*3.4. Future Changes in Water Stress, Water Demand, and Water Supply*

Climate change is a significant element in the forward projection of water availability. The availability of water is a key factor for the development of agriculture and industry, as well as a requirement in satisfying the increasing needs of populations as standards of living are improved. Limitations of water availability will often form a major constraint on development plans [19]. Consequently, inadequate knowledge of the physical, technical, and socioeconomic aspects of water resources induces degradation of river basins.

The projections presented in Figure 2 indicate that the Maningory (4), Tsiribihina (6), and Mangoky (8) basins will experience water stress (low-to-medium, 10–20%), most notably in the central–western and eastern regions of Madagascar. The projected changes in the total blue water (water supply) in the Mahajamba (1) and Maningoro (4) basins (located in the northern and eastern regions) are much higher (100–300 cm) compared with changes in the Mangoky (8), Onilahy (9), and Mandrare (11) basins (10–30 cm). The future water demand will be higher in the Maningory (4), Betsiboka (3), Tsiribihina (6), Mangoro (7), and Mangoky (8) basins (10–30 cm), which are located in the central highlands. Overall, the projections indicate an increasing water demand, water stress, and water supply in the major river basins. Factors that may induce pressure on water resources include socioeconomic growth, urbanization, agricultural expansion, and climate change. This would result in water scarcity for agriculture, drinking, and other domestic purposes in those river basins.

**Figure 2.** Projected change of water stress, water demand, and water supply from the baseline (1950–2010) to a future period (2040) under the business-as-usual scenario RCP8.5/SSP2. Source: WRI Aqueduct projections 2015 (Data available at https://www.wri.org/aqueduct, accessed on 25 May 2020).

Figure 3 shows that the water stress score is higher in Japan than in Madagascar. As indicated in Table 2, Japan's water stress score is medium-to-high (20–40%), while it will remain low-to-medium (10–20%) for Madagascar under the business-as-usual scenarios for the years 2020, 2030, and 2040. Notably, the agricultural sector has the highest water stress score in both countries. Thus, the agricultural sector consumes a larger amount of water, compared with other sectors; there is less competition among users in the industrial sector than in the agricultural sector. Agriculture is the driver of Madagascar's economy. In particular, agriculture dominates the overall use of Madagascar's land and water resources, and it provides livelihoods for more than 70% of the population [42]. Although Japan is an industrialized country, the agricultural sector is considered a very important sector, which

dominates 65% of water use [43]. These results indicate that action must be taken to ensure that there is sufficient water in the future for both humans and the environment.

**Figure 3.** Comparison of water stress in Madagascar and Japan. Source: Aqueduct 3.0 Country and Province Rankings.



#### *3.5. Problem-Solving Based on Japan's IRBM Experience*

Relevant information about the existing IWRM policy, legal and strategic frameworks and their importance for the SDGs, and climate change in both countries were investigated in the previous sections. The results indicate that Madagascar has several water resources and climate change-related issues. We found that climate change induces pressure on water availability. The projections indicate an increasing water demand, water stress, and water supply in the major river basins. A reasonable approach to tackle those issues could be the adoption of effective and sustainable policies as shown in the case of Japan.

The findings of this study show that Japan has decentralized water policies and effective coordination among the central and local governments [17]. This water plan identifies long-term water supply and demand prospects, as well as means of improving water use stability, through water efficiency measures and effective use of the existing infrastructure [18]. In addition, the country has developed region-specific integrated water resources management tailored to regional climatic and social conditions. The most important relevant finding was the integration of the five ministries related to water to ensure better integration and coordination of the water resources. This intersectoral approach helps to solve the problem of overlapping responsibilities and conflicting decisions.

Regarding the adaptation to climate change through IWRM, the country adopted an integrated approach to managing surface water and groundwater by considering the balance between water supply and water demand, as well as between water quantity and quality. Indeed, stakeholder participation and information sharing help to cope with climate change and social needs. Japan's IWRM promotes sustainable water use and effective water cycle governance through an appropriate policy and frameworks involving relevant sectors and stakeholders. IWRM is promoted from perspectives such as groundwater and surface water, water quantity, and water quality (both upstream and downstream); it also promotes water efficiency and environmental conservation. Stakeholder integration in water facility planning, designing, and operation is embedded in the policy framework [15]. Japan's river management system integrates flood management, water utilization, and environmental conservation. The establishment of several laws increases the resilience of water systems to global change pressures (dams, groundwater, waterworks; sewerage, water pollution control, etc.). Concrete action must be implemented to preserve water resources and manage the major river basins. Effective implementation of IWRM now requires all sectors to work together to achieve the shared vision of peaceful economic development. The establishment of the IRBM framework is recommended to enable the major river basins to optimally use their water resources to meet the needs of the people.

On the whole, these findings suggest that successful implementation of the IWRM approach in Madagascar needs systematic planning and implementation to achieve sustainable and resilient solutions Figure 4. In the context of Japan's experience, this proposed framework shows the process from a problem's discovery to the resolution. First, we identified the main issues and the elements that caused those issues in terms of river basin management (Sections 3.2 and 3.3). Then, we considered the structure of the problem by recognizing the connections among the elements and searched for leverage points to improve the situation. Finally, we proposed appropriate solutions to solve the problems by using systematic methodologies. The river basin management in Madagascar has challenges because of political, environmental, social, and water resources issues. Those issues are interconnected and affect water resources in terms of quality and quantity. The proposed framework considers seven important solutions: research and technology prioritization and usage, infrastructure creation, local consultation and participation, sectoral integration, effective governance, information and telecommunications technology and capacity building, and financial resources.

**Figure 4.** Example of the systemic thinking approach to IWRM in Madagascar.
