SSV is all natural, no Dam, There is a left hand diversion that removes water during run off that lowers the cfs flowing into the SSV.
SSV is calculated Saint Vrain in town minus NSV below buttonrock
I don't even think (could be wrong) that eddyflower takes out the stuff removed from Left Hand diversion. So if that is true then the flow shown for SSV on eddyflower is typically lower than shown and you can go to the website below to figure out true flow.
Here's all the info you could want about these drainages actual flows.
This will not give you info about October hole though.