Main estuaries of Ecuador, a review from estuarine
Castro Rodas Divar, Chang Gómez José.
Faculty of Maritime Engineering and Biological, Oceanic and Natural Resources Sciences (FIMCBOR)
Campus "Gustavo Galindo", Km 30,5 Via Perimetral
Guayaquil - Ecuador
This document presents a brief summary of the main estuaries of Ecuador with its main characteristics as part of the course of
Key words- Estuaries, Ecuador, climatology
The estuaries correspond to one of the places with the
most biodiverse marine-terrestrial ecosystems, which include
many species of birds, fish, crustaceans, molluscs and other
species, both macro and microscopic. They are characterized
by the presence of mangroves, which are trees very tolerant
to sudden changes in salinity, which is why it is common to
see them in estuaries and coastal areas, at the same time these
trees slow down the effect of waves in coastal areas.
The estuarine areas offer a range of ideal conditions to
house a number of endemic species of these ecosystems, in
addition to providing improvements in environmental quality
for their ability to filter water contaminants.
One of the main problems of these ecosystems is the
constant contamination to which they are exposed, such as
detergents, domestic and industrial wastewater, pesticides,
etc. As a special case, the Gulf of Guayaquil, which receives
three quarters of the polluting waste of the entire coast, as an
important fact we also know that a total of 6,400,000 liters of
pesticides were consumed (most of which are extremely toxic
and their use is prohibited in other countries) which
corresponds to the70% of national consumption.
Another problem are human activities such as
aquaculture, mining and overfishing, which have caused
serious impacts in biodiversity and on the quality of life of
the population. For example, the mangrove forest has been
deforested, which is intimately associated with the estuaries,
much of the fauna and flora of these have migrated or
disappeared, giving rise to ecosystems considered in danger
of extinction, such as river estuaries. Chone, Muisne and
The estuaries of Ecuador are found along the entire
coastal profile (Fig 1), which will be detailed by province.
Fig. 1: Provinces of coastal Ecuador.
The province of Esmeraldas, is located in the northwestern
part of the country. The climate of Esmeraldas varies from
tropical sub humid, humid subtropical and subtropical very
humid, with an average temperature of 23°C (Wikipedia, s.f.).
Much of its economy corresponds to tourism due to its
beaches. Other contributions for its economy are based on the
export of shrimp, bananas, tobacco, coffee and cocoa among
the most important. It has some ports, but the main one is in
the City of Esmeraldas (capital of the province) which is one
of the most important for Ecuador. The geography of the
place corresponds to plains with hills of maximum 30 masl
(meters above sea level). Below are some important features
of the most important estuaries in this province.
i. Mataje River estuary
This river is particularly important as it serves as a natural
boundary between Ecuador and Colombia, has an
approximate area of 684 km2 and has an average flow of 35
m3/s (América, 1998), this area having a humid tropical
climate, has abundant animal species such as bats and
marsupials, monkeys, anteaters, sloths, carnivorous animals
such as tigrillo, rodents such as squirrels, guacharaca, guatusa,
guanta; variety of birds such as woodpeckers, mountain
guans, sparrowhawks, hummingbirds and others; amphibians
like toads and frogs. We also find reptiles such as alligators,
snakes and turtles and insects (Aguayo, 2005)
Table 1: Technical details of Mataje River.
In this area there is an ecological reserve (Manglares
Cayapas Mataje Ecological Reserve), which is responsible for
protecting the biodiversity present in this place, since
anthropogenic activities such as aquaculture, mining, oil
exploitation and overfishing have caused environmental
problems such as the destruction of habitats whose most
serious negative impacts are the loss of biodiversity and the
reduction of the quality of life, as well as the erosion and
sedimentation of the place.
ii. Esmeraldas River estuary
This estuary is one of the most impacted due to
anthropogenic reasons since the presence of mangroves has
been completely eliminated due to the shrimp ponds installed
along most of the estuary, it has an approximate area of 20401
km2 and has an average flow rate of 680 m3/s, being the
second largest in Ecuador, after the Guayas river (América,
Table 2: Technical details of Esmeraldas River.
The hydrographic system of the Esmeraldas River is
formed by the Blanco, Guayllabamba, Toachi and Quinindé
Rivers. Its source is found in the melting of the mountain
range and the Guayllabamba River is the longest tributary that
collects the waters from the north of the Inter-Andean alley.
From the confluence of Esmeraldas and Guayllabamba in
Quinindé to the mouth, it is navigable. The capital,
Esmeraldas, is 3 km from the estuary (Wikipedia, s.f.).
The climate is between tropical humid, and tropical
monsoon, with a high temperature throughout the year
(approximately over 25°C), it is also known that the average
annual rainfall in this area is of 1980 mm, for this reason it
corresponds a Dense training always green throughout the
year (Aguayo, 2005).
At the end of the river bed is one of the most important
ports in the country, the port of Esmeraldas.
Which is located on the left margin of the mouth of the river
Esmeraldas, at an altitude of 5 meters above sea level, the
reason why this port is one of the most important in the
country, is because of being a few hours by land of the inter-
Andean or sierra region and mainly with the country's capital.
The Maritime Port is made up of two docks, that of the
Commercial Port with 10 m., Of average depth and the fishing
port whose average depth is 4.5 m., On the right margin of the
mouth of the Esmeraldas River the Punta Este is formed and
on the left margin, Punta Coquitos is formed, the distance
between them is 2 nautical miles.
The prevailing winds in the port area have the following
• During the last hours of the night and the first hours
of the morning a breeze is experienced from land with
predominant directions of the south and southwest, with
moderate speeds that oscillate between 5 and 9 knots.
• During the last hours of the morning and the first of
the afternoon the wind comes from the sea, with directions
west and northwest and speeds a little bigger than the
winds of earth, the speed of the predominant current in the
area varies between 1 to 3 knots with northwest - north
direction, but in the anchorage area it increases due to the
speed of the current up to 4 knots and its direction varies
to the northwest during the low tide and to the southwest
during the high tide.
• It is estimated that the probability of finding winds
with speeds greater than 4 knots is 30% between the
months of September to November.
The observed waves have an average height of 0.4 m,
sometimes reaching a maximum of 1 m., The sea temperature
has an annual average of 25.9°C. The area is relatively quiet
in terms of winds and waves. Their waves usually come from
the northwest, west or southwest, their height oscillates
between 0 and 1.8 m., For the waves that do not exceed 0.6
m., Which are the most frequent, the periods are between 0
and 4s. , the registered currents vary for the dry and rainy
season (December-May), during the rainy season the speeds
can reach values around 5 knots with northwest direction
during the reflux and up to 4.5 knots in flow towards the
northeast, while for In the dry season the maximum speeds
reach 1.2 knots during the reflux and 0.9 knots in the flow,
keeping the direction presented in the rainy season for each
tidal state. (INOCAR, 2012)
Manabi is located south of the province of Esmeraldas, is
the third most populated province of the country, its capital is
Portoviejo. Among its most important features we have that
this province, due to the presence of a cordon of mountains
(Cordillera Chongón-Colonche) that do not exceed 300 masl,
has no influence of major rivers in most of its territory,
however, in the area corresponding to the Chone River, it has
great biodiversity due to its influence in the sector.
i. Chone River estuary
Like the estuaries of the Esmeraldas River, in the Chone
River the presence of shrimp farms on the fringe of the
estuary has almost completely eliminated the presence of
mangroves, has an approximate area of 2483 km2 and has an
average flow of 26 m3 / s. the largest and most important river
in the province of Manabi. This sector is characterized by an
arid to semi-arid tropical climate, which is why there are very
marked rainy and dry seasons, from December to May the
rains are concentrated and the rest of the year corresponds to a
dry season, it is estimated that it presents an average annual
rainfall of 1070 mm, so it is also known that the maximum
temperature that presents is 32ºC and the minimum is 13ºC.
Table 3: Technical details of Chone River.
The bay is surrounded by high hills whose heights range
between 150 and 300 m, in a southerly direction. The type of
tide is semidiurnal, maintaining the characteristic of 2 high
tides and 2 low tides a day, the steepest tide are between the
months of December to April with an average tidal amplitude
of 3.04 m. The prevailing wind in the area comes from the
west and in a smaller proportion from the northwest,
maintaining an average annual speed of 6 knots. The waves
produced by the winds are of low height being even smaller
inside the bay due to the shallowness. On the outside of the
bay the waves are strong, especially in the months of June,
July, August and September. (INOCAR, 2012)
The Guayas province is located south east of the province
of Manabí, it is the most populated city in all of Ecuador, the
city of Guayaquil, which is in turn the most densely
populated. Here, the most important river in the west basin of
South America is formed, the Guayas River, which is born in
the Gulf of Guayaquil, which is the largest water inlet in all
of West South America, reaching a length of 230 km and in
which large processes occur of mixture, two large members
stand out in the Gulf of Guayaquil; the Guayas river already
mentioned and the “Estero Salado”.
i. Guayas River/”Estero Salado” estuaries
The Guayas River is the most important river in the
country and it is the largest hydrographic basin of the Pacific
coast of South America with a total area of 32112 km2 and
has an average flow of 835 m3/s, it should be noted that this
river receives 75% of discharges from the entire Ecuadorian
coast. Its main tributaries are the Daule and the Babahoyo
with their others tributaries. The Guayas River and the
“Estero Salado” constitutes an important maritime route used
in commercial activity.
The “Estero Salado” comes hand in hand with the Guayas
River, currently linked by the presence of locks at the height
of the southern part of the city known as Cobina estuary. Here
there are serious pollution problems in the northern part of the
estuary due to the presence of heavy anthropogenic activities,
as it descends to the southern part, it diminishes a bit although
its impact is still notable. In this area of the country (Guayas)
there are two marked seasons, the dry season and the wet
season, which, like Manabí, is humid from December to May
and dries the rest of the year. Within this system (Estero
Salado-Rio Guayas) you can clearly notice the effect of tides
including the change of direction of the river which causes
beneficial mixing effects for the purification of substances
harmful to the ecosystem. (Aguayo, 2005)
Table 4: Technical details of Guayas River.
D. El Oro
It has an area of 6,188 km² and a population of 643,316
people. The capital of the province of El Oro is the city of
Machala, the fifth largest city in the country, considered the
"banana capital of the world" (Wikipedia, 2017).
Located to the south of the Province of Guayas, it has
great influence in the banana market worldwide, reaching
multinational treaties for the export of said product, it is the
last province in the south of the country before we meet the
border with Peru and in what corresponds to their rivers, they
have a large amount of sediments due to the use and abuse of
their bodies of water due to the extraction of minerals, which
has even generated serious problems of sedimentation and
erosion of their beaches at present.
i. Jubones River estuary
The coasts of the province of El Oro are special with
respect to the others, since they are susceptible to certain
changes due to the erosion suffered by the coasts when
receiving the impact of tidal flow and the amount of
sediments that remain in beaches. Thanks to this, the
sedimentary terraces are formed, which then with the action of
the mangroves give rise to the islands and archipelago visible
from the part of Machala to Huaquillas.
Table 5: Technical details of Jubones River.
The river Jubones is the most important river in the
province of El Oro with a total area of 4054 km2 and has an
average flow of 59 m3/s, the climate here is the same as the
Guayas, with two marked seasons, the dry and the wet. It has
an average annual rainfall of 898 mm with an average
temperature of 22°C.
Aguayo, L. (2005). Principales Estuarios en la Costa
América, C. d. (1998). Evaluación de los Recursos de Agua
INOCAR. (2012). Derrotero de las Costas Ecuatorianas.
Wikipedia. (s.f.). Recuperado el 19 de Diciembre de 2017, de
Wikipedia. (19 de Diciembre de 2017). Provincia de El Oro.