The Fluvial Systems and Coastal Landscapes

 Although Dominica is quite small in size, only 290 sq. miles, the island features 365 rivers of all shapes and sizes. All of these rivers are perennial and flow year round. All of the rivers are either carrying bedloads or dissolved loads.

The Roseau River is an example of bedloads. The sediment is transported along the bed of the river and is clearly visible on the sides and bottom of this river. (Source: www.cifuk.org) 

One of the many nameless streams in Dominica. This is an example of a meandering stream channel.  It is a single channel and features cut banks.

The Indian River is an example of dissolved loads. The water is very clear but you can see the chemically  dissolved sediments in the river bed.


Dominica has some of the most beautiful coastal landscapes: these landscapes were even filmed for the set of Pirates of the Caribbean. Since there are so many different environmental and weather factors that influence this island, it possesses so many different types of coastal landscapes. These include depositional, erosional, and biological landforms.   

Pointe Baptiste Beach is one of many depositional beach landscapes. (Source: www.bellecovevilla.com)  

A section of the northeast coast of Dominica is an excellent example of erosional  landforms. Since Dominica is very vulnerable to hurricanes and storms, there are many beautiful coastal landforms like this one. (Source: www.dominica-weekly.com)

Calibishie is another example of a depositional landscape, specifically a tombolo. There are many sea caves and arches in Calibishie as well (Source: www.caribbeantravelmag.com)


Sources: (www.adominicavirtual.com, www.visit-dominica.com, www.en.wikipidia.org, www.dominica.gov.dm)

Climates and Hurricanes

The climate in Dominica is tropical and wet with very distinguished warm temperatures and heavy rainfall. It's climate is moderated by northeast trade winds. These trade winds temper the excessive heat and humidity by its steady flow. The steep interior slopes on this mountainous, rugged island also alter the temperatures and winds. Although many factors influence the temperature, the ranges are very slight. The average temperatures range from 78.8°F (January) to 89.6°F (June).

Another stormy day on the coast of Dominica, featuring a few different types of clouds:  Altostratus, Nimbostratus, and Stratocumulus clouds.

Most of the island's water supply is brought in by the trade winds. The humidity readings are tied to the rainfall patterns, and recorded to be between seventy and ninety percent. Hurricanes periodically develop from the severe trade winds, rainfall, humidity, and heat. Dominica is especially vulnerable to hurricanes because it is located in the hurricane region of the Caribbean. 

Hurricane Allen was the most recent and devastating hurricane to hit Dominica, in August 1980. Many agricultural commodities were destroyed. (http://www.class.noaa.gov/) 

Map conveying annual precipitation on the island (http://www.junglebaydominica.com/images/rainfallmap1.gif)


Sources: (http://www.thedominican.net/about/dominica.htm), (http://www.in-west-indies.com/dominica/discover/geography.htm), (http://www.dominica-weekly.com)  

The Unique Hydrology and Soils of Dominica

The hydrology and soil are other very distinctive geological qualities that Dominica possesses. It is one of Earth's most rain-drenched lands; in turn, the abundance of water runoff forms many cascading rivers and natural pools throughout the island. 

The Emerald Pool is an example of one of the natural pools created from water runoff.

Dominica is very water rich with swift-flowing highland streams, which cascade into deep gorges and form natural pools and crater lakes. The principal rivers that flow westward into the Caribbean are the Layou and the Roseau Rivers. The major river that empties eastward into the Atlantic is called the Toulaman River. The largest crater lake in Dominica is the Boeri Lake.

Boeri Lake occupies about five acres and is about thirty six meters deep. Not only is this the largest crater lake, it is also the deepest and highest in altitude on the island. This lake is located in the Morne Trios National Park, a world heritage site.

There are many landslides throughout the island, most resulted from hurricanes in the late 1900's. The unusual hydrological characteristics displayed in the tropical clay soils in these landslides convey that these soils are highly porous. The high water content in the soil led to flow-sides which caused debris to travel great distances across low-angled slopes.

One of the landslides caused from Hurricane Dean in 2007.

Sources: Hydrology and Soils (http://www.domex2011.com/hydrology-soils), Dominica Geology (http://countrystudies.us/caribbean-islands/60.htm) 

Morne Trois Pitons National Park

The beautiful Morne Trois Pitons National Park located in the southern central part of Dominica includes several amazing rare landforms, showcasing a large range of biodiversity. This blog will focus specifically on the 1,342 meters high volcano pile: Morne Trois Pitons, the fifty fumaroles, the world's second largest boiling lake, and the deep faults featured in its valleys. 

Morne Trois Pitons, located east of Roseau (friendsofworldheritage.org) 

Morne Trois Pitons, which translates to "mountain of three peaks", is actually three balsaltic spike-like remains from large amounts of lava spill that occurred during the Miocene period. The five active volcanoes in this park are shield volcanoes. Since lava flows have a low angle which produce visible escaping gas, there are areas in the park that feature many fumaroles.   

         

The Valley of Desolation features more
than fifty fumaroles and hot springs.
(tripadvisor.com)

Due to volcanic activity, the
landscape is constantly changing under different stresses creating faults in the landscape. (en.wikipedia.org)

The Valley of Desolation, named in reference to its contrasting barren landscape, is a dramatic example of active volcanism. Fumaroles are openings in the Earth's crust that emit gases and steam. Due to the major volcanic explosion combined with the constant emissions, the landscape lacks vegetation. 

My volunteer group and me on the trail in the Valley of Desolation on our way
to the boiling lake. You can see in comparison to us how much steam some
of the fumaroles produce.

A view of the boiling lake on a very clear day. There was so much steam from
the lake that this is the clearest picture I have of the lake itself.

The boiling lake is a flooded fumarole that is about sixty three meters across. The water collected from rainfall seeps through the bottom and is heated past the boiling point by the hot lava. An investigation of this phenomenon reported in the late 1800's conveys that a geyser actually developed in the center of the lake. This geyser can spew boiling water and mud up to eighteen meters high. The water along the edges of the lake have been measured to be 180 to 197 degrees Fahrenheit.

 Sources: Virtual Dominica (http://www.avirtualdominica.com/worldheritagesite.cfm); UNESCO World Heritage Center (http://whc.unesco.org/en/list/814)

Introduction

Hi Everyone! I'm Wesley Tok, a student at University of Colorado Denver. I chose Dominica for my virtual field trip location. 

One of many freshwater rivers that run throughout the island. The water is so clean, you can drink from it without any filtering. 

I had the privilege of doing volunteer work on this amazing island for a month about four years ago. I have been very lucky to have traveled to many places across the world, but Dominica has a special place in my heart. The beauty of this island is captivating and nothing short of breathtaking. 

I am so intrigued with all the mountainous terrain and gorgeous landscapes in Dominica. This island also features the world's second largest boiling lake. I am excited to learn more about this tiny island, as well as educating others.   

A picture of my volunteer group and me (in the blue) petting a mother leather back turtle while laying eggs on the beach.