A San Rafael developer has filed a preliminary application to construct a five-story residential building in unincorporated Mill Valley.

The project at 258 and 260 Redwood Highway Frontage Road would include 43 apartments and a 54-room residential care center. Under state law, the care center would count as a single dwelling because it would have a shared kitchen.

“The market really would welcome this project for seniors,” said the developer, Jack Krystal.

Amy Kalish, chair of the Tamalpais Design Review Board, called the proposal “baffling,” given the risk of flooding in the area.

Krystal purchased the land just south of the Richardson Bay Bridge from the Gulf Oil Co. in the early 1970s. He has proposed numerous projects for the site, all rejected by the county.In 1977, Krystal proposed building a 12-story, 300-room hotel on the site. By 2018, he had scaled the project back to a three-story, 33,701-square-foot hotel, a 2,625-square-foot spa and 3,775 square feet of commercial space. That proposal also went nowhere.

This time could be different. A flurry of new state laws over the last several years have stripped local jurisdictions of their authority to deny or even substantially amend housing projects.

Because the 2.2-acre site is included among the 148 zoned for development in the county’s housing element, the project’s approval would be ministerial. That means it would not be subject to the California Environmental Quality Act or denial by local elected bodies.

The county’s housing element zoned the property for 36 dwellings, but Krystal’s application says he plans to invoke a state housing density bonus law that he says will entitle him to 11 bonus apartments.

To take advantage of the law and build more residences than permitted by local zoning, developers must include a certain percentage of affordable dwellings in their projects. The more affordable residences they provide, the more bonus residences they receive.

The application says Krystal will include three apartments priced to be affordable to households at 50% of the area median income, two at 80% and two at 120%. For a three-person household, that would mean annual income of $88,150, $141,000 and $201,550, respectively.

The remaining apartments would be priced at the market rate. All 43 apartments would have one bedroom.

Krystal’s application says the proposed building site adjacent to Richardson Bay is in an area designated as a flood zone by the Federal Emergency Management Agency.

“This property is not just in the flood zone,” Kalish said. “The parcel is shown on a recently released Bay Area 2100 projected sea-level rise map as completely underwater in the next 25 years.”

“Five stories at that location, when the area is already frequently underwater and impassable — the whole freeway exit can be closed due to tidal flooding — is misguided,” she said.

Kalish said the plan to locate 90 parking spaces in an underground parking structure that will be designed to be floodproof seems “bizarre.”

Krystal said he sees no problem with the plan.

“You just build it high enough,” he said, “and then you have sliding automatic gates and sump pumps underneath so the water will be kept out.”

Krystal’s application says he also intends to use density bonus waivers to avoid complying with the county’s form-based code. Adherence to the code, which consists of objective building standards such as the height and setbacks, is required under ministerial review.

Nevertheless, under density bonus law, developers can be awarded concessions and waivers exempting them from complying even with form-based codes, if they demonstrate the exceptions are necessary to make their projects feasible.

Krystal’s application said he will seek waivers from the county’s form-based code related to the size and mass of the building.

Marin County’s form-based code limits buildings to four stories and 50 feet in height. Krystal’s five-story building would be 65 feet tall.

Krystal also proposes to build adjacent wind turbines that would exceed the height of the building.

The code also sets a limit of 24 apartments per building.

The application states that Krystal will seek a waiver of a general plan requirement for a 100-foot setback from the Richardson Bay wetlands. His proposal calls for a 50-foot setback.

Krystal also plans to seek a concession to allow him to locate the 54-room residential care center on the first and second floors of the building.

Krystal said he also owns about 15 acres of land below Richardson Bay, often referred to as “underwater streets.” The state originally sold the tidelands to private investors in the 1870s, and the buyers had a map drawn up showing future streets and lots. An aborted plan called for filling in the entire bay to create a sort of West Coast Venice with canals.

The plans Krystal submitted to the county with the preliminary application call for installing oyster beds among the underwater streets northeast of the building site.

“The local residents way back when used to feed themselves with oysters that grew in that area,” Krystal said. “This would be a next step.”