View source for Engineering:Aquatic weed harvester

[[File:Weed cutting boat in action.png|thumb|265px|Truxor in action on a freshwater lake]]
[[File:Bdg kosiarka Brda 1 7-2015.jpg|frameless|right|alt=An aquatic weed harvester]]

An '''aquatic weed harvester''', also known as a '''water mower''',<ref>{{cite web|url=http://www.ktbs.com/story/22502823/arklatex-in-depth-salvinia-fight|title=ArkLaTex In-Depth: Salvinia fight|author=Neil Shaw|date=4 June 2013|publisher=|access-date=11 February 2016}}</ref><ref>{{cite web|url=http://www.dailyinterlake.com/members/this-county-planner-handles-the-tough-conflicts/article_8f362db2-6b0d-11e5-a810-6f9aeced6f14.html|title=This county planner handles the tough conflicts|work=Daily Inter Lake|access-date=11 February 2016|archive-date=8 July 2018|archive-url=https://web.archive.org/web/20180708212656/http://www.dailyinterlake.com/archive/article-8f362db2-6b0d-11e5-a810-6f9aeced6f14.html|url-status=dead}}</ref> '''mowing boat''' and '''weed cutting boat''',<ref name="Mills 2015"/> is an aquatic machine specifically designed for inland watercourse management to cut and harvest underwater weeds, reeds and other aquatic plant life.<ref name="TBO.com 2013"/> The action of removing aquatic plant life in such a manner has been referred to as "aquatic harvesting".<ref name="Satayut 2012"/>

==Overview==
Water is an important resource and in many countries, waterways are increasingly clogged by aquatic plant growth. This is particularly so in tropical countries where warmer water means the plants grow more quickly, and increasing run-off of fertilisers and effluent has exacerbated the problem. Irrigation ditches and pumps can become overgrown with vegetation, power station and factory water intakes can get blocked, boats can get hindered, fish stocks can be disrupted, and water moves more slowly, resulting in greater [[Earth:Evapotranspiration|evapotranspiration]] and a greater risk of flooding. In some large irrigation projects in India, canals have become so overgrown with vegetation that water flow has been reduced to a fifth of its previous amount. In Bangladesh, floodwater has washed mats of [[Biology:Eichhornia crassipes|water hyacinth]] onto paddy fields, overwhelming the emerging rice crops.<ref name=Council>{{cite book|author1=National Research Council|title=Making Aquatic Weeds Useful: Some Perspectives for Developing Countries|url=https://books.google.com/books?id=pG-8h6JufaEC&pg=PA1 |year=2002|publisher=The Minerva Group |isbn=978-0-89499-180-6 |pages=1–9}}</ref> Small fish can become entangled in excessive algal growth.<ref name="Satayut 2012"/>

[[File:Pond covered by Pistia, Odessa.JPG|thumb|left|Water lettuce (''Pistia stratiotes'') in Odesa, Ukraine|alt=A pond in Odesa, Ukraine covered with water lettuce (''Pistia stratiotes'')]]
[[Biology:Rice|Rice]] is the main aquatic plant grown for human food, but smaller areas of [[Biology:Watercress|watercress]] and water chestnut are also cultivated. In their native environments, aquatic weeds are part of a balanced ecosystem, and it is mainly introduced species of water plant that become [[Earth:Invasive species|invasive]] and cause problems by congesting water bodies. The worst culprits, found in both temperate and tropical waterways, are floating plants such as water hyacinth, [[Biology:Pistia|water lettuce]] and ''[[Biology:Salvinia|Salvinia]]'', fully submerged rooting plants such as ''[[Biology:Hydrilla|Hydrilla]]'' and [[Biology:Myriophyllum spicatum|water milfoil]] and rooting plants that reach the surface such as [[Biology:Typha|cattail]], [[Engineering:Papyrus|papyrus]], bulrush and [[Biology:Phragmites|reed]].<ref name=Council/>

==Weed harvesting equipment==
Weed cutting boats are developed to enable the maintenance of canals, lakes and rivers<ref name="TBO.com 2013"/> and to remove excessive aquatic life such as [[Biology:Algae|algae]] and other plants that may negatively affect a waterway's [[Earth:Ecology|ecology]]. Mechanical harvesters are large floating machines that have underwater cutting blades that sever the stems of underwater plants, gather the weeds and raise them on conveyor belts, storing the vegetation on board in a hold. Periodically this is discharged to a barge or an onshore facility. The harvested product can be [[Chemistry:Compost|compost]]ed, sent to a landfill site or used in [[Earth:Land reclamation|land reclamation]].<ref name=Washington>{{cite web |url=http://www.ecy.wa.gov/programs/wq/plants/management/aqua026.html |title=Aquatic Plant Management: Mechanical Harvesting |publisher=Washington State Department of Ecology |access-date=3 March 2016}}</ref> In developing countries aquatic vegetation may be harvested by hand or by net from the shore, cut and harvested by boat and lifted ashore by hand, crane, pump or conveyor system. The harvested vegetation may be used for the feeding of livestock. To reduce the high moisture content and to make it easier to transport, the weed can be chopped and pressed.<ref>{{cite book|author1=National Research Council|title=Making Aquatic Weeds Useful: Some Perspectives for Developing Countries|url=https://books.google.com/books?id=pG-8h6JufaEC&pg=PA67 |year=2002|publisher=The Minerva Group |isbn=978-0-89499-180-6 |pages=67–68}}</ref> Other uses to which the harvested vegetation can be put include ensiling the material for livestock fodder, adding it to the soil as a bulky organic fertilizer, manufacturing the raw material into pulp, paper or fibre, and [[Biology:Fermentation|fermenting]] it to produce [[Chemistry:Methane|methane]] for energy production.<ref name=Council/>

[[File:Weed harvester 6520 from Berky.jpg|thumb|alt=The conveyor belt on this weed harvester from the German manufacturer Berky transports the aquatic plants on its hold after cutting them|Made by the German manufacturer Berky, with a conveyor belt and cutting unit]]

==Advantages and disadvantages==

Mechanical weed harvesters are effective at clearing aquatic weeds and the machines provide immediate relief from nuisance vegetation that interfere with navigation and recreation. Aquatic plants contain nitrogen, phosphorus and potassium that is bound in the vegetation, by removing the plants the nutrients are also removed. Removal of the biomass (plant material) prevents the build-up of muck and sediment on the bottom of the lake that occurs from the rotting weeds.  Mechanical harvesters can also be used to improve the fishery by leaving behind aquatic vegetation for food and habitat.
Aquatic weed machines are expensive and does require a capital investment and the process may need to be repeated several times in a growing season. Small fragments of weed may remain in the water and may spread to other locations thereby aiding in the dispersal of invasive species. However, a recent study by the Chautauqua Lake Association found that the harvesters left [https://spectrumlocalnews.com/nys/capital-region/news/2022/04/15/water-clarity-in-chautauqua-lake-showing-measurable-improvement-over-last-year less than 1% of the loose plants behind]. Some areas may be too shallow for the mechanical harvester and it may be unable to access restricted locations.<ref name=Washington/> Submerged tree stumps can damage the machine.<ref name="Satayut 2012"/> Aquatic weeds can also be utilized as a source of [[Earth:Biofuel|biofuel]].<ref>{{cite book|title=Making Aquatic Weeds Useful: Some Perspectives for Developing Countries|url=https://books.google.com/books?id=n2krAAAAYAAJ&q=harvester&pg=PA108|year=1976|publisher=National Academies|pages=108–|id=NAP:14402}}</ref>

An alternative to mechanical harvesting is the use of herbicides, which are easy to apply and less expensive, but may have unwanted adverse impacts on the environment.<ref>{{cite web |url=http://www.ecy.wa.gov/programs/wq/plants/management/aqua028.html |title=Aquatic Plant Management: Aquatic Herbicides |publisher=Washington State Department of Ecology |access-date=3 March 2016}}</ref> While many aquatic herbicides have received EPA approval and are considered safe for aquatic environments, long-term studies have found that aquatic herbicides can have major impacts on fish reproduction. Researchers at the University of Wisconsin-Madison found that fathead minnows exposed to concentrations of fluridone showed signs of endocrine disruption.<ref>{{cite web | url=https://www.seagrant.wisc.edu/news/herbicide-study-finds-good-news-bad-news-for-use-of-fluridone-in-lakes/?fbclid=IwAR2v8VenEmprYtJiwNgzrtr4pltq6DTcgBSfpGHhD5EEXc-Bl-8X4jpGGpk | title=Herbicide study finds good news, bad news for use of fluridone in lakes &#124; Wisconsin Sea Grant | date=15 March 2022 }}</ref>

==By region==

===Africa===
[[File:Kenya Kisumu Harbour Hyacinths 1997ke09b21.jpg|thumb|Water hyacinth growing in Lake Victoria at [[Place:Kisumu|Kisumu]]]]

In June 2015 in Uganda, use of the aquatic weed harvester was recommended by the country's Ministry of Agriculture to reduce water hyacinth growth in Lake Victoria, which has caused a scarcity of fish in the lake.<ref name="www.newvision.co.ug 2016"/> The scarcity of fish has negatively-affected the livelihood of locals who live in the lake's region.<ref name="www.newvision.co.ug 2016"/> Additional types of machines were recommended to address the problem, which were the hydraulic harvester, take out elevator and [[Earth:Dredging|dredger]].<ref name="www.newvision.co.ug 2016"/>

===India===
[[File:Zoetermeer De Leyens Broekwegwetering Mowing boat (2).JPG|thumb|A mowing boat]]

In August 2015 in [[Place:Hyderabad|Hyderabad]], India, an aquatic weed harvester was used to remove algal weeds and trash from Hussainsagar Lake.<ref name="Singh 2016"/> An amphibious hydraulic excavator was also used.<ref name="Singh 2016"/> The work was performed to address pollution problems at the lake, which had accumulated significant algae and rubbish such as plastic bags and plastic waste, food wrappers, and various garbage, some of which was floating atop the lake.<ref name="Singh 2016"/>

===United States===
Some U.S. companies manufacture aquatic weed harvesters.<ref name="TBO.com 2013"/> One such machine manufactured by a U.S. company can cut around one-half an [[Acre|acre]] of weeds a day, and costs over $100,000.<ref name="TBO.com 2013"/>

Tampa, Florida used an aquatic weed harvester in 2013 to clear aquatic plant life from lakes in the area.<ref name="TBO.com 2013"/>

In 2012 in Leoni, Michigan, an aquatic weed harvester was used to remove [[Biology:Algae|algae]] from Center Lake.<ref name="Satayut 2012"/> The algae appeared to have roots, and other techniques such as attempting to kill it with chemicals were unsuccessful.<ref name="Satayut 2012"/> The machine used collects algae and weeds that live at the bottom of the lake, removing them from the waterway.<ref name="Satayut 2012"/>

==See also==
*Mechanical weed control
*{{section link|Eichhornia crassipes|Uses}}
*[[Engineering:List of agricultural machinery|List of agricultural machinery]]
*[[Earth:Water resource management|Water resource management]]

== References ==
{{Reflist|30em|refs=
<ref name="TBO.com 2013">{{cite web | title=Aquatic weed harvester clearing lake at Bobby Hicks Park | website=The Tampa Tribune | date=16 May 2013 | url=http://www.tbo.com/south-tampa/aquatic-weed-harvester-clearing-lake-at-bobby-hicks-park-b82492966z1 | access-date=11 February 2016 | archive-url=https://web.archive.org/web/20160309194224/http://www.tbo.com/south-tampa/aquatic-weed-harvester-clearing-lake-at-bobby-hicks-park-b82492966z1 | archive-date=9 March 2016 | url-status=dead }}</ref>
<ref name="Satayut 2012">{{cite web | last=Satayut | first=Lisa | title=Clearwater Lake Association tries aquatic weed harvesting over chemicals | website=MLive.com | date=23 July 2012 | url=http://www.mlive.com/news/jackson/index.ssf/2012/07/clearwater_lake_association_tr.html | access-date=11 February 2016}}</ref>
<ref name="Singh 2016">{{cite web | last=Singh | first=S Bachan Jeet | title=HMDA to Procure Excavator to Clean Hussainsagar Lake | website=The New Indian Express | date=11 February 2016 | url=http://www.newindianexpress.com/cities/hyderabad/HMDA-to-Procure-Excavator-to-Clean-Hussainsagar-Lake/2015/08/24/article2990387.ece | access-date=11 February 2016}}</ref>
<ref name="www.newvision.co.ug 2016">{{cite web | title=Water hyancinth causes fish scarcity | website=New Vision | date=11 February 2016 | url=http://www.newvision.co.ug/new_vision/news/1327892/water-hyancinth-causes-fish-scarcity | access-date=11 February 2016}}</ref>
<ref name="Mills 2015">{{cite web | last=Mills | first=Chris | title=An Amphibious Weed-Cutting Boat Is the Only Vehicle I Would Ever Need | website=Gizmodo | date=30 August 2015 | url=https://gizmodo.com/an-amphibious-weed-cutting-boat-is-the-only-vehicle-i-w-1727638509 | access-date=11 February 2016}}</ref>
}}

==Further reading==
* {{cite web | last=O'Connor | first=Brian | title=Wasilla has new weapon in fight against weeds | website=Mat-Su Valley Frontiersman | date=10 February 2016 | url=http://www.frontiersman.com/news/wasilla-has-new-weapon-in-fight-against-weeds/article_d72cae80-633c-11e5-8a13-9f867ccdd873.html | access-date=11 February 2016}}
* {{cite web | last=Richard | first=Raven | title=Columbia Irrigation District Hopes Aquatic Weed Cutter Cuts Their Problems | publisher=NBC KNDO/KNDU | date=13 July 2015 | url=http://www.nbcrightnow.com/story/29539420/columbia-irrigation-district-hopes-aquatic-weed-cutter-cuts-their-problems | access-date=11 February 2016}}
* {{cite web | author=Murphy, Justin | title=$40,000 needed to fix weed-cutting boat | website=The Citizen | date=14 February 2012 | url=http://auburnpub.com/news/local/needed-to-fix-weed-cutting-boat/article_8ac12410-56be-11e1-ad50-001871e3ce6c.html | access-date=11 February 2016}}
* Gorham, Peter (November 2008). [http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0020/256403/Aquatic-weed-management-in-waterways-and-dams.pdf "Aquatic weed management in waterways and dams"]. New South Wales Government. Department of Primary Industries.
* Thamer, Sarah (July 2020). [https://www.wisn.com/article/aquatic-weed-harvester-made-in-wisconsin-helps-keep-lakes-useable/33283165# "Aquatic Weed Harvester made in Wisconsin helps keep lakes useable"].

[[Category:Agricultural machinery]]
[[Category:Cutting tools]]

{{Sourceattribution|Aquatic weed harvester}}