Research Essay: Uncovering Vancouver’s Sewer Systems: a humbling experience
Final Maps
Kitsilano/South Granville Catchment
Fraser Area – Manitoba Catchment
Fraser Area – South Hill Catchment
Executive Summary
The City of Vancouver has set a goal to replace all combined sewer pipes with separated storm water and sanitary pipes by 2050. What this means is that both raw sewage from buildings and storm water drained from the surface run through the same pipe system. During high rainfall events, flooding may occur, and raw sewage can flow out the outfalls directly into water bodies without having undergone treatment. Vancouver is divided into 19 catchment areas, in which all pipes flow to the same outfall(s) or treatment facility. We took open data from the City, as well as catchment data from the City’s private servers, in an attempt to make large scale static maps showing the current location of all pipes within each catchment, as well as the flow direction of each pipe to be used in conjunction with VanMaps for planning purposes. As well, we were to make an infographic focused on the False Creek catchments, to show connections between people’s lives and the water quality in False Creek. Design
Decisions for Catchment Maps
The static catchment maps have been designed to be used in conjunction with VanMap to deal with issues specific to VanMaps as an interactive map: the pipes and flow arrows are only visible when zoomed in at the block scale. Due to the necessary transferability of information between online and static map use, our design decisions were limited to the aesthetics of VanMap. Most of our design decisions were aimed at reducing the noise present in our maps and working around data that was not collected with visualization in mind. We used a larger stroke width for the larger diameter trunk pipes. Flow arrows were coloured black in order to create contrast against the coloured pipes and underlying white space. We created this white space by lightly colouring the property parcels, establishing a space to display our thematic data. To highlight the catchment of interest, we overlaid all other catchments in view with a transparent layer, so they became lower in the visual hierarchy. We attempted to utilize offsets, transparency, and different line types, however our data was altered in unacceptable ways after using each technique. Offsets moved the sewer pipes in haphazard ways, changing line transparency blended pipe colours, and using different line types strayed too far from VanMap format. While the final maps may not effectively utilize cartographic design principles, the final outcome was created following a user centered design process that created what was requested by the City of Vancouver.
Infographics for “Water flows downhill” (created by Linden Maultsaid-Blair)
False Creek Infographic (Mobile) – Linden
False Creek Infographic (Web) – Linden
We included the stormwater and combined pipes to show the comprehensive network that allows ALL surface contaminants to flow into the creek when rainwater falls. We used the same colours as the catchment maps for the pipes but had more freedom in design decisions because there were fewer restrictions. The legend was symbolized with fun pipe shapes. We chose orange as a contrast to the blue of water, and copied approximate outfall locations from VanMap. We added the official logo and some historical flavour text. Finally, we wrote five ‘fun fact’ bubbles including information to connect people to the water quality.
Limitations
The major limitations we faced in this project were the data and visual adherence to VanMap. Spatially, all of the data points and lines laid in a very narrow cluster, making it very difficult to create maps that were both visually pleasing and easy to read. Pipes were not organized in cohesive extents. Each pipe was inventoried by the year it was built, with several pieces on each street. Associated with each of the pipes were individual flow arrows creating redundant visual elements on the map when symbolized. A single street could contain 4 different types, each consisting of several pieces, and each with a flow arrow associated with it. Compounding this issue were the specific aesthetics of VanMap we had to adhere to. The pipe colours are green, red, and magenta and this presented a couple problems. Red and magenta are difficult to distinguish while glancing at the map, while green and red can cause issues for colour blind users. We attempted to work around these issues with various tools in ArcMap and Adobe Illustrator to no avail. To display the pipes, we tried to use the ArcMap offset tool, which did not shift the pipes in a uniform manner. We tried to offset them in Adobe, but other variables we had to visualize made this unmanageable. Finally, we tried to change stroke widths, but this did not create the clarity we desired. For flow, we tried to get around using the Flow Arrow layer by using the Network Analyst tool to create a flow network using the pipes, which did not work. We then attempted to use the Disperse Markers tool, however the flow arrows ended up in random positions relative to the pipes they were supposed to be indicating flow for. Our final decision was to symbolize them by angle and rotation and delete redundant arrows, which we have done for two of the catchment maps. While this did work, it was time consuming, taking 1 ½ hours per catchment. Unfortunately, from this experimentation we found that the density and complexity of the data did not allow for much modification. We also added manhole covers, street names, property parcels, and parks.