The core challenge is implementing integrated and effective urban water management plans for Antananarivo

Antananarivo's city faces recurrent flooding and landslides, affecting several neighborhoods annually. In January 2022, the town witnessed 12,000 displaced individuals (1), around 10 fatalities (1), and significant damage to 8,000 hectares of agricultural land and 4,500 buildings (2). These problems stem from challenging topography, uncontrolled urban expansion, and reactive rather than preventive measures, exacerbated by climate change. This context highlights the need for an integrated approach to sustainable urban development.

Key issues include difficulties accessing geographic data, as obtaining data requires navigating multiple entities and platforms. Additionally, data fragmentation leads to non-standardized, specific datasets, complicating their usage. An example is the disjointed relationship between administrative boundaries and census results.

Furthermore, no unified geospatial platform for managing stormwater and wastewater data is slowing project implementation and decision-making in urban sanitation and development. The proposed solution is a Sanitation Geoportal, aimed at enhancing the coordination of planning tools and stakeholder actions. This platform will centralize and democratize geographic data related to sanitation and cross-cutting themes, streamline project development by enabling online data consultation, and reduce costs, such as reprography expenses, by replacing physical documents with digital versions.

The urbanization of Antananarivo has evolved haphazardly since Madagascar's independence, significantly encroaching on the wetlands of the Betsimitatatra plain. Driven by its economic allure, this urban sprawl has surged without the support of large-scale infrastructure projects since the 67 Ha development. Consequently, most of the city's neighborhoods now face severe sanitation issues.

Flooding and poor sanitation characterize these challenges. Floods are common during the wet season, largely due to obstructed drainage systems clogged with solid waste and vegetation. Additionally, inadequate wastewater systems force residents to connect to stormwater drains, creating environmental and health hazards.

Institutionally, multiple actors, including two key ministries, are involved in the city's sanitation efforts. However, coordination and organizational problems are prominent, compounded by financial and technical constraints. Funding is deficient, and there is a pressing need to enhance staff capacity. On the user level, strategic behavioral changes are essential, as sectoral degradation fosters further non-compliance.

In late January 2022, the four main rivers crossing the city experienced severe flooding. This was particularly evident along the left bank of the Ikopa River, where flood zones extended beyond the usual boundaries. Analysis via GIS revealed that approximately 4,500 buildings, mainly residential and housing around 58,000 people, were directly affected, inundating 165 hectares of residential areas.

The economic repercussions were severe, especially for agriculture. Over 8,000 hectares of farmland, predominantly rice fields, were impacted. Additionally, about 337 km of roads were submerged, affecting transportation, commerce, and daily mobility. The floods of the week of January 17 covered 120 km², or 15% of the urban area, excluding water bodies.

In the southwest, flooding was exacerbated by a breach in the left bank of the Sisaony River at Ampitatafika. This led to the inundation of low-lying areas, primarily rice fields. By January 2023, the breach remained unrepaired, causing ongoing flooding during the cyclone season. The resulting devastation formed a large lake, submerging extensive agricultural parcels in the Fokontany of Anjanamaintso and Ambohidava.

The Sanitation Geoportal for Antananarivo presents a pioneering approach to addressing the city’s pressing sanitation and environmental management challenges.

This innovative project leverages advanced geospatial technologies to create a sustainable, resilient, and smart solution, uniquely suited to the complexities of urban management in the African context. Below is a detailed explanation of the project’s approach and innovations:

1. Addressing Key Sanitation and Environmental Management Challenges

The Geoportal will consolidate data from multiple sources into a single, accessible platform. This integration facilitates comprehensive analysis and coordinated planning across different sectors, overcoming the current fragmentation of data and responsibilities among various entities.

By incorporating real-time data capabilities, the Geoportal will offer dynamic monitoring of stormwater and wastewater systems. This functionality enables quick responses to emergencies like floods and pollution incidents, significantly enhancing urban resilience.

The platform fosters improved coordination among governmental bodies, NGOs, private sector participants, and local communities. By providing a shared, transparent data interface, it promotes a holistic approach to urban planning and sanitation management, ensuring that diverse interests and insights are integrated into decision-making processes.

2. Innovations in Resilience

The Geoportal will utilize predictive modeling to forecast potential sanitation and environmental risks. This capability allows for proactive planning and intervention, reducing the impact of natural hazards such as floods. For example, it will predict areas at risk of flooding and suggest preventive measures based on historical data and real-time inputs.

A dedicated module within the Geoportal will focus on environmental risk management, offering real-time alerts for hazards like flooding and landslides. This system ensures timely dissemination of critical information, enabling authorities and communities to act swiftly and effectively.

The platform will support scenario-based planning, allowing users to simulate various intervention strategies and assess their outcomes. This flexibility is crucial for adapting to changing environmental conditions and urban growth patterns.

3. Sustainability Innovations

The Geoportal’s design as a centralized hub for geospatial data eliminates redundancy and promotes the efficient use of resources. It simplifies access to critical information, reducing the time and cost associated with data collection and analysis.

By providing open access to data and planning documents, the Geoportal encourages public participation and transparency. This inclusivity not only educates communities about sanitation issues but also fosters a culture of accountability and collaborative problem-solving.

The Geoportal’s capability to streamline project planning and resource allocation enhances the efficiency of sanitation infrastructure investments. It reduces wastage and ensures that financial and material resources are deployed where they are most needed, aligning with principles of sustainable development.

4. Smart Innovations

The Geoportal will feature a modern, intuitive interface designed to be accessible to users with varying levels of technical expertise. This ease of use promotes widespread adoption and integration into everyday planning and management activities.

The platform’s ability to automatically process and update data ensures that users have access to the latest information without the need for manual intervention. This automation reduces administrative burdens and enhances operational efficiency.

Designed with interoperability in mind, the Geoportal can integrate with other systems and platforms, allowing for future expansions and adaptations. This scalability ensures that the platform remains relevant as urban management needs evolve.

The Sanitation Geoportal for Antananarivo is set to significantly enhance the well-being of target populations, foster economic development, promote social inclusion, and advance environmental protection in Antananarivo.

The Geoportal will centralize and visualize data related to stormwater and wastewater management, addressing critical sanitation issues. Enhancing coordination among stakeholders and providing real-time data, will streamline interventions in sanitation infrastructure, reducing the frequency and severity of flooding and landslides. This will directly mitigate health and human security risks associated with poor sanitation and lack of rainwater management. Improved infrastructure planning facilitated by the Geoportal will lead to cleaner neighborhoods, particularly in flood-prone areas. This will enhance overall public health by reducing exposure to unsanitary conditions.

The Geoportal will aid in safeguarding agricultural lands from flooding, preserving the productivity of about 8,000 hectares of farmland affected by past inundations. This is crucial for local rice farmers, ensuring economic stability and contributing to food security. By providing a unified platform for data, the Geoportal will enhance the efficiency of resource allocation in sanitation and infrastructure projects. It will enable precise and timely interventions, minimizing costs associated with emergency responses and improving planning efficiency. Reduced flooding and improved sanitation will enhance the reliability of transport networks, facilitating smoother movement of goods and people. This will bolster commercial activities and economic transactions, especially in areas previously disrupted by poor infrastructure.

The Geoportal will democratize access to sanitation and environmental data, empowering communities to participate in planning processes. By making data and planning documents available online, citizens can better advocate for improvements in their neighborhoods. The platform will improve communication among government agencies, NGOs, and local communities. Providing a common data interface and clarifying roles will foster more inclusive and collaborative planning efforts, ensuring diverse community needs are met. By offering open access to sanitation and urban planning data, the Geoportal will enhance transparency in decision-making processes. This will build trust between citizens and authorities, improving public engagement and accountability.

The Geoportal will support better management of wastewater and stormwater, minimizing pollution of water bodies and soils. Effective planning will prevent sewage system overflows and illegal waste disposal, leading to cleaner urban environments. By integrating data on urban planning and environmental management, the Geoportal will promote sustainable development practices. It will ensure new developments consider ecological impacts and contribute to urban resilience against climate-related challenges. The platform will include modules for assessing and alerting environmental risks like flooding. This capability will enhance the city’s responsiveness to environmental threats, mitigating potential impacts on ecosystems and human settlements.

The Geoportal will enable adaptive planning through real-time data and predictive modelling, allowing Antananarivo to proactively respond to environmental changes and urban growth, thus ensuring long-term resilience. The project will stimulate the development of geospatial and geomatic skills locally, fostering technical expertise and innovation in geospatial professions, crucial for sustainable urban management.

The Sanitation Geoportal for Antananarivo exemplifies a groundbreaking solution to urban sanitation and environmental management challenges in the city.

Through the integration of diverse geospatial datasets, real-time monitoring, and predictive analytics, the Geoportal offers a comprehensive decision-support tool. It consolidates fragmented data, enhancing coordination among stakeholders and promoting efficient resource allocation. Our methodology involved extensive data analysis, stakeholder engagement, and the integration of existing geospatial platforms. By developing an intuitive and accessible user interface, the Geoportal fosters transparency and community participation. The platform's ability to adapt to changing conditions through scenario-based planning and real-time data integration enhances the city's resilience against environmental hazards.

Key findings highlight the Geoportal’s potential to streamline urban planning, optimize infrastructure investments, and improve emergency response. The platform's centralized data hub and automated processing capabilities reduce administrative burdens and enhance operational efficiency. Additionally, by incorporating local insights and providing open access to data, the Geoportal promotes sustainable development and empowers communities. This project not only addresses immediate sanitation needs but also lays the foundation for ongoing improvements in urban management practices. However, an open question remains: How can we further enhance the integration of emerging technologies such as artificial intelligence and machine learning to predict and mitigate urban environmental challenges more effectively?