Maipo River

{{Infobox river

| name = Maipo River

| image = Río Maipo.jpg

| image_caption =

| map = Maipo River watershed.png

| map_size = 250

| map_caption = Maipo River watershed ([https://mghydro.com/watersheds/shared/3ECB2F Interactive map])

| source1_location = Andes Mountains, south of Unnamed Hill 3996

| source1_coordinates = {{coord|-34.225|-69.849|format=dec}}

| mouth = Pacific Ocean

| mouth_location = San Antonio, Chile

| mouth_coordinates = {{coord|-33.6134|-71.6288|format=dec|region:CL_type:river|display=inline,title}}

| tributaries_right = El Volcán, Yeso and Colorado

| subdivision_type1 = Country

| subdivision_name1 = Chile

| length = {{convert|250|km|abbr=on}}[http://www.sinia.cl/1292/articles-31018_Maipo.pdf Cuenca del río Maipo] {{webarchive|url=https://web.archive.org/web/20120212042019/http://www.sinia.cl/1292/articles-31018_Maipo.pdf |date= 2012-02-12 }}

| discharge1_avg = {{convert|92.3|m3/s|abbr=on}}

| basin_size = {{convert|15,304|km2|abbr=on}}

}}

The Maipo River is the main river flowing through the Santiago Metropolitan Region and the Valparaíso Region of Chile. It is located just south of the capital of Santiago. The Mapocho River, which flows through central Santiago, is one of its tributaries. Its headwaters are on the west slope of Maipo volcano, in the Andes. The Maipo River is by far the major source of irrigation and potable water for the region.{{cite book |last=Cai |first=Ximing |title=Modeling Water Resources Management at the Basin Level: Methodology and Application to the Maipo River Basin |author2=Claudia Ringler |author3=Mark W. Rosegrant |year=2006 |publisher=International Food Policy Research Institute |location=Washington DC |isbn=978-0-89629-152-2 }}

The river's mouth bar have moved to disconnect the river from the sea several times in history, for example, after the 2010 Chile earthquake and then again since January 19, 2023.{{Cite news |title=Río Maipo no desemboca en el mar desde el jueves pasado: Las razones del fenómeno |url=https://www.emol.com/noticias/Nacional/2023/01/26/1085003/rio-maipo-no-desemboca-mar.html |last=Olivares Nieto |first=B. |date=2023-01-26 |access-date=2023-01-27 |work=Emol |language=Spanish}} This last change in bar morphology was a consequence of a storm surge. By January 28 a ditch had been made to reconnect the river to the sea.{{Cite news |title=Río Maipo vuelve a desembocar en el mar tras construcción de zanja para encauzar caudal |url=https://www.biobiochile.cl/especial/aqui-tierra/noticias/2023/01/28/rio-maipo-vuelve-a-desembocar-en-el-mar-tras-construccion-de-zanja-para-encauzar-caudal.shtml |last=Zamarin |first=Felipe |date=2023-01-28 |work=Radio Bío-Bío |year=2023}} Governor of Valpraíso Region Rodrigo Mundaca criticized however the fact that works were carried out without permission.

Low discharge rates caused by excessive uptakes of water in Maipo River have been credited for the inability of the river to break naturally through the bar in January 2023.