Project Description:

This study involves a detailed slope analysis of Mokwa LGA to understand its topographical variability and how it influences environmental planning, land use, erosion vulnerability, agricultural zoning, and infrastructural development. Geographic Information System (GIS) tools were employed to derive slope gradients from a Digital Elevation Model (DEM) of the area.

Study Area Map:

Mokwa Local Government Area, located in the southwestern part of Niger State, Nigeria, spans approximately 4,338 km². The region is characterized by undulating terrain, river networks (notably the Niger River), and diverse land uses including agriculture, settlements, and forest patches.

Problem Statement:

Mokwa LGA faces increasing challenges in land degradation, gully erosion, and poor infrastructure planning due to inadequate topographic analysis. Without a clear understanding of the area's distribution of slope, sustainable land use and development decisions remain difficult.

Goal

The goal of the project is to conduct a comprehensive slope analysis of Mokwa LGA using GIS to:

• Categorize land based on slope steepness

• Identify erosion-prone zones

• Support land use planning and disaster risk reduction efforts

  Tools Used

  • ArcGIS 10.8

  • Google Earth Pro (for validation and digitizing)

  • Cartographic tools (for map design)

    Data Used

    • Digital Elevation Model (DEM): SRTM 30m resolution from USGS Earth Explorer

    • Administrative Boundary Shapefile: Mokwa LGA boundary from Grid3 portal

      Methodology

      The methodology adopted for this project are:

      Data Acquisition:

      1. Download SRTM DEM from USGS portal and Mokwa Local Government Area boundary (shapefile format) from Grid3 portal.

      2. Pre-processing

         • Masked DEM to Mokwa LGA extent using the raster mask feature in ArcMap toolbox.

         • Reproject data to UTM Zone 32N (WGS84 datum) for accuracy.

      3. Slope Generation:

         • Use the "Slope" tool in ArcGIS Spatial Analyst to generate the slope analysis.

         • Generate slope in degrees and classify into slope categories:

           • 0–5°: Flat

           • 5–15°: Gentle

           • 15–30°: Moderate

           • 30°: Steep

             Key Findings

             The projects an overview of Key findings which are as follows

             • Over 65% of Mokwa LGA consists of flat to gentle slopes (0–15°), making it ideal for agriculture and infrastructure.

             • Moderate slopes (15–30°) are found near escarpments and riverbanks, which may pose erosion risk.

             • A small percentage (<5%) exhibits steep slopes (>30°), often located near ridges or isolated highlands.

             • The Niger River floodplain aligns with flat terrain, supporting seasonal farming but also vulnerable to flooding.

             • Areas with steep slopes require conservation strategies such as terracing and afforestation to prevent erosion.