For the vast and diverse continent of Africa, communication can be a challenge. Between Africa’s 54 independent countries and over 2,000 unique spoken languages, it is not uncommon for one region or one water body to be known by a plethora of different names depending on who and where you ask.
This causes issues for researchers and those unfamiliar with the area when conducting research. Besides that confusion, people’s pride in their native language and the potential significance of the name to them can also cause barriers if researchers use what locals consider to be the wrong name.
In recent research published in the journal Physics and Chemistry of the Earth, Texas Water Resources Institute Research Specialist Duncan Kikoyo, Ph.D., developed a framework that harmonizes the characterization of drainage units on the continent, comparable to those used in the United States and Europe for identification of drainage areas of water bodies.
Common language empowers research
“During my earlier work, research and study that involved working on water resources-related projects in Uganda, Kenya, Tanzania, Botswana, and Ghana, I was intrigued by the lack of a coherent system for identifying and inventorying hydrological data on the continent,” Kikoyo said.
He found that it was common to find the same drainage area classified differently because the definition was not standardized.
“Boundaries of drainage areas could also be conflicting because agencies or researchers would use different input data and methods for generating boundaries,” he said. “At the regional level, the naming of some water bodies was contentious.”
However, his experience working in the same field in the U.S. has been different.
“Boundaries are pre-delineated, and the definition of hydrological units is standardized,” Kikoyo explained. “Looking in retrospect at the challenges of working with hydrological data in Africa, I was impelled to develop tools or frameworks that could harmonize and ease the process of identifying, locating, storing, and retrieving hydrologic data on the continent.”
“I wanted to put in place a product that anybody can go to and easily locate and get any drainage area of interest, without going through the hassle of delineating the area,” he said.
There are several potential benefits of using harmonized drainage area datasets, particularly for the African continent. Kikoyo emphasized that without pre-delineated baseline drainage boundaries, areas of interest are traditionally delineated using inconsistent methods, based on terrain datasets of varying resolutions, which leads to inaccurate and conflicting drainage unit boundaries.
Cases of waterbodies and associated drainage areas with dissimilar names and descriptions are prevalent across the continent, he said. For transboundary studies where the naming of study regions could be contentious, or for cases when names of drainage areas are not known, a streamlined system for coding drainage areas provides an alternative framework for the identification of drainage units.
Organizing a vast continent’s watersheds
Using frameworks used in the U.S. and Europe as examples, Kikoyo developed and implemented a hierarchical framework he named the “African Drainage Basin Dataset” (AfDBD), which groups drainage areas on the continent into different classes.
“Drainage areas are grouped into different levels,” he said. “At the continental level, all drainage areas are grouped into ‘Systems’ depending on their location (mainland or islands), drainage direction (to the Indian Ocean, Atlantic Ocean, or the Mediterranean Sea), and type (endorheic or exorheic).”
From there, the grouping of drainage areas was primarily determined by the size of the drainage unit, surface water flow, and hydrological features. By using standard criteria Kikoyo was able to further break down these systems into smaller, nested regions, sub-regions, basins, sub-basins, and catchments. Catchments can further be subdivided into secondary, tertiary catchments and even more if needed.
Each system and its subdivisions are assigned codes that help identify them and show their location. “The whole idea was to create a simplistic identifying framework for locating drainage areas,” Kikoyo said. “You don’t have to know the name of the river – you can identify the drainage unit from its parent system by looking at the assigned code.”
Publishing this research is the culmination of three years of work for Kikoyo. With this first phase done, his next goal is implementation. “It took time because I wanted to get it right,” he said.
His eventual goal is for this dataset to be readily available for use in the public domain.
“Going forward,” he said, “I will work towards engaging agencies and researchers in Africa to have the proposed framework adopted and used across the continent.”
Read the full paper here.