Modification: Correction to our maps

-Removed the background color from the title

-Included the map showing the results of our ACP

-Included the sources of our research on our maps

-Included the dates on our maps

Link to our questionnaire and interview guide

Abstract

Access to safe drinking water and sanitation remains a major challenge in Africa, with notable differences between tropical and sub-Saharan regions. In tropical Africa, where the equatorial climate and abundant rainfall (1,500 to 2,500 mm/year) characterize the region, water resources are more abundant. However, despite this water wealth, countries such as the Democratic Republic of Congo suffer from poor infrastructure management, limiting access to safe drinking water for a large portion of the population. In contrast, sub-Saharan Africa, with its semi-arid to arid climate and low rainfall (100 to 600 mm/year), faces a more complex situation. Water resources are limited, often irregular, and poorly distributed, exacerbating water supply challenges.

The situation varies considerably from one country to another. For example, in Cameroon, rural populations suffer from limited access to safe drinking water, while in Gabon, access to piped water is more widespread. In sub-Saharan Africa, factors such as drought, conflict, and ineffective governance further complicate the situation. Overall, both regions share common challenges, including rapid population growth, lack of infrastructure, and lack of financing, but sub-Saharan Africa faces greater obstacles due to water scarcity and climate impacts.

Introduction

Access to safe drinking water, basic sanitation, and adequate hygiene practices is fundamental to human health and overall well-being. Indeed, the availability of these essential services not only keeps populations healthy but also contributes to sustainable development (WHO and UNICEF). The United Nations’ sixth Sustainable Development Goal (SDG6) underscores the need to ensure universal access to water and sanitation and to sustainably manage water resources by 2030 (UN 2015). However, many regions in Africa face considerable challenges in this area, particularly the Sahelian and tropical regions. These two geographical regions, with contrasting conditions, are distinguished by their climates and socioeconomic conditions.

The Sahel, characterized by a semi-arid climate with limited water resources and extreme environmental conditions, leaves populations suffering from water scarcity, recurrent droughts, and often insufficient infrastructure to serve their populations. Conversely, tropical African countries benefit from more abundant rainfall but also face problems accessing clean water and appropriate sanitation. The challenges in tropical Africa are linked to water management. Although they have more abundant water resources, their management remains hampered by gaps in governance and investment in water infrastructure.

The objective of this study is to analyze these disparities by comparing levels of access to drinking water and sanitation services in selected Sahelian and tropical African countries. It also aims to identify the key factors influencing these gaps and explore possible solutions for more equitable and sustainable management of this vital resource. Water represents approximately 70 percent of the Earth’s surface, constituting a vital natural resource essential to sustaining life and the functioning of ecosystems. Access to it, particularly in the form of safe drinking water and associated adequate sanitation systems, is recognized as a fundamental human right and a determining factor in public health,
development, and environmental stability globally. In Africa, although progress has been made in recent decades regarding access to safe drinking water and sanitation, the situation in 2020 revealed significant regional disparities, reflecting complex and persistent challenges. These differences in access raise questions not only about the sustainable management of this essential resource in a context of climate change and rapid population growth, but also about how communities, in their geographical and socioeconomic diversity, can meet their basic water needs while preserving their health and their environment. In this context, it appears crucial to analyze the disparities in access to drinking water and sanitation between Sahelian African countries and tropical African countries. Therefore, what are the gaps in access to drinking water and sanitation between Sahelian African countries and tropical African countries, and what are the consequences?

Research Questions

What are the gaps in access to an improved drinking water source between Sahelian countries and tropical African countries? What are the differences in terms of access to improved sanitation facilities in these two regions? What is the relationship between the proportion of the population practicing open defecation and the incidence of diarrheal diseases? To what extent do unsafe water resources and poor sanitation contribute to mortality from waterborne diseases? How does the average cost of drinking water for household’s influence access to this resource in the countries studied?

Objectives

The objective of this study is to analyze these disparities by comparing levels of access to drinking water and sanitation services in selected Sahelian and tropical African countries. It also aims to identify the key factors influencing these gaps and explore possible solutions for more equitable and sustainable management of this vital resource. Specifically, this will involve: . Collecting available data from databases . Conducting an analysis using data processing and analysis tools . Interpreting the results

Keyword Definitions

Access to water: Refers to a population’s ability to obtain a sufficient quantity of quality water to meet its basic needs. Access to sanitation: Refers to the availability and use of facilities and services for the hygienic disposal of human excreta (urine and feces). Hygiene practices: A set of individual and collective measures aimed at preventing disease and promoting health through cleanliness and the adoption of healthy behaviors. Waterborne disease: Any disease caused by the consumption of contaminated water or by contact with unsafe water.

Literature review

Literature reviews

Access to drinking water and sanitation remains a global problem despite efforts made in this area. The United Nations has recognized since 2010 that “physical and affordable access to sanitation, in all spheres of life, that is safe for health, hygienic, safe, socially and culturally acceptable and that ensures privacy and dignity.” International human rights law obliges States to work towards universal access to water and sanitation for all, without discrimination, while giving priority to those who need it most. But according to the article BAROMETER (1), it appears that 4.2 billion people, or more than half of the world’s population, still live without safely managed sanitation, that is, without hygienic and private toilets that safely eliminate fecal sludge. And 673 million people still practice open defecation in 2017 according to the WHO/UNICEF report (2019). And although access to water has become an international right, approximately 2 billion people lacked access to safely managed drinking water services in 2020. (2) As for the African continent, despite governments’ commitment to the United Nations Sustainable Development Goals (SDGs) and the African Union’s Agenda 2063, most countries are far from achieving their goal of ensuring the availability and sustainable management of water and sanitation for all (United Nations, 2015, 2023; African Union, 2015, 2023). (3) The urgency of ensuring water security is heightened by the effects of climate change, particularly prolonged droughts that threaten agriculture and household water supplies. (4)

The latest Afrobarometer surveys conducted in 39 African countries reveal little progress toward the goal of universal access to safe drinking water and sanitation. “Water supply ranks fourth among the most important issues Africans want their government to address. About one in four citizens say their homes have often lacked safe drinking water in the past year. Only a minority of Africans have access to piped water and sanitation, with rural and poor populations
suffering notable disadvantages. A growing majority of respondents consider their government’s performance in water and sanitation to be unsatisfactory” and “In addition to safe drinking water, protecting the health of Africans requires effective management of human waste, as highlighted in Agenda 2063 and the SDGs (African Union, 2015; United Nations, 2015). On average, across 39 countries, less than one-third (31%) of citizens live in communities with sewer systems accessible to most households. Sanitation infrastructure varies considerably from one country to another, from less than two in ten in Malawi (5%), Niger (9%), and Mozambique (9%) to more than two-thirds in South Africa (69%), Morocco (72%), and Tunisia (79%) (5). As for tropical and sub-Saharan African countries (6), a general overview reveals notable differences in rainfall and hydrography. Tropical Africa is characterized by an equatorial climate with high rainfall (1500 to 2500 mm/year) and a prolonged rainy season (6 to 9 months) with high regularity. Furthermore, this region of Africa has a high hydrographic density with major rivers such as the Congo River (4,700 km), the Ogooué River (1,200 km), the Oubangui River, and also large lakes such as Lake Tanganyika and Lake Kivu.In contrast, sub-Saharan Africa has a semi-arid to arid climate with low and irregular rainfall (100 to 600 mm/year) and a short rainy season of 2 to 4 months. There is also strong interannual variability with extreme episodes (floods and droughts). The direct consequence of this low precipitation is a more limited hydrography with seasonal rivers and some endorheic basins characterized by high evaporation.However, taken individually, each country has its own challenges in terms of access rates to water and sanitation depending on its realities. (3) For the Democratic Republic of Congo (DRC),”despite the abundance of water resources (approximately 52% of surface water resources, 23% of renewable water resources within the continent) only 42% of the population has access to drinking water, according to a 2017 WHO and UNICEF report. This situation is exacerbated in cities, particularly in the capital Kinshasa, due to accelerated and uncontrolled population growth. This growth has not been accompanied by adequate development of water distribution networks. The result is severely degraded hygiene and sanitation conditions (7) >> mentions the article RESEARCH PAPER. According to the report by the NGO UNITED HANDS OF AFRICA, Cameroon section (8), Cameroon faces numerous problems in the water sector. Cameroon has one of the largest groundwater and surface water reservoirs in Africa. It includes five large basins and three large underground reservoirs. However, we note significant variability between regions. Only 10,000 m3 of water was available to the population out of a total estimated need of 250,000 m3 of water per day. Cameroon has 103 urban drinking water stations and more than 3,000 rural water stations and points. However, there are no wastewater treatment plants in the public service. In rural areas, only 43.5% of residents have access to drinking water, while the remaining majority must travel sometimes long and perilous journeys. For some residents, water from rivers and backwaters is the only accessible source of water. Access to water points remains a real challenge for these residents since the roads used are very poorly maintained and very uneven. The rate of access to drinking water and sanitation services is estimated at 3.9% and 34% respectively. In Gabon, nearly eight out of ten Gabonese (78%) live in areas with a water supply system, a quarter (26%) live in areas with a borehole or a drilled well, and half (49%) of respondents have access to a wastewater treatment system. Three-quarters (76%) of Gabonese say they have lacked drinking water in the last 12 months “sometimes”, “several times” or “always”. According to a survey by AFROBAROMETE (9) and the United Nations annual report on Gabon (10),In the Central African Republic, there is a paradox between the abundance of water resources and the rate of accessibility to drinking water. Access rates are among the lowest in the world (significant political instability and insecurity since 2013 - 20% of the country’s population displaced and refugees). One-third of the country’s population uses unimproved water sources or surface water. There is significant pressure on water and sanitation services: abandonment, destruction, water contamination, and weak local governance capacity. Abundant water resources are available due to heavy seasonal rainfall and the presence of stable rivers, but these resources are poorly distributed in space and time and poorly exploited due to insufficient regulatory texts in the water sector. 100% of CAR sub-prefectures have WASH (Water Hygiene and Sanitation) needs of severity 3, 75% are affected by flooding during the rainy season, and 50% have had WASH needs of severity since 2015 (11) >> according to a pS-Eau report. For Sahel countries, between insecurity and drought, the water and sanitation situation is not surprising. As for Mali, “More than four in 10 Malians (43%) report having lacked drinking water at least once in the year preceding the survey, including 22% who experienced this lack”several times” or “always.” Three-quarters (75%) of Malians live within walking distance of a borehole or dug well, and nearly half (47%) live in areas with piped water systems. Only 15% of Malians get their water from taps in their homes, and 9% from taps in their yards. The majority use public taps or fountains (22%), tube wells or boreholes (19%), protected wells (20%), or unprotected wells (12%). One in nine respondents (11%) live in areas with a wastewater disposal system. The vast majority (80%) have toilets inside their compound, while a minority use toilets or latrines inside their homes (11%) or outside their compound (7%). Access to water ranks sixth among the most important problems Malians believe the government should address. The majority (59%) of citizens approve of the government’s performance in providing water and sanitation services>> according to an AFROBAMETER report (12). As for Burkina Faso, according to data from the Ministry of Water and Sanitation at the end of 2017, 73.4% of the Burkinabe population had access to drinking water in their households (compared to 91.7% in the localities covered by ONEA and 66.2% in the rest of the country). Access to drinking water in the cities of Ouagadougou, Fada, Koudougou, and Ouahigouya is 100%. In total, 23 of the localities covered by ONEA had a 100% rate. At the same time, 21.6% of the population had access to toilets in their households (compared to 38.3% in the localities covered by ONEA and 15.1% in the rest of the country). This situation of access to water and sanitation is the cumulative result of the political commitment and sustained efforts of the Burkinabe government over several decades. However, there is a gap between these figures and reality because these figures are often difficult to understand for
ordinary citizens, but also for parliamentarians in their mission to monitor government action. For example, access to drinking water in the 23 cities served by ONEA, which have an access rate of 100%. This means that the entire population in each of these localities has access to drinking water for household needs. However, many households still suffer from water cuts that are quite common in Ouagadougou as in these different localities. The observation of the gap between the figures for access to drinking water and the perceptions of citizens is similar in several rural localities. According to the Présimètre survey conducted in 2018, 63.4% of the population is dissatisfied with drinking water and sanitation services. Furthermore, 67% do not believe that the government’s “Zero Water Fetching” objective will be achieved by 2020. > according to the work of Juste Hermann NANSI (13). As for Niger, the report of the Ministry of Water (14) indicates that the situation in terms of access to water and sanitation has actually improved in recent years. The household access rate to optimal drinking water services in 2020 is as follows: << optimal service in urban areas increased by 6.1 points from 42.70% in 2019 to 48.8% in 2020, unlike in rural areas where this rate decreased by 2 percentage points (3.8% in 2019 compared to 1.8% in 2020). The main factors that can explain this increase in urban areas are linked to the increase in social connections, i.e. 14,943 in 2020 out of 19,300 planned and 39,527 over the period 2016-2020. However, there is a very large variation in this proportion depending on the residential area and the regions. Consumption of this type of water is more widespread in urban areas (48.8%) than in rural areas (1.8%). Indeed, this is linked to the realization of more significant investments in urban areas, promotional connections, the proportion of the population living in urban areas is lower compared to that living in rural areas and the level of household income is relatively high in urban areas. Regarding rural areas, the drop in optimum service of 2 percentage points in 2020 is linked to the observed transition from basic and limited services which saw their proportion increased compared to 2019. In 2020, basic service in urban areas decreased by 0.9 points, from 46.3% in 2019 to 45.4% in 2020. This decrease is due to the increase in optimal service. However, it should be noted that despite this slight decrease in the rate, the indicator remains significant, as it is well above the target objective of 15% in 2020. As for rural areas, basic service increased by 14.7 points, from 35.7% in 2019 to 50.4% in 2020, exceeding the target objective of 50% by 0.4 points. This is explained by the construction of infrastructure (10,558 equivalent PEMs completed between 2017 and 2020). In the regions of Maradi (63.7%), Tillabéri (56.6%), and Diffa (55.5%), this proportion is significant, even exceeding the national average (49.6%). (1) Regarding sanitation in 2020, optimal service in urban areas increased by 6.6 points, from 26.5% in 2019 to 33.1% in 2020. This increase is explained by the population’s awareness of behavior change and the effective operationalization of the Niamey City Wastewater Treatment Plant (STBV). As for optimal service in rural areas, it was 1.4% in 2020, more than twice its 2019 value of 0.6%. Across the country, this optimal service increased by 1.62 points, from 4.48% in 2019 to 6.10% in 2020. Depending on the region, the proportion of people using safe sanitation services varies from 1% in Dosso to 45.5% in Niamey. According to a World Bank report (15) for Chad, the rate of access to basic water service has stagnated as a percentage (around 40%) and remains, in 2017, significantly below the 2015 target of 60.5%. Taking into account the broader definition of access to basic or improved services, the SDG indicator increased by five points over the same period. Progress in absolute value is much more significant because the population with access to an improved source increased from 4.2 million in 2000 to 8.3 million in 2017. This demonstrates the impact of strong demographic growth on the evolution of the access rate and the challenge for the development of services in a country where the birth rate remains very high (5.8 children per woman in 2017). Sanitation development in Chad is embryonic. According to the JMP, only a minority of the population (15.3%) has access to basic sanitation (improved or not, depending on whether the toilet or latrine is private [8.3%] or shared [7.0%]). With an open defecation (OD) prevalence of 67.0%, affecting 9.9 million people in 2017, Chad is among the countries where this practice remains the highest in the world, particularly in rural areas (82.0%). On-site sanitation facilities, where they exist, rarely meet the criteria for improved sanitation, and fecal sludge is disposed of in the natural environment, as is wastewater (domestic and industrial). There is no collective sanitation network, and public latrines are rare. Mauritania had a drinking water access rate of 77.81% in 2020 according to the World Bank, although a large portion of the population, especially in desert areas, still faces difficulties in accessing drinking water. This research by various researchers shows that African countries face several major challenges in ensuring access to basic services, caused in particular by rapid population growth, the effects of climate change, protracted conflicts, as well as poor governance and limited financial resources. In sub-Saharan Africa, although progress has been made in recent decades, access to water and sanitation remains inadequate, with significant disparities between countries and even within each country, between urban and rural areas. The challenges related to access to drinking water in these countries are multiple. First, the infrastructure is often obsolete and insufficient. Many sub-Saharan African countries lack sufficient water distribution networks to meet the growing needs of their populations. For example, most sub-Saharan African countries rely on traditional wells, unsecured springs, or informal systems to access water. Investment in modern infrastructure is insufficient. Furthermore, water management is marked by poor governance, inconsistent planning, and a lack of transparency, exacerbating inequalities between urban and rural areas.

Furthermore, climate change is contributing to water supply problems. Extreme weather events, such as drought, are affecting water supplies in countries like Chad and Burkina Faso, where freshwater resources are increasingly dwindling. One of the main obstacles to improving access to safe drinking water and sanitation in Africa remains a lack of financing. The lack of public investment in the water and sanitation sector is exacerbated by the absence of effective financial mechanisms. According to the World Bank (2020), Africa needs $30–50 billion annually to achieve the Sustainable Development Goals (SDGs) related to water and sanitation. However, less than half of this amount is currently financed by local governments andinternational donors, creating a major gap. Public-private partnerships (PPPs) can play a crucial role in achieving these goals, but require strong governance to avoid pitfalls related to corruption and mismanagement of funds. # Presentation of the Study Area ## Geographic Location

Figure 1:map of the sountries studied
Figure 1:map of the sountries studied

The study area covers the Sahelian countries and tropical climates in West and Central Africa. These countries include : • Sahelian countries: Burkina Faso, Mali, Niger, Mauritania, and Chad. • Tropical climate countries: Cameroon, Central African Republic, Congo (DRC), Gabon. Main Geographic Features: The Sahel is characterized by a semi-arid climate with a short rainy season and low rainfall. Tropical countries enjoy a hot and humid climate, with abundant rainfall favorable to dense vegetation and agriculture. Geographic Coordinates : • Latitude: Approximately 10°N to 20°N for Sahelian countries. • Longitude: Varies between 15°W and 30°E depending on the country.

Materials and Methods

Materials

To conduct our study, we used the following tools: Our World in Data database: Our research relied on the Our World in Data database. This website is the result of a collaboration between researchers from the University of Oxford and the non-profit organization Global Change Data Lab. It provides a vast amount of current and varied data, particularly in the fields of education, water, health, the environment, energy, agriculture, and population. This site allowed us to access data from organizations such as the World Bank. R-Studio software: We used R-Studio software for the processing and statistical analysis of the collected data. QGIS software: was used for management, analysis, and map creation. Office suite: to complete this work, we used Office suite tools, including Microsoft Word for writing this report, Microsoft Excel for channeling the data extracted from the database, and Microsoft PowerPoint for the oral presentation of our work results. kobocollect software: a web-based platform for creating and managing questionnaires. Zotero software was used to manage bibliographic references for research and report writing.

Methods Sampling Methods As part of our work, we conducted data extraction. This data comes primarily from the Our World in Data platform, particularly from the water and sanitation section. From this topic, we extracted the following information: population density,

The database offers a vast amount of information (provides a large amount of information), and a wide range of information for many countries around the world. Therefore, it was necessary to select the countries to study. Thus, from all available countries, we selected a sample of nine. This selection was carried out using the quota sampling method. This is a non-probability method applied when there are already subgroups within the population (e.g., men and women), and consists of including at least one element from each subgroup in the population under study. In our case, the subgroups identified are Sahelian African countries (Burkina Faso, Mali, Niger, Mauritania, Chad) and tropical African countries (Cameroon, Congo DRC, Gabon, Central African Republic). For each of these countries, we obtained figures for the following variables: Total investment flow on sanitation: reflects the total annual investment for each country on sanitation. Total investment on access to water per capita: represents the average expenditure per person to ensure or improve access to water. Proportion of the population using unimproved water sources: refers to the percentage of people within a given population who rely on drinking water sources considered less safe and less hygienic than improved sources. Proportion of the population with access to improved sanitation facilities: reflects the percentage of people within a given population who use sanitation facilities considered more hygienic and better able to separate human excreta from human contact. Proportion of the population practicing open defecation: reflects the percentage of people within a given population who defecate in open spaces such as fields, bodies of water, or other outdoor locations, rather than using sanitation facilities. Availability of handwashing facilities: refers to the presence and accessibility of means for individuals to wash their hands with soap and water in a given location.

Diarrheal disease incidence: reflects the number of new cases of diarrhea occurring in a given population during a specific period. Mortality attributed to unsafe water sources and poor sanitation: refers to the number of deaths occurring in a given population during a specific period that are directly related (attributable) to water consumption and adequate sanitation facilities. Investment in water and sanitation: refers to the allocation of financial resources. Population density: reflects the number of individuals living in a given unit area. Average household cost of drinking water: represents the average amount that households spend to access drinking water. We focused on the year 2020, for which almost all data was available for all countries. We have missing data, particularly for the average cost of water, which we searched on other sites.

questionnaire

Link to our questionnaire :https://kf.kobotoolbox.org/#/forms/aurVqr2SMEKCCpQhzzZoRF/summary

Link to our interview guide: https://kf.kobotoolbox.org/#/forms/ayWRnbpMHCm5HReUF2JsxS/summary

Date of the survey: yyyy-mm-dd

Country:

Locality:

GPS coordinates:

Latitude (x.y 0) Longitude (x.y 0) altitude (m) precision (m)

Name or ID of the survey team:

Household consent:

O We consent to participate in this survey.

O We do not consent to participate in this survey.

General Information

Respondent’s gender:

O Male

O Female

Respondent’s age:

1/4 Number of people living in the household

Educational level of the household head:

O No education

O Primary

O Secondary

O Higher

Access to Drinking Water

What is your main source of drinking water?

O Borehole

O Tap at home

Public fountain

Traditional well

O Surface water (river, dam, etc.)

Is the water source protected from contamination?

Yes

No

O I don’t know

How many minutes does it take on average to access drinking water (round trip)?

Less than 15 minutes

Between 15 and 30 minutes

O More than 30 minutes

Is water available whenever you need it?

O Always

Sometimes

O Rarely

Do you pay to access water?

Yes

NO

If yes, how much per month? CFA

2/4 Have you ever experienced illnesses after drinking water from your main source?

O Yes

O No

Sanitation

What type of toilet do you primarily use?

O Modern latrines (improved pit or flush toilet)

Basic latrines

  1. No toilet (open defecation)

Do you share your toilet with other households?

O Yes

No

No toilet

Do you have access to a wastewater management system (sewer, soak pit, etc.)?

O Yes

O No

Hygiene

Do you have a handwashing device at home (tap bucket, sink, etc.)?

O Yes

No

Do you always use soap to wash your hands?

O Always

Sometimes

O Rarely

Never

Public Health

In the last two weeks, has a household member suffered from diarrhea?

Yes

No

If yes, how many people?

Do you know of any deaths in your community caused by waterborne diseases (cholera, typhoid, etc.)?

O Yes

O No

O Option 3

If yes, specify:

Resultat

The Principal Component Analysis (PCA) conducted in this study made it possible to synthesize and visualize the complex relationships between socioeconomic, environmental, and health variables characterizing the countries studied. This statistical tool was used to identify the main dimensions that explain disparities in access to drinking water, sanitation, and public health in Sahelian and tropical African countries. The PCA results highlight the differentiated contributions of each variable in the formation of the main axes. These axes reflect central themes, such as access to basic services and challenges related to infrastructure and resource management. They also allow for segmenting countries according to their relative performance, thus providing an in-depth understanding of the specific issues in each region. In what follows, the detailed PCA results will be presented, highlighting the most contributing variables, key correlations, and clustering observed between countries. These results provide a solid basis for guiding recommendations and perspectives on sustainable development and public policies.

tableau
tableau

The PCA (Principal Component Analysis) graph shows the representation of the variables in the space defined by the first two principal dimensions (Dim 1 and Dim)

#realisation de l'ACP#
library(FactoMineR)
res.pca <- PCA(data, graph = FALSE)

res.pca=PCA(data,scale.unit=TRUE,ncp=5,graph=TRUE)

2). Here is a detailed analysis: 1. Explained Variance: • Dim 1 (41.30%): Explains 41.30% of the total variance. This dimension appears to capture the major variations related to sanitation and health indicators. • Dim 2 (17.24%): Explains 17.24% of the total variance. It appears to reflect secondary factors, such as population density and associated costs. 2. Position and Contribution of Variables: • Variables Correlated to Dim 1: o Pppdpair, MASEMA, PMD, TMNPASEP: These variables are close and well aligned on the Dim 1 axis, indicating that they contribute significantly to this dimension. This shows that practices such as open defecation, high rates of diarrheal diseases, and mortality due to unsafe water are associated with poor sanitation conditions. o PPAASPA and Ppia (opposite): These are in opposition to the above variables, showing that access to safe drinking water and improved sanitation is inversely related to inadequate sanitation practices. • Variables correlated with Dim 2: o PPUIANM and PPUSEA: These variables are highly correlated with each other and partially explain Dim 2, representing the use of unimproved water and sanitation. o CMEPM and Dp: These variables are slightly correlated with Dim 2 and reflect aspects related to costs and population density. 3. Relationships between variables: • Variables close to each other on the circle: o PPUIANM and PPUSEA: Very close, they indicate a strong positive correlation. o MASEMA, PMD, and TMNPASEP: These variables show a close relationship with risk factors related to unsafe water and poor sanitation. • Opposite variables: o PPAASPA and Pppdpair: Indicate a strong opposition between access to drinking water and open defecation. o CMEPM and PPAASPA: Access to drinking water appears to be negatively related to the average cost of water. 4. Overall interpretation: • Dim 1 contrasts degraded sanitation conditions (Pppdpair, PMD, MASEMA) with improved infrastructure (PPAASPA, Ppia). • Dim 2 captures differences related to the use of unimproved water and sanitation sources (PPUIANM, PPUSEA) and economic factors such as the cost of water (CMEPM).

The presented Scree plot illustrates the proportion of variance explained by each of the principal components (dimensions) in a principal component analysis (PCA).

#valeur propre#
valeur.propre=get_eigenvalue(res.pca)
screen.plot=fviz_eig(res.pca,addlabels = T,ylim=c(0,75))
screen.plot

Here is the analysis and interpretation: 1. Observation of the bars (variance explained): • Dim 1 (41.3%): The first dimension explains 41.3% of the total variance, indicating that it captures most of the information in the data. • Dim 2 (17.2%): The second dimension adds 17.2% of the variance, helping to complete the representation of the data. • The following dimensions (Dim 3 to Dim 8) explain decreasing proportions of variance, with significantly smaller contributions. • Elbow : • The point where the slope of the chart changes significantly• (forming a kind of bend) is between Dim 2 and Dim 3. • This suggests that the first two dimensions are sufficient to represent a large part of the information contained in the data (41.3% + 17.2% = 58.5%). 3. Remaining dimensions : • Dimensions from Dim 3 onwards make a marginal contribution (<13%), which means that they only add a limited amount of additional information. • Dim 6 to Dim 8: These dimensions have a very low variance (<5%), and their contribution can be overlooked in an overall interpretation. 4. General interpretation : • The majority of the information can be captured by the first two dimensions (58.5% of the total variance). These dimensions are therefore sufficient to visualize and interpret the principal relationships between variables. • The other dimensions provide specific information, but they are less significant in terms of explained variance

graph illustrates the contribution of variables to the first dimension (Dim 1) of Principal Component Analysis (PCA).

#contriution des variables aux axes#
fviz_contrib(res.pca,choice="var",axes=1,top=13)

fviz_contrib(res.pca,choice="var",axes=2,top=13)

fviz_contrib(res.pca,choice="var",axes=1:2,top=13)

fviz_pca_var(res.pca,col.var="contrib",gradient.cols=c("blue","green","red"),repel = T,title="contribution des variables aux axes")

Here is the analysis and interpretation: 1. Understanding the Contribution of Variables to Dim 1 The contribution of a variable to a dimension indicates the extent to which that variable influences that principal component. High values mean that the variable is strongly involved in the Dim 1 axis. 2. Analysis of contributions • Most influential variables on Dim 1: MASEMA (Mortality attributed to unsafe water sources and lack of sanitation) (~20%) • o PMD (Proportion of diarrheal diseases) (~18%) • o Pppdpair (Proportion of the population practicing open defecation) (~17%) • o CMEPM (Average Cost of Drinking Water for Households) (~15%) • o Ppia (Proportion of the population with access to improved sanitation facilities) (~14%) These variables are the most important in explaining the variance captured by Dim 1. Moderately influential variables: • PPAASPA (Proportion of the population with access to an improved drinking water source) (~12%) • MTNPASEP (Average Time Needed to Access a Source of Drinking Water) (~5• %)→ They have an influence, but less marked on Dim 1. Weakly influential variables: o PPUIANM, DDLM, Dp, PPUSEA (~0-3%) They contribute very little to Dim 1. 3. Overall interpretation Dim 1 seems to be an axis linked to sanitary conditions and access to drinking water. MASEMA, PMD and Pppdpair dominate, suggesting that this dimension could represent a gradient of public health and hygiene: A High Dim 1 value could be associated with poor sanitation quality, high mortality due to unsafe water and a high prevalence of diarrheal diseases. Conversely, a low Dim 1 value could be associated with better sanitation infrastructure and safer access to safe drinking water

Contribution of individuals

#contribution des individus#
fviz_contrib(res.pca,choice="ind",axes=1,top=13)

fviz_contrib(res.pca,choice="ind",axes=2,top=13)

fviz_contrib(res.pca,choice="ind",axes=1:2,top=13)

Analysis and interpretation of the graph This graph represents the contribution of individuals (countries) to dimension 1 (Dim-1) of Principal Component Analysis (PCA). The bars indicate the percentage of contribution of each individual to the Dim-1 axis. Detailed analysis : 1. Gabon (contribution > 30%) : o Gabon is the individual who contributes the most to the formation of dimension 1o. That means that Gabon stands out strongly according to the variables correlated to this axis. . Chad and Niger (~20-25% contributions) : o These two countries also have a strong contribution to Dim-1, but less than Gabon. They probably share similar or opposite characteristics to Gabon in the variables most correlated with Dim-1. 3. Mauritania and Congo (lower contributions, ~10-15%): These countries influence Dim-1 moderately. They may be closer to the average of the countries on the variables that make up this axis. 4. Cameroon, BF (Burkina Faso), Central African Republic, Mali (very small contributions): These countries contribute little to Dim-1. They are either close to the mean or little influenced by the variables correlated to this axis. Overall interpretation: • Dimension 1 (Dim-1) represents an axis of data variability that could be related to socio-economic, health, or environmental indicators, depending on the variables included. Countries with a strong contribution (Gabon, Chad, Niger) stand out particularly on these indicators. Countries with a low contribution are likely to be less influenced or close to the average of the values for these variables.

Analysis and Interpretation of the PCA Graph of Individuals

#creation des graphiques pour individus pour voir des ressemblances entre individus#
#fviz_pca_ind(res.pca,col.ind.sup = "blue",repel=TRUE)#

Analysis and Interpretation of the PCA Graph of Individuals This graph represents a Principal Component Analysis (PCA) of the countries according to the first two dimensions (Dim 1 and Dim 2), which explain respectively 41.3% and 17.2% of the variance of the data. 1. Under standing the Chart Each point represents a country positioned according to its characteristics on the Dim 1 and Dim 2 axes. The position of countries indicates their similarity or difference according to the variables taken into account. The closer two countries are, the more they share similar characteristics. The further away a country is from the center, the more extreme values it has on the axes.

  1. Analysis of the distribution of countries Position on Dim 1 (41.3%) To the left of the 0 axis (negative on Dim 1): Gabon, Mauritania and Cameroon are in this zone. According to the analysis of the variables, this dimension seems to be associated with sanitary conditions and access to drinking water. Their position suggests better sanitary conditions with wider access to drinking water and improved sanitation facilities. To the right of the 0 axis (positive on Dim 1: Chad, Niger and Burkina Faso (BF) are located here. his indicates that they are characterized by less

Overall interpretation

#fviz_pca_biplot(res.pca,repel=TRUE)#
#install.packages("Factoshiny")
library(Factoshiny)


#esultat = PCAshiny(data)
#resultat1 = HCPCshiny(data)#

Countries on the right (Mauritania, Cameroon, Gabon) seem to have better sanitation conditions and better access to drinking water. Countries on the left (Chad, Niger, Burkina Faso) are characterized by limited access to safe drinking water, higher rates of diarrheal diseases and a high practice of open defecation. Congo and the Central African Republic seem to be distinct from other countries, which could be linked to 3. Overall interpretation Countries on the left (Mauritania, Cameroon, Gabon) seem to have better sanitation conditions and better access to drinking water. Congo and the Central African Republic seem to be distinct from other countries, which could be linked to particularities 3. Overall interpretation Countries on the left (Mauritania, Cameroon, Gabon) seem to have better sanitation conditions and better access to drinking water. Countries on the right (Chad, Niger, Burkina Faso) are characterized by limited access to safe drinking water, higher rates of diarrhoeal diseases and a high practice of open defecation. Congo and the Central African Republic seem to be distinct from other countries, which could be linked to particularities Mali is close to the center, which suggests that it is in the an intermediate situation between the two groups.

#fviz_pca_biplot(res.pca,repel=TRUE)#

library(Factoshiny)


#resultat = PCAshiny(data)
#resultat1 = HCPCshiny(data)

Analysis and Interpretation of the Hierarchical Dendrogram This dendrogram represents a hierarchical ascending classification (CHA) of countries according to the variables used in the Principal Component Analysis (PCA). It makes it possible to group countries with similar characteristics in terms of access to water, sanitation and public health. 1. Reading the dendrogram Countries are grouped according to their similarity: the closer a country is to another on the tree, the more they share similar characteristics. The vertical axis represents the distance (or dissimilarity) between the groups: The higher a merge is in the graph, the more different the groups were before they were reunited. 2. Analysis of the groups formed First major group (in blue): Niger, Chad, Burkina Faso, Mali, Central African Republic These countries form a fairly homogeneous cluster. They are grouped together because they have poor access to drinking water and sanitation. It can be assumed that the prevalence of diarrheal diseases, mortality from unsafe water and open defecation are high in these countries. Second group (in green): Mauritania, Cameroon This cluster is distinct from the first, suggesting less critical water and sanitation conditions than in the first group.These countries could have better access to health and health infrastructure.More efficient management of drinking water.Special case (in red): Congo The countries in the first group (Niger, Chad, Burkina Faso, Mali, and the Central African Republic) require special attention in improving their water and sanitation infrastructure. The third group (Mauritania and Cameroon) could serve as a benchmark for understanding what policies have been implemented to improve the situation. Congo and Gabon require more detailed analysis to understand why they stand out from the others.

#graphique de contribution#
#fviz_pca_ind(res.pca,col.ind="cos2",gradient.cols=c("blue","green","red"),repel = T,title="contribution des individus aux axes"#)

Analysis and Interpretation of the Individual Contribution to the Axes Graph This graph represents the contribution of countries to the first two dimensions resulting from the Principal Component Analysis (PCA). The color of the points corresponds to their contribution (cos2) to the principal axes • Red/Orange: strong contribution Green: intermediate contribution Blue: weak contribution 1. Reading the axes Dim 1 (41.3%): This dimension captures 41.3% of the total variance, which means it contains a large portion of the information. Dim 2 (17.2%): This dimension captures 17.2% of the variance, i.e., a smaller but still significant proportionTogether, these two dimensions explain 58.5% of the total variance, which is good coverage. 2. Analysis of Country Contributions Countries that contribute the most (high contribution – high cos2, in red/orange) • Congo (in red, top left):  It strongly influences Dim 2, which means it has unique characteristics compared to the other countries.  Its distance from the other points suggests that it has an atypical profile in terms of access to water and sanitation. • Gabon (in orange, bottom left):  It also contributes strongly, but in the opposite direction to Congo.  This indicates that it has characteristics that are opposite to Congo in terms of water and sanitation infrastructure. Countries with an intermediate contribution (medium cos2, in green) • Mauritania and Cameroon:  They have a more moderate contribution, but influence Dim 1.  This means that they share characteristics intermediate between the extreme groups. Countries that contribute little (low cos2, in blue/yellow) Burkina Faso (BF), Mali, and Central African Republic:  They are close to the center of the graph, meaning they do not strongly differentiate the main axes.  They have a more homogeneous profile and are not particularly atypical. • Niger and Chad (in yellow, right):  They contribute slightly more than BF and Mali, but remain relatively close to the center.  They are related to the dimensions but do not exert a strong influence on group differentiation. 3. Overall Interpretation • Congo and Gabon are the most distinct countries in this analysis, occupying opposite positions on the PCA. • Niger and Chad are more aligned with Dim 1, meaning they share similar characteristics. • Burkina Faso, Mali, and Central African Republic have a more neutral profile, contributing little to group differentiation.

Map and recommendation

Recommendations and Outlook for Improving the Situation

To improve access to drinking water and sanitation in sub-Saharan and tropical Africa, several actions must be undertaken. First, it is essential to improve water governance through effective, transparent, and well-planned public policies. Governments must implement sustainable water resource management strategies that take into account the effects of climate change and the needs growing populations. Second, it is crucial to increase investment in infrastructure. This can be achieved through strong public-private partnerships, as well as increased international financing. Countries must seek new sources of financing to support large-scale water and sanitation projects, particularly in rural areas. Finally, efforts must be made to strengthen local capacities for water and sanitation resource management. This requires training of technicians, establishment of monitoring and evaluation systems, and the involvement of local communities in project management.

Conclusion

Access to safe drinking water and sanitation remains a major challenge for many African countries, particularly in sub-Saharan Africa and tropical Africa. Significant progress has been made, but persistent challenges remain. Additional investment, improved governance, and better management of natural resources are needed to improve the situation. Through concerted efforts, the region can overcome these challenges and ensure universal access to safe drinking water and quality sanitation.

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