River
San Juan River
500 km from source to mouth · Argentina.
ArgentinaFlows into Desaguadero River
In numbers
Length
500km
Average flow
110m³/s
Basin
39,906km²
Drop
2,728m
from 3,268 m to 540 m
Country
1
The journey
From source to mouth
500 km of river and 10 stops on the way: 5 towns and cities on its banks, dams, bridges and the tributaries that feed it.
- 0 kmSourceat 3,268 m
- 182 kmRío de los Patostributary
- 279 kmLos Caracoles Dam
- 304 kmPunta Negra Dam
- 331 kmQuebrada de Ullum Dam
- 332 kmUllum Dam18 km²
- 353 kmVilla Paula de Sarmiento19,092 people
- 353 kmChimbas73,829 people
- 358 kmVilla General San Martín29,789 people
- 358 kmAlbardón20,413 people
- 390 kmVilla Don Bosco3,571 people
- 500 kmDesaguadero Riverat 540 m
Water level along the river (RiverATLAS; the height is exaggerated). Towns: GeoNames and Wikidata; bridges, dams and tributaries: Wikidata.
River in the Argentine province of San Juan
At the mouth it carries 110 m³/s on average: an Olympic pool every 23 seconds. It drops from 3,268 m to 540 m, 5.5 m per kilometre on average. Its basin covers 39,906 km², about the size of CH. 1.7 million people live in it. Highest water: from February to March. Dams and reservoirs hold back a large share of its water (25% of a year's flow).
Where to start
- ChimbasLargest city on its banks · 73,829 people
- Domingo Faustino Sarmiento Airport (UAQ)Nearest airport with scheduled flights, 14 km from the cityCar hire at UAQ airport (San Juan)Discover Cars · Affiliate link↗
- On the water1 ferry piers, marinas, boat rentals and boat ramps along the river (OpenStreetMap)
- From January to March and from October to NovemberThe best months to visit
San Juan River, month by month
Highest water: from February to March
Best months to visit: from January to March and from October to November.
From about 48 m³/s in the lowest month to 220 m³/s in the highest. An estimate: the monthly flow is modelled from the lowest and highest months of WaterGAP (RiverATLAS, 1971–2000) and the rain and snow along the river (WorldClim). Dams change the real rhythm. The chip is the average air temperature; below it, the month's rain.
Plan the trip
Plan the trip: boat trips, a bed by the river, a car
Some links above are affiliate links: if you book through them we may earn a commission, at no extra cost to you. It never changes what the data on this page says.
The basin
San Juan River: the basin in numbers
48,303 km² of land send their water to this river. This is what lives on it.
- 1.7millionpeople live in the basin
- 35/km²people per km²
- 2,534maverage altitude of the basin
- 205mmof rain a year (basin average)
- 7.1°Caverage air temperature
- 7%protected areas
- 0.1%covered by lakes
- 8%permafrost
- 0.9km³held in reservoirs
What covers the basin
- 1% Forest
- 3% Cropland
- 10% Pasture
- 1% Towns and cities
RiverATLAS (HydroATLAS v1.0, CC BY 4.0): land cover, people, protected areas, glaciers and dams over the whole basin upstream of the mouth.
Along the river
San Juan River: what you find on the way
- 1Weirs
- 1Waterfalls
- 1MarinasPlaya del Embarcadero
- 3River beachesPlaya Costa Magna, Playa habilitada para bañistas
From OpenStreetMap, within 2.2 km of the river. Not mapped is not the same as not there.
Cross-checked with our atlases
San Juan River in our other atlases
What our sister atlases know about the waterfalls on this river, the lakes it flows through, the beaches at its mouth, the mountains where it rises and the islands off its mouth.
1lake on its wayLakeyas
Lakes and reservoirs (1)
Lakes it flows through, by Lakeyas
- Ullum Damkm 23918km²
Lakeyas is coming soonOpen Lakeyas ↗
From space
The source and the mouth, seen from orbit
Sentinel-2 cloudless 2016 by EOX IT Services GmbH (contains modified Copernicus Sentinel data 2016), CC BY 4.0. The glowing line is the river as drawn by RiverATLAS.
Photos
San Juan River in pictures
Tributaries
Where it flows, and what flows into it
It flows into
Desaguadero RiverArgentina1,515 km150 m³/sTributaries (3)
Also: Rio Mendoza, Río de los Patos, Castaño Viejo River
In the same basin
ChileWhere these numbers come from
| Name, length, places | Wikidata (Q933176) · CC0 |
|---|---|
| Course, profile, basin | RiverATLAS v1.0 (HydroATLAS, Linke et al. 2019) · CC BY 4.0 — followed from the source to the mouth given by Wikidata |
| Flow | WaterGAP (RiverATLAS), 1971–2000 · CC BY 4.0 |
| Climate along the river | WorldClim (RiverATLAS), 1970–2000 · CC BY 4.0 |
| Towns, bridges, dams | Wikidata · CC0; GeoNames · CC BY 4.0 |
| Along the river | © OpenStreetMap contributors · ODbL |
| Images | EOX Sentinel-2 cloudless 2016 · CC BY 4.0; Wikimedia Commons |
| Our other atlases | Lakeyas — Wikidata · CC0; © OpenStreetMap contributors · ODbL; GeoNames · CC BY 4.0; HydroLAKES · CC BY 4.0; NOAA OISST |
Every source and licence is on the data sources page.
The family
Do you prefer beaches, lakes, mountains, waterfalls, islands, rivers or canyons?
Same idea, other landscapes: field atlases built on open data, month by month, in seven languages.
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Every island from the sea up: size, sea temperature, ferries and 3D.Coming soonVisit 
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Every river from source to sea: the journey, the flow and the basin in numbers.You are here
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