CALGARY -- A flood postponed their convention in the spring -- now Conservatives are facing a deluge of political challenges as they gather in the party's heartland.

The ongoing Senate expenses scandal and allegations of a coverup at the most senior levels is expected to be a hot topic in the convention corridors, even if the upper chamber is not officially on the agenda.

The Conservative caucus and senior ranks have been wearied by the controversy. Some say they have felt broadsided by constant bursts of new information -- including embattled Sen. Mike Duffy's latest revelation that the party paid $13,500 for his legal fees. That's in addition to the $90,000 the prime minister's chief of staff secretly gave to Duffy to repay contested living expenses.

But the roller-coaster ride in Ottawa hasn't appeared to put a damper on registrations for the convention.

MPs and delegates began streaming into the city Thursday, as registration opened at a the Calgary stampede grounds -- an area that was underwater during the June floods.

Party president John Walsh says despite the change in dates due to this spring's flooding in Alberta, he predicts a record 3,000 people will attend Stephen Harper's keynote speech Friday night.

Conservatives, particularly those with roots in the Reform and Canadian Alliance parties, have been known to be keen debaters on the party's internal rules and on its policies.

Several proposals for changes to the party's constitution would put more power in the hands of the grassroots, including more oversight over the candidate nomination process.

A preliminary list of policy resolutions, to be debated in private sessions throughout the day on Friday, touched on a number of areas -- notably on labour issues.

One proposal would require federally regulated unions to report annually on how much they spend on political donations and campaigns, and allow members to opt out of those expenses. Another would declare opposition to mandatory union memberships.

Some more controversial resolutions include one condemning sex selection during pregnancy -- viewed by some as a tactic for reopening the abortion debate. There is also a motion to have the party rule out support for legalizing euthanasia or assisted suicide.

There are several motions regarding firearms, including one that would allow Canadians to own any type of firearm -- including handguns -- unless the right is removed through due process.

Walsh says members are also anxious to start focusing on the election in 2015, the kind of field work in which the party has excelled in the past.

"This is an excellent refresher for our members and our movement to get together, talk ideas and get retooled in our thinking toward that election," Walsh said in an interview.

"We pride ourselves in having the best (riding) ground organization in the country, and getting all of our key activists and volunteers in one place for discussions, for training, for resources...is extremely important for us as we gear up."