Project Description
This project focuses on analyzing and mapping flood-prone areas within Mokwa Local Government Area (LGA) using satellite imagery and geospatial techniques. By integrating Landsat 8 imagery with GIS-based elevation and hydrological data, this project identifies vulnerable zones, helping stakeholders in flood preparedness, mitigation planning, and sustainable land use management.
Study Area
Mokwa LGA is located in Niger State, Nigeria, bounded by the River Niger to the west and characterized by a mix of flat floodplains and slightly elevated terrains. The area experiences seasonal rainfall from May to October and is prone to recurrent flooding due to its proximity to water bodies and inadequate drainage infrastructure. Agriculture is the dominant economic activity, making the region highly sensitive to flooding events.
Problem Statement:Mokwa LGA faces persistent flooding challenges, especially during the rainy season. These floods damage farmlands, displace communities, and affect infrastructure. Yet, there is a lack of spatial data and visual tools to guide proactive planning and response.
Goal:The goal of this project is to develop a spatial flood risk map for Mokwa LGA using geospatial technologies to support evidence-based decision-making in disaster risk reduction, land use planning, and environmental management.
Tools and Data Used
Satellite Data:
Landsat 8 OLI/TIRS Imagery was used for LULC and NDVI analysis)
Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM)
Software & Tools:
ArcGIS tool used for spatial analysis and map creation
Excel tool was used for basic data analysis and attribute statistics
Other Data:
Rainfall data downloaded from climate knowledge portal
Hydrological data & analysis from Digital Elevation Model (DEM) used to extract fill, stream network, flow accumulation, stream order, flow direction, distance from stream.
Local administrative boundaries from Grid3 & OpenStreetMap (OSM) portal
Methodology (Brief)
1. MCDA(AHP) Approach: The applied methodology for this project is GIS-based multi-criteria approach for flood risk assessment. The AHP was selected as the criteria weighted method in the context of MCDA. The criteria used in determining the flood risk/hazard are based on the parameters that contribute most to river floods.
2. Image Acquisition & Preprocessing: Landsat 8 and DEM data were downloaded and preprocessed using ArcGIS tool (e.g., Raster Mosaicking, Extract Mask, reclassification, and enhancement).
Flood Risk Zoning: Using the DEM, slope and elevation were analyzed to identify low-lying, flood-prone areas.
Index Calculation: Multi Criteria Decision Process MCDA & Analytic Hierarchical Process (AHP) techniques to overlay all the reclassified dataset and assess flood risk zones were computed.
Overlay Analysis: All layers were integrated to reclassify flood risk zones (Very High, High, Moderate, Very Low & Low).
Map Production: Final flood risk maps were generated and validated flood prone areas using satellite image from google earth and location points (Coordinates).
Key Findings and Visuals
Findings:
Approximately 19% of Mokwa's land area was classified as very high flood risk, especially near the River Niger and major tributaries, 13% land areas was classified as High flood risk, 23% land areas was classified as moderate risk, 18% land areas was classified as very low risk and 27% was classified as low risk flood areas.
Areas with low elevation (<200 meters) and poor vegetation cover showed higher flood exposure.
