Water and Sediment Quantity and Quality Generated in Check Dams as a Nature-Based Solutions (NbS)

Abstract

The study evaluates the implementation of check dams as nature-based solutions to address soil erosion, improve sediment quality, and enhance water retention in the Urku Huayku ravine, located on the Ilaló volcano in Ecuador. Weekly water and sediment samples were analysed from 2021 to 2023. Critical parameters measured include pH, electrical conductivity, nutrient concentrations, and organic matter content. Macroinvertebrates were collected to assess biodiversity changes using the Andean Biotic Index (ABI) and the Shannon Diversity Index. Results show significant improvements: water quality remained neutral (average pH 7.06), while sediment organic matter increased from 0.2% in 2021 to 3.2% in 2023. Additionally, biodiversity improved, with a 355.6% increase in macroinvertebrate abundance. Statistical tests confirmed the positive impact of check dams on sediment and water quality. The study also identified potential areas for additional check dam installations using QGIS analysis, emphasising steep slopes as ideal locations. This study demonstrates the efficacy of check dams in the restoration of degraded ecosystems and underscores their pivotal role in climate change mitigation. Through the enhanced storage of sediment organic matter, check dams facilitated the capture of approximately 58% of carbon. Additionally, they contributed to improved biodiversity. Further research is recommended to optimise dam placement and explore additional biodiversity indicators in Andes Mountain water bodies over 3000 m above sea level.