Arlington studies helping property owners with creek erosion issues

If your property backs up to a creek, you likely own it, at least to the center of the creek bed. The homeowner behind you owns the other half.

And the city owns none of it. That becomes important when the steady or sudden erosion of a creek bank begins threatening a fence, or a shed, or a home.

According to a city policy on the books at least since 1993, the city, while acknowledging its responsibility for protecting against flooding, does not repair erosion problems on private property, even those caused by flooding.

“If it’s your own property, you have to be a responsible property owner and take care of what you’ve purchased,” said Councilman Charlie Parker, who recently spent $37,000 to shore up an advancing creek bank with a 12-foot-tall stone-and-mortar wall on his property.

But some of his colleagues, especially after the torrential rains and flooding in May and early June, and a deluge of complaints about clogged creeks and battered banks, said they wanted to explore options. They asked a council subcommittee and the city’s storm-water management staff, which has several watershed studies underway, to look into erosion problems citywide and run cost estimates.

“That kind of brought it to a head,” Mayor Jeff Williams said. “Some of these erosion problems are so big they’re too much for one property owner to take care of.”

The staff continues to prepare for a likely meeting with the council in early January, but the preliminary numbers on just two creeks, presented to the council in October, were astounding.

Repairing all identified trouble spots along a combined 50 miles of Rush Creek — out of a total 141 miles of natural streams in the city — would cost about $268 million. The “highly unstable” sites, which cost roughly $11 million per mile to repair, accounted for $39 million and 3.5 miles of those totals. An additional 22 miles of “moderately unstable” creek banks, which cost about $7 million per mile to repair, accounted for $154 million.

Johnson Creek has 2.8 miles of highly unstable erosion sites that would cost $31 million, 2.6 miles of moderately unstable sites at a cost of $18 million and 0.6 mile of moderately stable sites at $2 million, a total of $51 million.

Those cost projections come with a caution: They could be as unstable as some of those creek banks. Mandy Clark, manager of the city’s storm-water engineering operations, said the figures “were intended as a starting point for council discussion.” She’s worried about people getting their hopes up for a solution that could be years away — or too costly to do at all.

“The only thing I’m sure of,” Clark told the council’s Community and Neighborhood Development Committee on Oct. 27, “is that these numbers aren’t right.”

Clark’s field crews have had plenty to work on outside of the erosion issue, especially since the almost daily spring rains caused massive flooding that overwhelmed the city’s drainage system and exposed its weaknesses.

“We’re very proud of what we’ve done in our flood-mitigation projects,” Clark said. “At a cost of $59 million since 2009, we have alleviated 358 flooding problems.”

Several were completed in the past year, including improvements to the adjacent Willow Bend and Thousand Oaks subdivisions, at Kelly Elliott Road and Interstate 20, where 22 homes had flooded.

“We increased the storm drain capacity,” Clark said. “We also teamed with our street engineering group and our water department to install new water and sanitary sewer lines and repave the roadways all at one time.”

Another current major repair is along Lennox Lane, where erosion along south Fish Creek had crept from 76 feet away from the road in 1997 to washing out the ground under a sidewalk along the road this year.

The city has 13 flood-mitigation projects in design, three in construction and 40 drainage projects slated for funding.

The erosion reports are part of six consultants’ studies of the city’s 10 watersheds, evaluating water flow within the creeks, flooding problem areas and potential repairs for flood control and stabilizing streams.

The studies gather information that, in part, helps the Federal Emergency Management Agency update its flood plain maps of the Arlington area and its flood insurance rates.

The city has current contracts for four of the six studies for a total $4.73 million. The remaining two studies will start in the next three years, Clark said.

The first study focused on Fish Creek and Cottonwood Creek, a joint project with Grand Prairie using a FEMA grant, completed in 2010. Seven flood-mitigation projects came out of that study. Two of the projects are under construction, and a third is in design.

The Rush Creek study started in 2010 after its watershed took a lashing from Tropical Storm Hermine, causing heavy flooding that threatened homes and infrastructure. The study is nearing completion and will be submitted to FEMA in early 2016.

The newest study began this year and includes all of Lower Village Creek and major Trinity River tributaries in north Arlington.

Studies still to come are scheduled for Upper Village Creek, adjacent to Lake Arlington’s east shore, and the remaining Trinity tributaries in 2017. Then Lynn Creek, Bowman Branch and Walnut Creek in far south Arlington will be evaluated in 2018.

The studies and the repairs are funded from a monthly $5.25 storm-water utility fee on residential water bills; commercial bills are calculated based on buildings, parking lots and other water-impervious surfaces. The residential fee will increase by 50 cents a year until it tops out at $7.50 in 2021.

Clark said the total utility fee revenue will be about $14 million for 2016, which includes operations, debt service and flood-control projects. Funds for flood-control projects are limited, let alone for erosion projects.

Currently, the only way a private property owner’s erosion problem improves is as a byproduct of a larger project to protect city bridges, roads and other public infrastructure, Clark said.

Williams said he and some council members are talking about possibly creating a special fund to which private property owners could apply for assistance if they meet certain criteria. Neither the criteria nor the funding source has been determined.

But Williams said the financial assistance could be weighted toward “erosion that could be getting to multiple homes, or to businesses.”

Parker, on the other hand, says the current policy is the correct one.

“Cities don’t have that kind of money,” he said. “Anybody who lives on a creek is going to have to deal with some form of erosion. That’s just the way nature goes about its business.”

This story was originally published November 28, 2015 at 6:52 PM with the headline "Arlington studies helping property owners with creek erosion issues."