land Article Using Time-Series Remote Sensing Images in Monitoring the Spatial–Temporal Dynamics of LULC in the Msimbazi Basin, Tanzania Herrieth Machiwa 1,2 , Joseph Mango 1,3 , Dhritiraj Sengupta 1 and Yunxuan Zhou 1, *   Citation: Machiwa, H.; Mango, J.; Sengupta, D.; Zhou, Y. Using Time-Series Remote Sensing Images in Monitoring the Spatial–Temporal Dynamics of LULC in the Msimbazi Basin, Tanzania. Land 2021, 10, 1139. https://doi.org/10.3390/land10111139 Academic Editor: Richard C. Smardon Received: 23 September 2021 Accepted: 22 October 2021 Published: 26 October 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 State Key Laboratory of Estuarine and Coastal Research, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China; machiwa.herrieth@udsm.ac.tz (H.M.); jsmmango@stu.ecnu.edu.cn (J.M.); dhritiraj@sklec.ecnu.edu.cn (D.S.) 2 Department of Computer Science and Engineering, College of Information and Communication Technologies, University of Dar es Salaam, P.O. Box 33335, Dar es Salaam 14112, Tanzania 3 Department of Transportation and Geotechnical Engineering, University of Dar es Salaam, P.O. Box 35131, Dar es Salaam 14113, Tanzania * Correspondence: zhouyx@sklec.ecnu.edu.cn; Tel.: +86-138-1882-8655 Abstract: The basins containing rivers and wetlands are very significant to the surrounding dwellers in various ways, altogether aiming at boosting the economy for most developing countries. Unfortu- nately, the benefits are frequently overlooked and lead to basin mismanagement and degradation posed by increasing population. This study used population and satellite data to quantify the extent of land-use and land-cover changes along the Msimbazi valley between 1990 and 2019. Geographic information system and remote sensing techniques were used in the analysis and processing of remotely sensed images acquired in 1990, 2000, 2010 and 2019. The results reveal that the dominant area is built-up land that occupied 39.3% of the total in 1990 and gradually increased to 42.6% in 2000, 54.1% in 2010 and 65.5% in 2019. Moreover, forest and agriculture that in 1990 had been the second and third largest in size, respectively, had been decreasing throughout the entire period. The population increase had been threatening wetland vegetation during the initial 10 years (1990 to 2000); however, the wetland vegetation showed subsequent improvement after the implementation of some government initiatives. Other land cover, such as bush land and grassland, showed minority status with inconsistent changes in either increase or decrease. These findings imply that the Msimbazi Basin suffers much from uncoordinated human activities that consequently degrade its fertility. This degradation can be observed as well from the population distribution maps that show that a huge stress is being exerted along the riverine due to population growth and urbanization. The study also highlights that a lack of intensive management plans that are supported by clear legal commitments for optimal and sustainable resource utilization contributes to wetland deterioration. Keywords: remote sensing; spatial–temporal changes; human activities; wetland 1. Introduction Globally, river and wetland ecosystems provide significant benefits for humans. Ac- cordingly, different conventions have been formulated to define their conservation for sustainable use. The Ramsar Convention of 1971, for example, defines wetlands as areas of marsh, fen, peat land or water, whether natural or artificial, permanent or temporary, with water that is static, flowing, fresh, brackish or salt, including areas of marine water, the depth of which at low tide does not exceed six meters [1,2]. These areas are recognized as the most important environmental components due to their substantial benefits biologically, ecologically and economically [3,4]. Some biological and ecological benefits derived from wetlands include providing habitats for specific flora and fauna, mitigating flooding, mini- mizing erosion, controlling pollution and regulating climate [5]. Furthermore, the wetlands support human livelihoods in numerous ways, such as by furnishing water for domestic Land 2021, 10, 1139. https://doi.org/10.3390/land10111139 https://www.mdpi.com/journal/land