By Bryan J. Zumwalt, GISP

Tampa Bay Water, a regional water authority whose jurisdiction includes three heavily populated counties in Florida (Hillsborough, Pasco, and Pinellas), is responsible for providing potable water to the Tampa Bay area's regional member government utilities. These local governments include Hillsborough County, City of New Port Richey, Pasco County, Pinellas County, City of St. Petersburg, and City of Tampa. Tampa Bay Water's mission is to develop reliable and cost-effective water supply sources to meet the growing demands of the region with minimal impact to the environment. Tampa Bay Water staff manages a vast infrastructure of pipelines, water treatment plants, reservoirs, and the largest seawater desalination plant in North America. This infrastructure serves an area with a current population of approximately 2.5 million people growing at close to 3 percent per year.

GOVNET provides users with thematic mapping capabilities for monthly parcel-level water use. This is a neighborhood-level thematic map showing potable water distribution for February 2008. The dark green parcels are the lowest water users (0-500 gallons per month), and the dark red parcels are the highest water users (more than 1 million gallons per month).

Tampa Bay Water relies on GIS for various aspects of its operations. Most notably, GIS is used to manage the regional water supply source rotation, which helps minimize impacts to its groundwater and surface water supplies, as well as the surrounding wetland and aquifer systems of the region.

In June 2007, Tampa Bay Water was tasked by its member governments to develop a high- resolution water distribution (consumption) application to analyze where and how the potable water was being used in the region. This application, named GOVNET, would become the basis for managing all future water conservation efforts.

GOVNET's functionality includes the ability to view, analyze, and query time-series water consumption data at various resolutions (regional, city, neighborhood, street, parcel) and retrieve charts, graphs, and reports for water demand.

GOVNET's use of temporal and spatial data heavily increases the memory and storage demands of the ArcGIS Server infrastructure. To model water distribution and consumption at the parcel level over time, Tampa Bay Water needed a reliable platform that would ensure adequate speed for data retrieval and map requests through the Web browser. With the help of ArcGIS Server technology's data caching abilities, Tampa Bay Water's GIS staff was able to render hundreds of gigabytes of time-series vector and raster data in advance for fast retrieval through the Web browser. This data is housed in Tampa Bay Water's enterprise GIS system, which includes a multiterabyte ArcSDE geodatabase server and various nonspatial SQL servers used to collect various water quality, consumption, SCADA, and wetland data.

The ArcGIS Server Web Application Developer Framework (ADF) provides users who have minimal GIS experience and training with a reliable template for GIS applications that Tampa Bay Water will use as the framework for all future application enhancements. Tampa Bay Water makes use of high-performance scalable servers to accommodate future growth of the GOVNET application, as well as simultaneous users and queries.

GOVNET also incorporates Microsoft's Virtual Earth to provide street-level photography and one-half-foot digital orthophotography from various third-party sources. Reporting tools allow a user to use statistics to view average, median, maximum, and minimum water consumption at user-defined intervals.

The successful implementation of GOVNET became possible because Tampa Bay Water had diligently collected time-series billing data from its member governments on a monthly basis from 1998 to the present at an account level. This data represents over a half million water use accounts across the region, all of which were subsequently geocoded to a physical parcel. The ability to view temporal water consumption at an individual parcel level gives Tampa Bay Water high-resolution thematic mapping abilities, which provided the base functionality for the GOVNET application. This account data is very important for regional demand planning and budgeting and is also used by Tampa Bay Water to model long-term demand forecasts for potable water, which allow the Tampa Bay Water board of directors to make decisions about future infrastructure needs and capital improvement projects.

The success of GOVNET is not going unnoticed in the Tampa Bay region. New requests for application access from local water demand managers and conservation coordinators continue to pour in. The Florida Yards and Neighborhoods Association recently utilized GOVNET to provide basin analysis for water users around the Brooker Creek Preserve, an 8,500-acre wilderness area managed by Pinellas County.

Tampa Bay Water is exploring future applications to the GOVNET framework, including incorporating conservation program data to allow demand managers to see how responsive water consumption is to targeted conservation measures over time. Using this targeted approach to conservation will help ease water demand for Tampa Bay Water and help further its goal of a reliable and sustainable water supply for generations to come.

About the Author

Bryan J. Zumwalt is the senior GIS application developer for Tampa Bay Water, a regional water supply authority for the Tampa Bay area. Prior to October 2006, he was senior GIS developer for PBS&J in Tampa.

More Information

For more information, contact Bryan J. Zumwalt, Tampa Bay Water (e-mail: zumwalt@tampabaywater.org).