Water hyacinths: Use them or lose them? A holistic approach to a multi-faceted problem

Lakes in tropical regions around the world suffer from the infestation of water hyacinth. Its proliferation is attributable to the influx of nutrient-rich waters, as rivers feeding the lakes are polluted with wastewater and run-off of fertilizer and manure from surrounding agricultural fields and husbandry within the catchment. The weed clogs waterways and intakes and affects aquatic life, water availability, transportation, fishing, irrigation, and tourism. Water hyacinth infestation has implications for human health, as it may facilitate the spread of water-related diseases. While water hyacinth may pose health risks, they have the potential to benefit human livelihoods when exploited for wastewater treatment, as fertilizer, for biofuel production or, when made into handicrafts, as a source of income.

A sustainable solution to these issues tackles both water quality deterioration and water hyacinth infestation, and “uses” water hyacinth instead of only attempting to “lose” them. We present a research project that identifies such solutions, applicable and appropriate within the local and cultural context of our study region, Lake Chivero, the main source of drinking water to Harare. The project consists of three main pillars: (1) performing systematic studies of causes and effects of water hyacinth spread based on satellite and empirical data; (2) scientifically investigating water hyacinth exploitation methods, and (3) engaging with stakeholders to co-develop strategies to address the challenges of water quality and water hyacinth. The project’s impacts will be a more healthy and resilient lake ecosystem, improved wellbeing of people depending on the lake, and more resilient communities at Lake Chivero and other lakes in Sub-Saharan Africa. It will thereby contribute to the achievement of the United Nations Sustainable Development Goals (SDG) related to health (SDG 3), drinking water (SDG 6), and sustainable communities (SDG 11). Moreover, the project is in line with the South African National Development Plan 2030 and the African Union Agenda 2063.