As of 1pm the day after the election Initiated Ordinance 300 is behind by just 43 votes. This is out of 79,175 for and 79,218 against. With more than 6,000 undervotes and 21 overvotes (Source: DenverGov) a recount seems incredibly likely.
With four other tax increases on the ballot this effort may have just been one too many for Denver voters. Also, opponents raised the issue of if this should be a function of city government. Though language was submitted to the blue book to oppose this measure there was no organized campaign against it other than statements made by the usual suspects.
The rest of the Denver tax increases, 2A, 301, 302, and 7G passed by wide to significant margins.
Parks – 61.44% yes
Mental Health – 68.11% yes
Childhood Healthy Meals – 57.42% yes
Flood Control – 60.04% yes (Denver alone)
Flood Control – 55.35% yes (source: Denver Post)