ideas on river flooding and participatory elevation maps - Laser and chalk-based DEM?

[Jeffrey Warren]

Hello all --

Public Laboratory staff have been talking with some potential partners about a participatory flood risk project, and the need for up-to-date elevation models has come up. More importantly, we've been worried about making that information legible to residents; DEMs or Digital Elevation Models are kind of obscure and even printing them as topographic maps and distributing them is not necessarily an ideal solution. 

We had a little brainstorm -- what if we did a participatory project to map elevation and flood risk, directly onto the community's buildings. I once saw a project showing where the sea level would reach by projecting it onto buildings. What if we just bought some cheap laser pointers, and used bubble-levels, tape measures, and right-angles to "draw" the flood levels (5 feet, 10 feet) onto buildings with chalk? 

This could be an engaging activity for kids, and it'd leave (erasable) markings throughout a small community of buildings, visible to passers-by and residents alike. (This could be done starting at the river water level as a baseline, anywhere along the water. It would only work in a very small community near water.)

Most of all, the process would itself be the means of disseminating the information and building local knowledge about flood levels and risk -- the act of investigating, documenting, and discussing would be an ideal way for residents to inform themselves, and it would occur in-situ. 

Finally, if they chose to, residents could draw these elevation lines on paper maps, carrying them around to mark the contours, and in theory, a DEM could be generated based on the photographed or scanned maps, if that's helpful or needed. I especially like that the experience would be the primary product, and most relevant to community safety, and that the digital product would be an optional by-product which residents could create afterwards. That way the technology doesn't have to stand between participants and the data, but the participants stand between the data and the technology.

Just wanted to air out these thoughts; any suggestions or critiques? It'd be fun to try out in a non-critical setting to see if it's at all feasible.

Jeff (& Shannon & Adam from PLOTS)

[Dan Beavers]

Sounds like a good idea to me.

On Fri, 13 May 2011 16:46:24 -0500, Jeffrey Warren <je...@unterbahn.com>
wrote:

> Most of all, the process would *itself be the means of disseminating the
> information and building local knowledge* about flood levels and risk --

[Marc Pfister]

On Fri, May 13, 2011 at 2:46 PM, Jeffrey Warren <je...@unterbahn.com> wrote:

> We had a little brainstorm -- what if we did a participatory project to map elevation and flood risk, directly onto the community's buildings. I once saw a project showing where the sea level would reach by projecting it onto buildings. What if we just bought some cheap laser pointers, and used bubble-levels, tape measures, and right-angles to "draw" the flood levels (5 feet, 10 feet) onto buildings with chalk?

I like the idea of marking buildings, but from the work I've done with
hydrologists it seems that flooding from rivers doesn't just end up to
X elevation - it will vary as it's throttled by the terrain and
features on it. So I don't think you can end up with a flood map. But
again, I think it would be neat to start with a flood map and actually
mark it out on buildings. With the owner's permission, to chalk a blue
line completely around a house would be pretty striking.

-Marc

[Eymund Diegel]

Hi Jeff, Shannon & Adam,

I have done exercises with local school kids (in Brooklyn, NY) where the issue of flood risk is couched not so much as a threat, but as an opportunity for a better understanding of stormwater management opportunities, and learning about the history of your backyard.

I take historical maps showing wetlands and streams, calibrate them to contemporary aerials of their playgrounds, and have students try to draw in chalk the imagined ecologies (streams, fish, bears, Indian villages)  that were under their feet.

This allows introducing discussion of what causes flooded basements, as kids chat with their parents, without getting into the touchier issue of "you bought a house in a flood zone".

The next step for this "one to one mapping"  (click here for the Borges Spanish version of the story) would be to move on from chalk, and make permanent "memory markers" of past marshes and streams, like those seen in European flood markers, or tsunami stones in Japan, by marking them on local neighborhood streets and sidewalks, at first with paint lines, maybe light cuts made with angle grinders, and eventually, should budgets permit, cobblestones, or special cement work.

Rather than just a conceptual exercise, this would be presented as "identifying green infrastructure opportunities" where historic flood zones are given preferential treatment for better stormwater management, street planting, infiltration storm pipe design and diversion systems to reduce flooding risk. 

The suggestion is to use historical maps for public outreach rather than the contemporary Flood Emergency Management Agency (FEMA) maps or DEMs, as the archival map data often tells us more about sea level rise impact areas than the more "property value conscious" FEMA maps and technically complicated DEMs.

There is an example of a conceptual Brooklyn project here to mark local historical flood zones with chalk and cobble stones, to support local community park building and school education programs. 

Hope this helps in your discussion.

Best

Eymund

[Andrew Whitacre]

Notwithstanding Marc's point about water-level variation, construction
teams and surveyors use rotating laser levels to mark off equal
heights on the four walls of a room...it might be striking to place a
rotating laser level in the middle of a street and get an immediate
360-degree feeling of where flood water would be on the surrounding
buildings. (Granted, you'd be talking about $200-$300 for a laser
bright enough to be seen.)

Regarding Eymund's chalk suggestion, do what he says and keep the
chalk drawings on the ground. :) I could see it being tempting to draw
little blue waves to mark, say, the level of an historic flood, but
it's so hard to remove chalk from vertical surfaces. Hard rain does a
great job of removing it from sidewalks, but building-sides need a
hose and good scrubbing.

Andrew

On May 14, 1:13 am, Eymund Diegel <eym...@gmail.com> wrote:
> Hi Jeff, Shannon & Adam,
>
> I have done exercises with local school kids (in Brooklyn, NY) where the
> issue of flood risk is couched not so much as a threat, but as an
> opportunity for a better understanding of stormwater management

> opportunities, and *learning about the history of your backyard*.
>
> I take historical
> maps<http://alabamamaps.ua.edu/historicalmaps/Coastal%20Survey%20Maps/inde...>showing

> wetlands and streams, calibrate them to contemporary aerials of
> their playgrounds, and have students try to draw in chalk the imagined
> ecologies (streams, fish, bears, Indian villages)  that were under their
> feet.
>
> This allows introducing discussion of what causes flooded basements, as kids
> chat with their parents, without getting into the touchier issue of "you
> bought a house in a flood zone".
>
> The next step for this "one to one

> mapping<http://www.youtube.com/watch?v=ZBI9SBiSq-o>"
>  (*click **here* <http://www.youtube.com/watch?v=if0YH_PC02Y>* for the
> Borges Spanish version of the story*) would be to move on from chalk, and

> make permanent "memory markers" of past marshes and streams, like those seen
> in European flood

> marker<http://www3.iath.virginia.edu/waters/flood_markers.html>s,
> or tsunami stones<http://www.nytimes.com/2011/04/21/world/asia/21stones.html>in

> Japan, by marking them on local neighborhood streets and sidewalks, at
> first with paint lines, maybe light cuts made with angle grinders, and
> eventually, should budgets permit, cobblestones, or special cement work.
>
> Rather than just a conceptual exercise, this would be presented as
> "identifying green infrastructure opportunities" where historic flood zones
> are given preferential treatment for better stormwater management, street
> planting, infiltration storm pipe design and diversion systems to reduce
> flooding risk.
>

> The suggestion is to use *historical maps for public outreach* rather than

> the contemporary Flood Emergency Management Agency (FEMA) maps or DEMs, as

> the *archival map data often tells us more about sea level rise impact areas
> * than the more "property value conscious" FEMA maps and technically

> complicated DEMs.
>
> There is an example of a conceptual Brooklyn project

> here<http://issuu.com/proteusgowanus/docs/ghost_streams_of_the_gowanus_maps>to

> mark local historical flood zones with chalk and cobble stones, to
> support local community park building and school education programs.
>
> Hope this helps in your discussion.
>
> Best
>
> Eymund
>

> On Fri, May 13, 2011 at 10:08 PM, Dan Beavers <dan.beav...@acm.org> wrote:
> > Sounds like a good idea to me.
>

> > On Fri, 13 May 2011 16:46:24 -0500, Jeffrey Warren <j...@unterbahn.com>

>  2010_04_17_PS_29_Stream_Reconstruction_on_Playground_w_historic_maps.JPG
> 704KViewDownload
>
>  2010_04_17_PS_29_Stream_Reconstruction_on_Playground.JPG
> 829KViewDownload

[Marc Pfister]

On Sat, May 14, 2011 at 8:02 AM, Andrew Whitacre <akwhi...@gmail.com> wrote:

> Regarding Eymund's chalk suggestion, do what he says and keep the
> chalk drawings on the ground. :) I could see it being tempting to draw
> little blue waves to mark, say, the level of an historic flood, but
> it's so hard to remove chalk from vertical surfaces.

Blue masking tape?

You could wrap it around trees, telephone poles, etc (with permission
yada yada...)

-Marc

[Marc Pfister]

On Fri, May 13, 2011 at 10:13 PM, Eymund Diegel <eym...@gmail.com> wrote:

> This allows introducing discussion of what causes flooded basements, as kids
> chat with their parents, without getting into the touchier issue of "you
> bought a house in a flood zone".

Touchy is definitely the word. I've had some LiDAR projects get 86'ed
at the last minute for precisely that reason.

- Marc