DEVELOPMENT OF WEB-BASED LOWER SHIRE ANNUAL FLOOD DISASTER RISKY AREA GEOPORTAL SYSTEM

GIS-based information is increasingly vital for the dissemination of flood information, aiding in early warning to flood-prone communities and informing the general public about the current flood conditions for responses. This study aims to develop a web-based system that visualizes and gives locations of flooded villages and essential structures such as hospitals, shelters, schools, markets, and safe routes. Apart from that, it also supports the spatial decision by using OSRM, which provides step-by-step travelling guidance and time estimates, which is a very important feature in disaster management. The system integrates remote sensing analysis techniques to identify flood risk areas and web web-based SDSS for optimal routing. Remote sensing data were processed to map areas prone to yearly floods based on flood criteria such as slope, elevation, land use and land cover, stream power index, topographic roughness index, curvature, and hydrology activities analysis. Risk areas were incorporated into the GIS routing and visualizations. The dissemination of flood incidents will be in three different modes, which include alerts, media content (videos and images), and as news. System testing demonstrated the web based geospatial technologies ability providing better spatial services to the flooding communities such as visualization of flooded or areas at risk of being flooded, travel guidance, optimization of routes, time estimates determination, location and proximity of structures in need from a victim position or any other marked starting point which are clearly geo-visualized. All these help to make spatially informed decisions, such as planning evacuation travel, travel guidance to unfamiliar destinations and time estimations which help in transportation. In addition to that proximity between or among places such as hospitals, shelters or schools which used as temporary shelters will be known along with their statistical details which aid in making better spatial decision and IV prioritize allocation of resources. The geoportal proved to be an effective and powerful tool for disseminating flood messages and showing the flood areas and places which are useful during floods which help in flood disaster management and coordination in Lower Shire

Remote sensing data were processed to map areas prone to yearly floods based on flood criteria such as slope, elevation, land use and land cover, stream power index, topographic roughness index, curvature, and hydrology activities analysis. System testing demonstrated the web based geospatial technologies ability providing better spatial services to the flooding communities such as visualization of flooded or areas at risk of being flooded, travel guidance, optimization of routes, time estimates determination, location and proximity of structures in need from a victim position or any other marked starting point which are clearly geo-visualized. In addition to that proximity between or among places such as hospitals, shelters or schools which used as temporary shelters will be known along with their statistical details which aid in making better spatial decision and IV prioritize allocation of resources. The geoportal proved to be an effective and powerful tool for disseminating flood messages and showing the flood areas and places which are useful during floods which help in flood disaster management and coordination in Lower Shire

The Lower Shire is composed of two districts Chikwawa and Nsanje which all made up 15 TAs. This is well known for its recurring flood which causes yearly devastating effect to lower shire communities. It is characterized by low lying topography with elevation ranging from approximately 10 to 100 meters above the sea level (GFDRR,2019). Receives an annual rainfall between 800 and 1,200mm as an approximate (World Bank, 2023). It also characterized by having densely population, with vulnerable settlements that face high exposure to flood hazards (Mwase et al., 2023). Shire River is the major river which run through and covers a lot of areas before ending into Zambezi river in Mozambique. There also other network of rivers which drain into it such as Ruo ,mwanza ,Makhanga ,Nkhate, Mapelera, Livunzu,Likhubula and Chidzimbi contributing the flooding force in Lower shire (Chinguwo, 2022).

District: Chikwawa

Coordinates: -16.2153, 34.6804