are sometimes used to lower the groundwater levels in the leaching
area. They consist of a trench of crushed stone with a perforated
pipe near the bottom. The water they intercept is piped "to grade"
at a lower area of the lot, or piped to a storm drain or catch basin
in the road. The curtain drain should lower the ground water at least
two feet below the bottom of the system.
Curtain drains are required
to be at least twenty-five feet upslope of the leaching area. If downslope
of the system the setback is fifty feet.
Curtain drains can be used in conjuction with leaching systems that
are elevated with "select" fill.
SELECT FILL is clean sand
or sand and gravel that is used to elevate a properly prepared area
in order to install
the leaching system high enough above groundwater
or ledge. It has the added benefit of spreading the soakdown area
of the leaching units by saturating the soils between rows. It must
be able to meet the specifications of a complex "sieve analysis" that
is detailed in the code and which is mainly designed to severely limit
the amount of fine particles (fines) in the fill material.
Sometimes select fill is also used for "wick" holes that penetrate
the bottom of a leaching area. This is sometimes done to allow saturation
of better draining soils below while keeping the bottom of the
system the requisite height.
Curtain Drains and Select Fill
Easton, Ct. ; Westport, Ct. ; Weston, Ct. ; Fairfield, Ct. ; Southport,
Ct. ; Monroe, Ct. ; Wilton, Ct. ; Newtown, Ct. ; Stratford, Ct. ;
Norwalk, Ct. ; Redding, Ct ; Darien, Ct. ; New Canaan, Ct. ; Shelton,
Ct. ; Oxford, Ct. ; Greenfield Hill, Ct. ; Trumbull, Ct.