Usually, when more people show up for your party than you were expecting, it is a good thing. More tickets to your show, more hits on your YouTube posting, more books sold on Amazon, more is good.

But in the case of new enrollment in the Falls Church City Schools, up by a whopping 6.34 percent between the last day of classes in June and the first day of classes last week, was met with more like a deep breath, a tight-lipped smile and another hard look at plans for current future capital improvement needs in the system.

Yes, enrollment growth was considered unprecedented when it hit 4.5 percent each of the previous two years, and the school system’s official consultants were proved way off the mark in projecting growth this fall.

Of course, we should all feel quite flattered and rewarded for success by this desire of so many young families to coming piling into the City of Falls Church to avail themselves of our school system. It’s getting to look a little like a stampede, like Thanksgiving-night department store sales.

Many residents, fearing high taxes, grumble that the City should be taking measures to deter this kind of population growth, saying the cost of educating new kids is more costly than any taxes that they might pay. But that is not necessarily the case, at all. Families occupying the City’s growing number of dense mixed-use rental and condo projects actually wind up paying more to the City than it costs to educate their children.

Then there are the intangible benefits, too. Youth and vigor is always a good thing, making older people feel younger and fuller of pep. Then there are all the collateral dollars that these new residents bring with them to spend near where they now live. All the money that is spent in restaurants, retailers and services nearby boost the overall well-being and tax paying capabilities of the City’s business community.

There will be a very vigorous debate both among City Hall and School Board circles this fall over how to meet the challenges of such growth in terms of city and school facilities – new buildings, bigger buildings, improved civic infrastructure. The City’s got a lot of borrowing capacity right now, and with interest rates still very low, the challenge will be to move with due expediency.

But on the other hand, this month’s enrollment growth may compel some who are planning such things to reconsider how to build with an eye to the possible new reality this represents. With one new mixed use project almost complete, and two more approved for construction this year, it will be hard to deny that 6 percent annual growth in school enrollment, and in the population overall, has become the “new normal.”

Project that out over the next two decades (what one must do minimally when building a new structure), and what Falls Church’s new look may entail might surprise you.