Shoreline management solutions at work."T" Walls
The three T wall units are designed as groins to stick out perpendicular to the bulkhead in the water to trap and hold sand that is normally carried along shore and out into the channel. They work best when there is significant sand in the ocean, river or bay system moving along the shore. They act to slow down the water thereby lowering the amount of entrained sand the water can carry and causing the sand to settle out between the groins.
Seament Shoreline Systems Inc. uses an upside down "T" design of
concrete sections that are bolted together to form the groins. Each piece
is ten feet long, two feet nine inches high and two feet six inches wide. 
The concrete is minimum 5000psi Department
of Transportation bridge grade mix with rebar placed horizontally and
vertically. They weigh approximately one ton each. A tongue and groove
joint is used between each section. An angled cut-out on the land ward end
of the Type A unit allows it to fit up against the L wall bulkhead splash
plate. The groins can be from 20 feet long with a type A and C unit, to as
long as needed by adding additional type B units in between them as
necessary. The Type C unit has a taper slanting to the seaward end to
present a "low profile" groin. The Army Corps of Engineers recommends this
to allow sand to pass downstream of the groin and help prevent the
creation of eddies at the end of the groin.