Napo River

The Napo River () is a tributary to the Amazon River that rises in Ecuador on the flanks of the east Andean volcanoes of Antisana, Sincholagua and Cotopaxi.

The total length is . The river drains an area of ca 103,000 km2. The mean annual discharge at Mazán is .

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 channels 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 , 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 (km2)Average discharge (m3/s) Lower NapoFrancisco de Orellana078103,307.797,147.86,611Mazán79.7685100,5187,0336,464.5Bellavista194.5110590,305.36,416.1–Santa Clotilde256.2411385,7706,124.45,700Campo Serio421.3514050,342.93,430.3–Cabo Pantoja546.816644,698.23,007.53,280Nuevo Rocafuerte574.117327,489.41,937.32,032Pañacocha67320321,731.41,552.1–Upper NapoPuerto Francisco de Orellana78224312,3431,0161,105Puerto Napo9504274,182.4260.9377.6

Discharge

Napo River at Bellavista average (Q), dominante (Qd) discharge (m3/s) and sediment load (S – million ton/year). Period from 1991/09–2009/08: Water yearQSQdWater yearQSQd1991/19925,667 28.608 6,0092001/20025,979 32.431 6,3351992/19937,104 47.718 7,4472002/20035,669 32.154 6,3121993/19948,013 67.159 8,5832003/20046,148 41.916 7,0541994/19956,055 34.801 6,5252004/20056,456 37.953 6,7671995/19965,956 34.017 6,4632005/20066,143 34.77 6,5231996/19976,262 38.258 6,7902006/20076,535 40.344 6,9421997/19989,839105.95610,3542007/20086,615 40.832 6,9771998/19996,839 51.48 7,6862008/20097,428 52.504 7,7491999/20006,725 49.735 7,5762000/20016,452 38.527 6,810Average6,660 44.953 7,161

Napo River at Bellavista average, minimum and maximum discharge (m3/s). Period from 2009/09 to 2023/08: Water yearMeanMinMaxWater yearMeanMinMax2009/20107,1772016/20177,273.63,20011,1502010/20115,768.21,64910,8602017/20187,2841,55013,5002011/20127,447.42,89412,2302018/20198,2342,85012,2002012/20137,452.73,10211,2302019/20208,1003,10012,7002013/20148,6523,23013,7002020/20218,4103,62014,0002014/20159,3364,81013,4502021/20226,8552,07813,5002015/20165,761498.610,2002022/20235,8491,20115,200 Minimum 498.6 m3/s (2016/02); Maximum: 15,820 m3/s (2015/07)

Napo River at Bellavista average, maximum, minimum and multiannual average (normal) discharge (m3/s) and anomaly (%): MeanMaxMinNormal(%)2010/09 – 2011/08SEP2,620.53,0891,9695,121.2–49OCT2,413.53,0611,6494,898.6–51NOV3,818.74,7782,6965,595.1–32DEC4,774.16,2404,1485,660.6–16JAN3,604.25,0012,1744,580.7–21FEB2,480.73,4781,9204,386.9–43MAR4,753.47,1273,7905,824.1–18APR9,206.810,2407,8657,502.423MAY9,561.510,0408,3488,941.37JUN10,193.810,8608,8219,422.98JUL9,846.310,5907,9048,844.711AUG5,944.68,6583,7586,610.8–10Mean5,768.26,9304,5876,449.1–122011/09 – 2012/08SEP4,551.35,4413,7575,121.211OCT5,344.96,9952,8944,898.69NOV4,4276,8783,0235,595.1–21DEC6,536.89,1605,2055,660.615JAN7,998.79,5014,8684,580.775FEB6,536.88,3025,1554,386.949MAR9,557.212,1505,4175,824.164APR11,843.712,23010,8707,502.458MAY10,322.710,7909,7028,941.315JUN8,878.89,9617,0119,422.9–6JUL8,189.39,2287,1978,844.7–7AUG5,1827,6053,9756,612.4–22Mean7,447.49,0205,7566,449.215.52012/09 – 2013/08SEP5,0377,8223,2495,096–1OCT5,1136,4574,6324,9184NOV4,1305,6603,1025,567–26DEC4,7556,8383,5685,698–17JAN7,5899,1833,8544,72361FEB5,8519,0714,1704,46531MAR10,06010,7409,1275,97368APR9,405106108,6757,68322MAY8,32210,5706,9328,999–8JUN10,49511,2309,7439,40012JUL9,67510,4108,4028,81710AUG9,0019,7768,3866,55137Mean7,452.79,0306,1536,490.815

+Napo River average discharge:PeriodDischargeRef.Francisco de Orellana (near mouth)2010–20151971–2000Bellavista (Mazán)1930–20061981–20201989–2010(Q–dominante: 1991–20091997–20152000–20112001–20122001–20092002–20082003–20092004–20102001–20052004–20062016–20171971–2000

Tributaries

List of the major tributaries of the Napo River (from the mouth upwards): Left tributary Right tributary Length (km) Basin size (km2) *Average discharge (m3/s)Napo1,089.03103,307.797,147.8Lower NapoSucusari590.739.8Mazán509.117,721.3532.9Yanayaçu1,34089Zapote140.89.3Papaya27817.5Tacshacuraray203.12,760.5196.5Huirina61033.2Tamboryaçu4,958327.2Pucara82750.4Curaray772.7726,704.72,044.4Tarapoto67946.1Gomez424.832.6Loro Caparin794.161.8Anshiri2,682.5202.1Santa Maria1,471.5107.8Aguarico502.513,404.5889.3Yasuní238.53,386.8237.7Tiputini380.44,423.1320.2Huiririma13.2Cariyuturi253.518.3Pañyaçu80876.768.4Indillana71.8636.351.5Itaya120.69.6Jivino121.7707.956Blanco24917.6Coca245.15,308.1338.9Upper NapoPayamino110.42,012.6171.2Suyunoyaçu198.816.8Suno96.71,891.4161.2Arajuno835.997.9Pusuno160.215.2Misahuallí68.71,659.6170.6Jatunyaçu1073,221.2302.7Anzu69.7817.175 *Period: 1971–2000

See also Lake Pilchicocha

References