FLOOD05724

• County: Statewide
• Basin: Statewide
• Title: Streambank Erosion Control Methods
• Date: 3/19/1984
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Floodplain Report/Masterplan

SHORT ROCK JETTY HARDPOINTS

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I. .seeded
Norma I
Water: Surrace

Stone Fill

TYPICAL SECTIOAl

Hardpotnts are effective In deflecting the current away from the eroding bank. A series
of jetties along the bank tends to create back currents between the jetties. This
produces a siltation of foreshore between the projecting dikes of rock. Rock should be of
sufficient weight to resist the river current.

The hardpolnt jetty consists of stone-fill structures placed Intermittently along an
eroding bank I Ine. The jetty Is placed to protrude a short distance Into the river channel
near the normal water surface level. A root section should be constructed Into the
bankl Ine to provide protection to prevent stream cutting action behind the hardpolnt. For
best resu I ts a $ar I es of hardpo t nts can be used. Back currents are formed a I low i ng
siltation to occur. This wi I I provide added bank protection.

ADVANTAGES:

1) No requirement for sediment deposit In hardpolnt field.

2) I mpermeab I I Ity al lows reduction of erosIon force of stream.

DISADVANTAGES: 1) Heavy equipment required for construction.

2) ModeraTely high firST COST.

3) Difficult to construct where access is limited.

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