Stormwater Modeling for better Asset Management

We’ve spent much of 2016 working on a stormwater modeling project with the folks at DHI for the City of Portland, Oregon’s Bureau of Environmental Services (BES). The project, known as the the Stormwater System Plan (SWSP), will ultimately provide BES with best management practice strategies for stormwater assets, and is – forgive the pun – groundbreaking.

Replacing aging infrastructure

Stormwater runoff is not the most sexy thing, and generally does not get a great deal of attention by the public, but it can be an incredibly destructive force to reckon with. Knowing ahead of time where there are risks can help mitigate those risks, and, quite possibly avoid the destruction of property. Much of the infrastructure that we depend upon is nearing, or well past, its end-of-life (EOL, as the engineers like to say). Stormwater modeling helps give engineers a better understanding of the weakest points in the system.

The last time this nation saw major infrastructure work was during the Eisenhower administration! Considering the fact that people who were born then are now retiring, now is a good time to turn our attention to the physical parts of our cities that are of the same age. This project will help BES to make more educated decisions when it comes to replacing or maintaining the assets that they are responsible for. When you think about it, these assets are a crucial part of modern life.

Understanding risks

BES is looking to have a better understanding of the risks associated with stormwater runoff in the cases of:

• Sanitary sewage releases – when untreated sewage is discharged from a sanitary sewer into the environment prior to reaching sewage treatment facilities. Portland’s Big Pipe project a few years ago helped minimize these events, but did not stop them entirely.
• Landslide hazards – this can range from small rockfall events to entire hillsides giving away. Having a better understanding of this problem can save lives and prevent property loss.
• Localized nuisance flooding – how to control low area flooding. Flooded basements are no fun for anyone!
• Loss of habitat – how does the local animal life contribute to controlling (or disrupting) stormwater runoff?
• Disruption to hydrologic cycle – this includes looking at how removing (or adding) vegetation impacts the water cycle.
• Approvable routes of conveyance – these are routes that property owners can use to dispose of stormwater that builds up on their property.

Building python scripts

Our role in the project has been to assist in the scripting and geoprocessing of the risk categories listed above. These scripts will help BES to run advanced models of stormwater runoff in order to help identify areas where assets are either nonexistent – and may possibly be needed - or present but in need of attention in some way. This can help focus the often expensive work. It’s important to have a way to prioritize the efforts and appropriately target investments where infrastructure is lacking, in most dire need of repair or replacement, or where considerations such as social equity or development and population dynamics call for it.

Vector Tiles for All!!

What are vector tiles?

Vector tiles are packets of geographic data, packaged into pre-defined roughly-square shaped “tiles” for transfer over the web. As with the widely used raster tiled web maps, map data is requested by a client as a set of “tiles” corresponding to square areas of land of a pre-defined size and location. Unlike raster tiled web maps, however, the server returns vector map data, which has been clipped to the boundaries of each tile, instead of a pre-rendered map image.

Why should one use vector tiles?

Compared to an un-tiled vector map, the data transfer is reduced because only data within the current view, and at the current extent needs to be transferred. Vector tiles are also faster to download than a tiled raster map, as vector data is typically much smaller than a rendered bitmap.

Additionally, with a tool such as Mapbox GL JS, styling can be applied later in the process, or even in the browser itself, allowing much greater flexibility in how data is presented. It is also easy to provide interactivity with map features, as their vector representation already exists within the client. 

How do we use them?

Our crack team of developers has deployed a vector tile server that allows us to serve mbtiles raster files, mbtiles vector files, and ESRI bundled cache files. At this point, we are using it for most of our client-hosted applications. It’s a faster solution than anything we’ve used in the past, and it allows our dev team to create tools and functions in our JS-based Map Viewer that take advantage of the flexibility of the tiles.

We like to share

We submitted the code to GitHub for anyone to deploy.  At the core of the MBTiles server are dual instances of a node.js script that has been customized and offered to the public. Everything windows users need to get this up and running is included in the repository. The mbtiles server, the .NET reverse proxy, and the service creation scripts.

Once you’ve installed the MBTiles server, starting a web service is as simple as copying either raster or vector mbtiles files into the mbtiles cache directory. Setting up an ESRI bundled cache service is just as simple; copy the arcgis server cache directory to your mbtiles cache directory and you’re done!

Let us know what you think, or if you have any questions!

Links

The Gartrell Group MBTiles server 

Script to install windows services

The script that we forked in order to create the windows services script

The time to make a plan is now

Reality: Emergencies happen

Contemplating worst case scenarios and one’s potential responses is clearly a source of amusement for many. But to public servants who shoulder the responsibility of providing critical services to citizens in a time of crisis, considering the ramifications of different types of emergencies can be a very sobering thing indeed.

Earthquakes, hazardous chemicals, disrupted transportation infrastructure, criminal sabotage, housebound staff, islands of isolation…little creativity is required to conjure visions of circumstances within which maintaining basic services and providing vital support to citizens can abruptly change from daily and routine to supremely challenging.

Preparation is key.

Preparing to Prepare

We are working with Washington County, Oregon to help assess their needs and optimize their resources so they are better equipped to plan responses to different types of emergencies. The project involves a broad group of stakeholders that extends across many County departments.

We’ll start by examining individual and shared needs and concerns to help define the ideal type of information needed in a variety of emergencies. Next, we’ll explore the best way to provide that information so that stakeholders may individually and collectively improve their planning and preparation for responding in times of crisis.

After we’ve spoken to shareholders, defined the necessary information, and explored options for sharing that information when the resources we take for granted on a daily basis have been compromised, we’ll provide recommended solutions and help the County in implementing them.

Common Functions

The necessary information needed by this particular set of shareholders will certainly be unique, but in our experience with helping organizations prepare for emergencies, we’ve found that the solutions start with many commonalities:

• They need to address geographic, place-based questions.
• They must cross functional, operational, and jurisdictional boundaries. Disasters tend not to honor human boundaries!
• They must be multi-disciplinary.
• A planning and training module is extremely important. The best way provide a truly coordinated response is continual training. Part of good planning involves assuring that emergency responders have “muscle memory” when it comes to their tools so there are no questions about how to use them.

Preparation Saves Lives!

No one wants a disaster to occur, but when they do happen, preparation can save lives. A solid plan, and useful tools can be the difference between a smooth recovery and a long haul.

If it’s time to assess your emergency preparedness and planning resources, feel free to drop us a line.