Why are there two separate umpire associations?

I would love to work games with the younger kids and umpires periodically.  I suspect the season is winding down, it may in fact be all done.
But I was surprised to find out that Calgary Minor is a separate entity from Calgary Women's Fast pitch (Calgary Softball Umpires Association).
This may explain why I am only scheduled for games for Industrial and/or at Shouldice.
How does this work and why are we split into two groups?

This is a great question, thanks for asking it.  There are no secrets to be kept here.  Although there are two organizations, both work closely with each other and some umpires do games for both Associations

CMSUA: Mandate is to cover games primarily for Calgary Minor Softball Association - Only Fastball
CSUA: Covers all non-minor ball, including Slow-Pitch and Fastball

The reason CSUA and CMSUA exist separately is to make sure that there is proper coverage of umpires for the leagues they are responsible for.

Slow-Pitch is a relatively new sport compared to Fastball.  Years ago, Fastball was huge (Men's more than Women's), and there wasn’t enough diamonds for all the teams.  Eventually all these players who loved Fastball realized they were too old for the sport, but still wanted to play ball.  This brought into place an alternate set of rules called "Slow-Pitch" which focused more on the casual adult player.

Slow-Pitch grew significantly over time, and many players from Fastball moved to Slow-Pitch.  There are now more Slow-Pitch team/leagues than Fastball.

Slow-Pitch is not the best game for kids to start playing (for various reasons which I will not cover here).  In order to keep the Softball sport alive, a group of umpires noticed that without a focus on Minor Softball, there would be no new players entering the sport.  This is also compounded by the fact that there aren't enough overall umpires.  CSUA cannot cover all ball that has been requested; there are Slow-Pitch leagues that have been turned away.

CMSUA (and Edmonton's equivalent "The Blue Crew") were founded to make sure that the sport of Slow-Pitch didn't take away from the important youth teams.  The members of these organizations have chosen to have Minor Softball as their priority.

Bottom line: After each Association has covered their primary responsibilities, their Assignor's have no problem sharing umpires between each organization.  If you are interested in doing more ball, contact your Assignor or Executive and ask to be put in contact with the other Association's Assignor.