MS. JEN GOLDBECKWelcome back. I'm Jen Goldbeck from the University of Maryland sitting in on "The Kojo Nnamdi Show." It sounds unlikely in the nation's capitol but when it rains hard raw sewage is sometimes released into the Potomac and Anacostia Rivers. That's because a hundred-year-old sewer system carries both sewage and storm water runoff to the water treatment plant. But during a big downpour it can't handle both so it sends the overflow into the rivers.

MS. JEN GOLDBECKTo comply with a court order, the district's water agency agreed to build a series of huge underground tunnels along both rivers that could store that access water and keep untreated sewage out of the rivers. The first tunnel is under construction beneath the Potomac across from Alexandria. Now the water agency wants to forego some further tunneling in favor of building so-called green infrastructure, like permeable pavement, rain gardens and rooftop water storage. But some environmentalists worry that there's no proof green infrastructure can do the job so they're reluctant to let go of the tunnels and the certainty that the rivers will be clean.

MS. JEN GOLDBECKThe proposal is up for public review. Here to explain is George Hawkins, general manager of the District of Columbia Water and Sewer Authority known as D.C. Water. Thanks for being with us, George.

MR. GEORGE HAWKINSDelightful to be here. Good morning.

GOLDBECKAnd later we'll have Matt Logan, president of Potomac Conservancy and Potomac Riverkeeper joining us. But George, remind us of the extent of the problem. The combined sewer system still serves one-third of the district. How much sewage flows into the Potomac and Anacostia Rivers each year when we have heavy rains?

HAWKINSThat's a great question. And your introduction was right on. When the city was designed about 100 years ago, the state of the art at the time was to build large sewer systems that would take both storm drain water that's coming off the streets. So you're walking down the street and there's a rainstorm. You see water going in the storm drain and you wonder where it goes. It goes to exactly the same pipe that's connecting into that building for sanitary flow into the same, which is why it's called combined sewers.

HAWKINSNow those work beautifully most of the time unless a lot of rainfall is going in there. And just like a movie when someone's stuck down there and the rainfall flows, that pipe will fill and an overflow will go to the river. That's a better alternative than having it go back to the street or going back to a building.

GOLDBECKSure.

HAWKINSIn an average hydrologic year -- that's a technical term but we pick sort of an average weather set of years to use as our measuring point as a comparison. In the years we've set about 3 billion gallons of combined sewage will go into all three of the rivers, Rock Creek, the Potomac and the Anacostia. Two-thirds of that flow go to the Anacostia. And obviously anything that flows to the Anacostia then flows into the Potomac, because that's where the Anacostia junctures with the Potomac.

HAWKINSSo about 3 billion gallons in an average year and we like to remove in total at the end of this project 96 percent of that overflow and get it handled and treated rather than going right to the river.

GOLDBECKIn 2005, D.C. Water signed a consent decree with the federal government to build several tunnels ten stories deep along parts of the Potomac and Anacostia Rivers. How will the tunnels allow the combined sewer overflow to be treated before it's released into the river?

HAWKINSThat's a great question. We, in essence, are building a new huge sewer system underneath the current system. We looked at a lot of alternatives before we selected the big tunnels. If we were going to go down and increase the size of our existing sewers, we'd have to be digging up city streets all over the city at the surface. And generally sewer pipes are underneath everything else in the streets, so the Pepco lines and Verizon lines, our own water lines, that's all above. And then below that is a sewer line and we'd have to dig down to do it. It would disrupt the whole city. The cost would be exorbitant.

HAWKINSSo what we're doing instead is really a marvel of engineering. We are building a giant sewer tunnel underneath everything else. As you said, ten stories underground. This is below metro tunnels. They're actually bigger than metro tunnels. The machine that we currently have trundling its way underneath the Potomac River, as we speak -- it is in operation right now -- is 100' down and it's 26' in diameter, almost three basketball hoops piled on top of each other is how big this machine is. It's gigantic.

HAWKINSAnd essentially what happens is rather than the overflow being routed to the river when there's a lot of rainfall coming in, it goes into a drop shaft which drops all the way down into this tunnel. And the tunnel is both containing it like a giant underground cistern, but it's also conveying it. It's taking it down to Blue Plains. Blue Plains is the largest advanced wastewater treatment plant in the world. It's what you see if you're driving 295 south right before you leave the district on your right side. It is also a technical marvel. It can do the job. The question is how to get that flow there in time when the existing pipes aren't big enough. So we're building this huge system underneath it all to convey it down to Blue Plains.

GOLDBECKYou too can join the conversation. How do you feel about digging giant tunnels near the Potomac and Anacostia Rivers to keep sewage overflow out of the rivers? Do you think green infrastructure should replace some tunneling to handle combined sewer overflow? You can join us by calling 1-800-433-8850, by sending us an email to kojo@wamu.org or by following us on Facebook or sending us a Tweet to @kojoshow. George, the first tunnel's under construction, thanks to a giant drilling machine you mentioned nicknamed Lady Bird. Where will this tunnel go?

HAWKINSThe whole show we were focusing on our prospect of doing a hybrid. To me it's not weather tunnels are good or green infrastructure's good. They both work well. They have different attributes and our current proposal is a hybrid between the two. But very importantly, the biggest segment of the tunneling that we're doing and the largest quantity of overflow is on the Anacostia. And that we are going to build the tunnel. In fact, the only thing we've done on the Anacostia side of the program is to build a bigger system than we anticipated.

HAWKINSSo when we originally planned it in 2005, we're now doing a bigger system and it's doing faster than we originally anticipated. So we've moved up the timeframe and we're building it sooner. That's the tunnel that's going now. It's going up the Potomac. It'll take a right turn up the Anacostia and finish the first phase at National's Ball Park. We have a big pump station there. A second phase of that tunnel will start at RFK Stadium and tunnel south under the Anacostia to the same place.

HAWKINSA third phase will go from RFK Stadium into the center of the city, particularly for neighborhoods in Bloomingdale and the Droy (sp?) Park which many people from the city know have had flooding problems that go back a century. That we are going to build. As I said, we've only increased its performance and moved it up as a scheduling matter. Where we're proposing green infrastructures on the other side of the city, we have a second very small tunnel plan for the Piney Branch, which is a tributary to the Rock Creek, and a larger tunnel but smaller than the Anacostia on the Potomac.

HAWKINSAnd what our current proposal is -- and this is what we are -- we are hopeful that people will support -- is we're going to omit building the Piney Branch tunnel and instead use green infrastructure. If we can capture storm water at the surface of the land before it hits the sewer than obviously the sewer won't overflow because the storm water hasn't gotten there yet. And if we can use it at the surface of land for street trees, for green, for all sorts of amenities that improve the quality of life in that neighborhood, there's a lot of benefits that come, as well as the water quality benefits.

HAWKINSSo the green infrastructure has a lot of advantages going for it. And for Piney Branch we'd like to eliminate the tunnel entirely. That's a fairly small tunnel. We're pretty confident we could capture that storm water in the Piney Branch water shed using green, bio swales, green roofs, all the techniques you mentioned. For the Potomac we have a bigger challenge because the quantity going to the Potomac is greater than is going to Rock Creek. And our modified proposal is to take the tunnel and make it about half as long as the current plan.

HAWKINSThe current plan is to build a tunnel. And one of our biggest challenges, no matter what else happens, is whether we're ever going to be able to build this tunnel on the Potomac because of where it's located. It's going to be built from south of the Kennedy Center right along the waterfront in Georgetown to north of Key Bridge. And we'll have construction of very, very substantial size going along a number of occasions with the current design. And there have been a lot of questions asked, included by the park service, about whether or not that should be built. Because we'll have to tear up a lot of the Georgetown waterfront.

HAWKINSOur proposal now is to build a tunnel about half as long, covering those areas where the quantity is the greatest, because the tunnel does have benefits. There's no question the tunnel captures the most storm water in the midst of the biggest part of the storm. And then use green infrastructure for the northern parts of where the tunnel would have been. That's where you think of the Georgetown Park all along the waterway, and use green infrastructure in that part of Georgetown. So that's our proposal is to handle water with a combination of tunnels and green infrastructure for the Potomac and the Rock Creek.

GOLDBECKAnd listeners, you can see photos and a video of the tunnel boring on our website kojoshow.org. We're going to talk a lot more about this green infrastructure, but we have a lot of people calling who are interested. And I'd like to start with Tom in Sterling, Va. Tom, you're on the air. Go ahead.

TOMOkay. Well, thanks for taking my call. I was curious. The gentleman mentioned at least twice that the majority of the overflow moves into the Anacostia. I'm wondering why that is. Is the Anacostia especially more capable to consume this overflow or how did it wind up moving into the Anacostia? What was the decision-making process or ecological concern?

HAWKINSTom, that's a great question. Two-thirds of the overflow we have in the city does go to the Anacostia. And that's not because the Anacostia can handle the flow. In fact, it's a bigger challenge on the Anacostia. The Anacostia is a very slow-moving river. So any contaminants or refuse that you don't want in the river that goes into the Anacostia sits there for longer because the water moves very slowly. It's a smaller water body. So in fact it does not assimilate waste very well.

HAWKINSBut the major trunk sewer lines that overflow -- the major one is called the northeast boundary trunk sewer. It goes underneath almost the entire length of Florida Avenue, cutting across the city. And it drains the largest area of combined sewer parts of the city to one giant trunk line that ends up at the Anacostia. It was designed in 1890. And the reason it's called the northeast boundary trunk sewer is because in 1890 Florida Avenue was the northeast boundary of Washington, D.C. There wasn't development to the north.

HAWKINSSo all this new development has occurred in these neighborhoods. That's going to the same sewers that were built 100 years ago. That's why there's overflow to such an extent. And it's happening to the Anacostia which is actually a river that cannot handle it as well ecologically. And that's why we're building the tunnel underneath the Anacostia first. And we've actually improved its design and are moving it forward in time because we want to get it done as quickly as we can.

GOLDBECKWe'll take a call from Paul in Washington, D.C. Paul, you're on the air. Go ahead.

PAULWell, thanks to both George and Matthew for their work protecting our waterways. I have a comment and a question. And the comment is, while supporting the shift, George, from some of this big pipe infrastructure to more of a mixed green infrastructure like you're proposing, why aren't we, instead of spending a couple hundred million dollars on the green infrastructure, spending over a billion like Philadelphia is doing?

PAULAnd the question that I have for Matt Logan and his organization is, why are you getting in the way of this very small shift in the ratepayer dollars to trying something that's based on sound science and that could be managed so that it could work. We may be over the -- overtime to scale it up. And if it doesn't work we can adjust.

GOLDBECKSo we'll have...

PAULI really don't understand why the environmental community is opposing this very modest and, from my perspective, not-adequate-enough proposal?

GOLDBECKWe'll have Matt weigh in on that after the break actually. But George, I'll let you respond first.

HAWKINSSure. And Paul, this sounds like Paul Schwartz, if I were to guess. How are you this afternoon?

GOLDBECKWe have Paul not on the line anymore.

HAWKINSOkay.

GOLDBECKSorry.

HAWKINSWell, Paul asks a great question. We originally proposed doing green infrastructure at a higher scale, more to the tune of what you suggested. Our problem is capturing quantities of rainwater at the peak volumes in the storm. There are three or four outfalls that have combined sewage that are coming into the Potomac right where the Rock Creek intersects with the Potomac. And most people know that as near the House of Sweden. And there's the boathouse right there.

HAWKINSThe amount of quantity -- the quantity that flows there in a short period at the peak of storms is so great that we felt in order to capture enough quantity at peak we needed a portion of the tunnel. It's all about performance. And what our estimation is, that we will achieve comparable performance with this project. There are other cities like Philadelphia in particular that has a tremendous green infrastructure program. I admire it but they don't capture the quantity of flow that we do because it's very hard to do, particularly at the peak points of the storm.

HAWKINSUnlike Philadelphia, we're trying to reopen a consent decree that already exists. So reaching a comparable performance level is very important to get in the door of opening the consent decree. So I actually started -- as Paul knows, we started out with a proposal to do more green infrastructure but we had a hard time reaching certainty on performance comparable to the tunnel unless we use this hybrid approach. So while, yes, it is less than we originally anticipated I personally would like to do more.

HAWKINSWe'll still be doing tens of millions of dollars of green infrastructure work over many years. We will make the market for green infrastructure in Washington. And that's still a very exciting prospect.

GOLDBECKSo we've been talking about green infrastructure but can you actually explain to us how does it work? Talk about permeable pavement, blue roofs and how they handle rainwater just so we get a sense of what this infrastructure would actually do for the problem.

HAWKINSSure. The challenge obviously, as I've been describing it, is that in a storm so much water is going into the storm drain and into the pipe that it overwhelms the size of the pipe to be able to convey all that flow. If you can hold and use the water before it gets to the storm drain, so it never gets there in the first place, you achieve the same goal as the deep underground pipe because you're reducing the amount of flow going into the sewer.

HAWKINSTo hold the water before it gets to the storm drain means using these green infrastructure techniques. If you build rain boxes the correct way, bio swales along streets, when you walk down the street and you see this beautiful tree and you wonder where does the rain -- how does the rain get to its roots when it's surrounded by concrete? Well, you can build the streets to allow water to infiltrate into the ground, be routed to the tree boxes and actually increase the amount of green that you can sustain along the street.

HAWKINSSo your street is greener. That has energy benefits. It has air quality benefits. And you contain the water instead of going into the storm drain, which is ultimately the goal of either the deep tunnel or the green infrastructure. The other huge benefit to green infrastructure -- there's air quality benefits, there's water quality benefits -- it works in every storm. So the tunnel only comes into play in the biggest rainstorms when you're going to have the overflow into the tunnel. That tree box is absorbing water in every single rainstorm. So it gives benefit all the time.

HAWKINSAnd the kind of work that you do in order to install it is the kind of work that's accessible to people in Washington, D.C. who need jobs because we'll be working on the street. Deep tunnel work, they call them sandhogs. It's an amazing technology. The machine -- it's pretty breathtaking what they're doing. But those are less accessible jobs to folks who are not highly specialized and trained. Doing work on the street to build green infrastructure, where you're capturing rainwater in green roofs where you're essentially putting in gardens on roofs to capture rainwater, to enhancing the green along the streets, so that's a nicer street to walk on. Who doesn't want to be under shade on a 100-degree day in Washington, D.C.?

HAWKINSIt is better for air quality, it is better for energy use. That's the kind of work that can improve quality of life but also give jobs to people who need it right here in the city.

GOLDBECKLet's take a call from Raymond in Washington. Raymond, you're on the air. Go ahead.

RAYMONDThanks for taking my call. Mr. Hawkins, how are you going to pay for the deep tunnel and the green infrastructure and how many years is -- do you estimate it'll take to finish both?

HAWKINSRaymond, that's a great question and it's one that we are concerned about on a daily basis. The ratepayers of Washington, D.C. are paying the vast bulk of the cost of either project, whether it's gray infrastructure or green infrastructure. This is ratepayer driven and anybody who gets a bill from D.C. Water in Washington, D.C. has seen their bill go up. And by far the largest single segment of our bill that's increasing is the part of the bill that is designed to pay for these deep tunnels, or would pay for green infrastructure. So it's on ratepayer bills.

HAWKINSWe project rate increases over the next ten years and beyond because this work is going to take that long and longer. Our current consent decree, which we are on budget and on time to finish, all the work would be done by 2025. If our proposal goes through and we do additional green infrastructure and modify the design of the tunnels, we would extend that work through 2032. So there'd be an additional seven years. The total cost is about the same but we do spread out that cost over a longer period of time so our ratepayers will see slightly lower increases to their rates, particularly in the 2020s, when by then rates will be very high.

HAWKINSThis is not for free, either project are multi-billion dollar projects in total. And it's our rate payers that are footing the vast bulk of the bill.

GOLDBECKWe'll continue our conversation about green infrastructure and clean water in D.C. after this break. I'm Jen Goldbeck and you're listening to "The Kojo Nnamdi Show."

GOLDBECKWelcome back. I'm Jen Goldbeck from the University of Maryland, sitting in for Kojo Nnamdi. I'm talking with George Hawkins and Matt Logan about clean water and green infrastructure in D.C. If you'd like to join the conversation you can call us at 1-800-433-8850. Matt, I'd like to bring you into the conversation. Matt is president of Potomac Conversancy and the Potomac Riverkeeper. Thanks for joining us.

MR. MATTHEW LOGANHi, Jen.

GOLDBECKI understand you're concerned about letting go of the tunnel without more proof that green infrastructure really works. Why is that?

LOGANLet me preface what I say by just mentioning that I'm president of Potomac Riverkeeper. In the past I worked at Potomac Conservancy and now I'm with Riverkeeper. We're clean water advocates for the DCA and all its tributaries. So my concern with green infrastructure is not that it won't work. We love green infrastructure. I've spent my career working to spread green infrastructure.

LOGANWhat the concern we have is that we're talking about a problem that is almost beyond most people's ability to imagine. We're talking about three billion gallons a year of untreated sewage going into our rivers and streams. That's billion with "B." And so what George is proposing is a solution that with the tunnels or with the green infrastructure that would leave more than 100 million gallons of untreated sewage going into our rivers.

LOGANAnd so to me that's a partial solution at best. And so when we look at this problem, what we see is an opportunity, not only to do the tunnels, but we believe you have to have the tunnels, as well as the green infrastructure. Our goal isn't to get it 96 or 94 percent of the way clean. We need to get it 100 percent clean. And there's a consent decree in place right now that is a legally binding agreement that requires D.C. Water to bring the water quality up to a certain level.

LOGANWith this proposal that George is shopping around, the commitment for actual water quality improvements would be traded away for an investment, a dollar investment, with no guarantees that it would work. And so once that's money is spent, if we're not enjoying the water quality benefits, well, we're out of luck. And that's just not good enough for the Potomac River.

GOLDBECKGeorge, do you want to respond?

HAWKINSSure. First, Hi, Matt. And I love the Riverkeepers. I've worked with Riverkeepers all over the country. I appreciate their advocacy. And see eye-to-eye with them almost all the time. I differ slightly with Matt in this case. And that's okay. Reasonable people can differ on issues like this. Water quality really matters. We all want the same outcome, which is clean and healthy rivers.

HAWKINSMy worry is that no matter what we do, green infrastructure or gray infrastructure, most of the water quality problems coming into Washington, D.C., come from north of us and run off regardless of what we do here. Nonetheless, I think that the 96, 98 percent -- what our listeners have to understand is that the percentage capture that we get will never be 100 percent. No matter what we design, if there's a storm big enough, it won't be big enough to handle the storm.

HAWKINSSo yes, we could get 100 percent of -- remember I said, average hydrologic year? We pick a series of years to use as our measuring point, but if we have a hurricane come through we won't have 100 percent capture because even more rainfall than even the biggest tunnel can handle, can come into the system. So we'll never be at 100. We're all seeking to get to the highest percentage we can for the dollars we're spending.

HAWKINSAnd I appreciate that Matt would like us to build the tunnels and the green infrastructure. I'm trying to balance, weigh on the side of our belief is there's very few -- this technique that we're -- what we're doing is called a long-term control plan. There's 770 cities in the United States that need long-term control plans. So we're in the soup with many other cities. 96 to 98 percent capture, which is what we're reaching here in D.C., is one of the best goals and achievements of any city in the country.

HAWKINSSo no city is expected to get to 100. 96, 98 is one of the very best. And it's our goal to have a comparable level of performance with this hybrid approach. Now, the question of whether it achieves, whether it's a tunnel or green, how all these consent decrees are set up is at the end of the projects -- which if the initiative is supported, we've proposed a 2032.

HAWKINSTiming is matter of negotiation, of course. Total amount that we invest in green infrastructure is a matter of negotiation. That's why we're open for public comment. We want people to comment. We encourage it, want it for whatever issues they have -- we hope including supporting it. But no matter what remedy we use, at its conclusion you start post-construction monitoring.

HAWKINSAnd there'll be another round of assessment of what's the water quality of the river, what's necessary, what are we achieving no matter what remedy we use that goes into the next round. In our industry that's the course of things. You always do what is required, do your current permit, it reaches what it's allowed and then you check to see what the status is and take more steps if needed. And that would be true in this case, as well.

HAWKINSWe are committed in our proposal to spending this $100 million through 2032, then we complete our work. We do post-construction monitoring and see how we're doing.

LOGANYou know…

GOLDBECKSo you -- oh, I'm sorry. Go ahead, Matt.

LOGANYeah, if I might respond. You know, once that billion dollars is spent I think it's -- I really think we have to view this as a once in a lifetime, once in a multi-generation opportunity that we're talking about fixing a 120-, 150-year-old problem here. And it may be a very long time until we're able to take that opportunity. I've not heard anything that would convince me that we should both delay this work and put an investment into green infrastructure to scale where it's really never been successfully implemented without guarantees.

LOGANFor us to say, let's go ahead and do this green infrastructure and then, you know, once we spend a billion dollars we'll take a look and see how we did, that's just not good enough. I mean we have to be thinking both how can we make this work with the tunnels, as well as through good planning, good local decision making and so on that's going to get us some better green infrastructure.

LOGANThere are countless issues that we're going to run into, as we look to implement some of this green infrastructure, whether, you know, does it go on public property or private property? Who is going to design and install it? What if a private property owner chooses not to comply? What if they don't maintain and repair it? You know, this is kind of a forever solution. How are we going to -- are we going to develop easements and covenants that are going to require property owners to maintain a rain garden on their property?

LOGANWhere would it go in a community like a Georgetown, that's already so heavily urbanized? And then what do we do about this 100 million gallon plus of untreated sewage that is still going into the rivers? I mean it's almost unfathomable that our solution is still a partial solution. But having said all that, I do want to congratulate George. He's brought energy and some progressive thinking to the agency. It's a pleasure to know that there is a discussion that we can have about this.

GOLDBECKGeorge, go ahead.

HAWKINSSure. Thank you, Matt, for the kind words. It's always nice to get them upon occasion. And I appreciate the points he's making. And I want to state again that the notion that there's 100 million gallons of untreated -- it's mostly storm water, but mixed with some sewage going into the rivers. That will be true regardless of whether we use infrastructure or gray. That's part of all of the consent decrees nationwide.

HAWKINSGetting to 100 percent is an illusory goal because there will always be a bigger storm that causes an overflow, no matter how big you design your remedy. The point of whether green infrastructure -- all of the issues that Matt raises, which are all good. I mean, are we going to use easements, what are we going to do on private property? We look forward to that.

HAWKINSAnd the engagement of the public with a green process that is engaging in their neighborhood and on their street and something they interact with, rather than something underground, to me is not only a good green outcome, it's good for the connection to people and infrastructure issues and environmental questions. And this is well enough known as a technology, as Paul, who called in earlier had mentioned, that EPA, U.S. Environmental Protection Agency absolutely supports this as a direction for combined sewer.

HAWKINSThe Obama administration absolutely supports this as a direction for combined sewer. And as I've said in our plan, we're using both. We're still going to build a very substantial tunnel as part of the Potomac effort and supplement it by green infrastructure and use a hybrid of the two. So we're confident in the performance and we're confident that it will work and that we do have enough experience around the country to know how this works.

HAWKINSI do agree that it's going to take a lot of creative new thinking to get this work. I'll give an example. When I first come to the District, I ran the Department of Environment. And we were evaluating the parking lots for the Nationals ballpark. And I was pushing for storm water bioswales on those parking lots. And we succeeded. So if you go to the Nationals ballpark you will see bioswales next to the ballpark, taking the storm water that's going off the parking lot into a bioswale, which is just the kind of thing we need.

HAWKINSSeveral years later when I lived down by the Navy Yard, I noticed there was a little tractor out there that was digging out the bioswales because they were filling up with silt. If you don't have someone going back cleaning them out, these devices will not work. That is absolutely right. And it's a challenge. On the converse side, that's a tremendous opportunity for a permanent green job, for someone to do that work over time. And we consider that a positive attribute.

HAWKINSThe argument that I would say is in favor of green infrastructure is that for dollar spent for gray, you get clear results. You know how much you capture and you know where you capture it. And we maintain it. A dollar spent on green, we believe the performance is out there to indicate how you capture, you improve the quality of life in that neighborhood. There's energy benefits. There's air quality benefits. And you have these jobs that are accessible for people who need them.

HAWKINSSo we think that dollar goes farther when you invest some of it in green -- in our case, out of the 2.6 billion dollar project, it's relatively modest, 100 million, that we're going to spend on green infrastructure. It still would be unprecedented in D.C. and I think would drive tremendous positive change in the city.

GOLDBECKWe have a lot of callers who want to weigh in on this. Let's start with Peter, in Washington. Peter, you're on the air. Go ahead.

PETERYes. Thank you for taking my call. I'm Peter Ensign, the executive director of D.C. Greenworks. And thank you for this opportunity. And I agree very much with George, talking about the opportunity for a great number of local jobs to be created from green infrastructure, whereas with the gray will drop off very quickly once the work is complete. As well as there are at least a dozen or more benefits that green infrastructure adds.

PETERI think that, you know, just to understand, green infrastructure, green roofs and rain barrels and rain gardens, these are relatively new practices in our country, compared to other parts of the world. And yet, they're quite traditional practices that have been used in some parts of the world for millennia. The one thing that we don't have is a lot of date on monitoring and performance.

PETERAnd the more that we build, the strong the impetus will be to actually put some funding toward the monitoring and analysis and evaluation of these green infrastructure projects. It's one thing to be able to measure a tunnel's capacity before you build it, but green infrastructure is something that requires this ongoing monitoring. And again, these are jobs that will be handed by mid and higher-level skill employees.

PETEROne of the biggest things is that these are visible projects. And so much of what goes on in a city to keep it running is underground and out of sight and away from people. And people just expect it to work. And one of the great benefits of green infrastructure is that it's something that's visible. You look outside your window, you walk down a sidewalk, and you see it.

PETERAnd one of my favorite lessons from working in this industry, is that when people see these things they respond positively to them. They say, oh, I've got a garden in front of my house when it's a bioswale. Or I've got a garden up on my roof and they have a green roof. And they're saving energy costs, they're capturing storm water, they're quieting their interior space.

GOLDBECKPeter, I'm going to ask you to hold there, just because we only have about a minute and a half left. So I'd like to give each of you kind of a 30-second response to all the issues that Peter raised in that call. Matt, why don't you go first.

LOGANSure. I agree with everything Peter has said regarding green infrastructure, and George, as well. I am excited by the possibility of having more green infrastructure in the community. But, you know, we can't sacrifice the Potomac River on an experiment either. And I think that's one of these things, that we have to take very seriously, is the proposal in front of us is one in which we would be losing certainty and it would extend the time frame out at least another seven years.

LOGANLBJ said 50 years ago the Potomac River's a national disgrace. I mean it's a disgrace that's taken this long for us to finally have a solution. And it's right here in our hand and to say, well, let's punt it down the road another seven years and let's trade certainty for a hopeful outcome, to me that's not the right way to use green infrastructure. We have to implement it. We want to implement it. But it can't be the entire cornerstone for the entire solution.

GOLDBECKOkay. And George, before I have you respond just really quickly, we do have a list of public meetings where people can comment. In the interest of time we'll post those on the website. If you can give us a really quick final response then we'll wrap up.

HAWKINSSure. I love Matt's comments. Like I said, we have common cause on almost everything. In this case green infrastructure is not what we're pinning our solution on. The vast bulk of our solution for the Potomac and the Anacostia and the Rock Creek is tunneling. We're adding green infrastructure at the margin, at a moment that will make a significant difference -- millions of dollars a year, each of those seven years of the extension is not us twiddling our thumbs.

HAWKINSWe'll be investing $5 million to $10 million every year in neighborhoods, improving as we go along, monitoring, just as Peter said, improving our practices, getting performance. And we can deliver so many good jobs and so many good outcomes for the same dollar, I say let's try it.

GOLDBECKThank you both for joining us. I'm Jen Goldbeck, sitting in on "The Kojo Nnamdi Show." Thanks for listening.