GRADED FILTER DRAINS IN DAMS

Successes And Failures in the Western Part of Virginia

Thomas I. Roberts, P.E., C.F.M.

Spillway Conduit Failures Spillway Conduit ProblemsSpillway Conduit Problems

Seepage along outlet conduit

Parts of an Embankment Dam

Groin

Toe Drain

Toe Drain Outfall

Outlet Works

Emergency

(Auxiliary)

Spillway

Principal

Spillway

(Inlet Riser)

Reservoir

Upstream Slope

Crest

Typical illustration with mention of Toe Drain

Section Through an

Earthen Embankment Dam

Note – Anti-Seepage Collar – Wrong!

Green Grass Shows Sliding Rafted

Materials. Note Lack of Rafted

Material Everywhere Else.

Rafted Materials

Cavity Between Rafted

Material and Face of Dam

Junk Fill In Dam

NEW FILTER DRAIN

ROUGH

FIELD TEST

OF

INSTALLED

FILTER

OUTFALL OF FILTER

DRAIN PIPE – NOT

CHECKABLE AND NOT

MEASUREABLE

NOTE - OPEN

GRADED STONE –

A BAD SIGN!

GRADED FILTER DRAINS IN DAMS

Successes And Failures in the Western Part of Virginia

QUESTIONS?

Thomas I. Roberts, P.E., C.F.M.

E-MAIL:

THOMAS.ROBERTS@DCR.VIRGINIA.GOV