Río Napo
The total length is 1,075 km (668 mi). The river drains an area of ca 103,000 km. The mean annual discharge at Mazán 6,660 m/s (235,000 cu ft/s).
Geography
Before it reaches the plains it receives a great number of small streams from impenetrable, saturated and much broken mountainous districts, where the dense and varied vegetation seems to fight for every piece of ground. From the north it is joined by the Coca River, having its sources in the gorges of Cayambe volcano on the equator, and also a powerful river, the Aguarico having its headwaters between Cayambe and the Colombia frontier. From the west, it receives a secondary tributary, the Curaray, from the Andean slopes, between Cotopaxi and the Tungurahua volcano. From its Coca branch to the mouth of the Curaray the Napo is full of snags and shelving sandbanks and throws out numerous canoes among jungle-tangled islands, which in the wet season are flooded, giving the river an immense width. From the Coca to the Amazon it runs through a forested plain where not a hill is visible from the river - its uniformly level banks being only interrupted by swamps and lagoons. From the Amazon the Napo is navigable for river craft up to its Curaray branch, a distance of about 216 mi (348 km), and perhaps a bit further; thence, by painful canoe navigation, its upper waters may be ascended as far as Santa Rosa, the usual point of embarkation for any venturesome traveller who descends from the Quito tableland. The Coca river may be penetrated as far up as its middle course, where it is jammed between two mountain walls, in a deep canyon, along which it dashes over high falls and numerous reefs. This is the stream made famous by the expedition of the Spanish conquistador Gonzalo Pizarro.
Hydrometric stations on the Napo River:
| Station | River kilometer (rkm) | Elevation (m) | Drainage basin
(km) |
Average discharge
(m/s) | |
|---|---|---|---|---|---|
| Lower Napo | |||||
| Francisco de Orellana | 0 | 78 | 103,307.79 | 7,147.8 | 6,611 |
| Mazán | 79.76 | 85 | 100,518 | 7,033 | 6,464.5 |
| Bellavista | 194.51 | 105 | 90,305.3 | 6,416.1 | – |
| Santa Clotilde | 256.24 | 113 | 85,770 | 6,124.4 | 5,700 |
| Campo Serio | 421.35 | 140 | 50,342.9 | 3,430.3 | – |
| Cabo Pantoja | 546.8 | 166 | 44,698.2 | 3,007.5 | 3,280 |
| Nuevo Rocafuerte | 574.1 | 173 | 27,489.4 | 1,937.3 | 2,032 |
| Pañacocha | 673 | 203 | 21,731.4 | 1,552.1 | – |
| Upper Napo | |||||
| Puerto Francisco de Orellana | 782 | 243 | 12,343 | 1,016 | 1,105 |
| Puerto Napo | 950 | 427 | 4,182.4 | 260.9 | 377.6 |
Discharge
Napo River at Bellavista average (Q), dominante (Qd) discharge (m/s) and sediment load (S – million ton/year). Period from 1991/09–2009/08:
| Water year | Q | S | Qd | Water year | Q | S | Qd |
|---|---|---|---|---|---|---|---|
| 1991/1992 | 5,667 | 28.608 | 6,009 | 2001/2002 | 5,979 | 32.431 | 6,335 |
| 1992/1993 | 7,104 | 47.718 | 7,447 | 2002/2003 | 5,669 | 32.154 | 6,312 |
| 1993/1994 | 8,013 | 67.159 | 8,583 | 2003/2004 | 6,148 | 41.916 | 7,054 |
| 1994/1995 | 6,055 | 34.801 | 6,525 | 2004/2005 | 6,456 | 37.953 | 6,767 |
| 1995/1996 | 5,956 | 34.017 | 6,463 | 2005/2006 | 6,143 | 34.77 | 6,523 |
| 1996/1997 | 6,262 | 38.258 | 6,790 | 2006/2007 | 6,535 | 40.344 | 6,942 |
| 1997/1998 | 9,839 | 105.956 | 10,354 | 2007/2008 | 6,615 | 40.832 | 6,977 |
| 1998/1999 | 6,839 | 51.48 | 7,686 | 2008/2009 | 7,428 | 52.504 | 7,749 |
| 1999/2000 | 6,725 | 49.735 | 7,576 | ||||
| 2000/2001 | 6,452 | 38.527 | 6,810 | Average | 6,660 | 44.953 | 7,161 |
Napo River at Bellavista average, minimum and maximum discharge (m/s). Period from 2009/09 to 2023/08:
| Water year | Mean | Min | Max | Water year | Mean | Min | Max |
|---|---|---|---|---|---|---|---|
| 2009/2010 | 7,177 | 2016/2017 | 7,273.6 | 3,200 | 11,150 | ||
| 2010/2011 | 5,768.2 | 1,649 | 10,860 | 2017/2018 | 7,284 | 1,550 | 13,500 |
| 2011/2012 | 7,447.4 | 2,894 | 12,230 | 2018/2019 | 8,234 | 2,850 | 12,200 |
| 2012/2013 | 7,452.7 | 3,102 | 11,230 | 2019/2020 | 8,100 | 3,100 | 12,700 |
| 2013/2014 | 8,652 | 3,230 | 13,700 | 2020/2021 | 8,410 | 3,620 | 14,000 |
| 2014/2015 | 9,336 | 4,810 | 13,450 | 2021/2022 | 6,855 | 2,078 | 13,500 |
| 2015/2016 | 5,761 | 498.6 | 10,200 | 2022/2023 | 5,849 | 1,201 | 15,200 |
| Average (2009–2023) | 7,400 | 2,413 | 11,709 | ||||
Napo River at Bellavista average, maximum, minimum and multiannual average (normal) discharge (m/s) and anomaly (%):
| Mean | Max | Min | Normal | (%) | |
|---|---|---|---|---|---|
| 2010/09 – 2011/08 | |||||
| SEP | 2,620.5 | 3,089 | 1,969 | 5,121.2 | –49 |
| OCT | 2,413.5 | 3,061 | 1,649 | 4,898.6 | –51 |
| NOV | 3,818.7 | 4,778 | 2,696 | 5,595.1 | –32 |
| DEC | 4,774.1 | 6,240 | 4,148 | 5,660.6 | –16 |
| JAN | 3,604.2 | 5,001 | 2,174 | 4,580.7 | –21 |
| FEB | 2,480.7 | 3,478 | 1,920 | 4,386.9 | –43 |
| MAR | 4,753.4 | 7,127 | 3,790 | 5,824.1 | –18 |
| APR | 9,206.8 | 10,240 | 7,865 | 7,502.4 | 23 |
| MAY | 9,561.5 | 10,040 | 8,348 | 8,941.3 | 7 |
| JUN | 10,193.8 | 10,860 | 8,821 | 9,422.9 | 8 |
| JUL | 9,846.3 | 10,590 | 7,904 | 8,844.7 | 11 |
| AUG | 5,944.6 | 8,658 | 3,758 | 6,610.8 | –10 |
| Mean | 5,768.2 | 6,930 | 4,587 | 6,449.1 | –12 |
| 2011/09 – 2012/08 | |||||
| SEP | 4,551.3 | 5,441 | 3,757 | 5,121.2 | 11 |
| OCT | 5,344.9 | 6,995 | 2,894 | 4,898.6 | 9 |
| NOV | 4,427 | 6,878 | 3,023 | 5,595.1 | –21 |
| DEC | 6,536.8 | 9,160 | 5,205 | 5,660.6 | 15 |
| JAN | 7,998.7 | 9,501 | 4,868 | 4,580.7 | 75 |
| FEB | 6,536.8 | 8,302 | 5,155 | 4,386.9 | 49 |
| MAR | 9,557.2 | 12,150 | 5,417 | 5,824.1 | 64 |
| APR | 11,843.7 | 12,230 | 10,870 | 7,502.4 | 58 |
| MAY | 10,322.7 | 10,790 | 9,702 | 8,941.3 | 15 |
| JUN | 8,878.8 | 9,961 | 7,011 | 9,422.9 | –6 |
| JUL | 8,189.3 | 9,228 | 7,197 | 8,844.7 | –7 |
| AUG | 5,182 | 7,605 | 3,975 | 6,612.4 | –22 |
| Mean | 7,447.4 | 9,020 | 5,756 | 6,449.2 | 15.5 |
| 2012/09 – 2013/08 | |||||
| SEP | 5,037 | 7,822 | 3,249 | 5,096 | –1 |
| OCT | 5,113 | 6,457 | 4,632 | 4,918 | 4 |
| NOV | 4,130 | 5,660 | 3,102 | 5,567 | –26 |
| DEC | 4,755 | 6,838 | 3,568 | 5,698 | –17 |
| JAN | 7,589 | 9,183 | 3,854 | 4,723 | 61 |
| FEB | 5,851 | 9,071 | 4,170 | 4,465 | 31 |
| MAR | 10,060 | 10,740 | 9,127 | 5,973 | 68 |
| APR | 9,405 | 10610 | 8,675 | 7,683 | 22 |
| MAY | 8,322 | 10,570 | 6,932 | 8,999 | –8 |
| JUN | 10,495 | 11,230 | 9,743 | 9,400 | 12 |
| JUL | 9,675 | 10,410 | 8,402 | 8,817 | 10 |
| AUG | 9,001 | 9,776 | 8,386 | 6,551 | 37 |
| Mean | 7,452.7 | 9,030 | 6,153 | 6,490.8 | 15 |
| Period | Discharge | Ref. |
|---|---|---|
| Francisco de Orellana (near mouth) | ||
| 2010–2015 | 7,400 m/s (260,000 cu ft/s) | |
| 7,500 m/s (260,000 cu ft/s) | ||
| 1971–2000 | 7,147.8 m/s (252,420 cu ft/s) | |
| 8,936 m/s (315,600 cu ft/s) | ||
| 4,555.23 m/s (160,866 cu ft/s) | ||
| Bellavista (Mazán) | ||
| 1930–2006 | 6,464 m/s (228,300 cu ft/s) | |
| 1989–2010 | 6,360 m/s (225,000 cu ft/s)
(Q–dominante: 6,865 m/s (242,400 cu ft/s) |
|
| 1991–2009 | 6,660 m/s (235,000 cu ft/s) | |
| 1997–2015 | 6,734.2 m/s (237,820 cu ft/s) | |
| 2000–2011 | 6,461 m/s (228,200 cu ft/s) | |
| 2001–2012 | 6,758 m/s (238,700 cu ft/s) | |
| 2001–2009 | 6,369 m/s (224,900 cu ft/s) | |
| 2002–2008 | 6,489 m/s (229,200 cu ft/s) | |
| 2003–2009 | 6,855 m/s (242,100 cu ft/s) | |
| 2004–2010 | 6,609 m/s (233,400 cu ft/s) | |
| 2001–2005 | 6,976 m/s (246,400 cu ft/s) | |
| 2004–2006 | 6,267 m/s (221,300 cu ft/s) | |
| 2016–2017 | 9,338 m/s (329,800 cu ft/s) | |
| 1971–2000 | 7,032 m/s (248,300 cu ft/s) | |
Tributaries
List of the major tributaries of the Napo River (from the mouth upwards):
| Left
tributary |
Right
tributary |
Length (km) | Basin size (km) | Average discharge (m/s) |
|---|---|---|---|---|
| Napo | 1,089.03 | 103,307.79 | 7,147.8 | |
| Lower Napo | ||||
| Sucusari | 590.7 | 39.8 | ||
| Mazán | 509.11 | 7,721.3 | 532.9 | |
| Yanayaçu | 1,340 | 89 | ||
| Zapote | 140.8 | 9.3 | ||
| Papaya | 278 | 17.5 | ||
| Tacshacuraray | 203.1 | 2,760.5 | 196.5 | |
| Huirina | 610 | 33.2 | ||
| Tamboryaçu | 4,958 | 327.2 | ||
| Pucara | 827 | 50.4 | ||
| Curaray | 772.77 | 26,704.7 | 2,044.4 | |
| Tarapoto | 679 | 46.1 | ||
| Gomez | 424.8 | 32.6 | ||
| Loro Caparin | 794.1 | 61.8 | ||
| Anshiri | 2,682.5 | 202.1 | ||
| Santa Maria | 1,471.5 | 107.8 | ||
| Aguarico | 502.5 | 13,404.5 | 889.3 | |
| Yasuní | 238.5 | 3,386.8 | 237.7 | |
| Tiputini | 380.4 | 4,423.1 | 320.2 | |
| Huiririma | 13.2 | |||
| Cariyuturi | 253.5 | 18.3 | ||
| Pañyaçu | 80 | 876.7 | 68.4 | |
| Indillana | 71.8 | 636.3 | 51.5 | |
| Itaya | 120.6 | 9.6 | ||
| Jivino | 121.7 | 707.9 | 56 | |
| Blanco | 249 | 17.6 | ||
| Coca | 245.1 | 5,308.1 | 338.9 | |
| Upper Napo | ||||
| Payamino | 110.4 | 2,012.6 | 171.2 | |
| Suyunoyaçu | 198.8 | 16.8 | ||
| Suno | 96.7 | 1,891.4 | 161.2 | |
| Arajuno | 835.9 | 97.9 | ||
| Pusuno | 160.2 | 15.2 | ||
| Misahuallí | 68.7 | 1,659.6 | 170.6 | |
| Jatunyaçu | 107 | 3,221.2 | 302.7 | |
| Anzu | 69.7 | 817.1 | 75 | |
Period: 1971–2000