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Thread: Putting private stuff in the public realm

  1. #1
    Cyburbian UrbaneSprawler's avatar
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    Putting private stuff in the public realm

    I’m finding myself more and more at odds with planners at work regarding willingness to extend certain private uses in public right-of-way. Wondering what folks like yourself as planners think, and wondering if you have similar situations and policies as a result. Here’s a typical scenario:

    Developer wants to redevelop in an older part of town, aggregating several parcels of land with existing single family homes along a collector street. The proposal is to tear down the homes at around 5-6 d.u./acre and intensify the aggregated parcels with multi-family housing above 15 d.u./acre. The area as it exists with single family homes might be 25% impervious surface, but now with the proposal, 75% impervious. As a result, storm drainage water quantity detention requirements kick in, as well as water quality (neither of which of course was originally required back in the days of the single family development).

    Generally, when the developer realizes the amount of land needed to set aside for storm drainage requirements and/or the costs associated with measures on the private side such as rooftop detention, there is a push from the developer to use the abutting public collector street as the system that will provide the water quality and water quantity detention requirements created in no small measure by the amount of additional impervious the development is proposing. The public street becomes an infiltration system where water passes through permeable concrete/asphalt. This is sold as well as being “green” in that water isn’t conveyed through storm drainage systems but is treated somewhat more at the source.

    My opinionated view as an engineer is that this extends too great of a private benefit at the expense of the public. A developer should meet storm drainage requirements required to be mitigated within the developer’s property and not use the public space to do so. Certainly there’s a need to push for density in urban areas, in my view the need for more urban density should still place the burden on the developer to mitigate their own impact. Certainly there’s a push for “green streets” everywhere, but from what I’ve seen, streets that infiltrate drainage seem to be for drainage that occurs within the street, not from impacts created on private property being pushed out into the public street system.

    Do you have a policy or viewpoint regarding how the public street system can be used to mitigate storm drainage requirements caused by development/redevelopment? Would love to get input on how you might (or might not) allow private impacts to be mitigated within the public realm.

  2. #2
    OH....IO Hink's avatar
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    Quote Originally posted by UrbaneSprawler View post
    Do you have a policy or viewpoint regarding how the public street system can be used to mitigate storm drainage requirements caused by development/redevelopment? Would love to get input on how you might (or might not) allow private impacts to be mitigated within the public realm.
    We do not allow this currently. I would be hesitant to take the responsibility without some agreement on shared costs or some other large concession from the developer. We require all development to meet the storm water standards (quality and quantity) which usually requires the developers to get creative. Rooftop gardens, bio swales, and rain gardens are all unique ways to deal with both quantity and quality. We are looking at ways to require this in our landscape code instead of our storm water regulations so we get away from exactly the issue that you seem to be in.
    A common mistake people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools. -Douglas Adams

  3. #3
    Unfrozen Caveman Planner mendelman's avatar
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    I agree with Hink that this just sounds like developers trying to pass off responsibility/cost...but I think Engineering probably needs to also open their minds too.

    Since redevelopment and good intensification of density is often a good thing, I have seen where the engineers understand that redevelopment of already developed land needs to be treated differently than greenfield development.

    In each place I've worked, the engineers allowed a credit for the exsiting impervious surface and only required detention/retention for the balance between existing and proposed. Have you considered suggesting this? Or do you guys already do this and the difference is still making the developer's panties get bunched?

    Additionally, if your storm system is already over-capacity, then the above may be moot anyhow.
    Last edited by mendelman; 05 Jul 2011 at 4:06 PM.
    I'm sorry. Is my bias showing?

    The ends can justify the means.

  4. #4
    Cyburbian UrbaneSprawler's avatar
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    Yes, we do give credit for existing such that the requirements are only for what they create as new impervious. Still their panties get bunched. I'm one of those engineers trying to "open their minds".

    We've certainly seen rooftop gardens, bioswales, rain gardens, and other techniques proposed and even built. With the case of rain gardens, we have them in right-of-way in locations in town, but they're addressing existing public street flows in an attempt to go "above and beyond", not displacing the private impact of additional impervious onto a public street.

  5. #5
    OH....IO Hink's avatar
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    Quote Originally posted by UrbaneSprawler View post
    We've certainly seen rooftop gardens, bioswales, rain gardens, and other techniques proposed and even built. With the case of rain gardens, we have them in right-of-way in locations in town, but they're addressing existing public street flows in an attempt to go "above and beyond", not displacing the private impact of additional impervious onto a public street.
    Well hell.... I got nothing.
    A common mistake people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools. -Douglas Adams

  6. #6
    moderator in moderation Suburb Repairman's avatar
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    For what you describe, the city needs to think about regionalizing water quality and detention to better enable redevelopment rather than forcing it within the same site. Basically, you create a drainage/water quality utility and the developers have to pay & connect into it, and then pay toward maintenance & upkeep. You could also look at creating a PID to cover maintenance & upkeep, and creating a fee-in-lieu system for the capital cost of regional drainage/water quality.

    If you design those facilities correctly, you can create some nice green spaces and attractive ponds within an urban redevelopment area.

    It is probably a more complicated solution, but ultimately I think it has the best potential to solve your long-term problem of addressing water quality/detention in redevelopment. While I think your developers are over-reaching, cramming such facilities on-site in a confined space does tend to drive costs higher than it would in a larger greenfield application.

    "Oh, that is all well and good, but, voice or no voice, the people can always be brought to the bidding of the leaders. That is easy. All you have to do is tell them they are being attacked and denounce the pacifists for lack of patriotism and exposing the country to danger. It works the same way in any country."

    - Herman Göring at the Nuremburg trials (thoughts on democracy)

  7. #7
    OH....IO Hink's avatar
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    Quote Originally posted by Suburb Repairman View post
    For what you describe, the city needs to think about regionalizing water quality and detention to better enable redevelopment rather than forcing it within the same site. Basically, you create a drainage/water quality utility and the developers have to pay & connect into it, and then pay toward maintenance & upkeep. You could also look at creating a PID to cover maintenance & upkeep, and creating a fee-in-lieu system for the capital cost of regional drainage/water quality.

    If you design those facilities correctly, you can create some nice green spaces and attractive ponds within an urban redevelopment area.

    It is probably a more complicated solution, but ultimately I think it has the best potential to solve your long-term problem of addressing water quality/detention in redevelopment. While I think your developers are over-reaching, cramming such facilities on-site in a confined space does tend to drive costs higher than it would in a larger greenfield application.
    We have done this for greenfield development where the infrastructure can be put in place prior to development, but I would imagine that the costs would be incredible to retrofit such a system.

    Off-topic:
    I have a great picture of myself in a 23' tall culvert that we put under a roadway for stormwater... pretty cool really.
    A common mistake people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools. -Douglas Adams

  8. #8
    Cyburbian ColoGI's avatar
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    Quote Originally posted by Suburb Repairman View post
    For what you describe, the city needs to think about regionalizing water quality and detention to better enable redevelopment rather than forcing it within the same site. Basically, you create a drainage/water quality utility and the developers have to pay & connect into it, and then pay toward maintenance & upkeep. You could also look at creating a PID to cover maintenance & upkeep, and creating a fee-in-lieu system for the capital cost of regional drainage/water quality.
    .
    There are several specs out there that treat treelawns and pedestrian zones as 'stormwater facilities' and use structural soil, permeable hardscape, grade changes, etc to capture some of this extra runoff. Seattle is pretty good at this. The EPA has some good ideas too (!).

    I'm on board with the regionalization bit, but that's planning process and the OP is concerned with project scale. That said, it is harder to do this if you don't have a plan for it. And if we consider these public facilities, or public/private facilities, we'd have an easier time of it, in my view. Gravity doesn't care about property lines.

    Nonetheless, we know how to do these things.

  9. #9
    Cyburbian UrbaneSprawler's avatar
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    Thanks all for the thoughts. Our stormwater utility has certainly undertaken master plan improvements for measure to help with floodplain concerns; installing regional facilities that help bring properties out of flood zones has been an ongoing endeavor, though not without controversy in that if it's done in areas that could now develop, there are the political leaders that question whether improvements to allow undeveloped areas is appropriate.

    Extending this practice to regionalizing water quality/quantity I suspect would raise similar questions of overly encouraging development by the politicos involved just for the initial expense involved as noted here and how long it could be expected until that initial expenditure is paid back. Beyond that though, I wonder if the practice of regionalizing these sorts of things is counter to what the LID movement of late is seeking, doing more treatment at the source, rather than installation of pipe/outfall systems that send water through considerable distances to reach a regional facility.

    Quote Originally posted by ColoGI View post
    And if we consider these public facilities, or public/private facilities, we'd have an easier time of it, in my view. Gravity doesn't care about property lines.
    Certainly I've seen this sentiment echoed from the planning side of the development. With that said, I'm just not of the understanding why there is perhaps this viewpoint of being willing to open up consideration of these as public facilities and be dismissive about traditional public-private concerns? Yes, gravity doesn't care about property lines, but does this mean a traditional public works viewpoint shouldn't care about this either? Should there be an expectation that perhaps the public should then be maintaining the drainage facilities in this case, which for greenfield development would always be the HOA/commercial business association?

  10. #10
    Cyburbian ColoGI's avatar
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    Quote Originally posted by UrbaneSprawler View post

    Certainly I've seen this sentiment echoed from the planning side of the development. With that said, I'm just not of the understanding why there is perhaps this viewpoint of being willing to open up consideration of these as public facilities and be dismissive about traditional public-private concerns? Yes, gravity doesn't care about property lines, but does this mean a traditional public works viewpoint shouldn't care about this either? Should there be an expectation that perhaps the public should then be maintaining the drainage facilities in this case, which for greenfield development would always be the HOA/commercial business association?
    Well, from the ecology point of view, it is a scalar problem. If we are willing to have regional detention ponds that serve several parcels, then we are moving out of our box/silo and thinking differently. Same with "regional" facilities in the ROW - it is both a scale issue [smaller scale than regional detention pond] and serving several parcels. Why is it serving several parcels? It is helping clean stormwater which benefits downstream users and makes treatment cheaper, lowering taxes a bit - benefiting several parcels. We all win when it is cheaper to treat stormwater at the source rather than further downstream, where impacts are multiplied.

    As to who maintains the ponds, I don't know if we have a good answer for that, especially in these budgetary times.

  11. #11
    Cyburbian DetroitPlanner's avatar
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    Are the soils conducive to retain water under the street?

    Will the developer agree to pay for making the street permeable?

    Who is going to be responsible should there be damages to the street? This will most likely cost more to maintain than a regular concrete or asphalt street.

    I can see pluses with this in terms of keeping the water on-site, but the devil is in the details.
    We hope for better things; it will arise from the ashes - Fr Gabriel Richard 1805

  12. #12
    Cyburbian UrbaneSprawler's avatar
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    Quote Originally posted by DetroitPlanner View post
    Are the soils conducive to retain water under the street?
    Generally in Colorado, no. Soils are typically expansive and clayey (unless in close proximity to a natural river or stream), making the introduction of water into the soils surrounding the pavement subgrade not viewed as a pleasant thing from a public works perspective. Underdrains would need to be considered.

    Will the developer agree to pay for making the street permeable?
    That would certainly be required, including potential underdrains, pavement subgrade stabilization measures, etc. We require with all public infrastructure, a warranty for a total of 5 years. We're just not sure about what could happen after 5 years, plus does a standard pavement rehab project years later result in a period of time in which the site temporarily loses its water quality/quantity function?

    Who is going to be responsible should there be damages to the street? This will most likely cost more to maintain than a regular concrete or asphalt street.
    We'd certainly have development agreement language indemnifying the town from damages caused by the developer/HOA as a result. Quantifying the incremental increase in maintainance costs is something we'd like to do, if we could arrive at a mechanism to do so.

    I can see pluses with this in terms of keeping the water on-site, but the devil is in the details.
    And it's in the details that would rather me respond back to the developer and say, no thanks. There isn't alignment from the town collective on this though.

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