Riprap

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Riprap used to protect a streambank from erosion Riprap Warren New Jersey.jpg
Riprap used to protect a streambank from erosion

Riprap (in North American English), also known as rip rap, rip-rap, shot rock, rock armour (in British English) or rubble, is human-placed rock or other material used to protect shoreline structures against scour and water, wave, or ice erosion. [1] [2] [3] Riprap is used to armor shorelines, streambeds, bridge abutments, foundational infrastructure supports and other shoreline structures against erosion. [1] [2] [3] Common rock types used include granite and modular concrete blocks. [4] [5] Rubble from building and paving demolition is sometimes used, [3] [6] 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.[ citation needed ]

Contents

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. [7]

The usage of riprap may not even stop erosion, but simply move it downstream. [8] 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 fabric or smaller riprap (crushed stone). [9]

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. [8] Riprap also covers and prevents plants from growing through, which can reduce shade over the water.

Introducing ripraps creates a rocky environment which can affect the ecology of a waterbody by making the ecosystem more heterogeneous. [10] While it can negatively affect some organisms by removing shoreline vegetation, the rock can provide important refuge for invertebrates and small fish. [8] [11] By preventing woody plants from growing and shading the water, riprap can also increase the amount of algae and hydrophytes. [12]

See also

Related Research Articles

<span class="mw-page-title-main">Longshore drift</span> Sediment moved by the longshore current

Longshore drift from longshore current is a geological process that consists of the transportation of sediments along a coast parallel to the shoreline, which is dependent on the angle of incoming wave direction. Oblique incoming wind squeezes water along the coast, and so generates a water current which moves parallel to the coast. Longshore drift is simply the sediment moved by the longshore current. This current and sediment movement occur within the surf zone. The process is also known as littoral drift.

<span class="mw-page-title-main">Groyne</span> Structure extending into a body of water to alter water flow

A groyne is a rigid hydraulic structure built perpendicularly from an ocean shore or a river bank, interrupting water flow and limiting the movement of sediment. It is usually made out of wood, concrete, or stone. In the ocean, groynes create beaches, prevent beach erosion caused by longshore drift where this is the dominant process and facilitate beach nourishment. There is also often cross-shore movement which if longer than the groyne will limit its effectiveness. In a river, groynes slow down the process of erosion and prevent ice-jamming, which in turn aids navigation.

<span class="mw-page-title-main">Geological hazard</span> Geological state that may lead to widespread damage or risk

A geologic hazard or geohazard is an adverse geologic condition capable of causing widespread damage or loss of property and life. These hazards are geological and environmental conditions and involve long-term or short-term geological processes. Geohazards can be relatively small features, but they can also attain huge dimensions and affect local and regional socio-economics to a large extent.

<span class="mw-page-title-main">Seawall</span> Form of coastal defence

A seawall is a form of coastal defense constructed where the sea, and associated coastal processes, impact directly upon the landforms of the coast. The purpose of a seawall is to protect areas of human habitation, conservation, and leisure activities from the action of tides, waves, or tsunamis. As a seawall is a static feature, it will conflict with the dynamic nature of the coast and impede the exchange of sediment between land and sea.

<span class="mw-page-title-main">Breakwater (structure)</span> Coastal defense structure

A breakwater is a permanent structure constructed at a coastal area to protect against tides, currents, waves, and storm surges. Breakwaters have been built since Antiquity to protect anchorages, helping isolate vessels from marine hazards such as wind-driven waves. A breakwater, also known in some contexts as a jetty or a Mole, may be connected to land or freestanding, and may contain a walkway or road for vehicle access.

<span class="mw-page-title-main">Revetment</span> Structures designed to absorb energy

A revetment in stream restoration, river engineering or coastal engineering is a facing of impact-resistant material applied to a bank or wall in order to absorb the energy of incoming water and protect it from erosion. River or coastal revetments are usually built to preserve the existing uses of the shoreline and to protect the slope.

<span class="mw-page-title-main">Coastal management</span> Preventing flooding and erosion of shorelines

Coastal management is defence against flooding and erosion, and techniques that stop erosion to claim lands. Protection against rising sea levels in the 21st century is crucial, as sea level rise accelerates due to climate change. Changes in sea level damage beaches and coastal systems are expected to rise at an increasing rate, causing coastal sediments to be disturbed by tidal energy.

<span class="mw-page-title-main">Accropode</span> Concrete breakwater element

Accropode blocks are wave-dissipating concrete blocks designed to resist the action of waves on breakwaters and coastal structures.

Hard engineering involves the construction of hydraulic structures to protect coasts from erosion. Such structures include seawalls, gabions, breakwaters, groynes and tetrapods.

Regarding the civil engineering of shorelines, soft engineering is a shoreline management practice that uses sustainable ecological principles to restore shoreline stabilization and protect riparian habitats. Soft Shoreline Engineering (SSE) uses the strategic placement of organic materials such as vegetation, stones, sand, debris, and other structural materials to reduce erosion, enhance shoreline aesthetic, soften the land-water interface, and lower costs of ecological restoration.

A-Jacks are a commercially made concrete product used in both open channel and coastal applications. They consist of two concrete T-shaped pieces joined perpendicularly at the middle, forming six legs. They are a product owned and patented worldwide by Poseidon Alliance Ltd.

<span class="mw-page-title-main">Tetrapod (structure)</span> Concrete breakwater element

A tetrapod is a form of wave-dissipating concrete block used to prevent erosion caused by weather and longshore drift, primarily to enforce coastal structures such as seawalls and breakwaters. Tetrapods are made of concrete, and use a tetrahedral shape to dissipate the force of incoming waves by allowing water to flow around rather than against them, and to reduce displacement by interlocking.

<span class="mw-page-title-main">Xbloc</span> Concrete breakwater element

An Xbloc is a wave-dissipating concrete block designed to protect shores, harbour walls, seawalls, breakwaters and other coastal structures from the direct impact of incoming waves. The Xbloc model was designed and developed in 2001 by the Dutch firm Delta Marine Consultants, now called BAM Infraconsult, a subsidiary of the Royal BAM Group. Xbloc has been subjected to extensive research by several universities.

Beach evolution occurs at the shoreline where sea, lake or river water is eroding the land. Beaches exist where sand accumulated from centuries-old, recurrent processes that erode rocky and sedimentary material into sand deposits. River deltas deposit silt from upriver, accreting at the river's outlet to extend lake or ocean shorelines. Catastrophic events such as tsunamis, hurricanes, and storm surges accelerate beach erosion.

Hudson's equation, also known as Hudson formula, is an equation used by coastal engineers to calculate the minimum size of riprap (armourstone) required to provide satisfactory stability characteristics for rubble structures such as breakwaters under attack from storm wave conditions.

<span class="mw-page-title-main">Coastal engineering</span> Branch of civil engineering

Coastal engineering is a branch of civil engineering concerned with the specific demands posed by constructing at or near the coast, as well as the development of the coast itself.

<span class="mw-page-title-main">Bridge scour</span> Erosion of sediment near bridge foundations by water

Bridge scour is the removal of sediment such as sand and gravel from around bridge abutments or piers. Hydrodynamic scour, caused by fast flowing water, can carve out scour holes, compromising the integrity of a structure.

<span class="mw-page-title-main">KOLOS</span> Concrete breakwater element

KOLOS is a wave-dissipating concrete block intended to protect coastal structures like seawalls and breakwaters from the ocean waves. These blocks were developed in India by Navayuga Engineering Company and were first adopted for the breakwaters of the Krishnapatnam Port along the East coast of India.

<span class="mw-page-title-main">Wave-dissipating concrete block</span> Shoreline defense

A wave-dissipating concrete block is a naturally or manually interlocking concrete structure designed and employed to minimize the effects of wave action upon shores and shoreline structures, such as quays and jetties.

<span class="mw-page-title-main">Jørgen Fredsøe</span>

Jørgen Fredsøe (1947) is a Danish hydraulic engineer who is recognized for his contributions within bed form dynamics in rivers and the marine environment and coastal morphology including bars and beach undulations. Together with professor B. Mutlu Sumer he initiated the research on scour (erosion) in the seabed around coastal structures applying detailed hydrodynamic interpretations. He was born in Randers, Denmark.

References

  1. 1 2 Trmal, Céline; Dupray, Sébastien; Heineke, Daan; McConnell, Kirsty (2009). "USING ROCK IN HYDRAULIC ENGINEERING – NEW GUIDANCE AN UPDATED VERSION OF THE MANUAL ON THE USE OF ROCK IN HYDRAULIC ENGINEERING". Coastal Structures 2007. Venice, Italy: World Scientific Publishing Company: 220–224. doi:10.1142/9789814282024_0020. ISBN   978-981-4280-99-0.
  2. 1 2 Breakwaters, coastal structures and coastlines : proceedings of the international conference organized by the Institution of Civil Engineers and held in London, UK on 26-28 September 2001. Allsop, N. W. H., Institution of Civil Engineers (Great Britain). London: T. Telford. 2002. ISBN   0-7277-3042-8. OCLC   51483089.{{cite book}}: CS1 maint: others (link)
  3. 1 2 3 "What is Riprap | Muse Hauling & Grading". www.musehg.com. Retrieved 2020-12-07.
  4. Aguilera, Moisés A.; Arias, René M.; Manzur, Tatiana (2019). "Mapping microhabitat thermal patterns in artificial breakwaters: Alteration of intertidal biodiversity by higher rock temperature". Ecology and Evolution. 9 (22): 12915–12927. Bibcode:2019EcoEv...912915A. doi:10.1002/ece3.5776. ISSN   2045-7758. PMC   6875675 . PMID   31788225.
  5. "Erosion Control Blankets vs. Rip Rap | East Coast Erosion". East Coast Erosion Control. 2020-05-22. Retrieved 2020-12-06.
  6. Brown, Scott A. (January 1989). "Welcome to ROSA P |". rosap.ntl.bts.gov. Retrieved 2020-12-06.
  7. Qi; et al. (June 2021). "Scour at pile groups and effects of riprap gradation and thickness on the scour reduction". Journal of Hydraulic Engineering. 52 (6) via ResearchGate.
  8. 1 2 3 Reid, David; Church, Michael (2015). "Geomorphic and Ecological Consequences of Riprap Placement in River Systems". JAWRA Journal of the American Water Resources Association. 51 (4): 1043–1059. Bibcode:2015JAWRA..51.1043R. doi:10.1111/jawr.12279. S2CID   129730847.
  9. Sfeir; et al. (August 2021). "RIPRAP FILTERS AND STABILITY OF RIPRAP COVERED SLOPES". Riprap for Scour Countermeasures via ResearchGate.
  10. Shields; et al. (June 1995). "Experiment in Stream Restoration". Journal of Hydraulic Engineering. 121 (6): 494–502. doi:10.1061/(ASCE)0733-9429(1995)121:6(494) via ASCE Library.
  11. Chhor, Auston D.; Glassman, Daniel M.; Smol, John P.; Vermaire, Jesse C.; Cooke, Steven J. (2020). "Ecological consequences of shoreline armoring on littoral fish and benthic macroinvertebrate communities in an Eastern Ontario lake". Aquatic Sciences. 82 (4): 73. Bibcode:2020AqSci..82...73C. doi:10.1007/s00027-020-00740-0. ISSN   1015-1621. S2CID   220857360.
  12. Fischenich, J. Craig (April 2003). "Effects of Riprap on Riverine and Riparian Ecosystems" (PDF). Wetlands Regulatory Assistance Program. Archived (PDF) from the original on June 1, 2022 via US Army Corps of Engineers.