3.1. Water Security in the ONSB
In this paper, a water security evaluation system including five sub-systems (external environment security, water resources security, water-society security, water economic security, and water-environment security) and 23 indicators related to climate, socio-economy, and water availability and consumption was considered. The observed (2010 and 2015) and projected (2025) values of each indicators were obtained from the Ministry of Water and Rural Water Systems, Sanitation and Hygiene regional directorate, Water and rural water systems regional directorate, Agriculture, livestock, and fishing regional directorate, National Meteorological services, and private institutions “Togolaise des Eaux.” The overall data obtained are depicted in
Table 2.
The data compiled from various sources are normalized. For the indicators expressing a better condition when their values are large, which is known as “larger is better” (positive), formula (12) is used while formula (13) is used for the indicators known as “smaller is better” (negative).
where,
i is the indicator, Xi the original value of
i, and
Ximin and
Ximax are the minimum and maximum value of the indicator,
i, respectively.
The values of the indicators were transformed into dimensionless values ranging between 0 and 1, as shown in
Table 3.
Taking into consideration the theory of catastrophe models, the water security system as well as the sub-system B1 meet the Wigwam model while the remaining sub-systems (B2, B3, B4, and B5) meet the butterfly model. Based on the fuzzy membership function of each involved model and the principle of the mean value (in sub-systems as well as the overall water security computation), the synthetic values of catastrophe assessment for the year 2010, 2015, and 2025 were calculated. The following equations were used for the establishment of the fuzzy memberships.
The butterfly catastrophe:
Value of each sub-system is computed using Equation (16) while the overall water security level is computed using Equations (17) and (18).
The overall results of the values of the sub-systems and the water security in ONSB are presented in
Table 4.
The values of water security sub-systems show that water-resources security sub-system followed an increasing pattern over the period of 2010 and 2015 (up to 47% in 2015 compared to 2010). This situation may be mainly due to the high stream flow in 2015 (45240 m
3/year) compared to the inter-annual stream flow (approximately 32946 m
3/year), which may be due to high rainfall combined with a moderate temperature). However, by 2025, the value of this sub-system is expected to decrease until 53% compared to the previous years. This situation may be attributed to the sharp increase of the temperature by 2025 (about 0.91 degree Celsius) compared to 2010 and 2015. This decrease in water-resources security in the sub-basin is in concordance with the results of the WEAP assessment of ground water resources under the changing climate in the Savanah region. As a matter of fact, the whole country faces a decrease in ground water resources (as the main source of water for a drinking purpose as well as dry season agricultural activities in the study area) with the savannah region to which the ONSB is part. It has been reported to completely exhaust its ground water resources by 2053 (under the extreme scenario of the RCP 8.5) [
17].
As for the water-society security sub-system, which defines the pattern between water as a resource and the society, the value has shown an increasing pattern over the period from 2010 to 2015 (up to 34% increase in 2015 compared to 2010). This situation may be due to the overall efforts for improving clean water access in order to achieve the Millennium Development Goals targets concerning clean water. This result is consistent with the National Institute of Statistic, Demographic, and Economic Studies (INSEED) findings, which reported that the access to clean water has followed an increasing pattern over the period from 2010 to 2015 [
33]. Nevertheless, this level of security is projected to decrease in 2025 by 33% compared to 2010.
At the same time, the water-environment security, which has to do with the health of the ecosystems (only quality aspect of water considered) has been characterized by a decreasing pattern over time especially compared to the year 2010 (decrease of the value of the system by up to 13% in 2025). This situation is consistent with the transboundary diagnosis of Volta River Basin findings where the degradation of the quality of surface water associated with the degradation of aquatic ecosystems has been recognized as one of the most acute problem in ORB, Togo [
49,
50]. This degradation in the study area is attributed to unimproved sanitation, inadequate management of domestic waste, bad fishing practices, livestock watering in the river bed, chemical from agricultural activities, and other domestic activities such as laundry in the river beds. However, the result showed that the ecosystem health will be improved by 2025 compared to 2015, which is considered as the worst. This slight increase may be due to the efforts planned for improving sanitation by ensuring access to improved latrines, which eradicates the open defecation.
For water economic security, the results depicted an overall increasing pattern (up to 33% in 2025 compared to the year 2010). This situation may be attributed to a substantial increase in livestock in the study area and irrigation projects (development of irrigation potentials known as “agropole”).
The final values of water security over time in the ONSB were obtained through the transformation of original synthetic values of water security. The transformation was done using the following equation, Equation (19), (with the overall result depicted in
Table 5).
As shown in
Table 5, the water security level assessment revealed an overall insecurity in the ONSB. The year 2010 has been depicted as ‘very insecure.’ Although 2015 is still in the same range of insecurity, the status of the sub-basin has improved compared to 2010. Lastly, projections depicted that the water security level will decrease by 20% in 2025 compared to the year 2015. This result is consistent with the findings of Gain et al. [
12], which reported that river basins are likely to experience ‘low water security’ over the coming decades.
Water insecurity in the ONSB is found to be the result of a combination of decreasing available water resources and water quality deterioration. However, considering water barriers proposed by Reference [
44], the per capita of water availability in the sub-basin decreases over time. The lowest values obtained (3033 m
3 per capita per year) are higher than the water stress threshold (estimated at 1700 m
3 per capita). This implies that that physical water insecurity in the ONSB is much more quality than quantity related.
3.2. Barriers to Water Security in the Sub-Basin
Although the existence of water management institutions as well as the efforts made to ensure water security by these institutions in the sub-basin, the water level is found to be insecure with the probability of being worse in the future. To be able to take measures in order to improve the future water status, existing institutions highlighted potential barriers. These factors were found to be technical (63%), institutional (44%), juridical (44%), environmental (37%), socio-cultural (22%), hydrogeological (19%), and demographical (19%). Other barriers include the siltation of river and unbeneficial source of energy for water mobilization. Most of the assessed institutions highlighted a range of barriers contributing to water insecurity in the sub-basin, explaining why, in some cases, the total exceeds 100%. The following are the details of barriers to water security in the ONSB.
(1) Technical barriers: The main highlighted technical barriers were limited fund (89%) and lack or limit water related data (40%). Other barriers included limitation in expert human resources (10%) and water infrastructures (5%). The limited fund was both in terms of a government investment in the water sector as well as the external aid in the efforts for universal provision of clean water. For the government, access to clean water is just one of the various existing priorities of the country. Thus, there are limited funds to be allocated to this need as well as other needs. As a matter of fact, the round table organized in June 2011 towards IWRM funding was without financial outcomes (MAEH, 2015). Limited water related data highlighted the fact that the data necessary, required for any sound planning, mobilization, and development of water is lacking. These data include the exact values of potential renewable water resources in the country or at the basin level, and the sectoral needs for water among others. This situation is reported to be associated with either an overestimation or underestimation of the available water resources as well as consumed water already used, and the potential user’s needs.
(2) Institutional barriers: Most of the assessed institutions have highlighted a range of institutional barriers including the limited collaboration among key actors (43%), the institutional instability (36%), the inadequacies in water and the related sector evolution (20%), absence of decentralized water management structures (14%), and the limited coordination within the sector (14%). The limited collaboration among water actors has to do with the limited concentration meetings between actors and the ineffective monitoring of water committees and clean water users and sanitation associations. Another aspect of the collaboration is the transboundary collaboration with other Volta River Basin riparian countries (especially between Togo and Burkina Faso). As a matter of fact, fishing communities in the sub-basin reported that the quantity of water in the Oti River in Mango regulated by the Kopienga dam (in Burkina Faso) has had impacts on the capture, which affects these communities’ overall revenue. The institutional instability has to do with the fact that the Ministry of Water and Rural Water Systems (MWRWS) that oversees water resources development, mobilization, and management has been submitted to an alternation of status, which acts sometimes as an autonomous institution and, at other times, as a dependent institution. As a matter of fact, the ministry acted as an independent structure only under the government of 2006 (year at which the ministry was for the first time established), between 2009 to 2013, and in 2018. Its dependency covered the periods from 2006 to 2008 (under the ministry of mining and energy) and 2013 to 2017 (under the ministry of rural equipment and the ministry of agriculture). This situation has been reported to be associated with perturbations in the process of implementation of activities at the central level, as the priorities of the ministry to which it is attached are, in most cases, privileged. Inadequacy in the water and related sector evolution concerns the water sector and the sanitation sector. Efforts are made to ensure water security (in terms of quality and quantity). However, respondents recognized that the sanitation sector is still lagging (open defecation is still going on) and reported the sector to be the “poor parent.” In fact, this aspect has been reported as being the “brain teaser” to water security. The ground observation has proven that local activities are still being managed by the central structures. All the directorates at the central level are not represented at the local level and all the water-related activities are coordinated only by the regional water and rural water systems directorate, which is specifically mandated as a technical service.
(3) Juridical barriers: The non-application of juridical texts (77%), the non-operationalization of management organs/financial instruments (36%), and the political will (20%) are the key factors that have been highlighted as being the juridical barriers to water security in the ONSB. As a matter of fact, organs to be adopted according to the water code in order to ensure an effective water resources management at a hydrological basin level are not established (basin agencies and basin committees) even after the decree 2012-004/PR on 29 February 2012 (article 1 of the section IV), which gives the mandate for the operationalization of these organs and institutions. Key water resources management organs, which are established, are not operational (i.e., National Water Council). The political will in this context has been referred to as the wrong oriented priorities of the government (as much effort is made toward infrastructures, housing, and electricity while the water sector is neglected). Another aspect of this will is that water mobilization is sometimes politically-based. As a matter of fact, water is provided, in some cases, as reward to some key political actors for their faithfulness and not on the need basis.
(4) Environmental barriers: Environmental factors that are hindering water security in the sub-basin are water pollution (76%), flood disaster (16%), and climate change (8%). Water pollution has been attributed to limited access to sanitary facilities and the norm of realization for those facilities (regarding the water tables and the treatment of the sludge). In this frame, it has been reported that, in some cases, the sealing mechanism in not considered. Out of these situations, both ground water and surface water quality are undermined. Another aspect of the pollution is the pollution by domestic waste due to unsustainable waste management practices in the areas as well as in the whole country. Furthermore, chemical farming represents a huge contributor to water pollution (as the agriculture represents the main activity in the area). In addition, some respondents highlighted flood as a barrier since, in some of the communities assessed, flooding events are sometimes associated with the destruction of water infrastructures (i.e., case of pipes), with the possibility of leaving the communities without water for years.
(5) Hydrogeological barriers. These barriers are related to the availability of water as well as the easiness for that water to be abstracted. Ground observation across the communities revealed a drying up of shallow water points, which hindered pumping water from boreholes between February and June. This situation is explained by the fact that the sub-basin falls under the Upper Proterozoic ages Volta basin is sedimentary-associated with discontinuous and localized aquifers. The productive layers are the sandstones of Bombouaka with the Dapaong group (with the Korbongou and Tossiegou formations) and the Mont Panbako group (with the Bogou formation), which lie in high depth in the area, especially around the Oti district characterized by a thick layer of clay. Thus, it requires us to go very deep in some areas in order to have access to water (making water abstraction complex). In addition, ground water is in some areas that are either very mineralized or have a high concentration of hydrogen sulphide. This situation is mainly due to the deep location of productive layers, which makes the recharged water sojourn for long period in rocks. In addition, the recharge capacity in the study area is one of the lowest (about 177 mm per year against 363 mm per year in Kara).
(6) Socio-cultural barriers: The socio-cultural barriers included the lack of sense for paying for water services, especially in rural areas, since water is still considered as a gift from God, “free”. This situation affected the profitability of the infrastructures. Thus, the inability of the management committees to ensure the maintenance of the existing infrastructures was affected. Another source of the problem is that communities ignore the impact of unimproved water on people’s health. As they stated, “our fore parents used to drink water from rivers, and they were strong.” The last socio-cultural factor encountered is regarding the use of latrines. For culture conservators, based on taboos, it is forbidden to use latrines (considered as a whole). This situation is considered one of the reasons why open defecation is still taking place.
(7) Demographic barriers: Population growth represented a key barrier in ensuring water in sufficient quality and quantity to communities.
In summary, beyond the common key factors that are contributing to water insecurity in Africa including weak/bad governance (the lack of funds, limited institutional and human capacity, limited/lack of coordination, lack of harmonization/application of laws and policies, inadequate data, water pollution) [
51,
52,
53], and the biophysical factors (hydrogeological characteristics, extremes, climate) [
53]. Water insecurity in the context of the ONSB is attributed to additional managerial factors including (institutional instability, the inadequacies in water, and related sector evolution, absence of decentralized water management structures, and the non-operationalization of management organs/financial instruments) and the local culture (i.e., taboos and bylaws).