Land Use/ Cover Dynamics assessment in the Right Upper Kikuletwa Sub catchment Pangani River Basin, Tanzania

Abstract

This study, compares two models (LCM and CA-Markov by MCPI) used for prediction of Land assesses the historical and future LULC Dynamics (LULCD) in the Right Upper Kikuletwa Sub catchment by utilizing Remote sensing and Geographical Information System (GIS) Techniques. This sub catchment with a total area of about 769.46Km2 is very potential for the water resources in Kikuletwa catchment and Pangani River Basin as well also to sustain the life of the community found in the catchment. The need of more precise models for LULC projection increases worldwide but also the spatial-temporal LULC Dynamics (LULCD)brought about by quickening pace in urbanization, population growth, agricultural activities, and other human economic activities has altered the surface of the earth including The Right Upper Kikuletwa Sub catchment, hence the concern regarding sustainable management of environment and land resources has been increasing too. The process of comparing models for more accurately projection and understanding the significant dynamics of these LULC changes is essential but not limited for successful planning and decision making, land management, resource allocation, environmental conservation and protection, hydrological studies and sustainable development applications. In order to achieve the specific objectives of this study, the Landsat (satellite images) data for 1993,2006 and 2018, DEM and other social -economic data were collected, processed then Land use/Cover classification under supervised classification, accuracy assessment and independent variables preparation was done through Remote sensing and GIS techniques using ArcMap 10.8, QGIS 3.28 and Google earth. Land Use/Cover simulation and projection was carried out in Terrset Geospatial Monitoring and Modelling System (Terrsetsoftware2020) through embedded Land Change Modeler (LCM)and CA Markov Models under given scenarios. Comparison of two Models (LCM and CA-Markov) and investigation of historical and future LULC Dynamics (LULCD) was done utilizing the Classified LULC maps, simulated LULC map and Projected LULC maps. However, in carrying the analysis, ArcMap, and Terrsetsoftware2020 were used. In the Accuracy assessment of Classified LULC by using Kappa Index, it was shown that all three classified LULC map had high accuracy with Kappa Index of 0.91,0.95,0.95 for 1993,2006 and2018 respectively. In comparison analysis between LCM and CA-Markov by MCPI the CA-Markov shows to be stronger than LCM Model for LULC Projection in this Sub catchment by having Standard Kappa (KST) of 0.7463 compared to 0.649 of LCM Model. Results of this study revealed that, based on historical to future LULC Dynamics (1993-2054), the trend shows that Agricultural land and Urban/Built up categories of LULC experienced and expected to experience increasing trend with area increase from 92.99Km2 308.11 Km2 by 2054 for Agricultural land and 25.16 Km2-147.64Km2 by 2054 or Urban/Buil up. Forest land and Range land shows decreasing trend from 272.58Km2-113.89Km2 by 2054 ,296.82Km2-124.59Km2 by 2054,12.67Km2 -1.92Km2 by 2054 for Forestland, Range land and Ice surface respectively. While Bare/Barren land shows decrease and then increase range from 69.07Km2- 60.74Km2-71.16Km2 by 1993,2006 and 2054 respectively. In Analysis of Change Annual Rate(CR) of each LULC Class, based on about 12years interval, for the whole study time(1993-2054)it was shown that the change rate vary whereby for Agricultural land varied between +0.85 to +6.51Km2/Year, Urban/Built up (+1.02 to +3.22 Km2/Year),Forestland (-1.42 to -4.18 Km2/Year),Bare/Barren land (-0.64 to +0.53 Km2/Year),Rangeland (-0.48 to -6.92 Km2/Year),Ice surface (-0.78 to 0.00 Km2/Year) and Water bodies(-0.01 to 0.18 Km2/Year).The persistence analysis indicated that for Historical(1993-2018) LULC Dynamics the persistence area was noticed to be 118.52Km2 for Rangeland,Agriculturalland(57.77Km2),Bare/Barrenland(44.10Km2),Waterbodies(0.01Km2),Urban/Buil tup(9.10Km2),Forest land(169.56Km2),Ice surface (1.94Km2).Future(2054)LULC Dynamics expected persistenceshowsAgriculturalland(194.98Km2),Urban/Builtup(62.96Km2),Rangeland(118.85Km2),Wat erbodies(0.83Km2),Bare/Barren land(66.5Km2),Ice surface(1.65Km2) and Forest land(112.1Km2). -Markov by MCPI over LCM model. However, it gave out insight regarding significant LULC Dynamics at the Sub catchment which would be incorporated into planning, decision making, catchment management program and various hydrological studies in the catchment. In order to secure sustainable functions of this sub catchment, it is recommended to carry out flood and hydrological resilience studies and implement Integrated Watershed Management.