Editing Geography of Venezuela (section)

==Hydrography==
{{See also|List of rivers in Venezuela}}
The [[Orinoco]] is by far the most important of the more than 1,000 [[List of rivers of Venezuela|rivers in the country]].<ref name=":0"/> Flowing more than 2,500 kilometers to the Atlantic from its source in the Guiana highlands at the Brazilian border, the Orinoco is the world's eighth largest river and the largest in South America after the [[Amazon River|Amazon]].<ref name=":0"/> Its flow varies substantially by season, with the high water level in August exceeding by as much as thirteen meters the low levels of March and April.<ref name=":0"/> During low water periods, the river experiences high and low tides for more than 100 kilometers upstream from [[Ciudad Guayana]].<ref name=":0"/>

For most of the river's course, the gradient is slight.<ref name=":0"/> Downstream from its headwaters, it splits into two; one-third of its flow passes through the [[Brazo Casiquiare]] (Casiquiare Channel) into a tributary of the Amazon, and the remainder passes into the main Orinoco channel. This passageway allows vessels with shallow drafts to navigate from the lower Orinoco to the Amazon River system after unloading and reloading on either side of two falls on the Orinoco along the Colombian border.<ref name=":0"/>

[[File:Venezuela Köppen.png|thumb|[[Köppen climate classification|Köppen]] climate types of Venezuela.]]

Most of the rivers rising in the northern mountains flow southeastward to the Río Apure, a tributary of the Orinoco. From its headwater, the Apure crosses the llanos in a generally eastward direction.<ref name=":0"/> Few rivers flow into it from the poorly drained region south of the river and much of this area near the Colombian border is swampland.<ref name=":0"/>

The other major Venezuelan river is the fast-flowing [[Caroni River (Venezuela)|Caroní]], which originates in the Guiana highlands and flows northward into the Orinoco upstream from Ciudad Guyana.<ref name=":0"/> The Caroní is capable of producing as much hydroelectric power as any river in Latin America and has contributed significantly to the nation's electric power production. Electricity generated by the Caroní was one of the factors encouraging industrialization of the northern part of the Guiana highlands and the lower Orinoco valley.<ref name=":0"/>

[[Lake Maracaibo]] occupies the central 13,500 square kilometers of the Maracaibo lowlands.<ref name=":0"/> The low swampy shores of the lake and areas beneath the lake itself hold most of Venezuela's rich petroleum deposits.<ref name=":0"/> The lake is shallow, with an average depth of ten meters, and separated from the Caribbean by a series of islands and sandbars.<ref name=":0"/> In 1955 a 7.5-meter channel was cut through the sandbars to facilitate shipping between the lake and the Caribbean.<ref name=":0"/> The channel also allows salt water to mix with the yellowish fresh water of the lake, making the northern parts brackish and unsuited for drinking or irrigation.<ref name=":0"/>

A recent global remote sensing analysis suggested that there were {{cvt|732|km2}} of tidal flats in Venezuela, making it the 36th ranked country in terms of tidal flat extent.<ref>{{cite journal |last1=Murray |first1=N.J. |last2=Phinn |first2=S.R. |last3=DeWitt |first3=M. |last4=Ferrari |first4=R. |last5=Johnston |first5=R. |last6=Lyons |first6=M.B. |last7=Clinton |first7=N. |last8=Thau |first8=D. |last9=Fuller |first9=R.A. |title=The global distribution and trajectory of tidal flats |journal=Nature |date=2019 |volume=565 |issue=7738 |pages=222–225 |doi=10.1038/s41586-018-0805-8 |pmid=30568300 |s2cid=56481043 |url=https://www.nature.com/articles/s41586-018-0805-8}}</ref>