Category: GSP270 Assignments

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Assessing hydrant coverage within a fire district

For the final project for a class, I took a look at how to delineate the area of a fire district that can reasonably be serviced by existing fire hydrants. The topic came up because firefighters are interested in seeing how far they can stretch an engine’s large-diameter hose from the nearest hydrant. They could use such maps to train new people unfamiliar with the reach of the hydrant network into rural areas. And the map data could be used to cross-check CAD data that automatically dispatches tenders to fires at certain addresses.

Another practical application of this work would be the prioritization of installing additional hydrants. One could easily see where can a hydrant could be added on or near existing water mains to serve the highest number of previously unserved structures.

“For effective firefighting it is of crucial importance that there are sufficient fire hydrants and that they are properly maintained” (Nisanci 2010). A fire engine arrives on scene with perhaps two to four minutes of water supply on board — connection to a hydrant or service from a team of slow-moving water tenders (tanker trucks) is therefore essential in the case of a working structure fire.

Methods

Hydrant coverage was calculated as 1000′ along the road network from each hydrant to account for the ability of a standard fire engine to deploy up to 1200′ of large-diameter hose from a hydrant to a fire scene (leaving 200′ for driveway length and hose routing). This type of buffer was calculated using the Service Area feature of Network Analysis in ArcGIS, because large-diameter hose can only practically be deployed along roadways.

In addition, a standard buffer was added to the coverage area defining a 400′ radius around each hydrant. This accounts for coverage from some hydrants that are not located on roadways or are at the end of roads but ostensibly could be utilized in the immediate vicinity (i.e. at the airport or a school).

These buffers were combined into a single layer, which was subtracted from the district’s boundary polygon, yielding a layer showing the areas not effectively served by hydrants.

Results

Sample detail of the map to ensure no further use of this unvetted analysis. Hydrants are circles colored by max water flow. The muted red shading is the area not reachable either within 1000′ by road (shown on the right) or 400′ in a direct line (shown on the left) from a hydrant.

The map above shows the un-hydranted areas of the district shaded in red. Of the 16,384 structures located within the boundaries of the district, 4,285 are located beyond hydrant coverage. Most hydrants are concentrated within the city.

Discussion

This fundamental output of the analysis can be used both in fire response (adaptation to the problem) and in adding hydrants (mitigation of the problem).

First, the map above can be used in greater detail to provide firefighters a concise expectation of where they will have effective hydrant coverage versus where they will need a tender-based water supply. The layer file can also be imported into the 911 center’s computer-aided dispatching system to automate tender response where it will be required.

Again, a detail of the map showing in blue-to-yellow heat map the high concentrations of structures that lie in the area unserved by hydrants.

Second, we can use this analysis to respond to the problem by adding fire hydrants where they are especially needed. For this purpose we turn to the map above, which is a heat map showing relative concentration of structures that are beyond hydrant coverage. The areas of high concentrations of significant size would, provided water lines are located nearby, be logical neighborhoods in which to add fire hydrants.

As with the first map, the muted red shades areas unserved by hydrants, and hydrants are shown as colored dots. The black squares are structures located in the unserved area.

Above is an area from the heat map in greater detail. It features a concentration of structures located adjacent to hydrant coverage but in the uncovered, shaded area. Given the adjacent water supply, areas such as this present opportunities for near-term addition of relatively few hydrants to better protect high concentrations of structures.

Suggestions for future study include performing fire-flow analysis based on building construction type, occupancy type and size and comparing required water flow to available water flow for each structure. Kaufman and Rosencrants (2014) describe a GIS-based method for doing and provide the tables necessary to make the calculations. Given the necessary inputs for structures, GIS would make such an analysis practical.

References and Data Sources

Road centerline, trail. park and district boundary data from Jefferson County GIS. Hydrant data from City of Port Townsend GIS and Jefferson Public Utility District GIS. Hydrology and structure data from WA Department of Natural Resources.

Kaufman, M. M., & Rosencrants, T. (2015). GIS method for characterizing fire flow capacity. Fire Safety Journal, 72, 25-32. doi:10.1016/j.firesaf.2015.02.001

Nisanci, R. (2010). GIS based fire analysis and production of fire-risk maps: The Trabzon experience. Scientific Research and Essays, 5(9), 970-977. Retrieved December 13, 2020, from https://academicjournals.org/journal/SRE/article-abstract/DDFB12518871

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Spread thin, will GIS specialization diminish?

The “GIS Technician” job is not long for this world, though I had a difficult time finding published thoughts to support this theory. Given the proliferation of GIS within university programs for various professional and academic fields, reliance on a GIS technician isolated in an office separate from professional and field staff will diminish over the next decade for three reasons: GIS-related workload will increase faster than GIS-specific staff can be funded and hired; staff already familiar with GIS will be frustrated with having to request work from an overloaded GIS office; and geographical intelligence is too essential to decision making to keep it locked away.

Despite what I believe is an obvious need for ArcGIS to become as commonly deployed and used as Microsoft Access, if not Microsoft Word, GIS applications continue to present a steep learning curve to those unfamiliar. Devotion to formal cartography and accuracy and precision in data and process require a level of training beyond simply dabbling in GIS. Licensing costs for software are high, or licenses controlled by a GIS office. GIS professionals may have both deserved and unreasonable protective attitudes regarding their earned training, skills and status as the keepers of geographical data, its analysis and its cartographic output. How would the industry get beyond these barriers?

Gao and Wang (2020) mention one approach in their discussion about university librarians supporting the GIS needs of students and staff. While a GIS-trained librarian is for some schools a specialty occupation, funding priorities and staff turnover make this arrangement less than resilient. The authors describe meeting the need instead by having GIS training become more accessible to a wider group of librarians (who may already study Python coding as part of library science, perhaps giving them a leg up to get beyond basic GIS operations).

Gelfert (2019) outlines some of the more specialized roles that will continue to be done by GIS professionals. While that article does not acknowledge my main point of wider GIS accessibility, it does reinforce my point that additional specialization will be required for anyone hoping to remain in a GIS-specific role.

Yes, some “Data Entry Clerk” and “Word Processor” positions have survived mobile apps and RFID tags for data collection, the desktop computer and email for written communication, desktop databases and cloud-based reporting systems for data analysis. Yet most of the skills that formerly required special training have been rolled into the requirements or assumed skillset of other positions. These relics of a previous era may provide a steady income and good working environment but are not high-paying, nor do they offer much in the way of advancement opportunities absent higher-level information-technology training and experience. If my theory about the future of GIS is correct, the basic GIS technician role will be the same in the near future. This leaves the open two routes for persons with GIS training: Fit that ability into a job that was historically only a consumer of GIS product rather than a GIS user, or obtain the database-administration, coding or other higher-level IT training necessary to remain in a GIS-specific role when everyone else in the office is able to do the basics.

Jessup and Lenzi (2007) illustrate my point for my current industry: maintenance of county-road networks. Since that paper was written, the state agency at the root of their study has purchased a new asset-management system based on ArcGIS for maintenance of the official records of county roads throughout the state. The system is set for deployment in 2021 and will replace a dated, text-only database. The manager of that system at each of the state’s counties will be forced from a textual environment into a GIS-based environment, one more way in which GIS escapes isolation and pervades operations and management.

Perhaps a Microsoft Excel level of penetration of GIS software and skill across the workforce should be the goal. Some people cannot understand a formula but use a single worksheet to make something they need. Others understand just enough about how a spreadsheet is supposed to function to mess it all up, but at least they do it on their own machine and their own copy of the data. Some think they know a lot about it and end up creating something so complex it should be in a database, not a spreadsheet. Others can do robust analysis in multiple worksheets with complex formulae for which the spreadsheet is the best tool. Regardless, everyone has it on their desk.

Gao, W., & Wang, Y. (2020). The Provision and Sustainability of GIS Services: How an Academic Library without a GIS Specialist Provides GIS Services. International Journal of Librarianship, 5 (1), 53-60. https://doi.org/10.23974/ijol.2020.vol5.1.160

Gelfert, A. (2019, February 25). GIS Job Titles of the Future… Retrieved December 07, 2020, from https://community.esri.com/t5/arcgis-enterprise-questions/gis-job-titles-of-the-future/m-p/305819

Jessup, E., & Lenzi, J. (2007, March). Washington State All-Weather Road GIS Mapping: Improving Statewide Freight Flows and Connectivity (Tech.). doi:10.22004/ag.econ.207827