Selecting Multi-function Survey Tools for GIS, Design, and Construction

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Limestone County, Alabama, lies at the northernmost boundary of the state, just below the Tennessee line. The City of Athens is the only major municipality within this rural county. Like many other undeveloped areas across the nation, Athens lies in an eddy created by the rapid current of development in neighboring areas. Athens is situated within a triangle of three larger rapidly developing communities—Huntsville, Decatur, and Florence. Even though Limestone County is still relatively rural and undeveloped, it is under the high-tech influence of Huntsville, a major center for aerospace research and development.

Jonathan Bedsole (pictured) is a very busy man. He’s the Staff Engineer for the Water Services Department in Athens, Alabama. Water Services is a division of Athens Utilities, a municipal corporation that also owns and manages water, wastewater, electric, and natural gas services for the City. His department serves approximately 9,500 water and 5,200 wastewater customers.

The Road to Athens

Jonathan Bedsole comes from a strong professional background. His father was a civil engineer for the Tennessee Valley Authority (TVA). While Bedsole was completing his degree in Civil Engineering at Auburn University, he worked in a co-op program with the City of Florence, Alabama. He was subsequently hired to fill a position that became available shortly after he completed his degree in 1997. His scope of duties included wastewater design tasks, subdivision inspections, site plan reviews, and working with the field survey crew from time to time. He also gained some fledgling GIS experience by cataloging street data for mapping purposes. Municipal layoffs at the end of 2002 left him seeking another position.

In December 2002, he was hired by Athens Utilities in his current capacity. Bedsole is responsible for all construction, inspection, and mapping of both systems. His duties include reviewing development and construction plans to make sure they meet City standards. He is also responsible for inspecting new construction as needed to ensure compliance. As problems arise, he contributes his engineering experience to seeking appropriate solutions. Recently he began work on a new challenge to his professional expertise–the implementation, creation, and management of a mapping database for his systems mandated to interface with Limestone County’s developing GIS network.

GIS Consortium

Limestone County established a Consortium to govern and direct the implementation of a comprehensive GIS network to serve governmental entities and public services. The participants include all City and County governments and utilities, the Sheriff’s department, local police departments, 911 emergency services, the City of Athens Public Works Department, and the regional hospital. Within this network, each participant will maintain its own database. The mission of the Consortium is to establish operational parameters that insure connectivity and compatibility among all users. All individual databases must be capable of being viewed and read by others without going to the owner’s site.

To guarantee that the entire GIS system is up to date, a county-wide flyover is planned. A grid of survey monumentation based on the Alabama State Plane West coordinate system will be set throughout the county. Surveyors will be then be required to tie their maps and as-builts to it. This will facilitate management of databases and enable them to be updated continuously and seamlessly.

Water Services Needs
Bedsole formulated a strategic plan to get the Water Services GIS database up and running. Starting from scratch, he realized the primary objective was the interface with the county-wide network. To better serve the needs of his department, he also wanted to create a system that could be used for accurate modeling and design purposes as well as mapping functions.

Bedsole’s first step was establishing a working relationship with a consulting firm in Huntsville that specializes in Asset Management / GIS services. The company has built several systems for other municipalities in north Alabama, including City of Florence utilities and the Athens Gas Department. The consultants will build the database framework, customized specifically for the needs of Water Services, and will supply the operating software. The acquisition of location and attribute data for all existing lines, valves, and treatment plant facilities will be the responsibility of Water Services. Once the database is built for the existing facilities, a direct data import function will enable it to be continuously updated as systems expand and new installations are constructed.

Purchasing instruments to acquire location data on existing facilities was the next step. Bedsole sought a solution that would also accomplish this and several other survey tasks. From time to time, his job requires him to locate unmarked property corners and boundaries. He also needs accurate as-builts of new facilities. Since he is responsible for designing new sanitary sewer and water facilities, primarily expansions and extensions of systems already in place, he needs to quickly obtain accurate data about existing installations. Bedsole set out to purchase a survey system that would meet his multiple objectives. Knowing that most GIS mapping systems were designed for submeter accuracy location tasks, he determined the need for "survey grade" instruments. Submeter instruments would probably produce acceptable results for water system installations, but would be useless for his intended wastewater system purposes.

Bedsole’s position as a municipal employee required that he comply with certain procurement policies to guarantee a public, competitive opportunity. To learn more about currently available products and their capabilities, he contacted three vendors for equipment demonstrations and recommendations. One of them was Hayes Instrument Company, a Topcon dealer located in Shelbyville, Tennessee. Bedsole knew about them through his work at the City of Florence. He was impressed with the service they gave them on repairing survey instruments.

In order to compose a comprehensive bid specification, Bedsole tried to address all his current and future needs. He included features like cell phone capabilities that would allow communication to a central base station on a network. After completing the demonstrations of products from three different manufacturers, he was satisfied that all three would meet his intended purposes. He proceeded to write a general specification that could also be filled by other products if they met his required criteria. The bid was advertised publicly.

Positive Results
Hayes Instrument Company came in with the lowest cost bid. Hayes’ proposal included both a Topcon HiPer Lite GPS system and a GTS 235W wireless total station, specifically targeted to meet the needs of Water Services. Roger Wheeler, sales representative from Hayes, scheduled a date for delivery and training on the instruments. Since Bedsole was fairly proficient with survey instruments, he didn’t require a lot of technical training. Bedsole planned to put the equipment to work immediately. He wanted to establish a grid of control points across his systems to expedite field operations. The control points needed to be set at secure locations where the GPS base antenna could be left unattended during working hours without risking vandalism or theft. He planned to locate these points on or near facilities such as wate
r tanks and treatment plants. After Bedsole’s orientation on the new equipment was completed, Wheeler stayed on and helped him collect a static GPS location. They set the first control point in the parking lot of Athens Utilities.

In the weeks that followed, Bedsole grew to appreciate the cable-free operation of the equipment (communications between the data collector and either the GTS 235W total station or the HiPer Lite GPS antenna are enabled wirelessly using Bluetooth technology) and the ability to swap back and forth between the total station and GPS unit while operating in the same database. Topcon’s GPS base and rover are essentially the same unit, but with different software configurations. When a Continuously Operating Reference Station (CORS) network is established in his operating area, he will be able to convert both units to rovers for a minimal cost without investing in new equipment.

Out in the Field
Recently Bedsole had an opportunity to use the HiPer Lite GPS system for an engineering application. A major creek formed by the confluence of two smaller streams flows through the downtown area of the City of Athens. Over the past year, this area has experienced serious flooding. The Public Works Department proposed the construction of two large detention basins to mitigate the storm water flow through the area.

A newly constructed wastewater line was located in the area of a proposed earth berm. An extension of this line was being considered to serve a new subdivision that is in the conceptual design stage. A water distribution pump station is also located in the area. Bedsole went to the site and surveyed all water and wastewater facilities in the surrounding area to determine potential conflicts and confirm that the new sewer extension could be placed in a northwesterly orientation under the proposed berm. The sewer extension was completed before the construction of the earth berm. Utilizing the HiPer Lite GPS system enabled Bedsole to determine a cost-efficient solution for a situation that could easily have been problematic in the future. He was impressed with the performance of the equipment, and commented, "I had a 10-foot wide swath cut by a bulldozer. I was actually working in tree canopy, pretty stout tree canopy, and got a survey-grade lock."

Bedsole described another situation where the GPS unit solved a problem. "We had a local surveyor who had a bust on a route and was trying to determine where it was," he said. "To help him out, we got together and shot several USGS bench marks. We were able to discover where the bust was. One of the bench marks was at the County Courthouse. The HiPer Lite G P S rover was within seven-hundredths of a foot of the known elevation at that point."

Completing the Database
Currently, Bedsole is in the process of obtaining location data on existing installations to build his GIS database. He is working on it himself as time allows, or as part of the routine of his other responsibilities. As new projects and subdivisions are constructed, he collects location and feature data before structures are built. At the present time, his department requires paper as-builts from contractors. Bedsole intends to change that requirement and make digital asbuilts mandatory, referenced to the Alabama State Plane and the countywide monumentation.

In the near future, he plans to hire one or two co-op students to use the HiPerLite and a tablet PC to collect point location data. Needing only minimal skills, they will still be able to shoot each point and enter a simple descriptor. To avoid inaccuracies, they will not be required to identify or determine any other attributes of the location.

Bedsole will travel the system with the field superintendents, who are most familiar with the existing installation, to determine and enter the attribute data for each location. As sections of the water and wastewater systems are completed, they will be incorporated in the G I S database. Bedsole expects that it will be three to four years to complete data acquisition and make the GIS database fully functional. At that point, he will turn his focus to utilizing the information gathered in a dynamic model for both the water distribution and wastewater collection systems.

Robert Davis is a technology writer who lives in Alabama.

A 806Kb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE