Evaluation of the potential of Bamboo for riverbank restoration : a case of River Nyamugasani in Kasese District, Uganda

Abstract

This study aimed to investigate the potential of bamboo growing as a nature-based solution for stabilising the bank of the River Nyamugasani. It specifically sought to (i) analyse the dynamics of land cover changes along the bank of the River Nyamugasani between 2010 and 2021, (ii) evaluate whether growing bamboo improves soil properties relevant to soil stabilisation, and (iii) assess the perceived implications of bamboo growing on riverbank stabilisation, including the socio-economic benefits and challenges associated with this nature-based solution. A 50-meter buffer was used to represent the bank of the River Nyamugasani, in which thirteen (13) land cover classes (NFA, 2003) were examined to determine the area covered by each land cover class. Targeted sampling was used to select sites along the riverbank with bamboo and comparable control areas to evaluate the direct influence of bamboo growing on riverbank stabilisation. Field surveys were conducted, and soil samples were collected at representative locations along the river with bamboo and control areas. To study the perceived implications of bamboo growing on riverbank stabilisation, several stakeholders at national, district, and local/community levels were interviewed. The interviews were structured and open-ended and explored bamboo's benefits, challenges, community perspectives, and sustainability considerations. The study found that the historical land cover changes along the riverbank have been shown to influence the river's course and flow. The key landcover changes between 2010 and 2021 included a loss of woodland (from 229.6 ha to 36.8 ha), a significant expansion of subsistence farmland (to 307.2 ha), and a decline in wetlands (to 97.1 ha), which reduced natural river buffering and increased the risk of riverbank destabilisation. The analysis of soil properties using Kruskal-Wallis and Dunn's Test found significant differences in bulk density, sand, clay, and silt percentages between bamboo and the other vegetation types, suggesting that bamboo growing influenced soil properties positively, and it has the potential to contribute to river bank soil stabilisation. The study found that most households were aware of nature-based solutions and recognised bamboo as a viable option for riverbank management. Respondents noted positive impacts such as improved habitat quality and increased species richness. However, challenges like potential invasiveness, competition with other species, debris contamination, and riverbank destabilisation were also mentioned. The study concluded that Bamboo growing was a beneficial nature-based solution for riverbank management, with potential benefits for soil stabilisation and ecological health. The concerns raised highlighted the need for targeted interventions and support to address these issues and ensure the successful implementation of bamboo growing. The study recommends that future research focus on the sustainability of soil stabilisation over time. Policymakers are advised to consider the socio-economic characteristics of the local community when implementing bamboo growing initiatives, including providing financial incentives and technical assistance. Additionally, integrating bamboo growing with other NBS should be explored to maximise the collective benefits for riverbank stabilisation.