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causes the PMF; (b) improved hydrometeorological monitoring, which yields better information about likely weather and water conditions; (c) improved watershed rainfall-runoff-routing model capabilities, including capabilities to describe watershed properties that influence runoff at greater resolution and with increased accuracy; and (d) changed atmospheric, hydrologic, hydraulic, or operational conditions. Following the 2017 incident, the pace of PMF re-analysis was accelerated. Activities included: 1. Developing a new watershed precipitation-runoff-routing model. In addition to commonly expected features, this model included snow accumulation and melt. The USACE HEC-HMS software application was used for this analysis [9]. 2. Calibrating the model with historical events, including events with snow accumulation and melt. Lake Oroville’s contributing watershed (the Feather River Basin) permits this, as it is well gauged with stream gauges, rainfall gauges, temperature, wind, and radiation sensors, and snow courses. 3. Selecting final model parameters for analysis of extreme events. 4. Verifying the model using data from precipitation events in addition to those selected for calibration. 5. Updating estimates of the PMP, using guidance from the NWS and DSOD. For this analysis, precipitation boundary conditions were defined by scaling observed storms to have PMP flood volumes. 6. Selecting appropriate initial snowpack and other conditions for application of the PMP storms to the HEC-HMS model. 7. Applying the model to compute PMF inflows. 8. Routing PMF inflows through the reservoir to determine maximum pool elevations and outflows. This was accomplished using the HEC-ResSim software application developed for and used in the reservoir operation analysis described above. Findings of the PMF study were as follows: 1. The adopted updated PMF inflow hydrograph has a peak flow equal to 21189 m3/s (743,800 ft3/s) and a volume of 3.8 billion m3 (3.1 million acre-feet). 2. Routing the adopted PMF inflow hydrograph with the as-built configuration of the dam and outlets yielded a maximum reservoir pool elevation equal to 280.1 m (919.1 ft) (NGVD29). This maximum reservoir pool does not spill over the dam (crest elevation 281.0 m [922.0 ft]). 3. With the adopted PMF inflow and gate operations, the peak outflow totals 20419 m3/s (721,100 ft3/s). 4. Wind wave setup and runup potential is great — up to 2.0 m (6.7 ft). However, the winds required to produce this extreme event are not likely to occur during large winter storms such as the PMF. 132