Transmission towers need booster seats too. Allegedly.

Some infrastructural features are so ubiquitous and operate so effectively behind the scenes that they become almost invisible—like most utility lines.  Compared to many developed nations, the United States still has a sizable portion of its electrical and telecomm wires hoisted high into the sky through utility poles.  In fact, outside the densely populated downtowns of major cities and some of the newer suburban developments from the last forty years, the majority of American settlements have not buried their utility wires underground.  This results in a broad swathe of urban/suburban neighborhoods where massive utility poles remain a commonplace feature.  Visitors from the UK (where most electric cables are buried outside of rural areas) or Netherlands (where virtually 100% of electric wires are underground) will absolutely notice these same overhead wires in the US because this configuration is the norm.  Meanwhile, in smaller cities and small towns, virtually all utility wires still run above the streets, even in the heart of downtown, sometimes with the assistance of enormous transmission towers.  Americans are simply used to it and have ceased noticing, which probably explains why I had mad at least a half-dozen stops to this shopping center in Prince William County, Virginia, before I became aware this strange arrangement.

transmission tower with earthen mound in Woodbridge, VA

I’ll concede that the teaser photo is a bit manipulative; I deliberately framed it to exclude details that I’ll review subsequently.  But even with this photo as evidence (and my article’s title as a pretty strong giveaway), my guess is that most readers won’t see anything too unusual.  It is, after all, a massive transmission tower common in almost all medium density suburban settings across the country.

Not surprisingly, this area in the big, borderless suburb of Woodbridge (not quite 25 miles south of Washington DC) is auto-dominated and generally medium to low density.  Sidewalk coverage is pretty good, endowing the area with fundamental walkability, though it’s hardly the preferred option for most.  With a vast shopping node nearby—the Potomac Mills Mall (over 1.5 million square feet all on one enormous floor), and, of course, the acres of parking that surround it—it’s no surprise that the utility company hasn’t invested to bury all those electric lines.  The area certainly isn’t close to rural and isn’t even exurban anymore, but enough space exists between buildings and wide roads that it simply isn’t cost efficient to dig trenches for high capacity transmission wires.  In fact, a pivot to the right of this photo reveals an all-too-common chasm of trees where wires and towers stretch to the horizon.

But those other towers, proximal to the one in the photo, are much more conventional than the featured one.  It’s time for me to stop cheating with how I point the lens.

transmission tower with earthen mound in Woodbridge, VA

This particular transmission tower is sitting on a massive mound of soil at least 25 feet high, bounded by a somewhat ramshackle-looking wooden retaining wall.  It’s definitely an outlier here in Prince William County, because stepping further backward—or a zoom-out—reveals nearby towers that sit firmly on the soil at grade, with no further intervention necessary.

transmission tower with earthen mound in Woodbridge, VA

So what happened at this particular transmission tower?  What’s the explanation for the mound?  The logical conclusion should be that it needed to fit in with the adjacent ones.  Would there have been a significant dip in the grade otherwise?  I’ll concede that it’s possible that would have been the case, but another view to the right (northward) doesn’t show evidence of any major incline.

So maybe it’s coming more through a pivot to the left—southbound?

This might be the solution.  Notice that these photo essentially feature two different sets of transmission lines, hoisted by towers with very different engineering.  The featured one on the mound uses a sort of inverted cone shape and metal lattice work, allowing simultaneous conveyance of lines in three pairs, one above the next.  The other tower has three poles that stretch to the ground, a planar form, and the six transmission lines get housed in one horizontal row.  But the next inverted cone shape tower in the horizon is indeed built on a hill.  Here’s a more uninterrupted view of that transmission tower in the distance.

So it does look like these transmission towers and their wires must manage a topographic incline.  Not being an electrical engineer, I can only speculate that it is wise to convey electricity at a gentle grade change whenever possible, perhaps in the interest of safety and/or efficiency.  However, we’ve all seen those hillside scars where a series of wires and transmission towers must overcome a slope far greater than anything in this part of Woodbridge.  It still leaves me scratching my head about why the utility company chose to build that mound.

Excavation is a tremendous cost, so I would certainly hope the provider didn’t simply dig somewhere else to supply the soil that built this clearly manmade mound.  Hopefully the need for a boost to this transmission tower’s placement coincided with the removal of excavation spoils from a construction project nearby.  In the grand scheme of scenario-building, this transmission tower and the mound may have been a sub-optimal solution given a miscalculation—that is, an ordering of the standard industry fabrication height for transmission towers that ended up not working, so a quick fix was necessary.  In other words, the utility company bought all these mass-fabricated towers of a certain fixed height, and special ordering an extra-tall one was more expensive the shipping the soil to help prop it up higher.

But is heaving soil onto the site as a step stool a quick fix?  I imagine it is generally stable; all the plant growth will help minimize erosion, and the retaining wall is likely stronger that it appears to my untrained eyes.  A survey of archived photos in this area indicates this mound has been here for at least a good decade.  But back in August of 2011, the earliest photo available, the back side of the mound (opposite from where I took all these photos) featured a small monitoring station perched on the sloped soil.  This station is now gone.

I can assert, as I’m sure many have, that the mound supporting this transmission tower looks jury-rigged.  Short-term.  Filled with additional efforts, like a retaining wall and signage, to help convince the public that it’s safe.  And I can subsequently contemplate a better-looking solution, like a sturdy pedestal built of concrete or some polymer that does not conduct electricity and can bear the tower’s weight.  (Concrete can slightly conduct electricity when it’s wet.)  Then again, maybe these towers require significant subsurface stabilization to keep them firmly rooted, especially in climates like Virginia’s that are prone to violent storms with high winds.  Perhaps these solutions aren’t as odd as I think they are; Americans just don’t usually encounter them within a stone’s throw of a massive regional mega-mall.  Or we just don’t notice them because they’re everywhere anyway, and this doesn’t deviate enough from the norm to get anyone’s dander up.  Maybe a Brit visiting Woodbridge would have a different opinion, because most suburban settings in that densely populated country do strive to bury all overhead power lines.

It’s pretty outlandish looking.  And probably even more extreme for any Dutch visitors, since Netherlands has purportedly (I cannot confirm) achieved a goal of 100% underground for all low-wattage transmission.  But these aren’t places that have the land available for a Potomac Mills Mall; the Low Country is among the most densely populated in the world.  And who needs cone-shaped transmission towers when they’ve got vintage windmills?

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2 thoughts on “Transmission towers need booster seats too. Allegedly.

  1. Chris B

    is it possible that the tower long predates the development, and that the original grade was higher and cut down around the tower to create flat/level building pads and parking lots?

    Reply
    1. AmericanDirt Post author

      Yeah, I guess that could be the case. I’d imagine the development is from the late 1980s. If that were true, the amount of excavation needed to get here would be something else.

      In the Google Street View here (https://maps.app.goo.gl/h4xsJ1UVM9AjyZD77) the mound is on the left half, and everything in the right half would have been excavated to reach a single grade that was sufficiently level to support the parking lot. It would have been huge, and I can’t see how that would be the most cost-efficient solution. Or why there’d be a disadvantage to bringing it all to an approximately 25-foot lower grade.

      Reply

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