Check dam

{{Short description|Small dam to counteract erosion}} thumb|right|Concrete check dams in Austria right|thumb|A steel check dam [[Image:Bioswale.jpg|thumb|right|278px|A common application of check dams is in bioswales, which are artificial drainage channels that are designed to remove silt and pollution from runoff.]] A '''check dam''' is a small, sometimes temporary, dam constructed across a swale, drainage ditch, or waterway to counteract erosion by reducing water flow velocity.<ref name="Marsh, Landscape Planning" /> Check dams themselves are not a type of new technology; rather, they are an ancient technique dating from the second century AD.<ref name='Agoramoorthy, "The Check Dam Route"'>{{cite journal|last1=Agoramoorthy|first1=Govindasamy, Sunita Chaudhary & Minna J. Hsu|title=The Check-Dam Route to Mitigate India's Water Shortages|journal=Natural Resources Journal|date=2008|volume=48|issue=3|pages=565–583}}</ref> Check dams are typically, though not always, implemented in a system of several dams situated at regular intervals across the area of interest.<ref name="MS DEQ, Erosion Stormwater Manual">{{cite book|last1=Mississippi Department of Environmental Quality|title=Erosion Stormwater Manual|publisher=Mississippi DEQ|pages=4–118|edition=4th|url=http://opcgis.deq.state.ms.us/Erosion_Stormwater_Manual_2ndEd/Volume1/Chap_4_Sections/4_4/V1_Chap4_4_Runoff_Conveyance_CD.pdf|access-date=October 21, 2014|archive-date=March 5, 2016|archive-url=https://web.archive.org/web/20160305022227/http://opcgis.deq.state.ms.us/Erosion_Stormwater_Manual_2ndEd/Volume1/Chap_4_Sections/4_4/V1_Chap4_4_Runoff_Conveyance_CD.pdf|url-status=live}}</ref>

== Types of Check Dams == There are two main categories of check dams. They are:

1) Closed type check dams. Closed-type check dams have been used commonly for hundreds of years, and are constructed without openings to block water and sediment flow. However, closed-type check dams may disrupt natural ecosystems through impeding the natural flow of water and sediment.<ref name=":0">{{Cite journal |last1=Chen |first1=Hung-En |last2=Chen |first2=Tzu-Yu |last3=Zheng |first3=Ya-Lin |last4=Chiu |first4=Yen-Yu |last5=Chen |first5=Su-Chin |date=2025-02-01 |title=Optimizing sediment control by adjusting the relative spacing between trusses/beams in an open-type check dam |url=https://doi.org/10.1007/s10346-024-02369-8 |journal=Landslides |language=en |volume=22 |issue=2 |pages=551–565 |doi=10.1007/s10346-024-02369-8 |issn=1612-5118|url-access=subscription }}</ref><ref name=":1">{{Cite journal |last1=Abbasi |first1=Naseer Ahmed |last2=Xu |first2=Xiangzhou |last3=Lucas-Borja |first3=Manuel Esteban |last4=Dang |first4=Weiqin |last5=Liu |first5=Bin |date=2019-08-01 |title=The use of check dams in watershed management projects: Examples from around the world |url=https://www.sciencedirect.com/science/article/pii/S0048969719317784 |journal=Science of the Total Environment |volume=676 |pages=683–691 |doi=10.1016/j.scitotenv.2019.04.249 |pmid=31054413 |bibcode=2019ScTEn.676..683A |issn=0048-9697|url-access=subscription }}</ref>

2) Open-type check dams. Open type check dams are likewise constructed across a waterway, but have openings to allow for water and sediment to flow more freely. Openings can be created by either implementing spaced trusses or beams into the design of the dam. The distance between these openings, based on whether trusses or beams were used in construction, can be designed to achieve a desired rate of sediment passthrough at the check dam.<ref name=":0" /> Furthermore, open-type check dams can be constructed to be modifiable, granting communities or governments the ability to better manage sediment and water flow by adding or removing modular sections of the dam.<ref>{{Cite journal |last1=Chiu |first1=Yu-Fang |last2=Tfwala |first2=Samkele S. |last3=Hsu |first3=Yung-Ching |last4=Chiu |first4=Yen-Yu |last5=Lee |first5=Chen-Yang |last6=Chen |first6=Su-Chin |date=2021 |title=Upstream morphological effects of a sequential check dam adjustment process |url=https://onlinelibrary.wiley.com/doi/abs/10.1002/esp.5178 |journal=Earth Surface Processes and Landforms |language=en |volume=46 |issue=13 |pages=2527–2539 |doi=10.1002/esp.5178 |bibcode=2021ESPL...46.2527C |issn=1096-9837|url-access=subscription }}</ref> [[File:Check dam Thadayana.jpg|thumb|A check dam across the Kudumbur River, in Kerala, India]]

== Function == A check dam placed in the ditch, swale, or channel interrupts the flow of water and flattens the gradient of the channel, thereby reducing the velocity. In turn, this obstruction induces infiltration and reduces erosion.<ref name="Marsh, Landscape Planning">{{cite book|last1=Marsh|first1=William M.|title=Landscape Planning: Environmental Applications|date=2010|publisher=John Wiley & Sons, Inc.|location=Danvers, MA|isbn=978-0-470-57081-4|pages=267–268|edition=5th}}</ref> They can be used not only to slow flow velocity but also to distribute flows across a swale to avoid preferential paths and guide flows toward vegetation.<ref name='Melbourne Water, "WSUD"'>{{cite book|last1=Melbourne Water|title=Water Sensitive Urban Design Engineering Procedures: Stormwater|date=2005|publisher=CSIRO Publishing|location=Australia|isbn=978-0-643-09092-7|page=140|url=https://books.google.com/books?id=AF9K93GWw2AC&q=WSUD%20Engineering%20Procedures%3A%20Stormwater%3A%20Stormwater|access-date=28 October 2014}}</ref> Although some sedimentation may result behind the dam, check dams do not primarily function as sediment-trapping devices.<ref name='Iowa SUDAS, "Design Manual"'>{{cite book|last1=Iowa Statewide Urban Design and Specifications (SUDAS)|title=Design Manual - Erosion and Sediment Control|date=2013|publisher=Institute for Transportation at Iowa State University|location=Ames, IA|url=http://www.iowasudas.org/manuals/design/Chapter07/7E-7.pdf|access-date=28 October 2014|archive-url=https://web.archive.org/web/20141109234810/http://www.iowasudas.org/manuals/design/Chapter07/7E-7.pdf|archive-date=9 November 2014|url-status=dead}}</ref>

For instance, on the Graliwdo River in Ethiopia, an increase of hydraulic roughness by check dams and water transmission losses in deposited sediments is responsible for the delay of runoff to reach the lower part of the river channels. The reduction of peak runoff discharge was larger in the river segment with check dams and vegetation (minus 12%) than in segment without treatment (minus 5.5%). Reduction of total runoff volume was also larger in the river with check dams than in the untreated river. The implementation of check dams combined with vegetation reduced peak flow discharge and total runoff volume as large parts of runoff infiltrated in the sediments deposited behind the check dams. As gully check dams are implemented in a large areas of northern Ethiopia, this contributes to groundwater recharge and increased river base flow.<ref>{{cite journal|last1= Etefa Guyassa|first1= and colleagues|title= Effects of check dams on runoff characteristics along gully reaches, the case of Northern Ethiopia|journal= Journal of Hydrology|date= 2017|volume= 545|pages= 299–309|doi= 10.1016/j.jhydrol.2016.12.019|bibcode= 2017JHyd..545..299G|url= https://biblio.ugent.be/publication/8518957|hdl= 1854/LU-8518957|hdl-access= free|access-date= 2020-08-31|archive-date= 2021-05-07|archive-url= https://web.archive.org/web/20210507165508/https://biblio.ugent.be/publication/8518957|url-status= live}}</ref>

== Applications ==

=== Grade control mechanism ===

Check dams have traditionally been implemented in two environments: across channel bottoms and on hilly slopes.<ref name='Garcia, Carmelo, "Check Dams"'>{{cite book|last1=Garcia|first1=Carmelo & Mario Lenzi|title=Check Dams, Morphological Adjustments and Erosion Control in Torrential Streams|date=2010|publisher=Nova Science Publishers|location=New York|isbn=978-1-61761-749-2}}</ref> Check dams are used primarily to control water velocity, conserve soil, and improve land.<ref>A conceptual model of check dam hydraulics for gully control:efficiency, optimal spacing and relation with step-pools C. Castillo, R. Pérez, and J. A. Gómez from Hydrology and Earth System Sciences 18, 1705–1721, 2014</ref> They are used when other flow-control practices, such as lining the channel or creating bioswales, are impractical.<ref name='USEPA, "Water BMP: Check Dams"' /> Accordingly, they are commonly used in degrading temporary channels, in which permanent stabilization is impractical and infeasible in terms of resource allocation and funding due to the short life period. They are also used when construction delays and weather conditions prevent timely installation of other erosion control practices.<ref name=NCDENR>{{cite book|last1=North Carolina Department of Environment and Natural Resources|title=Practice Standards and Specifications|date=2006|publisher=NCDENR|location=Raleigh, N.C.|pages=6.83.1–6.83.3|url=http://portal.ncdenr.org/c/document_library/get_file?uuid=efbff6bd-e595-4828-be6a-394be4c404c2&groupId=38334|archive-url=https://web.archive.org/web/20130724071109/http://portal.ncdenr.org/c/document_library/get_file?uuid=efbff6bd-e595-4828-be6a-394be4c404c2&groupId=38334|url-status=dead|archive-date=2013-07-24|access-date=28 October 2014}}</ref> This is typically seen during the construction process of large-scale permanent dams or erosion control. As such, check dams serve as temporary grade-control mechanisms along waterways until resolute stabilization is established or along permanent swales that need protection prior to installation of a non-erodible lining.<ref name="UDFCD, Urban Storm Drainage Criteria Manual">{{cite book|last1=Urban Drainage and Flood Control District|title=Urban Storm Drainage Criteria Manual Volume 3|date=2010|publisher=Urban Drainage and Flood Control District|location=Colorado|url=http://www.udfcd.org/downloads/pdf/critmanual/Volume%203%20PDFs/chapter%207%20fact%20sheets/EC-12%20Check%20Dam.pdf|access-date=28 October 2014|archive-url=https://web.archive.org/web/20120905051511/http://www.udfcd.org/downloads/pdf/critmanual/Volume%203%20PDFs/chapter%207%20fact%20sheets/EC-12%20Check%20Dam.pdf|archive-date=2012-09-05|url-status=dead}}</ref>

=== Water quality control mechanism === Many check dams tend to form stream pools. Under low-flow circumstances, water either infiltrates into the ground, evaporates, or seeps through or under the dam. Under high flow – flood – conditions, water flows over or through the structure. Coarse and medium-grained sediment from runoff tends to be deposited behind check dams, while finer grains flow through. Floating garbage is also trapped by check dams, increasing their effectiveness as water quality control measures. In addition to overall water quality, check dams have positive effects on biodiversity both in the water and in the surrounding area. In a study of check dams in the Andes Mountains, check dams were found to be effective in this way by both increasing the mass of organic matter within trapped sediments and the amount of macroinvertebrate individuals found near the dam. These trapped sediments also work as carbon capture. However, these effects may only apply in conditions or environments that are similar to mountainous streams.<ref>{{Cite journal |last1=Carrera-Villacrés |first1=David |last2=Gavilanes |first2=Petronio |last3=Brito |first3=María José |last4=Criollo |first4=Andrés |last5=Chico |first5=Alexander |last6=Carrera-Villacrés |first6=Felipe |date=2025-03-12 |title=Water and Sediment Quantity and Quality Generated in Check Dams as a Nature-Based Solutions (NbS) |journal=Water |language=en |volume=17 |issue=6 |pages=810 |doi=10.3390/w17060810 |bibcode=2025Water..17..810C |doi-access=free |issn=2073-4441}}</ref> Additionally, riparian vegetation has been found to increase in the presence of check dams, in turn increasing biodiversity and stabilizing the land with root systems. This has the effect of further reducing erosion, which can contribute to the check dam's overall effectiveness in protecting against disaster.<ref>{{Cite journal |last1=Ricci |first1=Giovanni Francesco |last2=Romano |first2=Giovanni |last3=Leronni |first3=Vincenzo |last4=Gentile |first4=Francesco |date=2019-03-20 |title=Effect of check dams on riparian vegetation cover: A multiscale approach based on field measurements and satellite images for Leaf Area Index assessment |url=https://www.sciencedirect.com/science/article/pii/S0048969718349210 |journal=Science of the Total Environment |volume=657 |pages=827–838 |doi=10.1016/j.scitotenv.2018.12.081 |pmid=30677948 |bibcode=2019ScTEn.657..827R |issn=0048-9697|url-access=subscription }}</ref> Check dams may be implemented with bioswales to manage stormwater runoff, and those structures together have been shown to be effective in facilitating runoff drainage into the surrounding soil.<ref>{{Cite journal |last1=Waickowski |first1=Sarah E. |last2=Purvis |first2=Rebecca A. |last3=Tormey |first3=Carmen C. |last4=Mullins |first4=Ryan M. |last5=Jacobson |first5=Brian |last6=McDaniel |first6=Andrew H. |last7=Hunt |first7=William F. |date=2025-08-01 |title=Quantifying the Water Quality and Hydrologic Benefits of Two Bioswales Receiving Highway Runoff in North Carolina |url=https://ascelibrary.org/doi/10.1061/JSWBAY.SWENG-626 |journal=Journal of Sustainable Water in the Built Environment |language=EN |volume=11 |issue=3 |pages=05025003 |doi=10.1061/JSWBAY.SWENG-626|url-access=subscription }}</ref>

=== Arid regions === [[File:Log Dam May Qoqah.jpg|thumb|Boulder-faced log dam in Maygwa, Ethiopia]] In arid areas, check dams are often built to increase groundwater recharge in a process called managed aquifer recharge. Winter runoff thus can be stored in aquifers, from which the water can be withdrawn during the dry season for irrigation, livestock watering, and drinking water. This is particularly useful for small settlements located far from a large urban center as check dams require less reliance on machinery, funding, or advanced knowledge compared to large-scale dam implementation.<ref>S. Parimala Renganayaki, L. Elango (April 2013). "A review on managed aquifer recharge by check dams: a case study near Chennai, India". : International Journal of Research in Engineering and Technology 2 (4): 416–423</ref><ref name='Agoramoorthy, "The Check Dam Route"' /> Additionally, local civilians can easily monitor and maintain these check dams to ensure optimal groundwater recharge. In one such study in India, it was found that check dams were highly effective when used and maintained for managed aquifer recharge, and the water collected by the dam was used to support around 16 percent of agricultural activity in the surrounding communities being served by the aquifers.<ref>{{Cite journal |last1=Dashora |first1=Y. |last2=Dillon |first2=P. |last3=Maheshwari |first3=B. |last4=Soni |first4=P. |last5=Dashora |first5=R. |last6=Davande |first6=S. |last7=Purohit |first7=R. C. |last8=Mittal |first8=H. K. |date=2018-06-01 |title=A simple method using farmers' measurements applied to estimate check dam recharge in Rajasthan, India |url=https://doi.org/10.1007/s40899-017-0185-5 |journal=Sustainable Water Resources Management |language=en |volume=4 |issue=2 |pages=301–316 |doi=10.1007/s40899-017-0185-5 |bibcode=2018SWRM....4..301D |issn=2363-5045|url-access=subscription }}</ref>

Check dams can be used in combination with limans to stop and collect surface runoff water.

=== Mountainous regions === As a strategy to stabilize mountain streams, the construction of check dams has a long tradition in many mountainous regions dating back to the 19th century in Europe. Steep slopes impede access by heavy construction machinery to mountain streams, so check dams have been built in place of larger dams. Because the typical high slope causes high flow velocity, a terraced system of multiple closely spaced check dams is typically necessary to reduce velocity and thereby counteract erosion. Such consolidation check dams, built in terraces, attempt to prevent both headward and downward cutting into channel beds while also stabilizing adjacent hill slopes. They are further used to mitigate flood and debris flow hazards.<ref>{{cite journal|last1=Mazzorana|first1=Bruno|title=The susceptibility of consolidation check dams as a key factor for maintenance planning|journal=Österreichische Wasser- und Abfallwirtschaft|date=6 June 2014|volume=66|issue=5|pages=214–216|doi=10.1007/s00506-014-0160-4|bibcode=2014OWasA..66..214M |s2cid=130712151}}</ref>

Case studies validate the effectiveness of these check dam systems. On the Guerbe River in Switzerland, where a series of over 100 check dams had been implemented to control landslides and other natural debris flow disasters, it was found that the check dams reduced the amount of sediment being carried by the river. The dams did so by flattening out the riverbed and retaining an initial amount of sediment, although the main impact came from the gradient change. However, the benefits of these dams are often erased in the event of a failure, which releases trapped sediment and destabilizes both the riverbed and surrounding land, increasing the risk of disaster.<ref>{{Cite journal |last1=do Prado |first1=Ariel Henrique |last2=Mair |first2=David |last3=Garefalakis |first3=Philippos |last4=Schmidt |first4=Chantal |last5=Whittaker |first5=Alexander |last6=Castelltort |first6=Sebastien |last7=Schlunegger |first7=Fritz |date=2024-03-07 |title=Check dam impact on sediment loads: example of the Guerbe River in the Swiss Alps – a catchment scale experiment |url=https://hess.copernicus.org/articles/28/1173/2024/ |journal=Hydrology and Earth System Sciences |language=English |volume=28 |issue=5 |pages=1173–1190 |doi=10.5194/hess-28-1173-2024 |bibcode=2024HESS...28.1173D |doi-access=free |issn=1027-5606}}</ref>

=== Temporary Test Dams TTDs === In the UK planning laws, applications and restrictions delay flood mitigation work. This can be counteracted by setting up Temporary Test Dams in watercourses that can then be monitored and valued. This does however require the landowners support. TTDs have proven to be a great way to get rapid action following a flood event and a way to get communities involved in the defence against future flood events.

== Design considerations ==

=== Site === Before installing a check dam, engineers inspect the site. Standard practices call for the drainage area to be ten acres or less.<ref name="MS DEQ, Erosion Stormwater Manual" /><ref name='USEPA, "Water BMP: Check Dams"' /> The waterway should be on a slope of no more than 50% and should have a minimum depth to bedrock of {{convert|2|ft|m|2|abbr=on}}.<ref name='Idaho DEQ, "Stormwater Best Management Practices"'>{{cite book|last1=Department of Environmental Quality|title=IDEQ Stormwater Best Management Practices Catalog: Check Dams BMP 32|date=2005|publisher=State of Idaho|pages=106–108|url=http://www.deq.idaho.gov/media/617590-32.pdf|access-date=28 October 2014|archive-date=22 December 2016|archive-url=https://web.archive.org/web/20161222200010/http://www.deq.idaho.gov/media/617590-32.pdf|url-status=dead}}</ref> Check dams are often used in natural or constructed channels or swales. They should never be placed in live streams unless approved by appropriate local, state and/or federal authorities.<ref name='Idaho DEQ, "Stormwater Best Management Practices"' />

=== Materials === thumb|Log dam in a gully, circa 1935, Missouri, US [[File:Log dam in Adawro river.jpg|thumb|Log dam in Adawro river, Ethiopia]] Check dams are made of a variety of materials. Because they are typically used as temporary structures, they are often made of cheap and accessible materials such as rocks, gravel, logs, hay bales, and sandbags.<ref name='USEPA, "Water BMP: Check Dams"' /><ref name="nyssen">{{cite journal |last1=Nyssen |first1= J. and colleagues|title= Boulder-Faced Log Dams as an Alternative for Gabion Check Dams in First-Order Ephemeral Streams with Coarse Bed Load in Ethiopia |journal=Journal of Hydraulic Engineering |date=2017 |volume=143 |article-number= 05016005|doi=10.1061/(ASCE)HY.1943-7900.0001217|url= https://lirias.kuleuven.be/handle/123456789/580811|url-access=subscription }}</ref> Of these, logs and rock check dams are usually permanent or semi-permanent, and sandbag check dams are built primarily for temporary purposes. Also, there are check dams that are constructed with rockfill or wooden boards. These dams are usually implemented only in small, open channels that drain {{convert|10|acre|km2|2|abbr=on}} or less; and usually do not exceed {{convert|2|ft|m|2|abbr=on}} high.<ref name=NRCS>{{Cite FTP |last1=USDA Natural Resource Conservation Services (NRCS)|title=Urban BMPs: Water Erosion|url=ftp://ftp-fc.sc.egov.usda.gov/WSI/UrbanBMPs/water/erosion/checkdam.pdf|server=usda.gov|url-status=dead|access-date=28 October 2014}}</ref> Woven wire can be used to construct check dams in order to hold fine material in a gully. It is typically used in environments where the gully has a moderate slope (less than 10%), small drainage area, and in regions where flood flows do not typically carry large rocks or boulders.<ref name=FAO>{{cite web|title=FAO Watershed Management Field Manual|url=http://www.fao.org/docrep/006/ad082e/ad082e03.htm|website=fao.org|publisher=Food and Agricultural Organizations of the United Nations|access-date=28 October 2014|archive-date=31 January 2019|archive-url=https://web.archive.org/web/20190131135915/http://www.fao.org/docrep/006/AD082E/AD082e03.htm|url-status=live}}</ref><ref name="nyssen"/> In nearly all instances, erosion control blankets, which are biodegradable open-weave blankets, are used in conjunction with check dams. These blankets help encourage vegetation growth on the slopes, shorelines and ditch bottoms. thumb|Log dam building in Adawro

===Size === Check dams are usually less than {{convert|2|to|3|ft|m}} high.<ref name="USDA BMPs">{{cite book|title=Urban BMPs: Water, erosion, check dams|publisher=United States Department of Agriculture|url=ftp://ftp-fc.sc.egov.usda.gov/WSI/UrbanBMPs/water/erosion/checkdam.pdf|access-date=4 November 2014}}{{dead link|date=August 2017 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> and the center of the dam should be at least {{convert|6|in|m|2|abbr=on}} lower than its edges.<ref name='USEPA, "Water BMP: Check Dams"' /> This criterion induces a weir effect, resulting in increased water surface level upstream for some, if not all flow conditions.<ref name="UK pdf">{{cite book|last1=Rickard|first1=Charles & Rodney Day, Jeremy Purseglove|title=River Weirs – Good Practice Guide|date=2003|publisher=Environment Agency|location=UK|page=xi|url=https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/290655/sw5b-023-hqp-e-e.pdf|access-date=4 November 2014|archive-date=23 January 2017|archive-url=https://web.archive.org/web/20170123023253/https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/290655/sw5b-023-hqp-e-e.pdf|url-status=live}}</ref>

=== Spacing ===

In order to effectively slow water velocity to reduce erosion and to protect the channel between dams in a larger system, spacing must be designed properly. Check dams should be spaced such that the toe of the upstream check dam is equal to the elevation of the downstream check dam's crest.<ref>{{cite web |url=https://wiki.sustainabletechnologies.ca/wiki/Check_dams |title=Check dams |author=Sustainable Technologies Evaluation Program |website=Low Impact Development Stormwater Management Planning and Design Guide |access-date=28 March 2018 |archive-date=8 December 2019 |archive-url=https://web.archive.org/web/20191208010116/https://wiki.sustainabletechnologies.ca/wiki/Check_dams |url-status=live }}</ref> This allows water to pond between dams and substantially slows the flow's velocity.<ref name='Iowa SUDAS, "Design Manual"' />

=== Effects on Sediment Control === While sediment control is often not the explicit main purpose of a check dam, check dams do have a large impact on how sediment moves through a waterway. Check dams are shown to reduce channel gradient upstream, but may not have the same effect downstream. In fact, while the channel gradient upstream may be completely inverted, a check dam acting as a sediment barrier will first form a scour pit at its foot, then cause sediment to accumulate in such a way that channel gradient is increased downstream. Thus, when check dams are implemented in a series, height and spacing of the dams must be optimized to account for both upstream and downstream effects of the check dams.<ref>{{Cite journal |last1=Chen |first1=Junqi |last2=Zhang |first2=Wen |last3=Cao |first3=Chen |last4=Yin |first4=Han |last5=Wang |first5=Jia |last6=Li |first6=Wankun |last7=Zheng |first7=Yanhao |date=2024-02-01 |title=The effect of the check dam on the sediment transport and control in debris flow events |url=https://www.sciencedirect.com/science/article/pii/S0013795223004155 |journal=Engineering Geology |volume=329 |article-number=107397 |doi=10.1016/j.enggeo.2023.107397 |bibcode=2024EngGe.32907397C |issn=0013-7952|url-access=subscription }}</ref> Check dams can also stabilize the sides of a channel, as well as trap an initial amount of sediment that will be retained as long as the dam is operational. Sediment retention by check dams is well documented and varies from site to site as environmental conditions and characteristics change.<ref name=":1" />

== Advantages ==

Check dams are a highly effective practice to reduce flow velocities in channels and waterways. In contrast to big dams, check dams are implemented faster, are cost-effective, and are smaller in scope. Because of this, their implementation does not typically displace people and communities nor do they destroy natural resources if designed correctly.<ref name='Agoramoorthy, "Small Size, Big Potential"'>{{cite journal|last1=Agoramoorthy|first1=Govindasamy, and Minna J. Hsu|title=Small Size, Big Potential: Check Dams for Sustainable Development|journal=Environment|date=2008|volume=50|issue=4|pages=22–34|doi=10.3200/envt.50.4.22-35|bibcode=2008ESPSD..50d..22A |s2cid=153334085|id={{ProQuest|224015181}}}}</ref> Moreover, the dams are simple to construct and do not rely on advanced technologies, allowing their use in rural communities with fewer resources or access to technical expertise, as they have been in India's drylands for some time now.<ref name='Agoramoorthy, "Small Size, Big Potential"' />

== Limitations ==

Check dams still require maintenance and sediment-removal practices. They become more difficult to implement on steep slopes, as water velocity is higher and the distance between dams must be shortened.<ref name='Iowa SUDAS, "Design Manual"' /> Check dams, depending on the material used, can have a limited life span but if implemented correctly can be considered permanent.<ref name='Iowa SUDAS, "Design Manual"' />

Check dams can and do fail, either from a structural breach or collapse, or not functioning in the way they were intended to. However, studies suggest that failure events can cause increases in flood discharge, but may not have a significant impact on overall flooding downstream. While check dam failure is not shown to have catastrophic consequences for the most part, some cascading failure instances, particularly in mountainous regions, can lead to loss of life and other destruction, as exemplified by a 1996 flooding event on the Aras River in Spain that killed 87 people, due in part to a cascading check dam system failure. Regular maintenance of check dams can help prevent failure.<ref>{{Cite journal |last1=Zhang |first1=Zeyu |last2=Chai |first2=Junrui |last3=Li |first3=Zhanbin |last4=Xu |first4=Zengguang |last5=Yuan |first5=Shuilong |date=2022-03-01 |title=Reconstruction and effects of a failure of a typical check dam system under an extreme rainstorm on the Loess Plateau, China |url=https://doi.org/10.1007/s11069-021-05101-0 |journal=Natural Hazards |language=en |volume=111 |issue=2 |pages=1401–1419 |doi=10.1007/s11069-021-05101-0 |bibcode=2022NatHa.111.1401Z |issn=1573-0840|url-access=subscription }}</ref><ref>{{Cite journal |last1=Piton |first1=Guillaume |last2=Carladous |first2=Simon |last3=Recking |first3=Alain |last4=Tacnet |first4=Jean Marc |last5=Liébault |first5=Frédéric |last6=Kuss |first6=Damien |last7=Quefféléan |first7=Yann |last8=Marco |first8=Olivier |date=2017 |title=Why do we build check dams in Alpine streams? An historical perspective from the French experience |url=https://onlinelibrary.wiley.com/doi/abs/10.1002/esp.3967 |journal=Earth Surface Processes and Landforms |language=en |volume=42 |issue=1 |pages=91–108 |doi=10.1002/esp.3967 |bibcode=2017ESPL...42...91P |issn=1096-9837}}</ref>

== Maintenance == Check dams require regular maintenance as typically temporary structures not designed to withstand long-term use. Dams should be inspected every week and after heavy rainfall.<ref name='Iowa SUDAS, "Design Manual"' /> It is important that rubble, litter, and leaves are removed from the upstream side of the dam.<ref name='USEPA, "Water BMP: Check Dams"'>{{cite web|last1=United States Environmental Protection Agency|title=Water Best Management Practices: Check Dams|url=http://water.epa.gov/polwaste/npdes/swbmp/Check-Dams.cfm|website=water.epa.gov|publisher=USEPA|access-date=28 October 2014|date=2014-08-06|archive-date=2015-09-01|archive-url=https://web.archive.org/web/20150901102443/http://water.epa.gov/polwaste/npdes/swbmp/Check-Dams.cfm|url-status=dead}}</ref> This is typically done when the sediment has reached a height of one-half the original height of the dam.<ref name='USEPA, "Water BMP: Check Dams"' />

When the site is permanently stabilized and the check dam is no longer needed, it is fully removed, including components washed downstream, and bare spots are stabilized.<ref name='Iowa SUDAS, "Design Manual"' />

==References== {{reflist}}

== External links == {{commons cat|Check dams}} * [https://dx.doi.org/10.11475/sabo1973.45.4_22 Trap Function of Bed Road by Steel-Slit Dam] Sabo Gakkaishi Vol.45 (1992-1993) No.4 P22-29

Category:Ecological restoration Category:Environmental engineering Category:Hydrology and urban planning Category:Landscape Category:Water conservation Category:Waste treatment technology Category:Water pollution Category:Dams by type Category:Desert greening