Eh. 10 feet is still wider than the majority of bike trails in Rock Creek park no? Excited to see this take shape. Does anyone know what is involved in the creek restoration? Will it result in more water making its way into Rock Creek? I ask because many don't realize that Rock Creek was once navigable. It's nice to look at now but I can't help but think how cool it would be to kayak or canoe down it. Maybe one day the water would even be clean enough to consider swimming or tubing in, as people get to do in cleaner cities like Boulder. I know I'm a dreamer but if a small dam was placed at the end of rock creek you could raise the water level slightly for recreation. You could open the dam to manage storm water and it could even generate a small amount of electricity for the city. Any knowledgeable readers know why the creek is no longer navigable? Is it that there is less water or more silt or what?

by John on Jan 13, 2011 10:00 am • link • report

@John, once on a hike with a group led by a park historian we were told the water level has diminished due to redirecting/controlling tributaries as development occurred for hundreds of sq miles all along the creek.

We also had Teddy Roosevelts favorite swimming hole pointed out, which once was 2-3x or more deeper than today.

by Tina on Jan 13, 2011 10:33 am • link • report

$7 MILLION DOLLAR 3-block hike bike path....seriously?

by Bill on Jan 13, 2011 10:47 am • link • report

Bill, the $7M is for the whole project which involves removing the existing crumbling road, mitigating the environmental damage from it, rebuilding the streambed, stabilizing the hill, building the trail - with expensive permeable material, adding the lights, landscaping and stormwater management work etc.... The trail is only about $1M of that.

by David C on Jan 13, 2011 11:29 am • link • report

John, I agree that the two feet is not a big deal. Here's what it says about stream restoration.

Under Option A, three priority areas of Klingle Creek (see Figure 7) would be stabilized to protect the trail and associated infrastructure. The stream channel would be resized and realigned at Priority Areas 1 and 3 to prevent future damage to new and existing adjacent infrastructure. Because of the narrow valley width in these two areas, the channel would be armored to ensure stability during all flows for the proposed trail alternatives. Stream bank and bed armoring would include a step-pool configuration to create a natural-looking channel, and the channel would be reconstructed with adequate capacity to prevent sediment accumulation in the channel at these locations.

At Priority Area 2, the Klingle Creek stream bed would be raised in order to cover and protect the existing DC Water sewer encasement pier footings. Appropriate bank protection would be installed adjacent to the riffle grade control. The outfall at the upstream side of the crossing would be reconstructed to prevent burial.

Furthermore, Option B would repair targeted channel and bank stability problems throughout the project area, for a total of 1,595 linear feet of stream channel restoration.
In areas not protected by bedrock, the channel would be reconstructed using step-pools to maintain a natural channel appearance, dissipate water energy, and protect stream banks. Bank stabilization techniques, such as but not limited to imbricated riprap, would be used in constricted areas. In wider valley areas, stream bank and adjacent hill slopes would be graded back at a 3:1 slope for improved stability. Bioengineering techniques and native plantings would be incorporated where possible.

by David C on Jan 13, 2011 11:38 am • link • report

@David C,

In truth, that same 6 million to be spent on infrasture improvements are the same whether the road was rebuilt back into a road, or repurposed into bikepath.

So yes, it is 7 million for a hike/bike path and considering the visceral flak the city council and the previous mayor got for "all those fancy bike lanes and dog parks", combined with the city being in the hole nearly half a billion (again, for the third time) I doubt this project is going to go anywhere soon.

by freely on Jan 13, 2011 11:51 am • link • report

Glad they are suggesting Option C! I hope the renovations will begin soon. I noticed landscaping is in the budget. I hope they focus on native plants, especially considering the degree of habitat surrounding the trail.
$7 - $10 million?!? Where does this number come from? Most of the budget estimates were $4 - $5 million.

by Lisa C on Jan 13, 2011 11:55 am • link • report

that same 6 million to be spent on infrasture improvements are the same whether the road was rebuilt back into a road, or repurposed into bikepath Or even if they wanted to just make it parkland. That's my point. The cost of the path is $1M the cost of fixing items unrelated to the path. It's $6M to clean up the area, repair utilities, etc... That is one part - and most of it has to be done no matter what (the no build option for the stream was removed from consideration, for example). Then it's $1M if you want to build a paved path.

If you think the $6M is part of the cost, then you might as well add the value of the land - which could probably fetch several million dollars - too.

by David C on Jan 13, 2011 11:57 am • link • report

Lisa, I doubled counted some things and should have just used DDOT's table on page 30. It's actually cheaper at $4.5M - $7M.

by David C on Jan 13, 2011 12:01 pm • link • report

@ David C - That makes more sense. As others have noted, there are a lot of necessary repairs for water quality concerns that need to happen regardless of any new surface put in the valley. Personally, I wish the storm water drainage repairs would happen ASAP, but I understand city budgets don't quite work that way.

by Lisa C on Jan 13, 2011 12:10 pm • link • report

@David C,

Well, no. Returning it to nature wouldn't require the 6 million in retaining walls and storm drain systems. And there wouldn't be any yearly maintenance either.

Its 6 million specficially for a hike/bike trail. You can try to parse it anyway you like but the fact of the matter is, it is going to be the most expensive hiker/biker path in the city and I would venture to say in the nation which considering the cities constant "half a billion in the hole" status doesn't lead me to think this is going to get done anytime soon.

by freely on Jan 13, 2011 12:20 pm • link • report

Freely, as noted above $6M is now on the end of the estimate - my apologies.

Let's say the District decided not to build a trail or a road. Would that cost $0. Only if they wanted to let the old road wash away into the stream and contaminate the soil. Only if they didn't want to repair the stream bed. Only if they didn't want to improve stormwater management off of the neighboring properties.

Of course, that isn't even an option since DC Water has said they need a facility on which they can drive their trucks occasionally to service the water line there (in the agency comments section).

Being generous, you could claim the trail is $4.1M which is the cost of the trail itself, the retaining wall, landscaping, the contingency fee, retaining wall, engineering and design and lighting. But as I said, DC has to build something there. The driver is not the trail, but DC water and the sewer encasement. Which means the retaining wall, landscaping, the contingency fee, and engineering and design are expenses that will be incurred trail or no trail.

Your the one who is parsing it. You're saying that the $20,000 someone spends for a car is $20K for a set of new tires. You can't use the whole price of the project and claim it is only paying for one part.

The cost of adding a trail to this project is a little over $1M. Lights add $0.1M.

by David C on Jan 13, 2011 12:40 pm • link • report

David C- The commenters pushing the 7 million dollar figure for the path are just the pro-roaders. They fought hard for the road and are still soar about the defeat. They aren't concerned with the districts bottom line and they know very well that the cost for the trail is not 7 million but they will keep putting that propaganda out there regardless of how clear you make it. I noticed though that they at least stopped calling it a "Hike/Bike path to nowhere". I guess it dawned on them that if the trail goes "nowhere" then so would the road they want so badly. But then the person behind that jewel of a slogan is off their rocker to begin with. The bottom line as you mentioned is the road would have to be removed and there is infrastructure to deal with. Similar work is being done just down the park by the Ellington bridge. Putting a trail there once complete just makes sense.

by John on Jan 13, 2011 12:59 pm • link • report

I'm with freely, David, you can parse the dollars however you want. But at the end of the day, the $7M price tag for a local hike trail for Woodley Park locals versus a $10M price tag for a road that everyone in the city can use seems to be more bang for your buck.

And in your speak David, your figure of $1M for a local park versus $3M for a road for everyone, again, more bang for the buck.

While I am a pro-roader, and proud of it, I would be shocked, at best, if the city is going to invest money for another park in Woodley Park.

by Bill on Jan 13, 2011 1:28 pm • link • report

The cost-benefit comparison between a $1M trail and a $3M road (if that is indeed the cost) is a legitimate question to be addressed. My main concerns are that we use the right costs and the right benefits in that comparison.

Along those lines, calling a trail, which in addition to having a recreation use also has a transportation use, a park is a bit disingenuous and sounds like framing.

In order to do the comparison, we'd need to know - for both options - construction costs, maintenance costs, environmental impacts, # of users, the health benefits of the trail, pollution caused by the road etc... I don't think anyone has all of those numbers. So while you may believe the road is the better option, that is largely a statement of faith at this point (as would a belief that the trail is the better option). You're welcome to place your faith wherever you choose, but there is no need to distort the facts to make your case - and feeling the need to do so should lead one to question the placement of their faith.

by David C on Jan 13, 2011 1:41 pm • link • report

Bill- shoot. I live in Mount Pleasant and I was under the impression that I would be able to use the trail too. Now that I know it's only for those wealthy Woodley Parkers I may have a change of heart.
Again, I could take the pro-roaders a lot more seriously if you didn't rely so heavily on propaganda. At the end of the day the road/trail debate is over. The valley restoration needs to happen and putting a trail there after the infrastructure is complete makes perfect sense. I don't see it happening in the near future either but I think it's time to accept that it's not going to be a road. Maybe when the city is done with the trail they can put you all on a bus and drive you over the trail for one last hit of nostalgia. Now can we discuss more logical things to do with our money like building a Rock Creek dam so I can canoe on it PLEASE.

by John on Jan 13, 2011 2:01 pm • link • report

Distort facts? The final EA provides costs for a road build which is $10M.

by Bill on Jan 13, 2011 4:18 pm • link • report

Distort facts? The final EA provides costs of $10M for a road build which is $10M. So the way I see it, in order to get to a path or a road, taxpayers will pay either $6M for a 3-block path (plus$1M for path) or $7M (plus $3M) to get a road.

by Bill on Jan 13, 2011 4:21 pm • link • report

This multi-million dollar trail makes the $400k dog park look like a bargain in comparison.

by Fritz on Jan 13, 2011 5:09 pm • link • report

"Go tell the Roadies,
Go tell the Roa-oh-dies,
Go tell the Roadies
that Klingle Road is dead."

by Sarah on Jan 13, 2011 5:45 pm • link • report

There is also a legal problem with the EA such as if you close a road for a hike/bike path it needs to go through the Street and Alley Closing Act, then you can build a hike/bike path. This EA does not want to do that as the land then would go to the abutting land owners who will not build a hike/bike path. So they are trying to say the road is OPEN but you cannot drive on it. We do not have any open roads in DC you cannot drive on. This is setting a precident in the city that would allow any road to close three blocks in the middle, such as this one, and turn it into a hike/bike path. An open road means it receives automobile traffic. What should happen here is the road should be rebuilt with a hike/bike path beside it for one city, unity. This is still a hike/bike path to nowhere that is not part of a bike commuting plan.

by Sally on Jan 14, 2011 7:30 am • link • report

Isn't 1500-1700 Pennsylvania Avenue a road you can't drive on?

by David Alpert on Jan 14, 2011 8:35 am • link • report

It is built as a road, not a hike/bike path, and was closed for security reasons by the Federal Government against the wishes of DC, who tried to keep it open. You might notice it is not 10 feet wide.

by Sally on Jan 14, 2011 8:49 am • link • report

There is simply no point in going through that endless Klingle Road dispute again. The Federal Government made it plain, through its stonewalling on the Environmental Impact Statement for the road, that the road will not be permitted. The "roadies" won the battle, totally, at the District level, in 2003. The Feds -- the National Park Service, presumably -- quietly vetoed it, and that's that. As CM Graham said, "the handwriting is on the wall,", when he pushed for District funding of the road, with no Federal support. That was a nonstarter at the Council, and the Council is not about go start the Klingle Road battles again.

It's over, road folks. The only question now is when and how to build the bike/hike path. Arguing for the road today is a complete waste of time.

by Jack on Jan 14, 2011 9:24 am • link • report

Jack, I see no argument nor debate, only healthy conversation (except for Sarah who I think is 2 years old), but the facts remain, why would anyone spend $7M for a 3-block path? That's absolutely absurd and like Fritz said, This multi-million dollar trail makes the $400k dog park look like a bargain in comparison.

by Bill on Jan 14, 2011 9:53 am • link • report

3 blocks? More like 8. http://www.klingletrail.com/images/locationmap.jpg

by Tina on Jan 14, 2011 10:38 am • link • report

Tina, that map just depicts the locale. The trail doesn't span, or start at Woodley Road, nor end at Porter/Rock Creek Park. It a section in between that area.

by Bill on Jan 14, 2011 10:55 am • link • report

..the planned trail will go from Cortland Pl. to the RCT. Those are the "Project Limits". See again the "options".

by Tina on Jan 14, 2011 11:02 am • link • report

Bill,

My comment about distorting facts was more aimed at Fritz who insists on calling this a $7M trail, instead of a $7M project with a trail, but now that you've signed on to calling it a "multi-million dollar trail", I guess that includes you too. The trail isn't that expensive. In fact the difference between the low end of the spectrum ($4.5M) and the high end ($7M) is entirely based on the unknowns related to the stream restoration. But why bother with that, since a $7M trail sounds so much worse (BTW, any idea what a trail normally costs per mile - especially one with a permeable surface?).

As does your calling it a 3 block trail. It's 0.7 miles. Those are some long blocks.

As does your calling it a local park. It's a trail in a park. It will serve a real transportation purpose.

As does your claiming the trail is only for Woodley Park, bu the road is for everyone. Not only is it wrong because both would be equally public, but most people in DC don't have a car. So the road would not be open to everyone. Most people can use a trail though. SO if either is more available to everyone it's the trail.

by David C on Jan 14, 2011 11:48 am • link • report

@David C: Look at the chronology of posts and get the target of your mudslinging correct.

And, by your math, this plan will cost between about $700k and $1M per 0.10 mile.

With the city's $400 million budget deficit, will this pass the laugh test?

by Fritz on Jan 14, 2011 12:45 pm • link • report

Fritz, you're right. You didn't distort the facts until after I used that phrase. My mistake. I got you confused with freely. Must've been the "F-R". Or maybe I'm psychic.

But now on to your post-comment distortion of facts. The trail costs a little over $1M, which places the cost at less than $200K per 0.1 mile. That's my math. Yours is flawed.

The city has a deficit. This project will be mostly paid for with federal transportation funding, so it won't really contribute to that. Also, in order to determine which projects rank higher than others it is critical to do a cost/benefit analysis. As I mentioned we have the cost and we can start to guess at benefits. But since I don't know which project you think outranks this, how much it costs or what its benefits are, I can't say where it should fall on the priority list.

But, since the project was specifically instigated by an act of the DC Council, and since repairing the stream is pretty important, I think it would pass the laugh test - if such a test existed. But I have difficulty speculation on the outcomes of imaginary tests. Call it a blind spot.

by David C on Jan 14, 2011 1:09 pm • link • report

So "the whole project, if the preferred alternative is built, would cost between $4.5 and $7 million" really means it will only cost $1M.

Except that you then have to add in another couple million.

But it really only costs a million.

Give or take.

That should be on the math curriculum at the George W. Bush School of Education and Learning.

But even at the imaginary $1M amount, that's still a whole lotta money for a 0.70 mile trail. Which still makes the $400k dog park look like a bargain.

by Fritz on Jan 14, 2011 1:32 pm • link • report

Fritz, I'll type this real slowly for you. The project will cost between $4.5-7 million. The trail is one part of the project. That part, the trail, will cost about $1M. There are other parts of the project that will cost $3.5-6 million. This really isn't that hard to understand. It's like buying a car. You can add heated seats to the $20,000 for $500, but that doesn't mean you're paying $20,500 for heated seats.

How much would you expect to pay for a 0.70 mile trail?

by David C on Jan 14, 2011 1:45 pm • link • report

I believe the pro hike/bike path folks have been telling the city council that the path will only cost about 2 million and that is why it was preferred over the road. What they did not tell the city council was the underlying structure has to be replaced, water remediation done and not just the stream bank repairs, this is the expensive portion of the project. Whether it is a road or path the most expensive portion is the underlying land that has been ignored and washing away for so many years. So now the price tag which are real numbers are not similar to what the council has heard in the past. It has gone from 2M to 7M and you still end up with a hike/bike path that WABA has called a neighborhood trail.

by Sally on Jan 14, 2011 3:51 pm • link • report

The road is not happening. Move on.

by David C on Jan 14, 2011 4:19 pm • link • report

Yes Fritz, you are absolutely correct. David, I know this is your list, but you are behaving quite rudely. We know you are supporting a hike bike path. We know you don't even live near the location, and we know you really don't care about any other opinion but your own, and that's certainly your prerogative (and your blog)but certainly respect others opinions and healthy conversations.

Look at the bottom line. To get that $1M bike path OR that $3M road, you going to have to spend some money. That amount is upwards of $6M.

You can't get there any other way so why insist on arguing what the end cost results will be?

by Bill on Jan 14, 2011 4:26 pm • link • report

The hike/bike path may not happen either.

by Bill on Jan 14, 2011 4:29 pm • link • report

Bill, where have I been rude. I do care about other opinions. If Fritz wants to express an opinion, I'd respect that. What you and Fritz are doing is expressing facts which are not correct. That I don't respect.

To get the bike path you do not need to spend $6M. You could build the path without fixing the stream. In fact I think the plan is to build the path first, and then fix the stream so that the path work doesn't damage the stream work. These are two completely separate projects and you're trying to couple them and then claim that they only produce the trail as a result instead of the trail and a several other improvements. That is not an opinion. You are trying to make a statement of fact. And the fact you are stating is wrong.

If the hike/bike path doesn't happen I can assure you that I won't bellyache about it on the blogosphere, distorting facts and spinning the story in a way that hides the truth.

by David C on Jan 14, 2011 4:39 pm • link • report

even if the trail isn't built the most expensive part of the 2-part project (restoration+trail) will be done: the creek bed restoration and related water/sewer infrastructure. The longer this part waits the more expensive the price tag to do it.

by Tina on Jan 14, 2011 4:50 pm • link • report

...because each passing year the job gets bigger due to ongoing erosion.

by Tina on Jan 14, 2011 4:52 pm • link • report

Why not do all the environmental remediation work, put in a dirt trail, and forgo the bike path?

Let's get real here, no bike commuter or casual cyclist wants to ride on sustained steep uphill grades if they can avoid it. So a paved trail would basically an amenity for performance cyclists. I see no reason why we should spend $1M on an amenity for a small, overwhelmingly wealthy group of people.

Hikers/runners/walkers can just as easily do their thing on a dirt trail, and it's much cheaper.

by Phil on Jan 14, 2011 4:52 pm • link • report

If you graduated from the Enron School of Accounting, then David C's math makes sense.

Which will happen first:
A) DC voting rights;
B) Gridlock Gabe's Streetcar to Nowhere;
C) Marion Barry pays his taxes; or
D) the $7M bike path?

Winner receives a lifetime supply of kudos.

by Fritz on Jan 14, 2011 4:54 pm • link • report

@Phil -a trail in KV would negate the current need to ride down Porter St to access the RCT eastbound -- and UP Porter from the RCT westbound. The grade in the valley is substantially less than Porter.

by Tina on Jan 14, 2011 4:58 pm • link • report

Fritz, if you want to make it interesting, I'd be willing to make an actual bet.

Phil, no bike commuter or casual cyclist wants to ride on sustained steep uphill grades if they can avoid it That's not true, some bike commuters go out of their way to find hills, because they use their commutes to train. But, even if your statement is true, just because they don't want to, doesn't mean they won't. Bike commuters will use this trail. I guarantee it.

A paved trail makes it accessible for more of the year, and to people in wheelchairs (which makes it easier to get federal money due to ADA requirements). It makes it easier to use for bicycle transportation as well.

Furthermore, we build all kinds of facilities for athletic uses (soccer fields, basketball and tennis courts, etc...). the District has a legitimate interest in seeing that people have a place to recreate and that they be healthy.

How many people will use the trail and how many do you need for it to worth $1M?

by David C on Jan 14, 2011 5:01 pm • link • report

This area already has plenty of bike paths, parks, and recreation facilities public and private. Sorry, but especially in the current budget environment there are more important priorities than another $1M amenity for wealthy neighborhoods that are already full of them. And I live close enough to this area that I might actually use the trail now and then if it were built

by Phil on Jan 14, 2011 5:08 pm • link • report

there are more important priorities For example? And remember, it will have to qualify for Federal Recreational Trails funding.

by David C on Jan 14, 2011 5:12 pm • link • report

@David C - do you know of any bike path or even bike lane access to the RCT anywhere in DC? I think this would be the first. Pretty certain the bike lane on Tilden ends before it gets to the point where RCT can be accessed. If I'm right -or even partially right (perhaps other access exists somewhere) a trail in KV would be a unique asset to biking connectivity.

by Tina on Jan 14, 2011 5:23 pm • link • report

The Tilden one does connect to the trail. The only other connection to this section of the RCT is at Water Street.

by David C on Jan 14, 2011 5:37 pm • link • report

BTW, from the repair Klingle Road website, rebuilding Klingle Road according to a 2003 study, would cost $5.5M. That is just the road. After 7 years, one would expect that number to go up.

http://www.repairklingleroad.org/consequences-costs.htm

That's what I mean when I say distorted facts.

by David C on Jan 14, 2011 5:42 pm • link • report

...and that estimate is for "less than a quarter mile", not 0.7 mi. minus 50 yards (the distance from the eastern barriacde to the RCT)

by Tina on Jan 14, 2011 5:48 pm • link • report

I'd like to see a lifecycle cost of the road versus the lifecycle cost of the trail. Repairs to the road were already common when the final washout occurred, how many years would it have been before the $10,000,000 road would have washed out again, and required more repairs?

Road supporters won't talk about the cost of repairs, but the trail would be available to cyclist commuters even when the counter-factual road would be uncomfortable to drive.

by Neil Flanagan on Jan 14, 2011 9:04 pm • link • report

The road was used for 139 years and was maintained like any other road in the city until DC did not maintain the storm water drains, a bridge collapsed and then the water started to break up the pavement as the repairs were not done. This hikke/bike path will require even more maintenance as the plan for a permeable surface (not yet used in DC) will require vaccuming every two weeks to get the leaves from the trees off the surface for it to remain permeable and drain the water. Never mind the trees themselves that keep falling in every storm we have. DC plans to vaccum it 4 times a year so it is set to fail before it is even built. A permeable surface requires constant cleaning and is very high maintenance, is not suitable for this steep slope and area. A road does not require this constant cleaning and maintenance. Either Ddot wants to keep the maintenance numbers appear low or they really don't understand this surface and its needs.

by Sally on Jan 16, 2011 6:30 am • link • report

The detractors are not considering the immediate and ongoing costs that delays have cost our environment. The area needs to be reclaimed and sooner rather than later. This is the bulk of the costs.

From there, do you just do the remedial work and leave it or do you add incrementally the bike trail, or do you spend even more money to add vehicular access?

On the question of the slope of the road, it is an easier climb that accessing Calvert Street or the Porter Street hill. To get to the same spot, for example for those traveling from Mt. Pleasant to Glover Park, it is a much easier climb than Cleveland Avenue.

by William on Jan 16, 2011 8:04 am • link • report

Sally, this hikke/bike path will require even more maintenance as the plan for a permeable surface (not yet used in DC) will require vaccuming every two weeks to get the leaves from the trees off the surface for it to remain permeable and drain the water. The EA says it will cost about $5840 per year to maintain the trail. It would be quite surprising if the cost of maintaining a 10-foot wide trail primarily used by walkers, runnners and cyclists was highter than maintaining a two-lane road primarily used by cars. Do you have a cost estimate for maintaining the road? If we pull forward the Net Present Value of the road and trail by counting the maintenance, I don't think it's going to help your case.

A permeable surface requires constant cleaning and is very high maintenance, is not suitable for this steep slope and area. DDOT, after extensive study, sees it otherwise. As they do with your claim that the trail needs 6 times as many cleanings as they plan. It's possible they're wrong, but you should either site a source or let me know how it is that you've become an expert in permeable surface trail maintenance. You're accusing DDOT of either willfully understating the costs or incompetently doing so. Either way, that kind of claim needs a little bit more than the word of an anonymous poster on a weblog.

A road does not require this constant cleaning and maintenance. Maybe not constant. But roads do require maintenance. This is an irrelevant distinction to make. And since DC doesn't clear the snow off of all bike trails, it seems the cost of clearing snow is a cost associated with just the road - for example.

by David C on Jan 16, 2011 11:29 pm • link • report

All you have to do is Google and you'll find that permeable surface and a gentle slope makes water flow at a slower rate and helps rain water to infiltrate into the surface faster. Klingle Road isn't a gentle slope and at some points >12% grade which makes the proposed permeable surface harder to absorb water.

Limitations of permeable surfaces:

In addition to the relatively strict site constraints for porous pavement, a major limitation to the practice is the poor failure rate it has experienced in the field. Several studies indicate that, with proper maintenance, porous pavement can retain its permeability (e.g., Goforth et al., 1983; Gburek and Urban, 1980; Hossain and Scofield, 1991). When porous pavement has been implemented in communities, however, the failure rate has been as high as 75% over two years (Galli, 1992).

Maintenance:
Porous pavement requires extensive maintenance compared with other practices. In addition to owners not being aware of porous pavement on a site, not performing these maintenance activities is the chief reason for failure of this practice. Typical requirements follow below:

Monthly:
Ensure that paving area is clean of debris
Ensure that paving dewaters between storms
Ensure that the area is clean of sediments

(Typically three to four times per year)As needed:
Mow upland and adjacent areas, and seed bare areas
Vacuum Sweep frequently to keep the surface free of sediment

Cost Considerations:
Porous pavement is significantly more expensive than traditional asphalt. While traditional asphalt is approximately 50¢ to $1.00 per square foot, porous pavement can range from $2 to $3 per square foot, depending on the design (CWP, 1998; Schueler, 1987). Subtracting the cost of traditional pavement, this amounts to approximately $45,000 and $100,000 per impervious acre treated, which would be quite expensive.

In addition, the cost of vacuum sweeping may be substantial if a community does not already perform vacuum sweeping operations.

by Bill on Jan 17, 2011 10:24 am • link • report

Bill what you've written, but not cites, does not say that the trail must be vacuumed every two weeks. It says the trail must be kept clear of debris. I ride the CCT, which is not vacuumed, and it mostly remains free of debris due to "sweeping" by bicycles. I don't see why four regular cleanings is inadequate.

In addition, the worst that will happen without regular maintenance is that the permeability of the pavement will be reduced from 70-80% to some lower number. With quarterly maintenance, I suspect that lower number will only be trivially lower. That is hardly a catastrophe.

Finally the data you cite is all pretty old. Wikipedia notes that "With more advanced paving systems the levels of maintenance needed can be greatly decreased..."

by David C on Jan 17, 2011 1:17 pm • link • report

Actually my data came from Wiki as well as from http://www.stormwatercenter.net, which is very up to date (not sure why quotes are old though).

As to your quote from Wiki that statement refers to concrete block permeable paving, "With more advanced paving systems the levels of maintenance needed can be greatly decreased, concrete block permeable paving requires no more maintenance than regular concrete paving as the grit between the blocks enhances the filtering properties of the pavement."

While Wiki does site advantages, the disadvantages outnumber the advantages and I understand there will be heavy 12-foot wide trucks using this 10-foot wide path:

Disadvantages of permeable paving
Runoff volumes
Permeable pavements are designed to replace Effective Impervious Areas (EIAs), not to manage stormwater from other impervious surfaces on site. Use of this technique must be part of an overall on site management system for stormwater, and is not a replacement for other techniques.

Also, in a large storm event, the water table below the porous pavement can rise to a higher level preventing the precipitation from being absorbed into the ground.
The best way to prevent this problem is to allow for adequate rain water run off at the pavement design stage.

Pollutant load
Highly contaminated runoff can be generated by some land uses where pollutant concentrations exceed those typically found in stormwater. These "hot spots" include commercial nurseries, recycling facilities, fueling stations, industrial storage, marinas, some outdoor loading facilities, public works yards, hazardous materials generators (if containers are exposed to rainfall), vehicle service and maintenance areas, and vehicle and equipment washing and steam cleaning facilities. Since porous pavement is an infiltration practice, it should not be applied at stormwater hot spots due to the potential for groundwater contamination. All contaminated runoff should be prevented from entering municipal storm drain systems by using best management practices (BMPs) for the specific industry or activity.[3]

Weight and traffic volumes
Reference sources differ on whether low or medium traffic volumes and weights are appropriate for porous pavements. For example, around truck loading docks and areas of high commercial traffic, porous pavement is sometimes cited as being inappropriate. However, given the variability of products available, the growing number of existing installations in North America and targeted research by both manufacturers and user agencies, the range of accepted applications seems to be expanding. Some concrete paver companies have developed products specifically for industrial applications. Working examples exist at fire halls, busy retail complex parking lots, and on public and private roads, including intersections in parts of North America with quite severe winter conditions.

Siting
Permeable pavements may not be appropriate when land surrounding or draining into the pavement exceeds a 20 percent slope, where pavement is down slope from buildings or where foundations have piped drainage at their footers. The key is to ensure that drainage from other parts of a site is intercepted and dealt with separately rather than being directed onto permeable surfaces.

Climate
Cold climates may present special challenges. Road salt contains chlorides that could migrate through the porous pavement into groundwater. Snow plow blades could catch block edges and damage surfaces. Sand cannot be used for snow and ice control on perveous asphalt or concrete because it will plug the pores and reduce permeability. Infiltrating runoff may freeze below the pavement, causing frost heave, though design modifications can reduce this risk. These potential problems do not mean that porous pavement cannot be used in cold climates. Porous pavement designed to reduce frost heave has been used successfully in Norway. Furthermore, experience suggests that rapid drainage below porous surfaces increases the rate of snow melt above.

Cost
Some estimates put the cost of permeable paving at two to three times that of conventional asphalt paving. Using permeable paving, however, can reduce the cost of providing larger or more stormwater BMPs on site, and these savings should be factored into any cost analysis. In addition, the off-site environmental impact costs of not reducing on-site stormwater volumes and pollution have historically been ignored or assigned to other groups (local government parks, public works and environmental restoration budgets, fisheries losses, etc.) The City of Olympia, Washington is studying the use of pervious concrete quite closely and finding that new stormwater regulations are making it a viable alternative to stormwater ponds.

Longevity and maintenance
Some permeable pavements require frequent maintenance because grit or gravel can block the open pores. This is commonly done by industrial vacuums that suck up all the sediment. If maintenance is not carried out on a regular basis, the porous pavements can begin to hold large amounts of water and cause flooding. With more advanced paving systems the levels of maintenance needed can be greatly decreased, concrete block permeable paving requires no more maintenance than regular concrete paving as the grit between the blocks enhances the filtering properties of the pavement.

Some permeable paving products are prone to damage from misuse, such as drivers who tear up patches of plastic & gravel grid systems by "joy riding" on remote parking lots at night. The damage is not difficult to repair but can look unsightly in the meantime. Grass pavers require supplemental watering in the first year to establish the vegetation, otherwise they may need to be re-seeded. Regional climate also means that most grass applications will go dormant during the dry season. While brown vegetation is only a matter of aesthetics, it can influence public support for this type of permeable paving.

Traditional permeable concrete paving bricks tend to lose their color in relatively short time which can be costly to replace or clean and is mainly due to the problem of efflorescence.

Efflorescence
Efflorescence is a hardened crystalline deposit of salts, which migrate from the center of concrete or masonry pavers to the surface to form insoluble calcium carbonates that harden on the surface. Given time, these deposits form much like how a stalactite takes shape in a cave, except in this case on a flat surface. Efflorescence usually appears white, gray or black depending on the region.

Over time efflorescence begins to negatively affect the overall appearance of masonry/concrete and may cause the surfaces to become slippery when exposed to moisture. If left unchecked, this efflorescence will harden whereby the calcium/lime deposits begin to affect the integrity of the cementatious surface by slowly eroding away the cement paste and aggregate. In some cases it will also discolor stained or coated surfaces.

Efflorescence forms more quickly in areas that are exposed to excessive amounts of moisture such as near pool decks, spas, and fountains or where irrigation runoff is present. As a result, these affected regions become very slick when wet thereby causing a significant loss of "friction coefficient". This can be of serious concern especially as a public safety issue to individuals, principals and property owners by exposing them to possible injury and increased general liability claims.

Efflorescence remover chemicals can be used to remove calcium/lime build-up without damaging the integrity of the paving surface.

by Bill on Jan 17, 2011 1:59 pm • link • report

Bill and Sally, if the problem is the novel paving type, why not push for conventional paving on the bike trail, which would be the cheapest option that preserves the right of way.

by Neil Flanagan on Jan 17, 2011 2:30 pm • link • report

Neil, we have, thanks! I also am concerned about the width (an erosion) since large trucks will be accessing the area that are wider than 10 feet.

by Bill on Jan 17, 2011 2:47 pm • link • report

So do you support a trail that is twice as permeable as a road (because it occupies twice the width of the road alternate) or do you merely support a road?

by Neil Flanagan on Jan 17, 2011 3:17 pm • link • report

Er rather, the trail occupies one half the width of a conventional road.

by Neil Flanagan on Jan 17, 2011 3:29 pm • link • report

Bill, that's fascinating reading, but none of it supports the argument that the trail will be more expensive to maintain than the road or that it will require bi-weekly vacuuming. Also, is the wheelbase of those trucks 12 feet? That seems crazy wide.

by David C on Jan 17, 2011 4:05 pm • link • report

DC Department of the Environment, who doesn't support the proposed alternative, stated they believes that the permeable pavement options considered are not appropriate for the valley because it does not function well with steep slopes or in narrow applications with a lot of edge.

DDOE also believes that permeable pavement will be difficult to maintain due to the high percentage of mature tree canopy and difficult access for vacuum sweepers. The difficulty in maintaining the system will lead to its FAILURE as it clogs over time with leaf litter.

But hey David, YOU can ride your bike up and down all day long and clear it for the rest of us!

by Bill on Jan 18, 2011 11:23 am • link • report

Bill, citation please. But before you do, here is DDOT's reply from the EA "The restriction of permeable materials on steep slopes lies with the ability to store water below the surface. As part of the stormwater treatment and storage, DDOT plans to install a swale with check dams, which would meet project requirements for stormwater management. The EA Design Report provides references for where the information on permeable materials was obtained, such as the National Asphalt Pavement Association."

As to cost DDOT replies "The total cost of the Preferred Alternative and options including construction of sustainable stormwater management infrastructure, restoration of Klingle Creek, access to Rock Creek Trail, and installation of lighting is $6,763,823. The annual trail maintenance costs would be approximately $5,840.
Based on the number of public comments received on the topic, the project team prepared a cost estimate for a road build scenario using DDOT standard cost estimating methods. Current costs to design, construct, and reopen the road to motor vehicle traffic would be $10,619,000. Although not included as part of the proposed action in the 2005 DEIS, restoration of Klingle Creek would also be required under this scenario in order to promote a sustainable road, and would cost an additional $1,075,000. Road maintenance would also cost approximately $5,840 per year. At an estimated cost of $11,694,000, the total cost of reconstructing the road is considerably more than the cost of the multi-use trail. Furthermore, the revised cost estimate to rebuild the road assumes that a number of design exceptions would be acceptable. Design exceptions would be required where the road would not meet current standards because of the constraints within Klingle Valley."

by David C on Jan 18, 2011 11:52 am • link • report

Bill, I did your job for you. I found DDOE's comments wherein they say "DDOE WPD would support Alternative 4 – 10-Foot Multi-Use Trail" and they do bring up the concerns about the permeable trail you mention. Supporting one alternative over another is not the same as not supporting the less preferable one. What's key is that they support a trail. DDOT's response "DDOT will modify Alternatives 2 and 3 (permeable trails) to include a bioswale, which is the same as that included for the nonpermeable trail alternative. The bioswale will provide additional storage and water quality benefits; thereby, creating more treatment in the event the permeable materials do not function properly in steeper areas or becomes impermeable over time. It should be noted; however, that the actual permeability of the trail does not decrease due to slope, any more than soil permeability does. The volume of storage available decreases as stone bed is reached. During very heavy rainfall, all permeable surfaces generate runoff. DDOT has no objection to providing a bioswale as additional treatment and plans to use this design in combination with the use of permeable pavement. Therefore, DDOT has revised to cost estimate to include maintenance of the permeable trail and the bioswale as part of Alternatives 2 and 3. Maintenance costs include the removal of leaf litter and other debris from the bioswale and the regular vacuum/sweeping of the trail. "

So DDOE preferred Alt 4 because it had a bioswale, and then DDOT added a bioswale to Alt 2 and 3. I suspect that if DDOE were asked now - after the addition - they might prefer 2 or 3.

by David C on Jan 18, 2011 12:44 pm • link • report

David, I can pick the EA to death just like you finding good and bad (like the National Park Service's statement: "Going forward, an increase in unchecked stormwater from the surrounding watershed could not only degrade the stream further, but structurally undermine the trail causing it to suffer the same fate as the former road.")

But instead, I'll let you have the last words since you've got the fire in the belly to always win or prove others are wrong, or demand citations; things that others on this blog don't seem to demand from you.

Good day.

by Bill on Jan 18, 2011 1:11 pm • link • report

Bill, I read that statement to mean that the issue of degradation needs to be addressed now, and that any solution to address the degradation needs to include the bioswale type solution already addressed in previous comments.

Leaving the "Valley" as is, is not an option, so now the question is, does the city exert the basic remediation, or do it with a trail, or do it with a road?

by William on Jan 18, 2011 1:18 pm • link • report

Bill,

I try to always cite my facts. And considering that the cost of the road was misrepresented, claims that can't be backed up have been made [ex:that the trail will need bi-weekly cleanings] and statements made that DDOE doesn't support the trail (even though it referred to alternatives that are different from the one's in the final EA); I think it's only reasonable to ask for citations of fact.

The thing is that a case could be made for the road or for no trail. You'd need to argue that the road, with 300 users per hour (or whatever), has a value in excess of the cost of the road and of the value of the trail. Line up all the pros and cons, attempt to give them a real value and show us where DC's valuation is wrong. Sure, I'd try to pick it apart if I thought anything seemed fishy, but I'd respect that.

But most of those in the pro-road side don't seem interested in actually doing that. Instead they just want to exaggerate, take things out of context, make false or unsubstantiated claims and generally hide from facts. And when people don't seem to be buying any of that, they take their ball and go home.

by David C on Jan 18, 2011 1:28 pm • link • report

@William. Yes, I agree with your analogy. It ain't perfect as they say, the trail could become a huge money pit for this city. I don't own a car but I do know we have transportation issues traveling back and forth across the park and this road affects many people from Wards 1, 4, and 3.

by Bill on Jan 18, 2011 1:33 pm • link • report