Assessing Rural Water Supply: A Geospatial Approach

BY JEREMY A. KELLER

Access to dependable water supply suffic-ient to achieve needed fire flows (NFF) is critical for any fire department, but for rural departments, this can pose special challenges. Rural departments often have limited access to pressurized municipal hydrant systems and must instead draft from static water sources to supply water shuttles supporting fire suppression operations.

Relying on off-site, often distantly located water supplies that are connected to the fire scene by a complex water shuttle system creates operational challenges unique to the rural environment. Rural departments must master the art of identifying and exploiting existing and potential water supplies in their operational area. Drafting and water shuttle operations are basic items in the operational toolbox of rural firefighters.

In the second edition of The Rural Firefighting Handbook, Dominic Colletti identifies the factors that must be addressed to successfully execute firefighting operations.1 Colletti’s “Big Five” are time, agents, hardware, people, and procedures. Each factor is deeply intertwined with water supply issues in the rural fire environment.

Time. The wider the geographic spacing of a rural water supply network, the longer it will take, on average, to get water to where it is needed. This is further complicated by rural road networks, which can be less than adequate for rapid fire apparatus deployment.

Agents. Water is the extinguishing agent for almost all fire suppression strategies and in some rural areas can be hard to come by. Areas with limited natural water supplies may require reinforcement with manmade static sources. Even areas blessed with numerous streams and ponds may find that these sources require improvement to be truly effective firefighting water sources.

Hardware. Rural departments must invest in the apparatus and equipment necessary to fully exploit their water supply network. Tanker apparatus (water tenders) are the backbone of successful rural water supply operations. An investment must also be made in the pumps, the drop tanks, the tools, and the appliances needed to support aggressive drafting and shuttle operations.

People. Sufficient personnel must be recruited and trained to effectively operate a staff-intensive rural water supply operation. Rural firefighters and support staff need training and experience in the specialized skills required for rural water supply operations. Department personnel must be able to draft from available water sources, set up drop tanks and other specialized equipment, and understand their role in a water shuttle operation. Drivers must be able to safely and effectively operate tanker apparatus on marginal roads.

Procedures. Water supply in a rural setting is an inherently complex operation. Departments and their mutual-aid partners must have procedures in place to facilitate operations that can effectively achieve needed fire flow requirements for every incident.

WHY WATER SUPPLY MATTERS

Although this may at first seem a no-brainer, it is instructive to review factors that should make development of an effective water supply network a high priority for any rural fire department.

Firefighter safety. You cannot conduct fire suppression safely without timely delivery of adequate water supplies to the scene. A robust, well-planned rural water supply network greatly enhances the safety of firefighters engaged in operations.

Tanker operations. Although tanker apparatus are not necessarily inherently unsafe, they are difficult to operate safely, particularly on rural roadways. The tendency of the large volumes of water to surge is a well-studied contributor to the frequent injuries and fatalities resulting from tanker apparatus rollovers. A well-planned rural water supply network with optimal spacing between sources can reduce the time that tankers need to be on the road and thereby reduce the hazards associated with operating these apparatus.2

Public safety. The availability of a robust water supply system enhances the fire department’s ability to provide excellent fire protection to the rural public. Minimizing the distance that fire tankers must travel on rural roadways during water supply operations further enhances public safety by reducing opportunities for traffic accidents involving fire apparatus.

Insurance rates. The local fire department can leverage well-designed rural water supply networks to achieve better fire protection ratings from the Insurance Services Office (ISO) or similar state rating agencies. In turn, this can result in cost savings to residents and businesses that benefit from lower fire insurance rates.

PREPLANNING

Establishing adequate water supply for rural fire incidents begins with intensive preplanning long before operations commence. Each rural fire jurisdiction is unique, and the characteristics of potentially viable water supplies vary widely depending on climate, terrain, road networks, land ownership, and a host of other factors. There is one universal truth, however: Encyclopedic knowledge of local water supplies is the hallmark of professionalism in the rural fire service.

To develop and make a potential rural water supply source fully useful for fire protection purposes, it must be known, characterized, and accessible.3,4

Known. You must identify potential water supply sources through preincident reconnaissance. Although you can ease the burden of this process somewhat by using aerial photography and other geospatial tools discussed below, you will always need on-the-ground verification to confirm the suitability of water resources.

Characterized. Once you have identified potential water sources, you must size them up for their suitability for fire protection. Potential water source factors that you must determine are the total usable volume, any seasonal restrictions (e.g., freezing and drought), ownership, and accessibility. Assess potential sources for their ability to accommodate improvements to enhance drafting such as dry hydrants, drafting basins, or apparatus staging pads (photo 1).

Photos by author.
1 Photos by author.

Accessible. Once you have identified a potential water source and found it suitable for fire protection, you must determine its accessibility. Physically, the source must be situated such that fire apparatus can successfully draft from it, which generally means that the source is relatively close to a roadway of some kind, although the specific distance will depend on each department’s capabilities. The source must also be legally available for the fire department to use. Whether publicly or privately owned, this will likely require the department to negotiate to obtain maximum access to the water source.

Geospatial information systems (GIS) are a powerful tool for rural fire departments to assess and improve their water supply networks. The basic data a department needs to identify, characterize, and expand its water supply network are available free for download from public sources for use in GIS applications (see “Public GIS Data Sources” sidebar).

Beyond simply providing a map of water sources, you can use GIS technology to produce a model of your department’s water source network, identifying which water sources are closest to a given location based on actual road distances and estimated travel times instead of simply estimating straight-line distances (Figure 1). Seasonal variations in water source availability can also be factored in, allowing you to analyze water supply networks under conditions in which some sources are known to dry up, freeze, or otherwise become unavailable (photo 2).

Photos by author.
2
Figure 1. Distance from Water Sources
One-mile road distance increments from developed water sources are depicted in color
One-mile road distance increments from developed water sources are depicted in color (green = closest, red = the most distant). Dark-green concentrations represent areas with pressurized hydrants or developed static water sources (usually dry hydrants). Orange and red concentrations show the areas of weakest water supply network coverage. The superimposed road network shows how the distance-based polygons follow the roadways away from the water sources. (Figures 1-6 by author.)

GIS analysis can also determine the areas where values-at-risk are concentrated, aiding in prioritizing water source development. You can effectively and defensibly differentiate areas based on population, housing unit density, or other factors.

Modeling a water supply network with GIS also enables you to conduct a “What-if?” analysis before committing to develop a new source. You can add potential water sources identified during assessment to the GIS model and rerun the model with the new source included. This will initially indicate whether the candidate water source will actually perform as desired, given its location, road networks, and other factors.

You should assess and improve a rural water supply network with the full participation of relevant partner organizations. The specific organization will vary by state and locality but generally will include the local conservation district and the state natural resources agency. The United States Department of Agriculture Natural Resources Conservation Service (NRCS) is another potential partner you can generally contact through the local conservation district. Other federal agencies may be valuable partners as well, particularly for areas with concentrations of federally managed lands. Engaging these partners can provide departments access to GIS, engineering, and hydrology expertise and, in some cases, inroads to grant funds to support water source improvements.

AN ASSESSMENT MODEL

As a conceptual framework for analyzing a rural water supply network, consider using the following four-phase model. The process described here is based on the well-known Observe-Orient-Decide-Act (OODA) loop process.

1 Define the current situation. The fire department must characterize the existing water supply situation as accurately as possible. First, it should identify all existing developed water resources and, using global positioning systems (GPS), maps, or aerial photos, obtain an accurate location for each source. Collecting additional water source data can make the analysis more powerful. Consider collecting data on flow rates, seasonal limitations, connector types and sizes, threads, and accessibility. The department will probably have to collect these data if they do not already exist.

Consider factors affecting water source access and usability. Road networks are the primary data source for this purpose. Ensure you use geographically accurate road data to allow a baseline distance analysis. Road data should also include traffic factors including speed limits, slope/grade, and pavement conditions, which can be used to develop a time-based analysis too. Identify mobility barriers such as weight-restricted bridges and rail crossings to more accurately characterize the ability of apparatus to move about on the road network. You can obtain basic road network data from the United States Census Bureau’s Topologically Integrated Geographic Encoding and Referencing (TIGER) system, although more accurate data can often be obtained locally from dispatch centers, county engineer offices, and other sources.

Finally, the department needs to know what values are at risk. Population and housing unit data are two primary examples. This information is available free from the United States Census Bureau and can be obtained down to the census block, the most granular level of census data. Another potential source is 911 address points, which may be obtainable from local dispatch centers that use computer-assisted dispatch (CAD) systems.

Once all the necessary data are obtained or collected, you must import them into a GIS-compatible format for the geospatial analysis. Specific details of this procedure will vary, and departments may need to seek assistance from a partner organization with GIS capabilities.

2 Coverage analysis/identify gaps. Once you have gathered all necessary geospatial data and put them in a common format, you can conduct a geospatial analysis of the current water supply network using any GIS software package with a network analysis capability. You can use GIS to model the water source network according to actual travel distance and estimated travel time along the road network.5,6 The more detailed road network data are, the more realistic the analysis results will be. The result will be mathematically generated polygons that provide a visual representation of water source network coverage (see Case Study below). Using this graphical depiction, the department will readily identify those areas of weakest coverage based on actual road distances and travel times.

3 Mitigation planning. Once it has identified areas of coverage weakness, the department can begin to develop a mitigation strategy to address deficiencies. Using the coverage analysis as a guide, you can focus reconnaissance for potential water supply sources on locations that will best address the identified gaps. Once you have identified potential new water sources and confirmed they are suitable and accessible, conduct a “what-if” analysis using GIS tools to further refine the selection process, giving funding priority to developing the most promising water sources.

In some cases, areas of poor water source network coverage may result from a simple lack of developable water sources. In these situations, an engineered solution-such as a large-volume storage cistern-may be beyond the local jurisdiction’s ability to fund. In this case, the department should consider alternative mitigation strategies, such as focused public education campaigns for the area of concern.

4 Mitigation implementation. Once the department has decided on a course of action together with any partner organizations, it must begin implementing the planned improvements. Desired improvements to water supply sources, such as dry hydrant and drafting basin installations, will require engineering design work. You will need to secure funding and obtain agreements with land owners to ensure water source access. The department should also develop a long-term maintenance plan for any improvements to ensure that the new water sources remain viable.

CASE STUDY: WEST LIBERTY FIRE DEPARTMENT

The West Liberty Fire Department (WLFD) is a volunteer organization that provides fire protection to a largely rural, 123-square-mile area in west central Ohio (Figure 2). The department has 20 firefighters, three engines (Type 1), three brush engines (two Type 6, one Type 4, also used as a tender), one truck/rescue unit, one Type 3 water tender, and one command vehicle. All resources are housed in a single station in the village of West Liberty.

Figure 2. Fire Department Coverage Area
The West Liberty (OH) Fire Department
The West Liberty (OH) Fire Department protects the village of West Liberty and all or parts of six adjacent townships in Logan (green) and Champaign (brown) counties.

The coverage area is primarily flat-to-rolling agricultural land with some wooded, hilly terrain in the eastern part. Overall, the WLFD protects a population of 7,898 (2010 census) and has 3,112 911 dispatch address points.

The department’s jurisdiction includes the village of West Liberty (1,805 residents) as well as several small unincorporated communities. Like much of western Ohio, several state and federal highways serve the area, complemented by a relatively dense network of county and township roads, most of which are paved, although many are narrow.

The department provides primarily traditional fire protection (structural and natural cover fires) and has some limited capability to respond to rescue and hazardous materials incidents. The department’s sister organization, the Macochee Joint Ambulance District, provides emergency medical response to the same coverage area. Politically, the department is a part of the West Liberty village government, protecting the village proper and providing fire protection on a contractual basis to all or parts of the six surrounding rural townships located in Logan and Champaign counties.

Because of limited funding and staff resources, the department has not been able to aggressively address the development of an effective rural water supply network. Presently, the department relies on the municipal hydrant system within the village of West Liberty and two improved drafting sites (dry hydrants placed in permanent ponds) as the only developed fire protection water resources.

Assessment. A geospatial analysis of the department’s existing developed water resources was conducted to determine where weak coverage areas existed and to begin mitigating the identified gaps. The coverage analysis was conducted in terms of road miles (one way) and travel time (minutes to respond one way).

To maintain consistency with ISO rating procedures, tanker travel speeds were capped at 35 miles per hour (mph) regardless of the rated speed limit of a given roadway segment. Overall, modeled speeds were uniformly handicapped by 10 percent to simulate the effect of grades, turns, intersections, and other impediments to travel. Individual road segments could have been further encumbered with specific speed reductions to account for terrain had road grades in the area been more severe. However, this was not deemed necessary to achieve a realistic model output.

For purposes of this initial assessment, it was assumed that all developed water sources were of equal quality for fire protection purposes. The department’s two existing dry hydrants and the village’s pressurized hydrants were considered equally effective fire protection resources, regardless of their actual characteristics. This is obviously a major assumption, since water sources can vary dramatically in their ability to provide effective supply for fire suppression. (1)7 However, subsequent iterations of the assessment can readily accommodate these variations in quality.

Although the results depict only the actual WLFD coverage area, the analysis also included all developed water sources and roads within a five-mile buffer area around the department’s jurisdictional boundary. We did this to ensure that the analysis did not overlook any potentially viable water source or travel route, regardless of whether or not it was actually within the coverage area proper.

We used population data from the 2010 United States Census to characterize the impact of potential water supply network improvements to values-at-risk in the department’s jurisdiction. Distance (road miles) and travel time (minutes) polygons generated using GIS software were overlaid on census block-level data for population and housing units. This allowed census blocks to be assigned to time and distance polygons using a process derived from the one the United States Environmental Protection Agency Computer-Aided Management of Emergency Operations suite software package uses to model populations impacted by hazardous material plumes.8

Results. The resulting analytical graphics provide an immediate visual assessment of the water supply situation. Both the distance (Figure 3) and time (Figure 4) analyses display the same general patterns. The eastern and southwestern portions of the department’s coverage area have the weakest water supply networks (shown by areas in yellow, orange, and red). These areas are estimated to be more than four road miles or seven travel minutes (one way) from a developed water supply source.

Figure 3. Distance from Existing and Potential Water Sources
The distances represent one-way road mileage from existing
The distances represent one-way road mileage from existing (left) and proposed (right) developed water sources. Orange and red areas represent those most distant from a water supply. Purple areas are within 1,000 feet of pressurized hydrants.
Figure 4. Travel Time from Existing and Potential Water Sources
One-way travel time in minutes from existing (left) and proposed (right) developed water sources. Orange and red areas represent those most distant from a water supply. Purple areas are within 1,000 feet of pressurized hydrants.
One-way travel time in minutes from existing (left) and proposed (right) developed water sources. Orange and red areas represent those most distant from a water supply. Purple areas are within 1,000 feet of pressurized hydrants.

To better quantify the existing water supply network in regard to its benefit to the community, the distribution of three values-at-risk factors relative to developed water sources were calculated by distance and travel time (Figure 5). Because these three factors were found to have distributions in close agreement, population alone was used as the only value-at-risk factor for the subsequent “what-if” phase of the assessment, serving as a surrogate for all three factors.

Figure 5. Values-At-Risk Factors
Comparison of percentage distribution of three values-at-risk factors
Comparison of percentage distribution of three values-at-risk factors (population, housing units, and 911 address points) by modeled travel distance (in road miles, left) and travel time (in minutes, right) from developed water sources, showing the close relationship between all three and demonstrating that population may serve as a reliable surrogate for all three factors during subsequent “what-if” model runs.

A “what-if” analysis was conducted for the study area to determine the potential impact of developing water sources in the identified areas of weak coverage. Three potential sites were identified using a combination of hydrographic data and aerial photography for purposes of the study (these sites would require ground verification of their suitability before initiating development).

The results of the model run were dramatic. With the addition of just three new sites, almost the entire geographic extent of the coverage area fell within four road miles or eight travel minutes of a developed water source (Figures 3, 4). These model results were further quantified with regard to population (Figure 6). The additional sites resulted in 95 percent of the study area’s population being within four miles of a developed water source whereas with the current water supply network, 95 percent of the study area is within six miles of a water source. Likewise, 95 percent of the population is within eight travel minutes of a developed water source under the proposed network, compared to 12 minutes under the current network. This represents a predicted 33-percent reduction in travel distance and time required to cover the same population.

Figure 6. Effect of Proposed Improvements
“What-if” analysis results in terms of population coverage improvements. Blue = existing coverage, red = coverage with three proposed water sources added. Population is displayed in terms of cumulative percentage by road miles and travel minutes from a developed water source. The hypothetical water supply network achieves 95% population coverage 33% faster than the existing network, in both time and distance. Further quantifying the analysis results, simple linear curves fitted to the data have significantly steeper slopes in the hypothetical network: 8.01% steeper for distance and 10.97% steeper for travel time.

•••

The rural water supply assessment methodology described here is meant to complement, not replace, existing fire protection rating systems (e.g., ISO or state systems). Properly implemented and interpreted, an assessment such as this would be a useful addition to a fire department’s planning toolbox and could provide a compelling argument for supporting a grant or levy to fund developing additional rural water supplies.

The case study above demonstrated how a 123-square-mile fire district could achieve marked improvements in water supply coverage with just three new developed water sources. For example, installing three dry hydrants in streams or existing ponds would cost less than $10,000 in many cases, a very modest investment for what will likely provide a big improvement in firefighter and public safety.

GIS is a powerful tool for assessing an existing rural water supply network’s effectiveness and developing strategies to mitigate coverage weaknesses. Although some rural fire leaders may initially feel that GIS tools are beyond their reach, this is not necessarily the case. Many potential partner organizations have in-house GIS capabilities, and many two- and four-year colleges have GIS programs and could be persuaded to perform an assessment as a student project. For those departments that want to develop their own GIS capabilities, low-cost options are available to obtain software through certain software providers’ home-use license programs or through TechSoup.org, a nonprofit specializing in providing information technology assistance to other nonprofit organizations, such as fire department member associations that can become 501(c)3 organizations.

Author’s note: Thanks to John Yablonski of Digital Data Technologies, Inc. (DDTI) for his assistance in obtaining much of the data used in the case study. DDTI provides data collection, GIS, and CAD support services to dispatch centers for both counties in the case study area.

Endnotes

1. Colletti, Dominic. (2012). The Rural Firefighting Handbook (second ed.). Lyon’s Publishing. Royersford, Pennsylvania.

2. United States Fire Administration. (2003). “Safe Operation of Fire Tankers.” USFA Publication FA-248. Web link: www.usfa.fema.gov/downloads/pdf/publications/fa-248.pdf.

3. Bachman, Eric G. (2011). “How to Ensure Your Water Supply.” (Volunteers Corner). Fire Engineering, 164 (12). December 2011, 10-17. Web link: www.fireengineering.com//articles/print/volume-164/issue-12/departments/volunteers-corner/how-to-ensure-your-water-supply.html.

4. Bachman, Eric G. (2005). “Water Supply Preincident Intelligence.” Fire Engineering 158(10). October 2005, 95-106. Web link: www.fireengineering.com/articles/print/volume-158/issue-10/features/water-supply-preincident-intelligence.html.

5. Price, Mike. (2006). “Got It Covered: Modeling Standard of Cover with ArcGIS Network Analyst 9.2.” ArcUser. Oct-Dec 2006. Web link: www.esri.com/news/arcuser/1006/files/covered.pdf.

6. Price, Mike. (2007). “Priming the Pump: Preparing Data for Concentration Modeling with ArcGIS Network Analyst 9.2.” ArcUser. Jul-Sep 2007. Web link: www.esri.com/news/arcuser/0807/files/socd.pdf.

7. Hickey, Harry E. (2008). “Water Supply Systems and Evaluation Methods, Volume I: Water Supply System Concepts.” United States Fire Administration. Web link: www.usfa.dhs.gov/downloads/pdf/publications/Water_Supply_Systems_Volume_I.pdf.

8. Arizona Emergency Response Commission. (2009). CAMEO Companion. Published September 2009. Web link: www.epa.gov/emergencies/docs/cameo/CAMEO_Companion_Sept_2009.pdf.

Public GIS Data Sources

National Hydrographic Dataset (NHD): a comprehensive database of streams and water bodies (e.g., ponds, lakes) maintained by the United States Geological Survey (USGS). Although not every single farm pond will be found in the NHD, it is a good baseline reference for locating most perennial streams and permanent static water sources. Link: http://nhd.usgs.gov/.

Stream Gages: a national network of watershed stream gages maintained by the USGS and cooperating organizations. Historic data available for many streams can help determine their suitability as a potential water source. Link: http://waterdata.usgs.gov/nwis/rt.

National Agricultural Imagery Program (NAIP): a program managed by the United States Department of Agriculture that captures aerial photos of agricultural areas during growing season. Full color imagery is regularly updated for most areas and is provided at one-meter resolution. This imagery can be used to help locate potential water sources not visible from the ground. Update cycles vary by state and county. Link: http://datagateway.nrcs.usda.gov/.

Topologically Integrated Geographic Encoding and Referencing (TIGER): This large dataset maintained by the United States Census Bureau includes such diverse data as political boundaries, place names, landmarks, and some hydrology. Although TIGER road data are not the most accurate source available, they are pretty good and can be used when more accurate local sources are not available. TIGER data can be linked to other Census data to help establish potential values-at-risk (e.g., population, housing units). Link: http://www.census.gov/geo/www/tiger/shp.html.

JEREMY A. KELLER is the community risk reduction officer for the Macochee Joint Ambulance District in West Liberty, Ohio, and a state geospatial information systems specialist for the United States Department of Agriculture Natural Resources Conservation Service. Involved in rural fire and emergency medical service planning since 1999, he served as a wildland-urban interface fire specialist for the United States Fish and Wildlife Service and as a fire prevention officer for the United States Forest Service, among other wildland fire positions. He has a bachelor’s degree in fire administration from Western Oregon University, has a bachelor’s and a master’s degree in natural resources management from Ohio State University, is a certified forester, and is a retired naval intelligence officer with more than 23 years of active and reserve service.

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