Even during a prolonged drought, the threat of flooding rarely strays far from the minds of residents around the fickle San Francisquito Creek, which 16 years ago washed over several Palo Alto, Menlo Park and East Palo Alto neighborhoods and inflicted about $28 million in damage.

On Wednesday, more than 100 residents who live near the most flood-prone bridge learned that help is finally on the way. Officials from the San Francisquito Creek Joint Powers Authority and the Santa Clara Valley Water District unveiled two possible alternatives for rebuilding the Pope-Chaucer Street Bridge, which has the lowest water capacity of all the bridges crossing the creek between Palo Alto and Menlo Park. If things go as planned, upgrades could begin as early as next summer.

For residents in the most vulnerable neighborhoods, including Crescent Park and Duveneck/St. Francis in Palo Alto and Willow Oaks in Menlo Park, the help can't come soon enough.

Numerous residents at Wednesday's meeting at the East Palo Alto Academy in Menlo Park cited the damage their homes suffered in February 1998, when they were pummeled by the largest flood on record and water topped over the creek.

Either of the alternatives unveiled this week would protect the area from floods of this sort, though both would fall short of the type of protection required to accommodate a "100-year flood," which by definition has a 1 percent chance of occurring during any given year.

One option would raise the bridge and portions of streets leading up to the bridge by 4 feet, a design that would increase water capacity but would also require the construction of retaining walls in front of four corner properties near the bridge to accommodate the grading.

The other option would leave the bridge at its current grade and avoid the retaining walls, but would require higher floodwalls than the raised-bridge alternative.

Kevin Sibley, civil engineer with the Santa Clara Valley Water District, called the "raised bridge" alternative the "standard engineer design."

The water district is the main funding source for the Pope-Chaucer project, with most of the money coming from Measure B, a bond measure voters passed in 2012. Sibley said this design would raise both the bridge and portions of Palo Alto Avenue and Woodland Avenue.

At first, this design would require infill under the bridge to make sure water does not exceed the capacity downstream, particularly in the most vulnerable area between U.S. 101 and the San Franciso Bay. As the creek authority completes other pending projects to boost flood protection in the downstream area, the infill would be removed, substantially widening the channel under the Pope-Chaucer Bridge.

Another long-term improvement would be construction of flood walls, ranging from 2 to 6 feet (the height varies because of the shifting road alignment). Once all these improvements are in place, the bridge would be able to withstand a 100-year flood and the residents around the bridge would no longer be required to purchase federal flood insurance.

The big drawback for this design, he said, would be the retaining walls in front of the four corner properties. Because of this impact, Sibley said, the water district is also considering an "at-grade alternative" that would rebuild the bridge at a slightly higher elevation than exists now. Because this would not provide the same level of flood protection as a raised bridge, it would ultimately require officials to build higher flood walls than in the "raised bridge" alternative. Here, they would have to be about 7 feet tall to achieve protection from a 100-year flood.

The creek authority, which includes elected officials from Palo Alto, Menlo Park, East Palo Alto and the water districts from Santa Clara and San Mateo counties, is also looking at rebuilding the Newll Street bridge between Palo Alto and East Palo Alto and, ultimately, the bridges at Middlefield Road and University Avenue.

Unlike last year's meeting on the Newell Street bridge, which attracted widespread criticism and a wide range of opinions about the design of the new bridge, the public hearing on the Pope-Chaucer bridge was a relatively subdued affair despite a standing-room-only crowd.

Most people welcomed the fact that something is finally getting done, though a few asked questions about the project's impact on trees and area aesthetics.

There was no heckling or jeering and the only comment that drew applause was Menlo Park resident Robert Filman's question about whether officials had considered getting rid of the bridge altogether (they did, before determining that traffic impacts would be substantial).

For Nancy Rjork, the big question was: Which alternative would provide the best flood control in the near term?

"What we want is to get the most water out of that thing as fast as possible and not count on the second part," said Rjork, a Palo Alto resident who said she suffered more than $100,000 in property damage during the 1998 flood.

Len Materman, executive director of the creek authority, called the reconstruction of the Pope-Chaucer Bridge "an important part of the solution for addressing the flooding problem" in the region.

The authority, he said, plans to spend much of 2014 determining the sequence of its many ongoing flood-control projects to make sure any individual projects don't end up pushing the flood problems to other parts of the watershed.

Currently, Materman said, the creek authority has the funding to perform the flood-control work between the Bay and U.S. 101 and to widen channels and rebuild numerous bridges, including the Pope-Chaucer Bridge.

Other measures that would be necessary to provide 100-year-flood protection -- including flood walls near the Pope-Chaucer Bridge – would need to rely on future funding sources. The creek authority, he said, is now evaluating possible tax measures that it can send to the voters in 2016 or 2017 to pay for these improvements.

"Our goal is to get out of the flood-insurance program," Materman said, noting that the requirement for flood insurance is costing the properties around the creek an average of $1,300 annually.

"We might have to phase that so that while we're doing other pieces -- widening other channels and the Newell Road bridge -- we don't impart risk on someone else over that process," Materman said.

Officials from the water district and the creek authority plan to hold another meeting on Jan. 29 to solicit more input about the design of the new Pope-Chaucer Bridge. If all goes as planned, Materman said, all the the environmental analyses will be completed by May 2015, paving the way for construction to begin. Barring unforeseen complications, it would take about a year to reconstruct the bridge, he said.