Editing Geography of Tuvalu (section)

===Aquifer salinization of Fongafale Islet, Funafuti===
The investigation of groundwater dynamics of [[Fongafale]] Islet, [[Funafuti]], show that [[tidal force|tidal forcing]] results in salt water contamination of the [[surficial aquifer]] during [[Perigean spring tide|spring tides]].<ref name="EAS">{{cite journal|author1=Nakada S. |author2=Yamano H. |author3=Umezawa Y. |author4=Fujita M. |author5=Watanabe M. |author6=Taniguchi M. |title= Evaluation of Aquifer Salinization in the Atoll Islands by Using Electrical Resistivity|journal=Journal of the Remote Sensing Society of Japan |volume=30 |year =2010 |pages=317–330|doi=10.11440/rssj.30.317 }}</ref> The degree of aquifer salinization depends on the specific [[topographic]] characteristics and the [[hydrologic]] controls in the sub-surface of the atoll. About half of Fongafale islet is reclaimed swamp that contains porous, highly permeable coral blocks that allow the tidal forcing of salt water.<ref name="GWD">{{Cite journal|vauthors=Nakada S, Umezawa Y, Taniguchi M, Yamano H |title= Groundwater dynamics of Fongafale Islet, Funafuti Atoll, Tuvalu |journal= Groundwater |volume= 50 |issue= 4 |date =Jul–Aug 2012 |pages=639–44 |doi= 10.1111/j.1745-6584.2011.00874.x |pmid=22035506|s2cid= 32336745 }}</ref> There was extensive swamp reclamation during World War II to create the air field that is now the [[Funafuti International Airport]]. As a consequence of the specific topographic characteristics of Fongafale, unlike other atoll islands of a similar size, Fongafale does not have a thick [[Lens (hydrology)|freshwater lens]].<ref name="GWD"/> The narrow fresh water and brackish water sheets in the sub-surface of Fongafale islet results in the [[taro]] swamps and the fresh groundwater resources of the islet being highly vulnerable to salinization resulting from the rising sea-level.<ref name="GWD"/>

In addition to the increased risk of salinized by the sea-level rise, the freshwater lens is at risk from over extraction due to the large population that now occupies Fongafale islet; the increased extraction can be exacerbated by a decrease of the rainfall recharge rate associated with the climate change.<ref name="EAS"/> Water pollution is also a chronic problem, with domestic wastewater identified as the primary pollution source.<ref name="AIW">{{cite journal| last = Fujita M., Suzuki J., Sato D., Kuwahara Y., Yokoki H., Kayanne, Y. |title= Anthropogenic impacts on water quality of the lagoonal coast of Fongafale Islet, Funafuti Atoll, Tuvalu|journal= Sustainability Science|volume= 8|issue= 3|pages= 381–390|year =2013 |url= https://link.springer.com/content/pdf/10.1007%2Fs11625-013-0204-x.pdf|doi= 10.1007/s11625-013-0204-x|s2cid= 127909606}}</ref>  Approximately 92% of households on Fongafale islet have access to septic tanks and pit toilets. However, these sanitary facilities are not built as per the design specifications or they are not suitable for the geophysical characteristics, which results in seepage into the fresh water lens and run off into coastal waters.<ref name="AIW"/>

On [[Funafuti]] and on the other islands, rainwater collected off the corrugated iron roofs of buildings is now the primary source of fresh water. On Funafuti a desalination unit that was donated by Japan in 2006 also provides fresh water.<ref name="JPDP">{{cite web|title = Japan Provides Desalination Plant to relieve Tuvalu's water problems |date =2 June 2006|url= http://www.fj.emb-japan.go.jp/pr_Japan_Provides_Desalination_Plant_to_relieve_Tuvalus_water_problems.html |publisher = Embassy of Japan in the Republic of the Fiji Islands |access-date=1 December 2011}}</ref> In response to the [[2011 Tuvalu drought|2011 drought]], Japan funded the purchase of a 100 m<sup>3</sup>/d desalination plant and two portable 10 m<sup>3</sup>/d plants as part of its Pacific Environment Community (PEC) program.<ref name="JNZ">{{cite web |title = Japan-New Zealand Aid Cooperation in response to severe water shortage in Tuvalu |date =4 November 2011|url= http://www.mofa.go.jp/announce/announce/2011/11/1104_01.html |publisher = Department of Foreign Affairs of Japan |access-date=1 December 2011}}</ref><ref name="J3">{{cite web |title = Japanese fund three desalination plants for Tuvalu |date = 17 October 2011 |url = http://www.desalination.biz/news/news_story.asp?id=6170&title=Japanese+fund+three+desalination+plants+for+Tuvalu |publisher = The International Desalination & Water Reuse Quarterly industry website |access-date = 1 December 2011 |archive-date = 7 May 2012 |archive-url = https://web.archive.org/web/20120507101412/http://www.desalination.biz/news/news_story.asp?id=6170&title=Japanese+fund+three+desalination+plants+for+Tuvalu |url-status = dead }}</ref> Aid programs from the European Union<ref name="10EDF"/><ref name="TWWSP1">{{cite web| url= http://ec.europa.eu/europeaid/documents/aap/2009/af_aap_2009_tuv.pdf |title= Tuvalu / Water, Waste and Sanitation Project (TWWSP): CRIS FED/2009/021-195, ANNEX | publisher=European Union|access-date=24 October 2011}}</ref> and Australia also provided water tanks as part of the longer-term solution for the storage of available fresh water.