Salt Treatment for Snow on the Trails?

[mstone]

@baiskeli 104130 wrote:

Like I said, the county, like communities nationwide, have spent a great deal of time and money reversing that. Instead of allowing runoff to flow directly into streams, they have built things like buffer zones, retention ponds, etc. to reduce the amount of water flowing straight from pipes.[/quote]

If you think that process has diverted more than a fraction of the waste water that goes into four mile run, I’m afraid you’re overoptimistic. If this is a priority issue for you, I’d suggest focusing on treating the remainder of the surface runoff from streets and parking lots that goes into four mile run. My guess is that one good sized commercial parking lot will account for more salt runoff than the whole trail. (Unlike the parks department, those guys really don’t care how much salt they’re dumping.)

Since your premise seems to be that everything outside the perimeter of the park is treated, and the trail is the only source of untreated pollution, I guess I can see your concern. Unfortunately, that premise is incorrect.

[baiskeli]

@jabberwocky 104135 wrote:

Yeah, it seems sort of ridiculous to be concerned about the tiny surface area of area MUPs compared to the truckloads of salt and chemicals dumped on, say, 495.

Not if you understand the whole system. 495 doesn’t run right next Four Mile Run. It isn’t inside the buffer zone that handles runoff. It has its own runoff mitigation system to help clean the water that it sheds. The bike trails, on the other hand, IS part of the buffer zone. So salt flowing from the trail into the stream just a few feet away may have a much greater impact than salt flowing a few miles through multiple ponds or whatever before it reaches the waterway. It’s not a matter of how much salt, but where it comes from.

[baiskeli]

@mstone 104136 wrote:

If you think that process has diverted more than a fraction of the waste water that goes into four mile run, I’m afraid you’re overoptimistic.

Can you prove this please? You seem to know how much is diverted. How much, and what’s your source?

If this is a priority issue for you, I’d suggest focusing on treating the remainder of the surface runoff from streets and parking lots that goes into four mile run. My guess is that one good sized commercial parking lot will account for more salt runoff than the whole trail. (Unlike the parks department, those guys really don’t care how much salt they’re dumping.)

You’re still not getting it. It’s not just how much salt goes down, it’s where it goes. A pound of salt next to a stream may have a much greater impact than a pound of salt in a parking lot farther from a stream. This is about quality, not just quantity.

Since your premise seems to be that everything outside the perimeter of the park is treated, and the trail is the only source of pollution,

That’s not my premise.

I guess I can see your concern. Unfortunately, that premise is incorrect.

How do you know? Again, please provide data. There are people out there who measure both the speed at which water flows and the concentration of pollutants and nutrients that reaches the waterways, and measure whether the concentrations exceed Total Maximum Daily Load (TDML) standards as set by the EPA. I presume you’ve looked all that up, so please share it.

[baiskeli]

It’s interesting that if this discussion were about, say, the impact of encouraging cycling as an alternative to driving, you’d hear motorists saying that the cycling population, and their ability to have a positive environmental impact, is tiny and therefore inconsequential and we shouldn’t waste time worrying about them. And then someone might say that cycling’s impact on traffic congestion doesn’t matter either since there’s still bad traffic on 495.

It’s more complicated than that.

[baiskeli]

FYI here’s some more info about stormwater management in Arlington. There are many ways that the county is working to slow runoff and reduce pollution, many right under you noses that you wouldn’t know are designed to do that. Just like you might not be aware that the parks around our streams aren’t just for fun, they are designed as buffer zones for water quality.

http://environment.arlingtonva.us/stormwater-watersheds/management/

Putting pollutants directly into these systems could defeat their function.

[TwoWheelsDC]

@baiskeli 104147 wrote:

FYI here’s some more info about stormwater management in Arlington. There are many ways that the county is working to slow runoff and reduce pollution, many right under you noses that you wouldn’t know are designed to do that. Just like you might not be aware that the parks around our streams aren’t just for fun, they are designed as buffer zones for water quality.

http://environment.arlingtonva.us/stormwater-watersheds/management/

Putting pollutants directly into these systems could defeat their function.

And I think that because Arlington is taking major steps to mitigate runoff, even if MStone is correct and these are largely ineffective, salting the trails would seem to undercut those efforts and the left hand clearly doesn’t know what the right hand is doing. Definitely warrants an ongoing discussion and further study, and…you know, data. If the data showed that salting the trails had a demonstrably more deleterious impact on the 4MR ecosystem, then I think we’d need to reconsider the cost/benefit calculation going on.

[jabberwocky]

@baiskeli 104141 wrote:

Not if you understand the whole system. 495 doesn’t run right next Four Mile Run. It isn’t inside the buffer zone that handles runoff. It has its own runoff mitigation system to help clean the water that it sheds. The bike trails, on the other hand, IS part of the buffer zone. So salt flowing from the trail into the stream just a few feet away may have a much greater impact than salt flowing a few miles through multiple ponds or whatever before it reaches the waterway. It’s not a matter of how much salt, but where it comes from.

I get what you’re saying, but road runoff doesn’t go to treatment plants or anything. It goes straight to the local waterway and eventually to the bay. I just seriously doubt that the tiny amount of runoff you get from an 8-10 foot wide MUP has a noticeable effect on local pollution. Treating trails for the occasional storm is a tiny drop in the pollution bucket. We are talking, what, 4-6 times a year max?

[Vicegrip]

This^

All kinds of side roads drain into 4MR. As said the amount of chlorides spread on the roads is many many thousands of times the material that might be used on the trails. Two things work to this.

1 on the roads contractors often get paid for tons used and have little reason to work harder to use less. Roads, parking lots large and small and all the other treated surfaces are often hit with trucks that hold thousands of pounds of materal per load. Most spreders are crude machines that dump at a fixed rate regardless of the trucks speed. Way too much some places not enough in others so the trend is more as too much is still bare pavement but too little is a failure. Spread a ton or 2 and go get more. Have a coffee while the front end loader dumps a few yards in and off you go.

2 On the trails it is not easy to truck large amounts of materials along with you and the human nature is to use it carefully and make it last as over use will require more work. I see this while training new workers. In the truck they start out by overspreading and when working from a wheelbarrow or 5 gal bucket they stretch it out. It is so pronounced that I am now the only one that runs a truck mount spreader.

Chloride builds up in our water systems. Retention pond systems just might make it worse as rather than makings it to the Potomac it soaks in and binds to minerals in the soil. Salt use has gone way up as we are risk adverse. Don’t treat the sidewalk and risk a lawsuit when the lady in the smooth soled high heel boots falls on “your ” ice.

Once fresh snow gets walked and ridden on plowing will not cut to clean bare pavement. The heat of compression warms and then lets the snow re freeze locking it to the pavement. Fresh snow on top shields the pavement from solar warming. Now you have a mess. If the trails were undisturbed prior to plowing a bobcat with a high speed cylindrical cleaning brush would clear clean dry snow. This will never happen and the trails are used by peds and bikes which require bare pavement.

Please excuse typos and blunt prose. Am typing from a touch pad.

[baiskeli]

@jabberwocky 104150 wrote:

I get what you’re saying, but road runoff doesn’t go to treatment plants or anything. It goes straight to the local waterway and eventually to the bay.

But no, much of it does not go streagiht into the local waterway. It goes into a retention pond or a similar situation that partially treats the water, passively.

I just seriously doubt that the tiny amount of runoff you get from an 8-10 foot wide MUP has a noticeable effect on local pollution. Treating trails for the occasional storm is a tiny drop in the pollution bucket. We are talking, what, 4-6 times a year max?

You’d be surprised. Again, the issue isn’t just how much, it’s the concentration. If a relatively small amount of salt hits the waterway all at once, it’s a bigger problem than if it trickles in. I think it’s worth examining.

[baiskeli]

@Vicegrip 104154 wrote:

All kinds of side roads drain into 4MR.

Once again – those roads don’t drain directly into 4MR, many drain into retention ponds or other buffers first. On the other hand, a trail that is right next to a stream, inside a buffer zone, will drain straight into the stream.

As said the amount of chlorides spread on the roads is many many thousands of times the material that might be used on the trails.

And as I said, it’s not just about the amount of salt, it’s where the salt comes from, which affects the concentration of salt in the water that runs into the stream.

You would clearly see that dumping a ton of salt directly into a stream would be much more harmful (and illegal) than dumping a ton of salt on a roadway, right? Because the concentration of salt would be much higher if you dumped it straight in, and the stream couldn’t handle the load all at once. That’s the point. Salt on a road could be different from salt on a trail just a few feet from a stream.

Chloride builds up in our water systems. Retention pond systems just might make it worse as rather than makings it to the Potomac it soaks in and binds to minerals in the soil.

Let’s wait to talk about whether retention systems work until everyone on this thread understands that they exist and what their purpose is.

[baiskeli]

@TwoWheelsDC 104149 wrote:

And I think that because Arlington is taking major steps to mitigate runoff, even if MStone is correct and these are largely ineffective, salting the trails would seem to undercut those efforts and the left hand clearly doesn’t know what the right hand is doing. Definitely warrants an ongoing discussion and further study, and…you know, data. If the data showed that salting the trails had a demonstrably more deleterious impact on the 4MR ecosystem, then I think we’d need to reconsider the cost/benefit calculation going on.

There you go. I just pointed out a potential problem and would like to know more.

[Steve O]

@baiskeli 104141 wrote:

Not if you understand the whole system. 495 doesn’t run right next Four Mile Run.

I-66 actually is sitting on top of 4MR in places, with runoff that essentially feeds right into it. Check out near Madison Manor and Westmoreland St.

GlenCarlyn Park is right next to 4MR, too. Last year I went through the parking area by the picnic pavilion and the salt was literally deep. Actually piles of it that would slow your bike down riding through. I would guess there was more than 500 pounds of salt on those 12-15 parking spaces and roadway–maybe more. In my mind, no one was going to use that pavilion in the dead of winter anyway–certainly far fewer than would bike or run or walk on the trail if it were clear. So with 20% of what was wasted on those parking spots immediately next to the stream we could have treated the trail from Columbia Pike to Rte 50. But it was a road. For cars. Even non-existent cars. Must clear it. And as Vicegrip pointed out, the more salt to get it done, the better.

Why not close the pavilion for a few days for “environmental reasons?” How is that different from essentially closing the trail for “environmental reasons?”

[baiskeli]

P.S. on watershed retrofitting in Arlington:

http://projects.arlingtonva.us/plans-studies/environment/watershed-retrofit-study/

This link has details about all the retrofits or proposed retrofits. The goal is to get rid of the old system of pipes running straight into streams. There are a few THOUSAND points named on the documents on this link identified as places where water could be diverted and passively treated before flowing into streams.

In the long run, this calls for incorporating the possibility of mitigating salt runoff from trails when retrofitting.

[baiskeli]

@Steve O 104167 wrote:

I-66 actually is sitting on top of 4MR in places, with runoff that essentially feeds right into it. Check out near Madison Manor and Westmoreland St.

GlenCarlyn Park is right next to 4MR, too. Last year I went through the parking area by the picnic pavilion and the salt was literally deep. Actually piles of it that would slow your bike down riding through. I would guess there was more than 500 pounds of salt on those 12-15 parking spaces and roadway–maybe more. In my mind, no one was going to use that pavilion in the dead of winter anyway–certainly far fewer than would bike or run or walk on the trail if it were clear. So with 20% of what was wasted on those parking spots immediately next to the stream we could have treated the trail from Columbia Pike to Rte 50. But it was a road. For cars. Even non-existent cars. Must clear it. And as Vicegrip pointed out, the more salt to get it done, the better.

Why not close the pavilion for a few days for “environmental reasons?” How is that different from essentially closing the trail for “environmental reasons?”

For the record, I didn’t suggest closing the trail for environmental reasons.

You point out a great example of overuse of salt. I hope the salt on the trail is used more wisely.

[Steve O]

@baiskeli 104170 wrote:

For the record, I didn’t suggest closing the trail for environmental reasons.

Yes, I didn’t mean to imply that.
At BAC meetings I have heard this excuse used, however, for not treating. Not actually close the trail, but effectively close it by leaving it impassable for most users.
I have always been an advocate of getting the snow off immediately, then no treatment is needed at all–or only spot treatments in tough spots. The rest just dries out. Faster, cheaper, better for our waterways. Win-win.

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