EFFECTIVENESS OF ECOSYSTEM-BASED ADAPTATION STRATEGIES FOR FLOOD MITIGATION IN LAKE NAIVASHA CATCHMENT, KENYA

Abstract

Several factors are affecting the hydrological cycles but human activities have played a major role in the experienced hydrological changes. Some human activities such as agriculture and industrialization have contributed to the change in the water balance through the extraction of water, construction of impoundments and climate change factors. Some of the methods used to mitigate floods in Kenya include the; establishment of early warning systems, establishment and improvement of infrastructure such as flood-resistant roads and bridges in affected areas, and community-driven initiatives such as the participatory mapping of flood-prone areas. Therefore, the main objective was to determine the effectiveness of ecosystem-based adaptation strategies for flood mitigation in Lake Naivasha catchment, Kenya. Based on the Socio-Ecological Systems (SES) Theory, this study has incorporated a multi-faceted design of field surveys, observations, and stakeholder interviews to meet the following specific objectives; to assess the severity of flood occurrence, to determine ecosystem-based adaptation strategies, and to examine the effectiveness of existing ecosystem-based adaptation strategies for flood mitigation in the lake Naivasha catchment. With a target population of 29,190, a sample size of n=395 comprising of stakeholders in different areas including fishermen, farmers, tour guides, and tourists and other residents was identified randomly and helped to collect data to determine the existing Ecosystem-based adaptation (EBA) strategies for mitigating floods in the catchment. The study employed a descriptive correlational method comprising of combined quantitative and qualitative approaches to comprehensively assess severity of floods in the Lake Naivasha catchment, identify the existing EBA strategies in the catchment and understand their effectiveness in mitigating floods in the catchment. Primary data was collected through structured questionnaires, key informant interviews, and focus group discussions. Descriptive analysis was used and this included a chi-square test used to analyze categorical variables to examine any significant differences between occupation and awareness of ecosystem-based strategies among participants. The findings of this study indicated that EBA strategies such as agroforestry and afforestation were the highly adopted non-structural strategies while soil conservation terraces and rain-water harvesting techniques were the highly adopted structural strategies and were highly effective in mitigating the floods hence combating the impacts of climate change (Sustainable Development Goal 13) such as flood risks, improving water quality and enhancing community resilience in Lake Naivasha catchment. From the study, 77.75% of the participants reported that they had experienced observable positive changes in flood occurrence with most of the residents (81.87%) who use afforestation and agroforestry claiming to have observed a reduction in floods occurrence in the catchment. The study revealed that afforestation and agroforestry were the most widely adopted non-structural EBA strategies, driven by their co-benefits and government support, while mulching and cover cropping were the least adopted due to a lack of knowledge about their application methods. The study recommends that more research should be done to understand other flood mitigation measures to help reduce the impacts of severe floods in the catchment, awareness creation among more community members regarding EBA strategies, their effectiveness in flood mitigation and how the community members can participate at the individual and community levels in adopting these strategies.