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Thread: Cross the wetland for connectivity, or stay out for preservation?

  1. #1
    Cyburbian plnrgrl's avatar
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    Cross the wetland for connectivity, or stay out for preservation?

    We, the city, have a dilemma. The city in which I plan is a smallish to mid-sized town, that has for the past few decades been built out. We primarily work with redevelopment, and not greenfield development.

    However, we have annexed a large amount of acreage in recent years, of which the property owners are now beginning to come to us for development permits. This area is green and undisturbed.

    So, the question is, is it better to force connectivity, while impacting a wetland or stream with oil and fluids that are emitted from cars, or to just build a bunch of cul-du-sacs to prevent wetland crossings altogether? Of course, there will be exceptions in many instances, but if it is a residential subdivision, connecting to another residential subdivision, where does the threshold of impact lie?

    Our bigger problem is that we don't have strong environmental protection regulations, since it hasn't been an issue to date. What has caused our concern is that the cul-du-sac is greater than 500', which is against our regulation. The owner is arguing that they have to be, since they don't want to impact the wetland to connect to the other side, preventing the creation of a long cul-du-sac.

  2. #2
    Cyburbian zman's avatar
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    Prevent ANY disturbance to wetland areas. See if your state/province/disputed zone has any regulations you can hang your hat on.
    You get all squeezed up inside/Like the days were carved in stone/You get all wired up inside/And it's bad to be alone

    You can go out, you can take a ride/And when you get out on your own/You get all smoothed out inside/And it's good to be alone
    -Peart

  3. #3
    Cyburbian ruralplanner's avatar
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    I would say that you are going to want connectivity. As much as I advocate for environmental protection, you also need to consider connectivity for emergency purposes and the purpose of zoning—to protect the human health, safety and welfare. We had a development (80 plus lot subdivision) a year or so back that included a proposed wetland and stream crossing. This was our first wetland/stream crossing proposal and in the end health and safety won out—we wanted connectivity. However in exchange for the crossing we required extensive inventories of wetland species, threatened plants and animals or habitat, a hydraulics and hydrology study to determine the impact the bridge would have on up stream and downstream water levels etc. etc. We also required 1.5 times wetland mitigation on the same site to make up for the wetland loss along with a management plan to prevent invasive species.

    This particular site has been dropped twice before by two previous developers after they found out what was involved in the wetland crossing. The previous developers argued against connectivity because they did not want to impact the wetland resource, in lieu of a connection they wanted cal-de-sacs and horseshoe roads. I have a hard time believing that the previous developers were interested in protecting the resource but were more interested in avoiding the resource and connectivity because it would be time consuming and above all costly.

    If you really don’t have local regulations to give you much authority, check your State requirements regarding impacts on wetlands and get to know the State folks who administer State requirements. They will be your strongest ally to helping you protect the resource as well as provide connectivity. On the other hand, if you can’t find a way to protect the wetlands I have to agree with zmanPLAN.

  4. #4
    Cyburbian Emeritus Chet's avatar
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    My beliefe is ANY urban wetland will fail. So you might as well connect. I have not witnessed a successful (unfunded) urban wetland in 20 years. So pay or do the right thing!

  5. #5
    Forums Administrator & Gallery Moderator NHPlanner's avatar
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    Depends on the wetland. If it's a high quality wetland, I'd say no to connection. If it's nothing more than a scrub shrub pocket, not connected to a larger wetland complex, and mitigation is available, I'd say connect.

    From a staff comment made to the Planning Board here last week (FYI - the cul-de-sac was approved with no connection)

    The Planning Department Staff realizes that the Conservation Commission and Planning Board have indicated their desire not to impact the wetlands by making this development’s roadway connect with XXX Lane. The Planning Department would like to reaffirm their position that a connected roadway is the Department’s preferred alternative, as connectivity of roadways and neighborhoods remains a goal of the Town’s Master Plan, and is a better alternative from a traffic flow perspective. The Planning Department will recommend a connected roadway system to the Planning Board when this application is heard for a public hearing.
    "Growth is inevitable and desirable, but destruction of community character is not. The question is not whether your part of the world is going to change. The question is how." -- Edward T. McMahon, The Conservation Fund

  6. #6
    Cyburbian hilldweller's avatar
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    Quote Originally posted by Chet View post
    My beliefe is ANY urban wetland will fail. So you might as well connect. I have not witnessed a successful (unfunded) urban wetland in 20 years. So pay or do the right thing!
    Would a subdivision of homes a 5 units per acre clustered next to a wetland fail or do you think it would it take higher densities/more impervious. You've got me wondering about some of these cluster projects....

  7. #7
    Cyburbian Greenescapist's avatar
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    I would argue in favor of connectivity, while trying to reduce the impact to any wetlands. Vegetated buffers, porous pavement, narrow streets, in sensitive areas could help.

  8. #8
    Cyburbian plnrgrl's avatar
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    Quote Originally posted by ruralplanner View post
    As much as I advocate for environmental protection, you also need to consider connectivity for emergency purposes and the purpose of zoning—to protect the human health, safety and welfare. We had a development (80 plus lot subdivision) a year or so back that included a proposed wetland and stream crossing. This was our first wetland/stream crossing proposal and in the end health and safety won out—we wanted connectivity. However in exchange for the crossing we required extensive inventories of wetland species, threatened plants and animals or habitat, a hydraulics and hydrology study to determine the impact the bridge would have on up stream and downstream water levels etc. etc. We also required 1.5 times wetland mitigation on the same site to make up for the wetland loss along with a management plan to prevent invasive species.

    If you really don’t have local regulations to give you much authority, check your State requirements regarding impacts on wetlands and get to know the State folks who administer State requirements. They will be your strongest ally to helping you protect the resource as well as provide connectivity. On the other hand, if you can’t find a way to protect the wetlands I have to agree with zmanPLAN.
    The connectivity is only required due to emergency access, no other reason by local regulation.

    We do not have any type of local environmental protection here in this very red region of the state. It just won't happen. What we have, we rely on the state regulations and permits for.

    The developer doesn't want to connect, because it is time and money to get the permit and construct the crossing. It's as simple as that. The City doesn't want to push the connectivity, although it is a regulation to connect any length of road more than 500', because they don't want to maintain the bridge. It's a financial decision all around.

  9. #9
    Cyburbian ruralplanner's avatar
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    If this is what you have to work with and need to forgo the crossing, you could at least require two access points to a main road—or a horseshoe like road pattern with smaller cal-de-sacs coming off of that At a minimum you may want to require a 66 foot wide outlot going through the wetland which is intended for future (road) access. The road may never be built, but at least the land is available in outlot form, if needed. On the plat and subdivision covenants, the outlot could be labeled for future road access. In the interim, the outlot could be there for foot traffic so the subdivision is not totally cut off from the rest of the community. Just a thought.

  10. #10
    Cyburbian jmello's avatar
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    Is the area in question urban, suburban or rural? Can the current roadway network handle the increased volume 20 years in the future?

  11. #11
    Cyburbian plnrgrl's avatar
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    Semi-suburban. It's transitioning from rural to suburban. The roadway would only serve to connect two subdivisions, nothing more. It would provide an outlet to a major corridor quicker than having to drive out through the east end of the cul-du-sac, all the way around to the west where the major transportation network is.

    We approached the developer about the two access points with a horseshoe drive. It is feasible, but the road would have to be at the perimeter of the property, since it is deep but not so wide. Also because we have a 100' separation requirement for roadways. Of course he doesn't want to pay twice for a road he only needs once.

  12. #12
    Cyburbian jmello's avatar
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    Quote Originally posted by plnrgrl View post
    Semi-suburban. It's transitioning from rural to suburban.
    IMO, this is one of the problems with our development patterns today. If the area is planned to be urbanized, then environmental concerns should take a back seat when necessary. Urban infrastructure is more important. We cannot realistically have cities in a forest, without pushing development even farther into the fringes. If the area is going to remain "semi-suburban" (whatever that is), then you should probably let the wetlands take precedence. However, if it will eventually urbanize, then build the roadway. We are playing catch-up in a few areas of our city because planners in the early-1990s did not see the need for connectivity in a rural-suburban transitioning area.

  13. #13
    Cyburbian Jeff's avatar
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    Connect em and replace them somewhere else.

    Wetlands can be crossed with minimal impact too. A little more expensive, but it is feasible.

  14. #14
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    Sorry this is rather late. If it's a city process though... you probably haven't resolved it yet, so I still have a chance to give you my $0.02.

    There are at least three ways in which your future development will impact the wetlands.
    - First, there is the connectivity issue you raise - the more you cut through the wetlands, the more you decrease total acreage, and the less habitat and functional watershed you have.
    - Second, depending on how you physically lay out the new developments - your cul-de-sacs can drastically increase the perimeter-to-area ratio of the wetlands. The more edge condition there is, the less quality habitat there will be (less interior, undisturbed conditions for wildlife species that are less tolerant of human impacts).
    - Third, a watershed (or a wetland) because impaired once effective imperviousness reaches 10%. This is a very well documented figure, so depending on how much new development you're adding, regardless of connectivity, the runoff and hydrology may become so messed up that the wetland will still be screwed. Sounds like a lot of good news.

    I'm not sure what kind of community you live in, how progressive or open to innovative zoning or density it is. Implementation concerns aside, here are somethings you might try:
    - The entire site may not be a wetland - conduct more detailed studies, and then give the areas that are wetlands a buffer (say 100 feet at least) and then build on the remainder, using best management practices for stormwater.
    - If this area is too small, or some landowners could potentially claim a takings, consider a transfer of development rights instead, deed restrict / easement those properties, and increase the density in the remaining areas - minimizing wetland impact as much as possible. The whole point of connectivity is to give a sense of urbanity, in which case townhomes etc may be more in keeping than 1-acre lots.
    - Depending on ownership and availability of other city owned properties, potentially swap the parcels that will be opened to development.

    In my mind, the choices are only connect or disconnect, so maybe if it's not too late you guys can still think about the larger shape of future growth before thinking about connectivity on site.

  15. #15
    Cyburbian Signature's avatar
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    urban limit line and created wetlands

    manicomio gave a great answer! Someone mentioned created wetlands as an option. From what I've seen, its difficult to create wetlands. The right soil and very subtle grading is required...not to mention water regime/hydrology. Done right, and you've got a nice wet, green, spongy wet meadow. Create a wetlands wrong and what you've got yourself is a golf course with ponds. People will sign off on that as if its a true mitigation, too.

    I will just emphasize that the //shape// will play a role -- as well as forecasting future urban growth. This is why Urban Limit Lines and In-Fill are such great tools.

    Manicomio points out that you want to minimize "edge" to reduce external influences on the preserved wetland habitat. Spot on. However, what in the foreseeable future will happen to this and adjacent parcels? I take it that this adjacent land is all private property bought up for the sake of future development. (Its not BLM land or some other kind of preserve.) So what will happen is that Road X leading out to Parcel A with its new homes will spur the owner of Parcel B (also off of Road X) to build. And a few shops and maybe a school will pop up in between town and the new neighborhoods. What of that wetland you tried to preserve? Well, if development is patchy as described above, then whatever moves you made now to protect the wetland by stalling connectivity might be cancelled out. Something to consider.

  16. #16
    Cyburbian Rumpy Tunanator's avatar
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    From what others have said, build it now. It will save the city headaches down the road.
    A guy once told me, "Do not have any attachments, do not have anything in your life you are not willing to walk out on in 30 seconds flat if you spot the heat around the corner."


    Neil McCauley (Robert DeNiro): Heat 1995

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