Riprap (in

North American English North American English (NAmE) encompasses the English language as spoken in both the United States and Canada. Because of their related histories and cultures, plus the similarities between the pronunciations (accents), vocabulary, and grammar ...

), also known as rip rap, rip-rap, shot rock, rock armour (in

British English British English is the set of Variety (linguistics), varieties of the English language native to the United Kingdom, especially Great Britain. More narrowly, it can refer specifically to the English language in England, or, more broadly, to ...

) or

rubble Rubble is broken stone, of irregular size, shape and texture; undressed especially as a filling-in. Rubble naturally found in the soil is known also as 'brash' (compare cornbrash)."Rubble" def. 2., "Brash n. 2. def. 1. ''Oxford English Dictionar ...

, is human-placed rock or other material used to protect shoreline structures against

scour Scour may refer to: Hydrodynamic processes * Hydrodynamic scour, the removal of sediment such as sand and silt from around an object by water flow ** Bridge scour, erosion of soil around at the base of a bridge pier or abutments via the flow ...

and water, wave, or ice erosion. Riprap is used to

armor Armour (Commonwealth English) or armor (American English; see American and British English spelling differences#-our, -or, spelling differences) is a covering used to protect an object, individual, or vehicle from physical injury or damage, e ...

shore A coast (coastline, shoreline, seashore) is the land next to the sea or the line that forms the boundary between the land and the ocean or a lake. Coasts are influenced by the topography of the surrounding landscape and by aquatic erosion, su ...

lines, streambeds, bridge

abutments An abutment is the Bridge#Structure types, substructure at the ends of a bridge Span (architecture), span or dam supporting its Bridge#Structure types, superstructure. Single-span bridges have abutments at each end that provide vertical and l ...

, foundational infrastructure supports and other shoreline structures against erosion. Common rock types used include

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

and modular

concrete Concrete is a composite material composed of aggregate bound together with a fluid cement that cures to a solid over time. It is the second-most-used substance (after water), the most–widely used building material, and the most-manufactur ...

blocks.

Rubble Rubble is broken stone, of irregular size, shape and texture; undressed especially as a filling-in. Rubble naturally found in the soil is known also as 'brash' (compare cornbrash)."Rubble" def. 2., "Brash n. 2. def. 1. ''Oxford English Dictionar ...

from building and paving demolition is sometimes used, as well as specifically designed structures called ''tetrapods'' or similar concrete blocks. Riprap is also used underwater to cap immersed tubes sunken on the seabed to be joined into an

undersea tunnel An underwater tunnel is a tunnel which is partly or wholly constructed under the sea or a river. They are often used where building a bridge or operating a ferry link is unviable, or to provide competition or relief for existing bridges or ferry l ...

Environmental effects

Sediment effects

Riprap causes morphological changes in the riverbeds they surround. One such change is the reduction of sediment settlement in the river channel, which can lead to scouring of the river bed as well as coarser sediment particles. This can be combatted by increasing the distance between the pieces of riprap and using a variety of sizes. The usage of riprap may not even stop erosion, but simply move it downstream. Additionally, the soil beneath the riprap can be eroded if the rock was just placed on top without any buffer between the layers such as a

geotextile Geotextiles are versatile permeable fabrics that, when used in conjunction with soil, can effectively perform multiple functions, including separation, filtration, reinforcement, protection, and drainage. Typically crafted from polypropylene or ...

fabric or smaller riprap (

crushed stone Crushed stone or angular rock is a form of construction aggregate, typically produced by mining a suitable rock deposit and breaking the removed rock down to the desired size using crushers. It is distinct from naturally occurring gravel, whi ...

Changes in organic material and the ecosystem

Riprap affects the amount of organic material in a waterbody by acting as a filter, catching wood and leaves before they can enter the water. Riprap also covers and prevents plants from growing through, which can reduce shade over the water. Introducing ripraps creates a rocky environment that can affect a waterbody's

ecology Ecology () is the natural science of the relationships among living organisms and their Natural environment, environment. Ecology considers organisms at the individual, population, community (ecology), community, ecosystem, and biosphere lev ...

by making the ecosystem more heterogeneous. While it can negatively affect some

organisms An organism is any living thing that functions as an individual. Such a definition raises more problems than it solves, not least because the concept of an individual is also difficult. Many criteria, few of them widely accepted, have been pr ...

by removing shoreline vegetation, the rock can provide important refuge for

invertebrates Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordate subphylum ...

and small

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

. By preventing woody plants from growing and shading the water, riprap can also increase the amount of

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

and hydrophytes.

Gallery

File:11-8-07 riprap photo.jpg,

Concrete Concrete is a composite material composed of aggregate bound together with a fluid cement that cures to a solid over time. It is the second-most-used substance (after water), the most–widely used building material, and the most-manufactur ...

rubble used as riprap along the

San Francisco Bay San Francisco Bay (Chochenyo language, Chochenyo: 'ommu) is a large tidal estuary in the United States, U.S. state of California, and gives its name to the San Francisco Bay Area. It is dominated by the cities of San Francisco, California, San ...

shoreline File:Sea defences - geograph.org.uk - 775461.jpg, Modular concrete block riprap File:Access to Beach is Blocked - geograph.org.uk - 1107949.jpg, Modular concrete block riprap File:Cape Hinomisaki Izumo04bs3200.jpg, Modular concrete block riprap File:Riprap.jpg, Riprap lining a lake shore File:Construction of river channel closing structure in the Mississippi NRRA (7df8f79e-1761-4967-a358-64b4e9a4d1c3).jpg, Riprap closing off a channel on the

Mississippi River The Mississippi River is the main stem, primary river of the largest drainage basin in the United States. It is the second-longest river in the United States, behind only the Missouri River, Missouri. From its traditional source of Lake Ita ...

File:Corps completes Yolo Bypass levee repairs (6792076725).jpg, Riprap protecting a

levee A levee ( or ), dike (American English), dyke (British English; see American and British English spelling differences#Miscellaneous spelling differences, spelling differences), embankment, floodbank, or stop bank is an elevated ridge, natural ...

File:Crews replacing riprap at Seawall.jpg, Crews replacing riprap at

Galveston Galveston ( ) is a Gulf Coast of the United States, coastal resort town, resort city and port off the Southeast Texas coast on Galveston Island and Pelican Island (Texas), Pelican Island in the U.S. state of Texas. The community of , with a pop ...

Seawall after a 1915 hurricane File:Dawlish Warren , Rip Rap and Coastal Scenery - geograph.org.uk - 1345833.jpg, Riprap protecting a concrete retaining wall

References

* Ciria-CUR (2007)
Rock Manual - The use of rock in hydraulic engineering
* N.W.H. Allsop (2002)
Breakwaters, coastal structures and coastlines
*US Dept. of Transportation (2004)

External links

Ohio Dept. of Natural Resources riprap guideUS Bureau of Reclamation publication on riprap for dam overtoppingUSGS Minerals Yearbook: Stone, Crushed
{{geotechnical engineering Building stone Types of wall Earthworks (engineering) Coastal construction