When it comes to the goals, it’s hard to find an issue with as little controversy as waterfront zoning in Portland.

Everyone says they want to preserve a vibrant working waterfront. Everyone agrees that property owners should be able to get a fair return on their investments. And most people believe that more flexibility for the kind of development allowed in the waterfront zone could further both goals.

Where things get sticky, however, is defining exactly how to allow that flexibility without driving out the water-dependent businesses that can’t operate anywhere else and replacing them with offices, restaurants or shops that could thrive anywhere in the city.

The City Council has made the latest attempt to strike the right balance, and while the councilors have voiced the right goals, it remains to be seen whether they have given themselves the tools to accomplish them.

Success for this venture will be measured in years, and will rest on the city’s ability to monitor and enforce the agreements of the waterfront property owners to meet their goals of increasing non-marine development while investing in marine infrastructure — all without displacing fishermen and the supporting businesses that make up the working waterfront.

First remember what’s at stake here: Because of its access to deep water and its history as a seaport, Portland’s waterfront is a scarce resource. Nature is not making anymore harbors like this one anytime soon, and modern environmental laws would make it very difficult to engineer one. What is lost in Portland would likely be lost for good.

And while commercial fishing has declined from its peak in the 1980s, the industry, especially the lobster fishery, is a solid job producer for the local economy. The sights, sounds and even smells of the working waterfront are an attraction for tourists who come to the city to experience something that they can’t get at home. An added challenge for planners and the property owners is that it’s impossible to know what the future holds for commercial fishing and how to leave a place for the working waterfront to expand if there is an opportunity.

The danger, if the city gets this wrong, is that what we see now on Commercial Street will be replaced with a sterile office and restaurant district, permanently crowding out the kinds of activity that Portland is known for.

With the stakes so high, we would have preferred seeing this ordinance pass with some of the amendments designed to protect against displacement of water-dependent uses that were proposed but not accepted by the council. What has been passed puts a heavy burden on the city, both its elected officials and its planning staff, to make sure that the owners are doing what they’ve said that they would.

For instance, it will be up to the city to make sure that developers are meeting the requirement to invest a portion of their non-marine- use revenue in waterfront infrastructure.

It’s also important to remember that not all the interested parties have spoken. In addition to the city, the state has a regulatory role here and the Department of Environmental Protection has to sign off on any new rules within the shoreland zone. It will consider input from other state agencies, including the Department of Marine Resources, which has an interest in preserving the fishing industry.

The DEP has 45 days to issue an opinion on the zoning — a time period that coincides with a change in administration in Augusta — and there is no way to know what effect, if any, that will have on Portland.

It will be some time before we know the consequences of this week’s council vote. But with so much at risk, no one should stop trying to achieve the goal of preserving the working waterfront that so many people share.