The graph normally used to ascertain the value of the Underlying is not functioning, which has a material impact on its reliability. Thus, the Underlying for this market is the data series which can be accessed by following this link: https://waterdata.usgs.gov/monitoring-location/01376520/#parameterCode=00045&period=P7D. To reach the Underlying, click “retrieve data”, select “Current time-series data”, and then click “retrieve”.