foundation area of the house. It's not uncommon for
these downspout and foundation areas to already have drainage
problems that cause wet basements. Adding to that foundation water flow can
aggravate many existing problems. Often times, downspout pipes and french drain pipes around the foundation of a house become
disconnected as soil settles over the years. Therefore,
before electing to use this solution for your french drain, make
sure everything is connected properly underground so that you won't
be adding to any existing problem with wet basement walls.
>> OVER THE HILL: With a large enough building lot, it's often possible to direct french drain
water onto the surface of the lawn. In effect, this only moves the
wet area to a different part of your property, but in the right
situations, this solution works well. Remember never to direct water
onto a neighbor's property.
>> INTO A DRY WELL:
Old-timers often used a drainage solution known as a dry well. A dry
well is nothing more than a large hole in the ground, backfilled
with rocks or large gravel. Water is piped into the dry well with
the intent of it percolating out of the dry well into the
surrounding soil. In ideal situations, with soil that drains rapidly,
this solution works well. However, if the surrounding soil is heavy
clay, the dry well may only act as a bath tub, filling with water,
which then flows backwards up the french drain pipe, re-flooding the
area you are attempting to drain.