City of Falls Church residents are faced with the prospect of up to a doubling of stormwater fees in the next few years, the fact that such an added financial burden will benefit in the range of only 48 houses in the City, and that such benefit will be only for modestly-sized storms in an era of violent climate change-driven weather events.
The Falls Church City Council, considering approving a bond issuance later this month to cover some immediate needs, was briefed on this mix of options for prospective stormwater capital improvements by City Manager Wyatt Shields, the City’s interim public works director Zak Bradley and members of the City’s Stormwater Task Force last month.
Given Council concerns expressed then, Bradley provided the Council with a four-page memo with more details of the prospects presented at this week’s Council work session that confirmed the parameters of the issues involved.
Council members Letty Hardi and Ross Litkenhous led the concerns expressed by the Council for the combination of high costs to all City residents and limited benefits, including the narrow impact on homes in the City’s flood plain and the limited benefit given the recent years’ growing severity of weather events.
The current policy is to “maintain the standard 10-year, 24-hour storm protection” (from a hypothetical once-every-10-year storm, a metric that has been obliterated by the recent years’ climate-change instigated weather events).
Hardi and Litkenhous urged the Public Works staff to explore more adequate options to simply putting larger pipes underground at six key areas around the 2.2-square mile City, which is essentially the limit to what the current plans are calling for. Even acquiring some of the properties in the highest-impact areas to dedicate to catch basins that would hold water during the peak periods of major storms would be a less expensive alternative, they said.
Councilman David Snyder asked whether the 10-Year-Storm metric is still realistc given the more severe weather patterns being experienced in recent years, or whether adhering to it now would be more like “just having a bandaid applied” when that limit is regularly being exceeded.
While neither Shields or Bradley could answer that question directly, except to cite difficulties that could arise from trying to adjust that metric, Council member Hardi echoed the concern and said that the City of Alexandria is currently undertaking a study of just that matter. The question, she said, is “Is this metric the right one or is it out of date?” adding “$12 million is a lot to spend on something that’s no longer a functioning standard.”
Still, the Public Works department is looking to get the OK by the Council to proceed with its current plans at next Tuesday’s meeting.
According to Bradley’s memo, the National Oceanic and Atmospheric Administration (NOAA) publishes intensity-duration-frequency curves that are revised periodically to reflect for higher or lower storm intensities and durations and frequencies of the so-called “10-Year, 24-Hour Storm” for any particular location and “should climate change continue to generate storms with increasingly greater intensities, durations and frequencies, a city such as Falls Church has two options for maintaining the standard protection.”
They are to “1. Periodically increase the size of all stormwater infrastructure in the city, including inlets, pipes, stream channel capacities, or 2. Implement upstream stormwater management techniques to reduce, retain or delay runoff from the watershed and thus reduce increased downstream flooding.”
He says that the first option “would be expensive and disruptive to neighborhoods and streets, with a virtually constant ongoing capital replacement program.” The inadequacy of this approach, he said, is why the Stormwater Task Force was tasked “with prioritizing investments based on frequency flooding and severity of damage to private property.”
This has led to the second alternative, he says, which “has been undertaken by many cities nationwide with varying degrees of success but not without substantial costs.”
Its water management components include property acquisition to move or raise flood-prone properties out of the watershed, repurposing open properties to stormwater detention and retention facilities, major reduction of impervious areas throughout the watershed, reopening or resurfacing historic stream channels and maintaining adequate open channel conveyance capacity, aggressive enforcement of stormwater “best management practices” (payments, fines, etc.), and maintenance of an expanded in-house stormwater management staff.
That alternative requires “an aggressive, long-term commitment to stormwater and watershed management throughout a jurisdiction,” and therefore “is expensive” and is dependent on some requisite conditions pertaining to density, eminent domain laws, aging of the existing system, and a “socio-political commitment.”
High costs of implementing such plans are usually due to years of ignoring and underinvesting in the infrastructure, known as a “run to failure” mode, and now, for Falls Church, “the City’s infrastructure is quickly deteriorating and is well past its expected design life.”
Of $900,000 being utilized this year, according to the report, $400,000 is being spent on smaller projects on Midvale and Poplar Drive. The remaining $500,000 is to continue engineering on three to four projects according to priorities recommended by the Stormwater Task Force, and the Council is to decide later this month.
Overall, a $12 million bond (or $17 million estimate if a 30 instead of 20 year bond) stormwater improvements to be considered by spring would be applied to six major projects, and Bradley in his memo questions whether there is any cost effective alternative.
“Historically, projects involving underground detention of stormwater have been very costly and need a significant amount of land to be effective. This was demonstrated to the City in the design and construction of the stormwater storage tanks under the tennis courts near City Hall. Extensive use of underground will quickly exceed the currently estimated $12 million,” he asserted.
