The Water Apportionment Accord (WAA) of Pakistan was instituted in 1991 to allocate Indus River water among Pakistan’s provinces. This paper assesses the performance of the WAA in terms of the accord’s ability to meet the barrages’ and environmental demands in the Lower Indus Basin. Use of metrics as assessment tools in water security and climate adaptation is an important field, with the potential to inform sustainable management policy. Reliability, resiliency, and vulnerability are used as indicators to define the system’s performance against supply. The results indicate from the pre-Accord period to the post-Accord period, the reliability of Guddu Barrage (the upstream-most barrage in the study) is not changed. However, at Sukkur and Kotri, the most downstream barrage in the study, reliability has significantly decreased. The Results reveal the high vulnerability of the Indus delta in Rabi season when the flows decline and the majority of the water at the Kotri Barrage is diverted.
