Let’s Talk Water Belize

Without the sun’s energy the water cycle would be virtually nonexistent

Last week, you learned that it is estimated that every year 17,292,174 gallons of water is available to every Belizean and that water is unevenly distributed in the world and in Belize.  The global mechanism that distributes water is the water (hydrologic) cycle.   Just like any cycle, the water continuously transitions between its three states, similarly to the wheels on our vehicles.  Those vehicle wheels will not turn unless some form of energy is applied.  The energy for the water cycle is primarily from the Sun.  The solar energy drives the water cycle by evaporating water in the oceans, lakes, rivers, and the soil.   The plants consume water from the soil through their roots and transpires it to the atmosphere in the form of vapour.  The vapour from evaporation and transpiration condenses in the atmosphere to form clouds and when the water droplets in the clouds gain enough mass they fall to earth as precipitation in the forms of rain, snow, hail or sleet.  As the water falls on the earth, some is intercepted and transpired by the trees, some makes its way over the ground and runs off to streams and rivers, or percolates through the soil to underground reservoirs called aquifers,  before making its way back to the lakes, seas and oceans.   Because this process is a cycle you can start at any point and you will eventually return to your starting point.  Remember the transitioning of water between its states requires energy, and the energy required for the water cycle is solar energy.  Without the sun’s energy the various processes in the water cycle would be virtually nonexistent. 

Here in Belize, our per capita water endowment is significantly greater than many other States in the Latin American and Caribbean Region.  Being a tropical country, we are not primarily concerned with water trapped in the ice caps and glaciers (except for climate change issues) because most of our water is in the form of evaporation, condensation, rainfall, and liquid on earth’s surface and underground.  The atmospheric processes that result in rains are of primary concern to the meteorologists, however when the rain falls and moves overland, the processes are of primary concern to the hydrologists.  Because these processes are interlinked the meteorologists and hydrologists activities are interconnected. 

The runoff processes are controlled by the characteristics of hydrologic units called watersheds. In simple terms a watershed is all that area from which all precipitation flows to a single river or set of rivers.  The largest watershed in the world is that of the Amazon River which has a catchment area of 2,372,492 sq. mi (6,144,727 sq. km).  There are forty identifiable watersheds in Belize of which sixteen are classified a major watersheds.  These watersheds transport runoff via the slopes of the Maya Mountains eastwards to the Caribbean Sea.

The majority of Belize’s rivers originate on the eastern slopes of the Maya mountains.  A notable exception is the Belize River watershed, the country’s largest (9434 sq. km)and longest river (˜180 miles)and possibly most important watershed.  The Belize River headwaters originate on the western slopes of the Maya Mountains main divide and descends its slopes skirting the northern lowlands before emptying into the Caribbean Sea near Belize City.  Other exceptions include the Rio Hondo and the New River that meander sluggishly across the northern plains before emptying into the Bay of Chetumal. 

Rainfall over minor catchments originating on the lower south-eastern slopes of the Maya Mountains supply ephemeral streams that support the coastal lagoons and ponds.  On the Central and Northern Coastal Plains, poorly developed and barely perennial streams and creeks supply the brackish coastal lagoons. 

Belize shares five major watersheds with Mexico and Guatemala.  When considering real basins (including Guatemala and Mexico), the Rio Hondo is comparative in size to the Belize River, however 31% of this river basin lies in Guatemala and 50.5% lies in south-eastern Mexico.  As is the case of the Rio Hondo, a large portion of the Sarstoon’s watershed, 91.2% lies in Guatemala.  Recently it has been determined that the Usumacinta river that traverses Guatemala and Mexico and empties into the Gulf of Mexico originates in Belize.
In our next article, we will discuss the importance of the Belize River.