City of Oak Hill Sanitary Board feature image - manhole location

From “Hard to Find” to “Hard to Miss”: How the City of Oak Hill Mapped Over 630 Manholes in Rural West Virginia While Rehabbing Them for the Future

Nestled in the heart of southcentral West Virginia, the 12-person City of Oak Hill Sanitary Board serves approximately 9,000 residents with wastewater services. Throughout the city, a forward-thinking culture allows Oak Hill GIS Coordinator Tyler Bragg, GISP, and the Sanitary Board to put proactive ideas into practice. This set the stage for a recent rehabilitation of both the data and infrastructure of one of the most rural portions of their sewer system.

The Challenge: Inheriting a Rural System with Unreliable Legacy Data

“We’ve spent days looking for manholes. You could be out there looking in the field, in a briar thicket where you can’t see anything, and meanwhile your truck could be parked right on top of it.”

— Kyle Hobbs, Collections System Foreman, City of Oak Hill Sanitary Board

In 2017, the Sanitary Board acquired the rural Arbuckle sanitary network from a local public service district (PSD). The inherited system, which now represents just under half of the board’s total service area with one-third of the system’s total manholes, is a little different from the urban system. The Arbuckle sewer infrastructure sprawls across steep wooded hills, gravel roads, and dense canopy — conditions that make both maintenance and mapping extremely difficult.

The Arbuckle system represents just under half of the City of Oak Hill Sanitary Board's service area, representing about 3.71 of 8.41 total squared miles. Arbuckle contains roughly one-third of total manholes in the system.
The Arbuckle system represents just under half of the City of Oak Hill Sanitary Board's service area, representing about 3.71 of 8.41 total squared miles. Arbuckle contains roughly one-third of total manholes in the system.

A Landscape That Complicates Everything

Finding manholes in this environment is often educated guesswork. Inherited mapping records, dating between 2010-2013, used mixed survey methods that frequently contained location errors ranging from 10 to 40 feet, with some manholes as far as 80 feet off. Much of this geospatial data came from older GPS equipment that performed poorly in the mountainous Appalachian woodlands. In such dense canopy, even aerial images offer little help locating manholes.

Densely wooded mountains make identifying manholes from aerial imagery, such as this drone photo taken by the City of Oak Hill, nearly impossible.
Densely wooded mountains make identifying manholes from aerial imagery, such as this drone photo taken by the City of Oak Hill, nearly impossible.

“All of our infrastructure was on the map, but it wasn’t all field verified,” Bragg said. “Unverified data is less authoritative than if we got something that we had mapped with a high-accuracy location and could expect to find quickly again and again.”

Field crews routinely spent hours trying to find lids supposedly located in briar thickets, gravel roads, or just somewhere in the woods.

“We’ve spent days looking for manholes,” Oak Hill Collections System Foreman Kyle Hobbs said. “You could be out there looking in the field, in a briar thicket where you can’t see anything, and meanwhile your truck could be parked right on top of it.”

Sometimes the only resolution to find a manhole was to run a camera and locator. While generally effective, this is a time-consuming and inefficient method to locate infrastructure that should be easily accessible, adding unnecessary time and frustration to daily operational tasks.

This ArcGIS screenshot shows the location of Manhole 66A in the Arbuckle system. Legacy records had placed Manhole 66A off the side of the road in vegetation, 35.82 feet away from its true location. In reality, Manhole 66A is located in the road, hard to see due to gravel cover.
This ArcGIS screenshot shows the location of Manhole 66A in the Arbuckle system. Legacy records had placed Manhole 66A off the side of the road in vegetation, 35.82 feet away from its true location. In reality, Manhole 66A is located in the road, hard to see due to gravel cover.
A photo of Manhole 66A, obscured by the gravel road it lies in.
A photo of Manhole 66A, obscured by the gravel road it lies in.

Aging Infrastructure and Inflow Problems

The Arbuckle network was built in the 1980s, when it was standard for manholes to have open ventilation. Today, such vents create infiltration and inflow (I&I) — when non-wastewater (e.g., stormwater, creek water, runoff) flows into the system. I&I adds volume, increases treatment costs, stresses the system, and increases the risk of backups.

In the 1980s, it was standard for manholes to have open ventilation. However, today vented lids like this one allow non-wastewater from storms, creek, and other sources into the system. This adds volume, increases treatment costs, stresses the system, and increases the risk of backups.
In the 1980s, it was standard for manholes to have open ventilation. However, today vented lids like this one allow non-wastewater from storms, creek, and other sources into the system. This adds volume, increases treatment costs, stresses the system, and increases the risk of backups.

The Solution: A Rehab Project Becomes a GIS Opportunity

“This was a great opportunity to leverage the fact we’ve already got a contractor and engineering firm visiting each manhole. It adds two minutes at each manhole, but it saves days of work later on.”

— Tyler Bragg, GIS Specialist, City of Oak Hill

In 2025, the Sanitary Board launched the Arbuckle Rehabilitation Project to evaluate and address every manhole’s needs. One consistent treatment every manhole got was replacing its lid and ring to drastically reduce I&I.

Because contractors and an engineering inspector would already be visiting all 630+ manholes, the city recognized a rare opportunity: collect a complete, high-accuracy, standardized inventory of the Arbuckle network. This would allow Oak Hill to replace inconsistent legacy GIS data with a single, authoritative dataset built for long‑term operations.

“This was a great opportunity to leverage the fact we’ve already got a contractor and engineering firm visiting each manhole,” Bragg said. “It adds two minutes at each manhole, but it saves days of work later on.”

The Sanitary Board already had a robust GIS workflow. Years of consistent use of apps like ArcGIS® Field Maps and ArcGIS Survey123 meant field crews were updating GIS data daily during routine field work. Bragg in his capacity supports not just the Sanitary Board, but also police, fire, parks and recreation, and many other municipal teams.

“It took years to get where we are, but now the information in the GIS is updated daily by the field technicians,” Bragg said. “Every bit of the data we enhance in the system helps them when they get on site for a reported issue.”

To further enhance the GIS, Bragg has also been using a high-accuracy Arrow Gold® GNSS receiver from Eos Positioning Systems. This helps him improve the location accuracy of certain infrastructure, such as critical sewer lines and underground taps. He connects the Arrow Gold to the free, local West Virginia CORS network for real-time kinematic (RTK) corrections, which deliver sub-inch accuracy in the city. Luckily enough, they even have a CORS base station located right in town.

“We are lucky and blessed to have not only a state CORS network, but also that in the city of Oak Hill we have a GNSS base station right here in town,” Bragg said.

The West Virginia CORS network has a base station located in Oak Hill. Every manhole rehabilitated during this project fell within a maximum radius of three miles from the base station in town.
The West Virginia CORS network has a base station located in Oak Hill. Every manhole rehabilitated during this project fell within a maximum radius of three miles from the base station in town.
Seen here is the actual West Virginia CORS base station; note the antenna near the building corner.
Seen here is the actual West Virginia CORS base station; note the antenna near the building corner.
In Eos Tools Pro, Bragg can monitor his location accuracy while the Arrow Gold and Arrow Gold+ are connected to the West Virginia CORS network. In urban areas, the 2.2 cm horizontal accuracy seen here is normal.
In Eos Tools Pro, Bragg can monitor his location accuracy while the Arrow Gold and Arrow Gold+ are connected to the West Virginia CORS network. In urban areas, the 2.2 cm horizontal accuracy seen here is normal.

The Workflow: Putting Maps in the Inspector’s Hand

To ensure any contractor could bid on the rehab project regardless of GIS or GNSS experience, Bragg equipped the winning engineering firm, The Thrasher Group, with city‑provided technology and training.

“We determined that the engineering inspector was the one who would do the data collection,” Bragg said. “The inspector would be looking at the completed manhole anyway, so we put a GPS and an iPad® in his hand and asked him to take two extra minutes to collect our data.”

Bragg first created a full GIS replica of the legacy Arbuckle data, so the inspector wouldn’t edit the city’s live operational layers. This kept authoritative data protected while allowing new, high‑accuracy updates to be collected in ArcGIS Field Maps.

To streamline data entry, Bragg built a simple, standardized form for ArcGIS Field Maps. Drop‑down choices, radio buttons, photo prompts, and other required inputs meant all incoming data would meet basic city standards.

Bragg standardized information the inspector needed to capture in ArcGIS Field Maps. Required attributes included at least two photos as well as specific information about the manhole and the rehabilitation work being performed.
Bragg standardized information the inspector needed to capture in ArcGIS Field Maps. Required attributes included at least two photos as well as specific information about the manhole and the rehabilitation work being performed.
Standardized attributes about each manhole that were collected included its environmental conditions, material type, lid type, lid size, number of inverts, and depth in whole feet. From this ArcGIS Field Maps form, we can tell Manhole 83 is a concrete manhole in a grass environment with a steel, water-tight 26" lid that has three inverts.
Standardized attributes about each manhole that were collected included its environmental conditions, material type, lid type, lid size, number of inverts, and depth in whole feet. From this ArcGIS Field Maps form, we can tell Manhole 83 is a concrete manhole in a grass environment with a steel, water-tight 26" lid that has three inverts.
Specific information about work performed during the project was also captured, including when and by whom the manhole was located as well as any problems with the manhole that would be addressed.
Specific information about work performed during the project was also captured, including when and by whom the manhole was located as well as any problems with the manhole that would be addressed.

Ensuring High Accuracy in the West Virginia Woodlands

The city purchased a dedicated iPad® and an Arrow Gold+® GNSS receiver, both of which would fold into their daily operations once the project ended. The Arrow Gold+ connected to the West Virginia CORS network, and the proximity to the city’s base station meant no manhole in the Arbuckle system was more than three miles from the antenna. Even in challenging canopy and deep valleys, this far improved the accuracy to just a few feet in the worst areas.

“When you get down into a valley, you lose accuracy pretty quickly,” Bragg said. “But with our proximity to the CORS network, it really did help with maintaining a higher level of accuracy.”

As construction crew from Green River Group, LLC, finish rehabilitating a manhole, The Thrasher Group Inspector Billy Smutko captures information about the manhole for the GIS. He uses ArcGIS Field Maps for data collection and the Arrow Gold+ GNSS receiver with the West Virginia CORS network for high location accuracy.
As construction crew from Green River Group, LLC, finish rehabilitating a manhole, The Thrasher Group Inspector Billy Smutko captures information about the manhole for the GIS. He uses ArcGIS Field Maps for data collection and the Arrow Gold+ GNSS receiver with the West Virginia CORS network for high location accuracy.
During the summer of 2025, interns Nicholas Kiser (orange shirt) and Matthew Buckland (yellow shirt) assisted The Thrasher Group with manhole rehabilitation efforts.
During the summer of 2025, interns Nicholas Kiser (orange shirt) and Matthew Buckland (yellow shirt) assisted The Thrasher Group with manhole rehabilitation efforts.

Meanwhile, Bragg set up an ArcGIS Dashboard to visualize construction status as data came in from the field.

“Effectively, we created a live as-built drawing,” Bragg said.

The "Arbuckle Rehab Project Construction Tracker" ArcGIS Dashboard enabled a live view into the work being done in the field.
The "Arbuckle Rehab Project Construction Tracker" ArcGIS Dashboard enabled a live view into the work being done in the field.

A Full Feature Swap and a Clean Slate

Once the project was completed, Bragg reviewed the new data, resolved anomalies, and snapped new underground lines from the updated manhole locations. He then performed a full GIS swap by archiving the old data and christening the newly collected data as the authoritative operational GIS for Arbuckle.

“It’s the clean slate we wanted,” Bragg said.

The Results: Accurate Data Transforms Daily Operations

The Arbuckle Rehabilitation Project transformed the Sanitary Board’s GIS. What had once been a dataset full of mismatched coordinates, missing attributes, and inconsistent documentation became a precise, standardized, and fully verified system.

High‑Accuracy Maps Across All 630+ Manholes

“You can see the difference between what they had in 2013 and what we have now,” Hobbs said. “The Arrow Gold+ really narrowed things in. Nothing from previous records compares.”

As Bragg put it: “Even two‑foot accuracy is better than 80-foot accuracy. If you get within two feet, you can find the manhole.”

The Arbuckle system’s manhole data has undergone a major accuracy upgrade. Manhole 54B is a good example: the ArcGIS screenshot reveals its true position in the roadway, correcting an 80.30‑foot discrepancy from the old dataset that had misplaced it down the road and off into the vegetation.
The Arbuckle system’s manhole data has undergone a major accuracy upgrade. Manhole 54B is a good example: this ArcGIS screenshot reveals its true position in the roadway, correcting an 80.30‑foot discrepancy from the old dataset that had misplaced it down the road and off into the vegetation.
Beyond GIS improvements, the rehabilitation project drastically improved the physical condition of each manhole in the Arbuckle system.
Beyond GIS improvements, the rehabilitation project drastically improved the physical condition of each manhole in the Arbuckle system.
This photo shows the interior of Manhole 73 — measuring 104 inches deep — shortly after it received its new lining and just before the installation of its replacement lid.
This photo shows the interior of Manhole 73 — measuring 104 inches deep — shortly after it received its new lining and just before the installation of its replacement lid.
This manhole has just received its new, fully sealed lid. Such physical improvements will help reduce inflow and infiltration of nearby water into the sewer system, thus resulting in reduced volume in the sanitary system.
This manhole has just received its new sealed lid. Such physical improvements will help reduce inflow and infiltration of nearby water into the sanitary system, thus reducing unnecessary volume.

Standardized Data for Every Asset

Beyond location accuracy, there’s now complete documentation for all structures. Each manhole now has standardized inside and outside photos, rehab notes, lid type, invert details, depths, and other essential attributes — captured uniformly across the entire system.

“What we had before were inaccurate locations and inconsistent photos and attributes,” Bragg said. “Now everything is standardized and accurate.”

Looking Ahead

The Sanitary Board is already responding faster to GIS requests from third parties.

“The Arrow Gold+ is already paying off,” Hobbs said. “We can answer engineering and design requests with confidence.”

The team expects field crews to spend less time searching for manholes and, as a result, be able to respond faster to incidents. The sealed lids will reduce I&I and associated costs.

Though Bragg acknowledges that this project came with its own share of challenges — from figuring out how to set up the technology to communicating project information — he believes the payoff is tangible.

“Not everything is sunshine and roses, as anyone who’s been part of a project knows,” Bragg said. “There were growing pains and lessons learned. But we knew from the beginning that the headaches and heartaches were worth it. Now we’re going to be that much more prepared.”

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