Reservoir sustainability indexing/estimation is introduced in this paper. capable of handling sparse data. It innovates by interconnecting a set of three variables: estimating Environmental Water Requirements (EWRs) by conceptual rules; estimating Reliability. Resilience and Vulnerability (RRV) criteria by using EWRs; and thereby calculating Sustainability Indexes (SI). https://themightyhobbyers.shop/product-category/lanyard/