Muli Raphael Wambua.2025-07-012025-07-012020-0210.4018/IJESGT.2020010102http://41.89.96.81:4000/handle/123456789/1892enDevelopment of a Non-Linear Integrated Drought Index (NDI) for Managing Drought and Water Resources Forecasting in the Upper Tana River Basin-KenyaArticle