Riprap

{{Short description|Rock or concrete protective armour}} thumb|260x260px|Riprap used to protect a streambank from erosion {{wikt}}

'''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 hard, heavy, unconsolidated material used to protect shoreline structures against scour and water, wave, or ice erosion.<ref name=":2">{{Cite journal|last1=Trmal|first1=Céline|last2=Dupray|first2=Sébastien|last3=Heineke|first3=Daan|last4=McConnell|first4=Kirsty|date=2009|title=USING ROCK IN HYDRAULIC ENGINEERING – NEW GUIDANCE AN UPDATED VERSION OF THE MANUAL ON THE USE OF ROCK IN HYDRAULIC ENGINEERING|url=http://www.worldscientific.com/doi/abs/10.1142/9789814282024_0020|journal=Coastal Structures 2007|language=en|location=Venice, Italy|publisher=World Scientific Publishing Company|pages=220–224|doi=10.1142/9789814282024_0020|isbn=978-981-4280-99-0|url-access=subscription}}</ref><ref name=":3">{{Cite book|title=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|date=2002|publisher=T. Telford|others=Allsop, N. W. H., Institution of Civil Engineers (Great Britain)|isbn=0-7277-3042-8|location=London|oclc=51483089}}</ref><ref name=":4">{{Cite web|title=What is Riprap {{!}} Muse Hauling & Grading|url=https://www.musehg.com/what-is-rip-rap/|access-date=2020-12-07|website=www.musehg.com}}</ref> Riprap is used to armor shorelines, streambeds, bridge abutments, foundational infrastructure supports and other shoreline structures against erosion.<ref name=":2" /><ref name=":3" /><ref name=":4" /> Common rock types used include granite and modular concrete blocks.<ref>{{Cite journal|last1=Aguilera|first1=Moisés A.|last2=Arias|first2=René M.|last3=Manzur|first3=Tatiana|date=2019|title=Mapping microhabitat thermal patterns in artificial breakwaters: Alteration of intertidal biodiversity by higher rock temperature|url= |journal=Ecology and Evolution|language=en|volume=9|issue=22|pages=12915–12927|doi=10.1002/ece3.5776|issn=2045-7758|pmc=6875675|pmid=31788225|bibcode=2019EcoEv...912915A }}</ref><ref>{{Cite web|date=2020-05-22|title=Erosion Control Blankets vs. Rip Rap {{!}} East Coast Erosion|url=https://www.eastcoasterosion.com/news/erosion-control-blanket-vs-rip-rap/|access-date=2020-12-06|website=East Coast Erosion Control|language=en-US}}</ref> Rubble from building and paving demolition is sometimes used,<ref name=":4" /><ref>{{Cite journal|title=Welcome to ROSA P {{!}}|url=https://rosap.ntl.bts.gov/view/dot/41174|access-date=2020-12-06|website=rosap.ntl.bts.gov|date=January 1989|last1=Brown|first1=Scott A.}}</ref> 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|date=December 2020}}

== 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.<ref>{{Cite journal |last=Qi |display-authors=etal |date=June 2021 |title=Scour at pile groups and effects of riprap gradation and thickness on the scour reduction |url=https://www.researchgate.net/publication/352680621 |journal=Journal of Hydraulic Engineering |volume=52 |issue=6 |via=ResearchGate}}</ref>

The usage of riprap may not even stop erosion, but simply move it downstream.<ref name=":0">{{Cite journal|last1=Reid|first1=David|last2=Church|first2=Michael|date=2015|title=Geomorphic and Ecological Consequences of Riprap Placement in River Systems|url=http://doi.wiley.com/10.1111/jawr.12279|journal=JAWRA Journal of the American Water Resources Association|language=en|volume=51|issue=4|pages=1043–1059|doi=10.1111/jawr.12279|bibcode=2015JAWRA..51.1043R|s2cid=129730847 |url-access=subscription}}</ref> 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).<ref>{{Cite journal |last=Sfeir |display-authors=etal |date=August 2021 |title=RIPRAP FILTERS AND STABILITY OF RIPRAP COVERED SLOPES |url=https://www.researchgate.net/publication/356101606 |journal=Riprap for Scour Countermeasures |via=ResearchGate}}</ref>

=== 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.<ref name=":0" /> 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 by making the ecosystem more heterogeneous.<ref>{{Cite journal |last=Shields |display-authors=etal |date=June 1995 |title=Experiment in Stream Restoration |url=https://doi.org/10.1061/(ASCE)0733-9429(1995)121:6(494) |journal=Journal of Hydraulic Engineering |volume=121 |issue=6 |pages=494–502 |doi=10.1061/(ASCE)0733-9429(1995)121:6(494) |via=ASCE Library|url-access=subscription }}</ref> While it can negatively affect some organisms by removing shoreline vegetation, the rock can provide important refuge for invertebrates and small fish.<ref name=":0" /><ref name=":1">{{Cite journal|last1=Chhor|first1=Auston D.|last2=Glassman|first2=Daniel M.|last3=Smol|first3=John P.|last4=Vermaire|first4=Jesse C.|last5=Cooke|first5=Steven J.|date=2020|title=Ecological consequences of shoreline armoring on littoral fish and benthic macroinvertebrate communities in an Eastern Ontario lake|url=http://link.springer.com/10.1007/s00027-020-00740-0|journal=Aquatic Sciences|language=en|volume=82|issue=4|pages=73|doi=10.1007/s00027-020-00740-0|bibcode=2020AqSci..82...73C |s2cid=220857360|issn=1015-1621|url-access=subscription}}</ref> By preventing woody plants from growing and shading the water, riprap can also increase the amount of algae and hydrophytes.<ref>{{Cite journal |last=Fischenich |first=J. Craig |date=April 2003 |title=Effects of Riprap on Riverine and Riparian Ecosystems |url=https://apps.dtic.mil/sti/pdfs/ADA414974.pdf |archive-url=https://web.archive.org/web/20220601074310/https://apps.dtic.mil/sti/pdfs/ADA414974.pdf |url-status=live |archive-date=June 1, 2022 |journal=Wetlands Regulatory Assistance Program |via=US Army Corps of Engineers}}</ref>

== Gallery == <gallery> File:11-8-07 riprap photo.jpg|Concrete rubble used as riprap along the San Francisco Bay shoreline File:Sea defences - geograph.org.uk - 775461.jpg|Modular concrete block riprap, in the form of Dolos 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 File:Corps completes Yolo Bypass levee repairs (6792076725).jpg|Riprap protecting a levee File:Crews replacing riprap at Seawall.jpg|Crews replacing riprap at Galveston Seawall after a 1915 hurricane File:Dawlish Warren , Rip Rap and Coastal Scenery - geograph.org.uk - 1345833.jpg|Riprap protecting a concrete retaining wall </gallery>

==See also== * Dolos * Debris * Gabion Basket * Rubble

==References== {{Reflist}} * Ciria-CUR (2007) - [http://www.kennisbank-waterbouw.nl/DesignCodes/rockmanual/introduction.pdf Rock Manual - The use of rock in hydraulic engineering]. * N.W.H. Allsop (2002) - [https://books.google.com/books?id=0XtfQ_iW0_YC&dq=%22rock+manual%22&pg=PP1 Breakwaters, coastal structures and coastlines]. *US Dept. of Transportation (2004) - [https://www.fhwa.dot.gov/environment/recreational_trails/publications/fs_publications/00232839/page10a.cfm?redirect Trail Construction and Maintenance Notebook]

==External links== *[http://soilandwater.ohiodnr.gov/portals/soilwater/pdf/stream/stfs16.pdf Ohio Dept. of Natural Resources riprap guide] *[https://www.usbr.gov/tsc/techreferences/hydraulics_lab/pubs/PAP/PAP-0790.pdf US Bureau of Reclamation publication on riprap for dam overtopping] *[http://www.dnr.state.mn.us/permits/water/answers.html#riprap Minnesota DNR] *[https://minerals.usgs.gov/minerals/pubs/commodity/stone_crushed/cstonmyb05.pdf USGS Minerals Yearbook: Stone, Crushed]

Category:Building stone Category:Types of wall Category:Earthworks (engineering) Category:Coastal construction