It’s Miller Time (Again) (Sorry)

Preamble:  Please believe me when I say that I am not obsessed with David Miller!  I am, however, hopelessly obsessed with the idea that sustainable urbanism is critical to our future.   And while I don’t doubt that Miller is a swell guy and this is nothing personal, in my view he and his cohorts are proliferating misinterpretations that will impede progress toward sustainable urbanism in Seattle.


Thank you David Miller for taking the time to respond to the Q&A, even though this is just some hack’s blog with the word “ass” in its title.   Many of your replies beg for followup, but first I should be a good sport and respond to your questions to me:

1. You obviously want to reduce the amount of SF in Seattle. How much should we have left?

By your definition, none, because I support allowing backyard cottages, a.k.a. DADUs in all single-family zones.  Assuming we’re ignoring DADUs, I cannot give you a precise number, but I assure you I am not calling for anything like the elimination of all single-family zones in Seattle.  I believe there are numerous areas in the city where strategic upzoning of single-family should be done, in particular where it is adjacent to transit corridors or stations, and the Beacon Hill light rail station area is one example.  To throw a number out, within a 10 year time frame, it would probably make sense to upzone something like 10 percent of our single-family zones to multifamily.  Not that radical.

What I am more concerned about than the exact number is the attitude among many in Seattle that single-family zones are untouchably sacred, such that the planning process hits an automatic dead end whenever the possibility of upzoning single-family is merely hinted at.  To most electeds it’s totally radioactive.  And this is the same attitude that you, David, displayed when you twice dodged my question about upzoning single family (#1 and #2).   And so I’ll ask you again:  Would you, or would you not, support any upzoning of single-family zones that are within one-quarter-mile of the Beacon Hill light rail station?  This is the kind of tough decisions elected officials have to make.

2. Given there is no convincing data showing green roof techniques can match the stormwater retention capability of conifers, plus the loss of truly permeable surfaces that inevitably result from upzoning SF to higher densities, how do you expect to upzone SF and avoid environmental damage and massive increases in Seattle’s stormwater treatment requirements? If you’re willing to sacrifice Seattle’s environment for environment elsewhere, that’s a valid answer as long as you also explain how we’ll deal with Endangered Species requirements in our urban watersheds.
3. Given the inevitable increase in stormwater treatment requirements (unless you pull a rabbit out of the hat in #2 and figure out what no stormwater expert in any jurisdiction has been able to answer for me), how will you pay for it in a way that does not hurt affordability.

I believe you are greatly overestimating the role of conifers in single-family zone hydrology.  In my Central Area single-family neighborhood I don’t see many conifers, though I realize they are more common in the north end. But let’s probe a little deeper with some math, shall we?  Tree canopy coverage in single family zones is currently 18 percent.  Assuming the tree type mix is similar to Seattle’s urban forests, conifers would make up about 15 to 20 percent of that 18 percent—or about four percent of the total land area in single-family zones.

But then we also must consider that tree cover in Seattle’s multifamily zones is currently 13 percent, which means you don’t lose all the trees going from single- to multi-family—you would expect lose a little less than a third of them.   Combining with the result above, the conifer tree cover that would be lost with a complete conversion of single-family to multifamily would be equivalent to roughly one percent of the total single-family land area.

Of course, a full zoning conversion like that will never happen—if there was a ten percent conversion as I proposed above, the conifer cover lost would on the order of a mere 0.1 percent of all single-family land.* It’s hard to imagine how that would result in a stormwater catastrophe.

Important aside: None of this is to say that urban trees don’t matter, or that conifers are not a valuable asset.  The point is we need reality-based policy.

I’ll venture to guess that the most common land cover in single-family zones is turf grass lawns, which have stormwater retention capacity significantly lower than that of conifers, and thus would be more easily replaced functionally by green roofs. And furthermore, green roofs are not the only available approach—there are many other strategies, including swales, rain gardens, rainwater harvesting, and pervious pavement. Seattle Public Utilities has been experimenting quite successfully with many of these techniques (pdf), and found them to be both effective and economical.

But listen:  I believe the answers to all of your concerns in #2 and #3 can be found in an existing multifamily development right here in Seattle:  High Point.  This development has roughly three times the density of a typical single-family neighborhood, and has a natural drainage system that eliminates runoff to the Seattle stormwater system (in all but the most extreme conditions).  And since it all drains to Longfellow Creek—a salmon-bearing stream and one of Seattle’s priority watersheds—I think it is safe to assume that it is in compliance with the Endangered Species Act.  The development also happens to provide affordable housing.

To be fair, it would be difficult to retrofit an existing neighborhood with a large-scale natural drainage system like the one at a High Point.   But on my reckoning, projects like High Point clearly demonstrate that we have the technology to economically offset the loss of pervious surface that would occur with modest single-family upzones.

(Do I even need to mention that Seattle isn’t the end of the story, that if Seattle loses 10 trees to save 100 on the urban fringe, then the region—and therefore all of us—benefit in the long run?  No, I didn’t think so.)

4. Do you agree we need to increase our urban tree canopy to 30%? If so, how would you accomplish this in a city that you believe should become more dense? Bonus points for addressing the conifers versus deciduous tree problem in your answer.

I’ll give you the answer you want:  infill in existing multifamily zones.  Did I get it?

I’m all for more trees.  But while it is true that single-family zoned land represents the biggest opportunity for increasing tree canopy in Seattle, that does not justify a moratorium on single-family upzones, as you would seem to believe.  The benefits of trees  must be measured against the benefits of density.   And there are all kinds of possibilities for increasing tree canopy in areas other than single-family if we try a little harder.  We all love trees, but policy must be based on rational, big picture assessments, not on myopic fancy.

Bonus: Deciduous are the ones that the leaves fall off of, right?  Or is it the other way around?  All I know for sure is we’ve got a deciduous conifer growing right in our traffic circle.


*This is a very loose calculation and is only meant to be an order of magnitude approximation.  The assumption that conifer cover in single-family is similar to urban forests overall is probably generous.  On the other hand, because conifers are so big they are less likely to thrive in multi-family than in single-family.

21 Responses to “It’s Miller Time (Again) (Sorry)”

  1. Kathryn

    Dan you are totally missing the Urban Villages and ignoring the Urban Village strategy. These have the oxymoron of Single Family zoning.

    When people say ‘single family zones’, they typically mean places that are not Urban Villages.

  2. ktstine

    I agree with you Kathryn, but there is a heck of a lot of single-family zoning within urban village boundaries in Seattle. And I think this is what has become most contentious, as zoning has been realized along major arterials and townhomes have proliferated adjacent to single-family a perception and/or real feeling that SF is “threatened” has emerged.

    A great way to work through this (and acknowledge it) would be a genuine neighborhood plan update process. Beacon Hill is a good example. Instead of taking the time to really involve and empower people, that update process was unleashed within a 6 month time-frame, with “final” drafts being produced this fall, perhaps not with neighborhood validation.

  3. F Buncher

    New band name: deciduous conifer

    The western larch is a nice example:

  4. Uncle Vinny

    Huh, I figured he was kidding about deciduous conifers! Ya learn something new every day.

    I’m interested to hear David’s reply, especially about green roof vs conifers.

  5. hiding behind an avitar

    Did you try calling David? Because posting on your blog is making this personal. This is safe territory for you with all your cronies at your side.

    Let ’em line up and take pot shots at David.


  6. Kathryn

    @ktstine Will the Urban Village boundaries be redrawn with the Beacon Hill plan? It’s kind of strange when I look at the zoning map.

    I agree about the lack of process. I think involvement by more neighbors to seriously look at the benefit of the station and the design of their neighborhood would be best.

    Two things would be useful. Conditional zoning (something that Miller has talked about) where current owners don’t get hit by a large tax bill based on up zones — and the assessment IS affected. And, zoning that provides a nice dropping off from the higher NC toward the Urban Village boundaries.

    Anyway, I understand Miller to be focused on the Urban Village strategy. The villages themselves need to be looked at, through a good Neighborhood Planning update process. Current village boundaries where there IS no focus of transportation and economic development need to be questioned. Others need to be adjusted.

    But, without conditional zoning and a better range of zoning options (true duplex), we might end up with what happened the last time in some areas like the CD — hardly any zoning changes.

  7. Ellery

    If David posted these questions to the blog, then the blog is a perfectly legit place to counter them.
    I dont think that looking at SF in addition to the UV stategy means that Dan or anyone else is necessarily ignoring the UV strategy. Yes, most growth should and will happen in the UV areas. But there are a lot of legit opportunities in SF zones for modest but meaningful zoning adjustments to give more housing options in Seattle, and the UV strategy should not be an obstacle to that.
    And Dan – thank you for addressing David’s tree concern, especially when it comes to DADUs. I have a 500sqft detached structure in my backyard that I hope to plumb someday. And despite its presence, I have planted four new trees on my property in the past couple years, and torn out 300sqft of impervious driveway to make a garden. Meanwhile, neighbors down the street, with no detached building, have chopped down two trees and covered their backyard with a concrete patio. DADUs are not a threat to our tree canopy. People are.

  8. Uncle Vinny

    I would like to take a moment to clarify that UV = “Urban Village” or “Uncle Vinny”. My many fans may continue to use the abbreviation as they see fit.

  9. ktstine

    I would love to hear about a case study or example of the property tax situation you present here. Are lots that were previously single family zoned that are now an “L” designation being hit with higher taxes? I would be surprised if that is actually happening on the ground, because assessments are only partially based on land value, the rest in the actual structure that is being assessed. So I am not sure I follow the logic for a “conditional zoning” designation.

    And I know we have talked about this, but I feel that we already have a variety of zoning options that “step down” from the NC-40 and 65 zones, these being the “L” designations that produce our beloved town home typology within urban villages in particular:

    The issue there, as often discussed here, is that many don’t like the product that this zoning produces, so instead of creating a new designation, perhaps we should fix what is wrong with the existing. Personally, I like the town home concept very much (in terms of density near services and transit, which works very well in my West Seattle neighborhood), but the typical execution (faux-craftsman) is terribly underwhelming.

  10. ktstine

    As I understand it, UV boundaries will not be changed. But, zoning within them may be changing. This has never been clear to the NPAC (where zoning changes are being proposed, esp. on Beacon Hill), I suppose we just have to wait for the draft updates this fall. NPAC’s consistent advice to the City was to talk early and honestly about where upzones will be proposed, but until now, upzones have only been discussed in concept, not by specific location.

    Also, I still maintain that the Sound Transit station was not engineered to sustain any kind of upzone atop it. Can anyone here substantiate this rumor?

  11. Joshua Daniel Franklin

    I think we all know what’s been replacing our urban tree canopy over the past decades: widened streets, driveways, surface lots, strip malls, garages, and interstates. Space for cars. U-District aerial photo 1940 (already quite dense, and most of those midrise apartments are still there) vs U-District aerial photo 2006. Hey, at least they planted some conifers along the side of I-5.

  12. lorax

    @7. “DADUs are not a threat to our tree canopy. People are.”

    That’s funny! Presumably these DADUs (which I am in favor of) grow from the ground like mushrooms?

    With respect to tree cover vs green roofs: coverage areas are a planners dream metric, but make a poor basis of comparison. Canopy cover and green roof area are apples and oranges. The real issue with respect to increased evapo-transpiration and sustainable hydrology is one of surface area. Trees have many, many orders of magnitude more surface area than a equivalent area of green roof. And green roofs have substantially more surface area then traditional roofing. Just saying…

  13. Bill Bradburd

    Dan – I invited you and other Central Area based HCA yappers a chance to come talk face to face with David Miller. We had about 12 Central Area activist/wonk types with him for over three hours. It would have been great to hear this as a debate and not a single sided rant. Next time take the bait.

    You live in a single family zone. Why haven’t you packed up and moved into a 400 sqft Belltown condo? Its really pathetic to hear all this density mantra coming form the likes of folks who live in houses in SF zones.

  14. Kathryn

    @ktstine This is totally unstatistical, but maybe someone would be able to run the numbers if such numbers can be gotten out of the assessor’s office.

    I pulled asessments of the same assessment time frame for a number of parcels of similar size, nearness to main roads, etc., in the CD, with still decent SF homes on them. The land portion of the assessment went up nearly one dollar per square foot in each jump from SF5000 to L1 to L2 to L3… Now that is just the land portion, which is NOT the whole assessment. It can even be the minor part of the assessment if the structure is nice.

    I’m not sure DADUs are really an issue for many neighborhoods. For Madison Valley, most of the existing Single Family zoned areas are chock full of simple duplexes, triplexes, tandem houses, DADUs and ADUs. These are NOT of the buildign sizes that we get with current LDT or L1, which would be monstrous in that context. If someone needs to replace, they have to go through the whole shebang of permission to be ‘non-conforming’ again. Or, they can build a McMansion. That is stupid IMHO.

    Trees go down when you build. Some trees should not go down. It should be a matter of design for a given site. And, trees should be replaced. The building inspectors usually does not care. DPD usually does not care when trees that were NOT supposed to be removed, are. Luckily I had photos of one incident. The developer got a fine, but he did not care. He planted trashy small trees and did not even plant another cherry tree, which would have taken 25 years to get back to what we had as a major feature on the street. The work people are doing is to get accountability into the mess.

    I don’t know how we can mitigate the landslide threat behind me when the trees that hold the soil down are all gone and the city is in denial that we are building on a watershed.

    Green roofs are of limited utility and not a silver bullet. In lowrise zones they usually do not make sense, except in apartment style buildings. Even then, better as a courtyard at ground or upper floor levels, and put soloar panels on the roofs for criminies sake!

  15. Ellery

    Hey lorax @11, you speak for the trees, right? My point is that I can have a SF house and DADU with eight trees on my lot, while a neighbor with the same 5000sqft lot takes their trees down without a DADU. It’s the choices that PEOPLE make, and the incentives/regulations (or lack thereof) that encourage certain choices over others. You need to blame the Onceler, not the Thneeds. SF property owners can make good choices–siting a DADU where it minimizes tree impacts, replace trees, add trees, etc–or bad choices. And we need better policies to support the good choices.

  16. ktstine

    @12 Bill
    Personally I think that single family homeowners are exactly the people in this town that need to be talking more about density!

  17. Ellery

    Right on, ktstine. I live in a SF zone, but I can advocate for options for my parents, my single sister, my kids when they move out, myself with an empty nest, can’t I??? I am privileged to have a SF home. Most people in the city can’t afford that. And a lot of other folks don’t even want that. So let’s give more livable options in the city for all people, in MF and SF zones.

  18. David in Burien

    “If you’re willing to sacrifice Seattle’s environment for environment elsewhere, that’s a valid answer as long as you also explain how we’ll deal with Endangered Species requirements in our urban watersheds.”

    Wha? He didn’t just use the ESA and salmon to make a zoning argument for SF, did he? Time for Mr Miller to get a better brief on ESA/salmon; not that the city council has much of a role to play in that game anyways.

    On the other hand Dan, be careful before you use Longfellow as a example of good things urban and salmon. First, Longfellow hosts Puget Sound coho salmon, but they’re not an endangered species. Puget Sound Chinook are, but Longfellow is too small for them. Second, although Longfellow could eventually serve coho well, it’s been the site of a few fairly stark and mysterious coho die-offs, probably owing to stormwater quality, and it’s being intensively studied by folks at NWFSC and the UW.

    On the other other hand, the main watershed function affected by the addition of impermeable surfaces to a watershed is peak-/base-flows. Stormwater quality comes next, but that’s mainly a roads issue and in the built environment, the roads are already there.

    So. What’s the best way to deal with rooftops and driveways? Purposeful LID and where things are already built out, put more people under each roof, aka consolidate structures, aka increase density in the built environment. At the same time, protect the natural drainage you have left and retrofit engineered solutions that return baseflows to streams in the places where impermeable surfaces cannot be removed.

    Among other things…

  19. Kathryn

    The point about yapping being yapping on a blog instead of getting involved in the Neighborhood Planning process, and studying and advocating for good legislation instead of talking in generalities.

  20. Kathryn

    @David you are talking about size, mass, scale and lot coverage. back to concretely, the new MF proposal leaves us hardly any difference in lot coverage between 4 different zones. Within reason, people do not care about how many people, especially those of us who grew up in the era of large families living in 1500-2500 sq ft homes. Now if i said I think the building sizes are too big and the lot coverage too much, I’d get yelled at as anti-density I bet.

  21. Joshua Daniel Franklin

    Well nuts, I think my comment had too many links in it… maybe an admin can find it. The point was that our tree canopy has mostly been turned into space for cars.

    I also found this pretty sweet 1940s picture of the U-District. Today’s campus still has lots of trees of course, but west of 15th there’s a whole lot of parking. Maybe we could have some sort of program to convert a few parking spaces of every surface lot into a conifer!

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