The high waterton flow is a release from Cheeseman (outflow > inflow). Cheeseman is nearly full, so they are probably releasing to accommodate runoff. It's hard to say whether the water will be stored in Chatfield, which has about 10k af free, or passed through. If it's passed through, Union would run in the fun level within the next week. Strontia is negligible from a storage perspective. It's really just a forebay for Denver Water (pisses me off that they ruined such a nice canyon for a "forebay."
Yes, waterton will be high again tomorrow, not like it's better or worse at high water, just different.