Assessment of Surface Storage Requirement for Mitigating Drought

This chapter analyzes the duration and severity of past drought events in two ephemeral Sonar and Bearma river basins using the monthly truncation approach, investigates the availability of flow during normal and drought years, and provides an approximate estimate of the artificial surface storage for drought proofing. To estimate drought duration and severity from intensity for a known truncation level, one needs to describe the drought for ephemeral river basins running dry in lean seasons and leading to zero value of the truncation level. If a drought occurs in the rainy season and continues to the dry season with a zero truncation level, the drought duration increases without altering the deficit volume. To assess the storage requirement for drought proofing, an artificial reservoir of an appropriate capacity is assumed to exist at the outlet of the basin to augment the deficit during droughts.