Water Modeling

Mapping & Management

Rod Franklin
Denver, Colo.

The modeling of natural and manmade water systems encompasses one of the more established uses of remotely-sensed imagery and applied GIS. But where exactly does this sector stand asof mid-2009? How far has it come?

On a foundational level, water mapping practitioners continue to make product choices that refine the boundaries of engagement for modeling environments, software interfaces and standards. Without question, the industry has achieved a certain level of maturity: Showcase projects feature geodatabase technology that, more than ever, help monitor the dynamic conditions of potable and non-potable water systems all over the world.

Figure 1 The WaterGEMS integration with ArcGIS allows users to analyze their network directly inside ArcGIS and to overlay model results in ArcGIS for presentation. Image courtesy of Bentley Systems, Inc.

At the project level, each effort tends to be characterized by its own set of wild cards. Sometimes specific technical challenges stand at issue. In other cases, time factors are tightly woven into project objectives. But perhaps the most universal set of variables is encompassed by the myriad ways in which geographic and legacy data are mingled—juggled might be a better word—to produce visual solutions that are useful in the guidance of human decisions.

The Journal of the American Water Resources Association observed a few years ago that a rich variety of technical approaches to water modeling, driven in large part by competitive jockeying, has come to disaggregate the art. “Currently,” it reported in a state-of-the-industry paper, “disparities in spatial scales, data accessibility, modeling software preferences, and computer resources availability prevent application of a universal interfacing approach.”

FIgure 2These orthoimages are of the Royal Palm Hammock quadrangle, which is located a few miles west of the Everglades National Park, in Collier County on the Gulf coast of Florida. The images were collected at a 1-m pixel resolution on December 3, 2004, using a Leica ADS40 airborne digital imaging sensor, as part of the statewide mapping program for Florida covering approximately 54,000 square miles. Images courtesy of the South Florida Water Management District and the USGS, and acquired and processed by Fugro EarthData.

Experts might agree that this fragmented status applies still. The industry, nevertheless, continues to put on new faces. Consolidation has changed up the vendor roster. With its purchase of Haestad Methods Water Solutions in 2004, and piqued by a national survey that it commissioned in 2007, Pennsylvania-based Bentley Systems has boldly staked its claim as the king of the water modeling hill.

Surveys answered by more than 800 industry professionals indicate that the company’s software leads in categories like distributions systems modeling, transient analysis, wastewater conveyance, storm water networks, and hydraulics calculation tools. In detention pond modeling, IntelliSolve Inc., a Cleveland company, emerged as the top innovator. Practitioners chose the U.S. Army Corps of Engineers as the preferred developer of floodplain management solutions. New solutions like Intermap’s NEXTMap USA product may change that, with its high-resolution 3D digital elevation and terrain models.

As a fully integrated concept in water systems engineering, however, GIS appears to have hills yet to climb. Survey respondents said that its status as a framework for an idealized working environment plays third fiddle to their general desire for systemic interoperability with existing industry standards (EPANET, the storm water management model and LandXML, for example), and second fiddle to CAD systems. Water modeling engineers indicated their preference for tools such as AutoCAD and Bentley’s MicroStation over solutions like MapInfo and ArcGIS, though MicroStation users can integrate data into ArcGIS. See Figure 1 on page 28.

The directions water mapping has followed as an applied science seem to be limited by fewer bounds. Each year, ESRI’s Special Achievement in GIS Awards (SAG) acknowledge local and regional water modeling campaigns all over the planet. Ceremonies in recent years have focused on projects in the U.S., Italy, Sweden, Norway, Costa Rica, Jamaica, Brazil, Uruguay, Peru, China, Sri Lanka and the Philippines. The company gave awards to seven water or wastewater projects in 2008, six in 2007, four in 2006, and six in 2005. These did not include SAG citations for water modeling efforts that may have been part of comprehensive projects initiated within the utilities, pipeline, forestry, government, engineering, environmental management and ESRI Conservation Program sectors.

City of Akron Public Utilities Bureau Centralization

One of the standout projects from last year’s SAG was orchestrated by the City of Akron Public Utilities Bureau (APUB). This organization was in the midst of a decade-long records conversion process for its water and wastewater departments when the decision was made to install a centralized system to manage work and inventory for all assets above and below the ground. For nearly 100 years, APUB kept its records by means of hand drafting onto cloth paper and mylar. Now, a geodatabase synchronized with its new exterior records application helps reduce inefficiencies in water system data access.

Southern Nevada Water Authority Rebates for Xeriscaping

A star of the 2007 SAG ceremony was the Southern Nevada Water Authority (SNWA) Water Smart Landscape program, which offers rebates to Nevada residents and businesses that convert their water-dependant turf coverage to xeriscape design. Using six-inch airborne imagery provided by Digital Mapping Inc., SNWA has been able to identify grassy areas and potential program applicants. The solution employs ArcGIS from ESRI, ERDAS Imagine, and Feature Analyst from Overwatch Systems.

Managing Water Resources in Florida

Given Florida’s richly tattooed water profile—it includes the Everglades and Intra-coastal Waterway, water supply canals, lakes, bays, estuaries and ports—managing water resources in the state is a complex issue, requiring accurate and up-to-date geospatial information. About five years ago, with existing data scarce or obsolete, mapping experts within the state were challenged to geographically isolate issues related to zoning, rights of way, engineering method, storm control, water quality, and the interests of wetlands and wildlife habitat versus those of sugarcane, sugar beet and citrus growers.

Figure 3These orthoimages are of the Royal Palm Hammock quadrangle, which is located a few miles west of the Everglades National Park, in Collier County on the Gulf coast of Florida. The images were collected at a 1-m pixel resolution on December 3, 2004, using a Leica ADS40 airborne digital imaging sensor, as part of the statewide mapping program for Florida covering approximately 54,000 square miles. Images courtesy of the South Florida Water Management District and the USGS, and acquired and processed by Fugro EarthData.

In order to fulfill their need for accurate and up-to-date geospatial information of their respective jurisdictions, the five water management districts in Florida teamed up with the USGS to collect high resolution digital airborne imagery of the entire state in 2004. The orthoimage mapping was completed by Maryland-based Fugro EarthData (formerly EarthData International). It was one of the nation’s first large-scale acquisition efforts taking advantage of the Leica ADS40 sensor’s ability to generate both natural color and false color renditions simultaneously. See Figures 2-3.

For the South Florida Water Management District alone, a total 16,800 individual map tiles were produced in both natural color and color-infrared rendition, and a total of more than 3 terabytes of image data was delivered. This dataset allowed the district to extract valuable information.

The state is currently involved in a statewide project to map the topo-graphy along the coastline using airborne LiDAR. The goal of this ambitious project is to allow state and local authorities to model the effects of sea-level rise on coastal communities. Fugro Earthdata is also involved in this project along with a number of other mapping companies.

Mapping Oyster Beds

Another project was initiated by the South Carolina Department of Natural Resources (DNR) for the purpose of identifying intertidal oyster beds. During low tide, the natural reefs that harbor this seafood delicacy tend to lie exposed above the state’s coastal ocean water line. In 2003, the DNR and National Oceanic and Atmospheric Administration’s Coastal Services Center determined that sub-meter spatial detail would be necessary to map adequately a targeted 1,500 square miles of reefs. Specialists also decided to use a combination of spectral and spatial data in distinguishing live oyster clusters from muddy, shell-covered reef substrate materials.<

To achieve these goals, GeoVantage Inc. (Swampscott, Mass.) built 22 lightweight, high-resolution multispectral cameras that it dispatched in up to 10 planes per flight session. The acquired data helped commercial interests efficiently collect and sell more than $1 million of oysters annually.

Categories of Water Modeling

To those who follow the multi-jointed state of the water mapping art, 2003 may seem like an epoch ago. The fact is, some water models develop over a period of years into data-centric Godzillas. Bentley Systems features one project on its Website that shows how certain products are sometimes necessary to simplify these modular epics of data aggregation. Asset management staff in Toronto deployed WaterGEM’s Skelebrator module to automate the skeletonization of the city’s water system model without losing hydraulic equivalence information and network connectivity.

From a GIS and data perspective, it helps to think of water research in categorical terms. Disciplines can be divided into the very broad areas of watershed characterization and management, floodplain management and forecasting, water quality, and permitting.

  • Watershed management: This multidisciplinary category includes terrain modeling, stream flow statistics and debris flow probability. The latter refers to flows of rock, earth, and other water-saturated debris that develop when the ground is rapidly soaked during heavy rainfall or snowmelt conditions. They can strike with little or no warning at avalanche speeds.
  • Floodplain management: Imaging and modeling projects support a combination of corrective and preventive exercises. Some may require the integration of data from a variety of sources, including zoning, subdivision, or building requirements, as well as those required by special purpose floodplain ordinances.
  • Water quality: This work involves the constituent analysis of groundwater and the characterization of groundwater recharge areas and surface water. Because the relationship between surface water and groundwater is usually symbiotic, cross-contamination is an issue, and GIS becomes a useful ally in the calculation of chemical mass load impacts and of migrations between surface and subsurface waters. GIS also can be helpful in the monitoring of water quality changes within specific zones, such as rivers or bays.
  • Permitting: Geographic information plays a key role in the determination of which businesses or activities are granted water rights or access to land in and around watersheds. Modeling with GIS facilitates permitting tasks in the areas of water quality monitoring, hazardous materials tracking, underground tank management and well log data management. It also applies in-site analysis, rights-of-way permitting and water flow analysis.

These applications have gotten top billing in some regions. The Pacific Northwest Regional Collaboratory (PNRC, a 2004 project of the U.S. Department of Agriculture) supported mapping exercises in the above areas throughout Idaho, Washington and Oregon. Its water resource forecasting projects sought to provide operational tools that could be used to improve estimates of streamflow in snow-dominated regions. Riparian analyses have focused on vegetated areas situated close enough to streams to influence the stream’s conditions, or to be influenced by the presence of a stream. PNRC campaigns also have delved into near-shore habitat restoration studies that are candidates for assistance by remote sensing technologies.

Other GIS projects have tackled water systems analysis in areas that are anything but pastoral. The previously-mentioned EarthData has experience here. Its contribution in 1997 to a Con Edison energy loss inventory for Manhattan stands as one of the company’s technical coups in urban water modeling. In a nutshell, EarthData achieved its goal of identifying a two percent reduction in total energy loss from steam fitting leaks within the city’s heating system by using airborne thermal surveys, video, and existing natural color aerial photography.

International Projects

Using spatial data to map all that is wet has gained global momentum. In the Puglia region of Southern Italy, GIS applications now display networked workstation data for drinking water in real time. In Venice, complex mathematical models are being processed by MicroStation operators to keep the city from sinking into the lagoon upon which it was built 1,200 years ago. Bentley also has completed water resource showcase projects in Istanbul, Turkey and in southern Australia.

A few years ago, Australia was a mishmash of unrealized GIS market potential. Intergraph Corporation (Huntsville, Ala.) was reporting its intent to use G/Technology as a means of streamlining operations at Melbourne’s 1.3-million customer South East Water corporation. Around the same time, Tensing USA of Rockville, Maryland released news of its mobility solutions GIS contract with Sydney Water Corporation—the continent’s largest water supplier and treatment company.

Consultants observed at the time that the sharing of spatial datasets between jurisdictions in Australia is not an assumed fact of life, at least in comparison with conditions in the United States. They also noted that imaging and GIS companies had begun to approach the Australian market more aggressively as talks advanced on a comprehensive national water policy. Those policy negotiations continue.

Some have said that the metropolitan regions of coastal Australia represent a GIS market that is at least as strong as that of North America. So there are new places that imaging and remote sensing can take those who devote themselves to watershed analysis, floodplain assessment, and storm water or sewage systems engineering. Even if water modeling has been around as long as GIS itself, there are yet miles to go.

Sensors & Systems | Monitoring, Analyzing and Adapting to Global Change | Stay in tune with the transformation. Subscribe to the free weekly newsletter.