Rain increases landslide threat along Shoal Creek

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– Every time it rains, the City of Austin has to take steps to prevent a landslide along Shoal Creek from becoming worse.

“We have floods and we have droughts and we know how to deal with those, essentially. This is something new and outside there,” said Mike Kelly, managing engineer with the City of Austin Watershed Protection Department. 

The Watershed Protection Department is still working on a plan to secure the landslide that affects four homes just above Shoal Creek. They hope to reach an agreement Friday. 

“We have seen a new crack develop that’s about 8-10 feet back from the original face of the slope that was exposed almost a year ago and, so, that’s concerning because it means that more is fixing to fall down,” Kelly said. 

City engineers are planning to use walls, soil anchors and nails to stop the dirt and rock from shifting any further, but first they need to work out a legal agreement for the cost and access rights from property owners who live along the edge. Options currently on the table will cost $8-16 million.

“The problem doesn’t care about the property boundaries,” said Kelly. “The solution will require all the property owners to work together.”

Until the slope is fully secured, the city hopes posted signs encourage people to keep their distance. 

“We appreciate people using their best judgement not to go on that area, because we have seen it move, and the worst case scenario is that if it moves and somebody’s on or near it, that it could cover a person and that would be a true tragedy,” Kelly said.  

When heavy rain falls in the area, that threat increases. That is why the city places sandbags in front of affected homes in Pemberton Heights.

“It’s to prevent more water from going on that slope, which can be a big factor in additional slides,” said Kelly.  

A federal study shows Austin weather could turn that into an uphill battle. The National Oceanic and Atmospheric Administration found the city is 30 percent more likely to get rainfall than previously thought. 

“More rainfall on the ground means floodplains get bigger,” said Kevin Shunk, flood plain administrator with the City of Austin. “When floodplains get bigger, that means more buildings, more homes, more roads are all going to be at flood risk.”

In fact, the city says 3,600 buildings will likely be added to the 100-year flood plain. That could impact insurance costs, development and even property values.

“We’re recommending some changes to the land development code, we’re recommending some changes to the design criteria manual, and then we’re restudying all the floodplains in the entire City of Austin,” Shunk said.