May/June 2006 · Vol. 69 · No. 6
May/June 2006
Following the Flow
by Norm King, Sam Talje, Michael F. Bloom, Jeff Scarborough
TxDOT's new approach to monitoring highway runoff promises
improved compliance with clean water standards.
|
The Houston, TX, area receives more than 114 centimeters (45 inches) of rain per year, much of it during major storms like the one shown here, flooding a local roadway not operated by TxDOT. TxDOT recently developed a GIS-based system to support the management of stormwater runoff from Texas highways. |
State departments of transportation (DOTs) operate
drainage systems that include ditches, channels, storm sewers, and culverts to
manage stormwater and runoff. In addition to stormwater, these systems can carry
pollutants, such as sediment, bacteria, trash, metals, and oils, from road
surfaces to natural waterways. Agencies that operate urban stormwater drainage
systems need to develop and implement detailed plans for reducing pollutant
levels in the runoff they discharge. They also need to obtain permits that
detail the requirements included in their plans, mandate annual reporting to
the governing regulatory agency, and require documentation of compliance
activities.
|
This inspector is recording information on a small outfall using a tablet computer to record structural and environmental information about the outfall pipe. The white dome in his backpack is the GPS receiver, which uses satellite signals to obtain a fix on the exact location. |
Many transportation agencies rely on hardcopy forms to document compliance with regulations regarding stormwater management. But this approach has limitations. One challenge in particular is producing reliable records demonstrating that stormwater discharge points, known as "outfalls," were inspected frequently enough. (An "outfall" is the
point at the end of a stormwater conveyance, such as a pipe or channel, at
which the stormwater enters receiving waters, such as a creek.) In addition,
physical access to hardcopy forms may be restricted when forms are stored in
one site and needed in another. Making phone calls and exchanging hardcopy
documents among DOT staff to support both decisionmaking and demonstrations of compliance can be time consuming. Data may be available
only in text format, making it difficult to display key information
graphically, unless a map is specially produced for the task. These limitations
become apparent when the data are required for a compliance audit, when
demonstrating compliance may become a cumbersome task.
The Texas
Department of Transportation (TxDOT) recently met these challenges by developing an electronic, automated tool that collects,
stores, and retrieves information on compliance with stormwater regulations.
According to TxDOT officials, the Outfall Tracking System (OTS) will streamline annual reporting, facilitate field survey and inspection work,
reduce compliance costs, provide greater access to information on drainage
systems, improve distribution and delegation of permit compliance duties, and create
a framework for automating and tracking compliance in the future.
"[Although]
it took a huge commitment of time and resources upfront to create this powerful
tool, TxDOT will reap the benefits for decades," says Dianna Noble, director of the TxDOT Environmental
Affairs Division.
For stormwater
management and monitoring, moving from hardcopy to electronic records is the
trail blazed in Texas.
DOTs as Stormwater System Operators
The burden of proof of compliance, which rests with State
DOTs and other entities that release pollutants or are otherwise responsible
for managing them, can be traced to the Federal Water Pollution Control Act Amendments
of 1972, better known as the Clean Water Act. The act aimed to regulate "point"
sources of pollution (for example, sewage treatment plants) entering the
Nation's "navigable waters." Subsequent years saw a general expansion of Federal and State regulatory involvement, and
in 1987
the U.S. Congress authorized the U.S. Environmental Protection Agency (EPA) to
develop and expand the National Pollutant Discharge Elimination System (NPDES) to regulate urban discharges of stormwater
pollutants (Section 402).
In the early 1990s, EPA issued Phase I regulations, as they are commonly known, which covered urban centers with populations greater than 100,000. Phase II regulations, issued in 1998 but effective in 2003, added smaller locations within "urbanized areas," as defined by the U.S. Census Bureau. Both sets of regulations require that certain entities, including State DOTs, develop and implement stormwater management programs.
Focusing on Illicit Discharges
In Texas, as in any State, the stormwater management program must be designed to reduce pollutants to the
maximum extent practicable as required in the Clean Water Act and its
implementing regulations. The
program must include (1) public involvement, education, and outreach; (2)
construction runoff and postconstruction stormwater management for new development
and redevelopment; and (3) good housekeeping, that is, minimizing or
eliminating contact between stormwater and onsite pollutants, such as oil used
for auto repair.
In addition, any stormwater program must include a component focused on
detecting and eliminating illicit discharges, which are nonstormwater discharges that generally contain higher
pollutant loads. Examples include drainage from unlicensed commercial carwash operations, leaking sanitary sewers, or
improperly plumbed industrial sites.
The
illicit discharge program requires periodic field inspections of outfalls
during dry weather. Field data must include the outfall location, any physical
observations, flow rate, and water quality measurements, if flow is present.
Once illicit discharges are identified, additional investigations must track
down their sources and, if possible, eliminate them either directly or through third-party actions, such as notifying a State
regulatory agency or neighboring municipality. The agency or municipality can
then levy appropriate fines or enforcement actions. Illicit discharges can
contribute high levels of pollutants that degrade receiving waters. Therefore,
regulatory agencies tend to emphasize strict implementation of this portion of
a discharger's stormwater management program.
Moving Toward Electronic Tracking
In 2004, TxDOT started updating its approach to managing
data, beginning with illicit discharge compliance, as it was the most data
intensive of the agency's stormwater programs. Managers of the stormwater
program and information technology staff in four TxDOT divisions and districts worked together to develop a model for how
outfall data would be collected, stored, and retrieved. TxDOT's Houston and
Dallas Districts, along with the Information Systems and Environmental Affairs
Divisions, also participated in developing the
comprehensive data management tool, which came to be known as OTS (Outfall
Tracking System).
OTS is a
collection of programs, Web pages, and a relational database with geographic
information, also called a "geodatabase." The initial system, largely completed
by the summer of 2005, included the following components:
- A customized field data collector used to gather
information during outfall inspections
- Web pages for collecting and loading data
associated with laboratory analysis results, desktop mapping of outfalls, and
other sources
- A statewide relational geodatabase that stores
outfall information along with reference information on geographic and other
physical features, such as streams, rivers, streets, roads, and geopolitical
boundaries
- A Web-based map viewer that displays, saves, and
prints full-color maps with color-coded outfalls (based on classification)
along with geographic information
- Custom, Web-based reporting tools that display
and print photographs, documents, sketches, and tabular information on outfalls
As of
December 2005, data collection functions were still under development. Although
the current OTS only accommodates manual loading of data, TxDOT officials
anticipate that the system will be able to upload data electronically by the
summer of 2006. Web-based functions for data collection will enable users to
upload desktop mapping information, hydrology
information, and the results of laboratory analyses. Users also will be able to
synchronize outfall inspection results from tablet personal computers (handheld
devices that can
be carried and used in the field to facilitate collecting data electronically). Users also will be able to create status updates,
input descriptive information about an outfall, and create links to scanned
documents.
"OTS is
so comprehensive because it came about through a collaborative, cooperative
effort," says Jim
Crisp, an environmental specialist with TxDOT's
Dallas District. "This is a tool [that] all TxDOT districts can use to address
regulatory compliance needs in a technologically advanced manner. OTS not only
provides huge labor savings for us, it is extremely user friendly too."
Outfall Organization
Because the Houston metropolitan area is flat, has
relatively impermeable soils, and is subject to intense rain exceeding 114
centimeters (45 inches) per year, local transportation officials sought a high
level of detail on stormwater outfalls and the contributing drainage areas.
To
capture this information, TxDOT developed an approach to collecting and mapping
data on desktop computers that involves the following steps:
- Collecting "as-built" drawings illustrating the
final configuration of constructed drainage infrastructure
- Digitizing the drawings and positioning them in
the proper coordinate system
- Tracing relevant portions of the drawings so key
information on drainage systems can be imported into OTS
- Documenting tabular supporting information about
each object, such as a description of the material, shape, size, and location
- Loading the information into OTS
Customized
desktop mapping tools and procedures support two mapping processes: inside the
right-of-way (ROW) mapping and outside ROW mapping. The former captures
information about roadway drainage areas discharging stormwater runoff through
outfalls. Outside ROW mapping captures information about regional watersheds draining
to hydraulic structures, such as culverts, pipes, and channels, at roadway
crossings.
System Design
The OTS design architecture developed by TxDOT includes
components based on geographic information systems (GIS) and Environmental Systems Research
Institute, Inc. (ESRI) software including the
following:
- SQL/Oracle® geodatabase
- ArcSDE® spatial database engine
- Web portal for easy information access and retrieval
- ArcIMS® Internet map server
- Automated desktop digitization applications for ArcGIS® and MicroStation
- ArcPad® application for automated field data collection, integrated with a global positioning system (GPS)
- Tadpole Technology's Go! SyncTM automated geodatabase synchronization from field data collectors
- Automated reporting for compliance regulations
|
An inspector records information on an outfall located under a highway overpass. In situations such as this where the overpass blocks transmission of GPS satellite signals, inspectors can define the outfall location by clicking on a detailed aerial photograph of the site displayed in ArcPad on the tablet computer screen. |
The relational database contains 42 spatial feature classes, 26 nonspatial tables, 97 tables for choosing domain attributes. The following systems and data are included in the design:
- Political and organizational boundaries
- Aerial photography
- Roadways
- Topography
- Land use
- Floodplains
- Watershed boundaries
- Outfalls and contributing drainage areas
- Crossing points and contributing drainage areas
- Outfall inspection results
- Hydrography (streams and rivers)
- Instruments and calibration records
- Laboratory results
The map viewer application was developed using ESRI's ArcIMS with ArcMap Server software, ASP, and JavaScriptTM. The Web interface application was developed using ASP.NET and the C# programming language.
The application that collects field data is a
customized application of ESRI ArcPad software using Microsoft Visual Basic® scripting. Synchronization is performed
using Go! Sync software combined with a Web application
for transferring nonspatial data.
|
"This
information is enormously useful in tracing the source of an illicit discharge,
one of our most challenging tasks," says Crisp. "ROW mapping also can be called upon in
drainage studies and planning efforts."
Peak
runoff flow rates at stormwater discharge locations can assist agencies with
determining pollutant loads as well as aid in planning and designing drainage
systems. TxDOT also is developing a way to collect data on hydrologic values
that will use traditional calculations to determine the peak runoff flow rates
arising from hypothetical storms. These calculations generally follow TxDOT's
design manual procedures. Calculated values will be stored in a simple
spreadsheet and then uploaded to OTS and the main geodatabase.
Field Inspection Improved
According to Crisp, one of the most powerful OTS tools is the
field data collector, which is a transportable tablet computer that enables
inspectors to record inspection results electronically rather than on hardcopy
forms. During an outfall inspection, as part of
the assessment of whether an illicit discharge may be present or is suspected,
field staff members make and record a number of measurements and observations
about the outfall. Inspectors typically determine if any flow is present. If
so, they record the flow characteristics, such as odor and color, and measure
and record water quality parameters using field instruments. Other indicators
of an illicit discharge are assessed, such as the presence of foam, staining,
distressed vegetation, or deposits.
In
addition, field observations confirm the size, material, shape, and other
physical factors of the outfall. Field researchers use the tablet PC to record
and then document the coordinates of the outfall using digital photos and
sketches. After completing the field work, some geographic information may need to be converted to a consistent coordinate system, and the collected data
will be uploaded to OTS and then to the main geodatabase.
With the mobile
OTS field data collector, TxDOT staff members can enter all this information
electronically via simple drop-down menus and point-and-click computer
functions. Field staff also may view detailed maps and aerial photographs of
the area being surveyed.
"Field survey efficiency is improved dramatically with the easy-to-use functions and the ability to see previously surveyed
outfalls, landmarks, roads, streams, and other features in the field," Crisp says.
|
TxDOT staff who collect data in the field can use the rugged Tablet PC (personal computer), shown here, even in bright direct sunlight. The computer's internal mounting hardware and rubberized corners make it impact resistant. Xplore Technologies® Corp. |
Intelligent Data Storage
All collected information, whether from field survey work, desktop mapping, or other input methods, is stored in a geodatabase that relates all collected information to objects and features in space. This means that information about a particular outfall is linked to geographic information, including the roadway, receiving stream, county, TxDOT district, land use, and drainage area. Each outfall, in turn, is linked to all of the inspection, hydrology, and desktop mapping results from that outfall.
According to Sonny Lelle, systems analyst/technical
project leader for TxDOT's Information Systems Division, the heart of OTS is
its approach to storing relational data. "With these linkages, powerful
reporting and data visualization tools can be created," Lelle says.
In
addition to an intelligent approach to storing relational data, OTS includes
custom programming to process data and to populate some geodatabase fields
automatically, without user intervention. One of these programs helps Texas
stormwater managers decide which outfalls require followup investigations by placing each outfall
into one of the following categories of illicit discharges: unlikely,
potential, suspect, or obvious.
Artificial
intelligence features of the OTS software classify outfalls by considering a
combination of visual and physical observations of vegetation conditions, staining, or
odors; field-measured water chemistry results;
and laboratory-measured water chemistry results. The software program used to
make the classification assignments runs overnight and identifies all new
outfall inspection results loaded into the geodatabase from the previous day.
"Now
stormwater managers can review inspection results within a day to determine
which outfalls require followup actions," says Crisp. "That improves the effectiveness of our
investigations or third-party notifications."
Better Mapping and Reporting
TxDOT officials report that the logical relationships,
geographic information, and artificial intelligence features of OTS make the
tool especially useful for reporting and mapping. Users select from an array of
views and formats to create the reports needed for compliance and decisionmaking.
OTS can
display, print, or save information in a graphic map
format or in text-based reports. The map viewer offers an interactive screen
that enables users to zoom, pan, and display a variety of geographic
information. The map viewer includes access to political and organizational
boundaries, aerial photography, roadways, topography, water bodies,
floodplains, and land uses, as well as outfalls, crossing points, and
contributing drainage areas.
|
In this screen capture from the desktop mapping tool, the left side shows a map of the major TxDOT roads within the urbanized areas in the Houston District. The right side lists the procedures for mapping outfalls and crossing points. A closeup portion represents an aerial photograph of a highway intersection with the mapping results, including the location of crossing points and outfall points, superimposed upon the photo.
Source: PBS&J |
Users
also may generate maps in Adobe® Portable Document Format (PDF) files, which can be printed, saved, or
e-mailed to others. Outfalls that were inspected in the field are automatically color
coded, based on inspection findings, to indicate
the likelihood that an illicit discharge is present. TxDOT stormwater managers
have found the mapping feature to be a valuable tool for planning and prioritizing inspection activities as well as followup
investigations to eliminate illicit discharges.
Five
standard, text-based report formats are available using the OTS data manager. TxDOT designed the reports, which feature
tables of data, to provide stormwater managers with information to support
decisions, input into annual reports, and document compliance activities. The
reports also can be used to manage and track inspection work performed by
contractors and third parties. Standard reports include the following:
- Outfall Datasheets, which summarize an
outfall's physical characteristics, location, mapping and inspection histories,
latest inspection results, and hydrologic information to assist with
maintenance and followup inspections. These reports, and the Crossing Point
Datasheets (below), are text-based and include two small embedded photographs.
- Crossing Point Datasheets, which provide
a summary of a crossing point's physical characteristics, location, mapping
history, and hydrologic information to assist with planning and maintenance
activities.
- Outfall Inspection Activity Reports,
which detail inspection activities on individual outfalls and indicate the
location, date of inspection, inspection type, inspecting organization,
discharge status, and status and date to manage contractors and keep track of
inspection rates. These and the other reports listed below are text-based and
appear in tabular format.
- Inspection Results Reports, which
summarize physical observations recorded at an outfall, such as odor, color,
size, and material to support followup investigations to eliminate illicit
discharges.
- Outfall Water Chemistry Reports, which
list the chemical constituents (field-measured or laboratory-measured) present
in any flow detected from an outfall to support followup investigations to
eliminate illicit discharges.
- Statewide Outfall Summary Reports, which
summarize inspection activities statewide and indicate the location, date of
inspection, inspection type, inspecting organization, discharge status, and
status and date to manage contractors and keep track of inspection rates.
Standard reports have fixed column headings; however,
they are designed to enable the user to select the data displayed under them.
Users can restrict or sort the data by defining criteria such as date range,
geographic area, outfall type, roadway, waterway, investigation status,
discharge classification, or size category.
Easy and Secure Access
All TxDOT employees who perform regulatory compliance
duties will
have access to OTS through the Internet using
standard Web browsers such as Microsoft® Internet Explorer.® Various levels of secure
access are granted to ensure data integrity and restrict editing, viewing, and
copying rights. Distributed access across the organization means more rapid
retrieval of needed information. It also means that TxDOT can delegate
compliance duties to a broader array of staff using the tool.
|
TxDOT employees now have full access via desktop computer to a wide spectrum of information on NPDES-permitted outfalls throughout the State. |
"With OTS being a Web-based system, we were
particularly concerned about security," Lelle says. "For instance, we voiced concerns
that the source code could be vulnerable to SQL [structured query language] injection. Effective
communication between the Information Systems Division and the contracting
staff resolved that concern."
SQL, both a
programming language and a specific database used by TxDOT, can be vulnerable
to hackers. When protections are not in place, a user or hacker might enter
programming commands
to delete or modify otherwise secure information.
The
current version of OTS allows data editing only with proper login credentials. An updated version, now under
development, will add comprehensive data change tracking and reporting. This
improvement will facilitate the automatic collection, storage, and retrieval of
edited information, including the date of the change,
the person making the change, the old record, the new record, and the reason
for the change. These features will further enhance stormwater compliance and
ensure a high level of data integrity.
|
This screen shot from the OTS map viewer zeroes in on an aerial photo of a stream crossing beneath I-45 north of Houston. Purple dots represent uninspected stormwater outfalls, and yellow shading represents outfall drainage areas. The OTS map viewer interface includes navigation, printing, and search tools (shown on the left). On the right, layer selection buttons enable users to change the information displayed, and a legend tab identifies the symbols and colors used on the map. |
Looking Ahead
As of December 2005, the first version of OTS is complete
and available to TxDOT staff via a secure Web server. The electronic field data
collector is undergoing pilot testing in the Dallas and Houston Districts, and
desktop mapping is underway in Houston. Automatic upload functions for hydrologic
data, mapping information, and field inspection results will be finalized
during the spring and summer of 2006.
|
Once construction is complete, new outfalls like the one shown here for an overpass on the Westpark Tollway outside of Houston can readily be incorporated into TxDOT's OTS. |
Planning
is underway for an expanded set of tools for tracking compliance to better
manage information associated with other programs that address stormwater
quality, namely public education, public involvement, construction, runoff
controls, new development, good housekeeping, and representative monitoring.
TxDOT
officials look forward to implementing these additional data management
technologies to further streamline compliance with stormwater quality
regulations and reduce costs. These features will enhance the State's automated
collection, storage, and retrieval tool that already facilitates accurate
inspection surveys and reporting, improves data accuracy and access, and
simplifies compliance reporting.
|
TxDOT maintains more than 79,000 centerline miles of roadway in the State. Agency officials are pilot testing the OTS in the Dallas and Houston Districts, with statewide rollout in other urban areas to follow. |
Norm King is the manager of TxDOT's Ecological
Resources Management Branch, Environmental Affairs Division, in Austin. He may be reached at
512-416-2319 or nking@dot.state.tx.us.
Sam Talje, P.E., is the director of hydraulic
design, surveying, and mapping at the TxDOT Houston District. He may be
reached at 713-802-5653 or stalje@dot.state.tx.us.
Michael F. Bloom, P.E., CFM, DEE is an associate in the Water Resources
Program of PBS&J's Houston office. He assists governmental entities in
complying with the Clean Water Act. He may be reached at 281-529-4202 or mfbloom@pbsj.com.
Jeff Scarborough is a program manager in the
Information Solutions group of PBS&J's Houston office. He may be reached at 281-529-4240
or jlscarborough@pbsj.com.
Other Articles in this issue:
Road Users Can Grow Old Gracefully—With Some Help
The Evolution of Advanced Research
Following the Flow
Acting Now, Building for the Future
The Battle of Its Life
A High-Tech Route for Freight Efficiency
Gearing Up for an Aging Population