Rip rap/ Rock armour by James Donnelly

The price

jdonnelly63147 — 2015-10-12 15:03:50 UTC

Construction coast 1,100 (£per meters a year)

Maintenance coast 5 (£per meter a year )

jdonnelly63147 — 2015-10-12 15:21:24 UTC

jdonnelly63147 — 2015-10-12 20:15:03 UTC

jdonnelly63147 — 2015-10-12 20:15:24 UTC

Purpose

jdonnelly63147 — 2015-10-12 20:25:18 UTC

To protect slopes, streambanks, channels, or areas subject to erosion by wave action.

Rock rip rap protects soil from erosion due to concentrated run off. It is used to stabilize slopes that are unstable due to seepage.

It is also used to slow the velocity of concentrated run off which in turn increases the potential for infiltration.

An example if this is Morecambe bay and Glynde Gap near east sussex

Where Practice Applies

jdonnelly63147 — 2015-10-12 20:27:07 UTC

Cut or fill slopes subject to seepage or weathering, particularly where conditions prohibit establishment of vegetation.

Channel side slopes and bottom.

Inlets and outlets for culverts, bridges, slope drains, grade stabilization structures, and storm drains; where the velocity of flow from these structures exceeds the capacity of the downstream area to resist erosion.

Stream banks and stream grades.Shorelines subject to wave action.

Advantages

jdonnelly63147 — 2015-10-12 20:28:54 UTC

Riprap offers an easy-to-use method for decreasing water velocity and protecting slopes from erosion. It is simple to install and maintain.

Riprap provides some water quality benefits by increasing roughness and decreasing the velocity of the flow, inducing settling.

Disadvantages/Problems

jdonnelly63147 — 2015-10-12 20:29:31 UTC

Riprap is more expensive than vegetated slopes.

There can be increased scour at the toe and ends of the riprap.

Riprap does not provide the habitat enhancement that vegetative practices do

Common Trouble Points

jdonnelly63147 — 2015-10-12 20:33:37 UTC

Excavation not deep enough: Riprap blocks channel, resulting in erosion along edges. Slope too steep: Results in stone displacement. Do not use riprap as a retaining wall. Foundation not properly smoothed for filter placement: Results in damage to filter. Filter omitted or damaged: Results in piping or slumping. Riprap not properly graded: Results in stone movement and erosion of foundation. Foundation toe not properly reinforced: Results in undercut riprap slope or slumping. Fill slopes not properly compacted before placing riprap: Results in stone displacement

Maintenance

jdonnelly63147 — 2015-10-12 20:34:10 UTC

Riprap should be checked at least annually and after every major storm for displaced stones, slumping, and erosion at edges, especially downstream or downslope. If the riprap has been damaged, it should be repaired immediately before further damage can take place.