It’s good fiscal planning, when tax collections are high, to set aside money for a rainy day, when there might not be enough to cover even the essential needs. And although Honolulu lacks the crystal ball that would forecast the dire circumstances of that rainy day, there are a few looming needs that the city can already anticipate.

Some of them — the unfunded liabilities for retirees’ health coverage and debts — were part of the landscape described by city Managing Director Roy Amemiya when he presented the city administration budget on Monday for Mayor Kirk Caldwell, who was traveling.

Amemiya said one reason to keep spending in check is the spike in debt service payments. But what should be clear is that completing the Honolulu rail project, currently facing cost overruns, also could affect the city budget in the not-too-distant future.

Given that prospect, it is a rational decision to apply a measure of austerity to municipal spending, to create some wiggle room for the time when the economy cycles downward, as it always does. The challenge for the administration, and the City Council members who review Caldwell’s plan, is to ensure that too many corners aren’t cut, producing more catch-up work in operations and maintenance downstream.

Amemiya underscored that the $210 million in federal funds Honolulu has supporting its bus system would remain for its dedicated purpose. These are funds that federal transportation authorities required as fallback revenues in the rail financial plan, so if they’re being sequestered, some other source to fill the rail funding gaps will have to be secured.

It’s not likely Honolulu would be able to squirrel away the entire deficit, projected at up to $910 million, so there’s sure to be more borrowing in the project’s future. And paying down debts and liabilities, as Caldwell proposes to do, would bolster the city’s bond rating to improve the terms of such a loan.

For example, it’s a smart move to make progress in paying more toward the health-fund liabilities than the minimum, when that’s possible — again, to reduce debt of the game while the budget allows for it.

Here’s why: Rating agencies take notice of liabilities such as retiree benefits, because their skyrocketing costs are seen as a burden on the $3.7 trillion municipal bond market.

They have been cited as factors in downgrades. In fact, rating agencies have recently cited growing unfunded liabilities in their bond rating downgrades and have precipitated bankruptcy filings in fiscally troubled cities across the country. Honolulu obviously needs to avoid becoming one more junk-bond statistic.

The outlines of the spending plan seem generally solid. Honolulu reaped the advantage of a $141 million "carry over" balance from the last fiscal year; a repeat appearance of such a windfall can’t be counted on.

In addition, the creation of the Residential A property-tax class seems to be yielding benefits. About 1,000 more properties were moved into this higher tax bracket, adding $8 million to the current $79 million in total revenues for the class.

A few other points:

» There are no plans for a bump in property tax rates. Of course, this is a relief, given that rising property values have made Oahu’s homeowners jittery about the tax bill they’ll face.

» The parks budget has increased $5 million, to $72 million total; at least that’s treading water. Even so, it’s not what the island’s overused parks really need, so expect to hear more about community involvement.

» The increase in funding for homelessness programs and an $18 million allotment for affordable housing are encouraging signs of commitment. But Council members do need to pore over administration priorities shown in its reduced $494 million capital improvements plan.

On the whole, the proposal represents a reasoned starting point on the path to a final budget that should restrain impact on the public purse and armor the city for future obligations it can anticipate, as well as something that appears like a bolt from the blue.