A year and a half after a towering retaining wall broke apart and threatened homes in the Rivermist and Hills of Rivermist communities, a different Northwest Side neighborhood is grappling with the city's longest-lingering retaining wall problem.

Six of the 14 retaining walls in the upscale Heights of Crownridge development still lack permits and construction has been on hold for some residential lots since November.

Two of the retaining walls are cracked, and one of those was deemed unsafe by an engineer and had to be lowered, according to documents on file with the city.

That wall sits on the property's southeast corner and was not built to specification. It was designed by the same engineer and built by the same construction company as the failed Rivermist wall.

Roderick Sanchez, director of the city's Planning and Development Services Department, said the city is monitoring all retaining walls and permits carefully, but that the involvement of the Rivermist team might merit extra scrutiny.

“If we were to see that same combination of builder and engineer, it's something we would look at a lot closer,” Sanchez said.

Engineer Russell Leavens, who designed both walls, declined to comment. Gravity Walls Ltd., the contractor that built the Rivermist wall and the cracked wall at Heights of Crownridge, did not return phone messages Thursday.

At its highest point, the wall was 21 feet tall.

Engineer Tim Theis inspected the wall and found a “significant vertical crack” and “slight bulging,” he wrote in a July 19 letter to neighborhood developer Brian Saathoff of Centurion American Development Group.

“It became clear that this wall was not built per the plans and it was decided that the wall height needed to be reduced for safety reasons,” Theis wrote. Saathoff said the wall was lowered 5 to 10 feet.

There are many types of retaining walls. The one that Theis inspected at Heights of Crownridge and the wall that collapsed at Rivermist were both gravity walls, which rely on their sheer weight to remain stable.

The problem with that type of wall is that inspections of the interior are difficult once the wall is completed. That problem was noted at Rivermist, and also in Theis' letter.

“Exactly how this type of stone and mortar construction occurred is nearly impossible to verify conclusively,” Theis wrote.

Another high wall that runs through the center of the subdivision has a vertical crack running along its northern portion, but the city has not received any engineering reports about the wall. Saathoff said solid rock runs behind that part of wall and it serves as more of a façade.

Scott Rozier, the owner of Rosch Co., which built the centrally located wall, said it is safe and the company stands behind its work. But he doesn't like to see the wall standing in an unfinished subdivision of bare rock and dirt. The neighborhood lacks grass and good drainage to control erosion, he said, and that's not good for retaining walls.

“There's a lot of things that aren't done that are affecting the integrity of those walls, quite frankly,” Rozier said. “There's a lot of erosion. In some spots, there are 100-foot-long gullies that go right to the retaining wall.”

After the Rivermist wall collapse Jan. 24, 2010, city officials told real estate developers across San Antonio that all retaining walls taller than 4 feet and built in the past three years had to go through a permitting process.

Most developers were able to produce original engineering documents and have engineers certify that the walls were built correctly.

But at the Heights of Crownridge, the city has flagged 33 vacant lots — about a quarter of the neighborhood — and won't allow building permits there because the homes would be adjacent to walls that lack permits.

With rockier soil and few residents, Heights of Crownridge does not appear to be a Rivermist in the making, and its walls do not pose an immediate safety concern, city officials said. The hilltop neighborhood near the Crownridge Canyon Natural Area park is sparsely populated and has only five homes built so far.

“If that whole thing collapsed, it really wouldn't hurt anything. It really wouldn't affect anybody,” said city engineer Richard Chamberlin. “But we're concerned. That's why we're holding those lots and not allowing any homes to be built near a wall where there might be a problem.”

The Heights at Crownridge is a custom-home neighborhood where prices start in the high $200,000s.

The Carrollton-based company that owns the Heights of Crownridge is not the original developer of the land, but must redo engineering work and make needed repairs — without having access to the original plans.

“The unfortunate thing is we had to do a little CSI work instead of pulling plans and saying, ‘OK here you go,'” said Saathoff.

The company has had engineers evaluate all of the retaining walls and has done drainage and erosion control work in the neighborhood. “We're doing our best to develop that site in a good way,” Saathoff said.The previous developer at Heights of Crownridge was a firm tied to real estate investor Shaul Baruch. Records show contractors filed liens for unpaid work and a bank foreclosed upon the property. One of Centurion's subsidiaries bought the land at a foreclosure auction on the steps of the Bexar County courthouse in June 2009.

The engineering work to consider wall stability isn't as straightforward as it might seem, he said. Engineers have had to consider the placement of future houses on lots and the weight of those foundations, which will put additional pressure on the walls.

Homeowner David Simmonds, who just purchased an existing home in the neighborhood, said that lingering issues with the retaining walls are not a concern as long as the developer is addressing them. He purchased for the view, and noted that the rocky terrain of the neighborhood likely means less of a chance for a Rivermist-type failure.

Sanchez believes that the market demand on the Northwest Side means a wall fix is inevitable soon. “Once this economy turns around just a little bit, that area will take off,” he said. “We're keeping an eye on it. The big hammer is that you can't sell those lots if you can't build on them. I know it's going to be fixed.”

A neighborhood by KB Home, the Woods of Alon, still lacks three retaining wall permits. But the highest of those walls is 5 feet, and a company spokeswoman said it expects to have the permit paperwork to the city next week.

Before Rivermist, local officials paid little attention to retaining walls in subdivisions. But the wall failure changed the way the city and Bexar County approach retaining wall construction, which has become more prevalent as development has pushed into the Hill Country.

The city has since added retaining wall regulations to the Unified Development Code, and requires developers to prove the walls were built to an engineer's specifications.

As part of the platting process, the county now asks for the wall's engineering design, proposed grading plan and, once it's complete, the engineer's certification.

Saathoff said the engineering and permit process has slowed the neighborhood's progress, but so has the economy. “You can't point the finger in just one direction,” he said.