   the pastaza (formerly known as the sumataraenock, charles reginald (1914) ecuador: its ancient and modern history, topography and natural resources, industries and social development charles scribner's sons, new york, pages 177â178, ) is a large tributary to the maraÃ±Ã³n river in the northwestern amazon basin of south america.ziesler, r. and g.d. ardizzone, g.d. (1979) "amazon system" las aguas continentales de america latina / the inland waters of latin america (copescal technical paper no. 1) fisheries and aquaculture department, food and agriculture organization of the united nations (fao), rome, isbn 92-5-000780-9, in english and spanish it has its headwaters in the ecuadorian province of cotapaxi, flowing off of the northwestern slopes of the volcano cotopaxi and known as the patate river. the patate flows south and in tungurahua province it is joined by the chambo river just upstream from the town of baÃ±os de agua santa just north of the volcano mount tungurahua and becomes the pastaza.instituto geografico militar del ecuador, mapa tungurahua 50,000:1topographic map baÃ±os, ecuador, series j721, sheet 3989 iv, 1:50,000 instituto geogrÃ¡fico militar (igm), quito, ecuador, september 2000, reprinted by the u.s. national imagery and mapping agency seven kilometers east of baÃ±os, it is dammed for the agoyan hydroelectic project, which has created a silty lagoon by the village of la cieniga. the agoyan dam was placed in that location specifically to leave the famous falls of agoyan, about 5&nbsp;km further downstream, intact. after the waterfall the river enters a gorge where there is very fast whitewater with class-4 rapids; it is often used for whitewater rafting although it is not considered to be of the same quality as the tena river and is therefore less popular for the sport.guia turistica del tungurahua, ministerio de turismo ecuador from the junction with the chambo, the pastaza flows almost due
International_rivers_of_South_America Ramsar_sites_in_Peru Rivers_of_Ecuador Rivers_of_Peru Tributaries_of_the_Amazon_River