Steven C. Veal, P.E. and Franziska Brun

As EPA's NPDES storm water permitting program moves from a permit application to a permit compliance basis, cities are faced with the prospect of tracking literally hundreds of varying compliance activities across their city. In addition to tracking activities, cities must document those activities and report either to EPA or their state permitting authority according to a strict and predefined schedule and format. Since the vast majority of the required permit compliance activities have a spatial component, Geographic Information Systems (GIS) represent a powerful tool to allow cities to track and report the required compliance task in an easily understood graphical format.

However, the NPDES program represents what cities like to refer to as an Aunfunded mandate@, and municipalities are often forced to cope with NPDES requirements using existing staff and resources. In most cases, budgets are not available for expensive GIS systems or staffs.

However, the advent of easy-to-use desktop GIS systems such as ArcView 3.0 brings the power of GIS to even the most cash-strapped storm water manager. Using AVENUE and other application development tools, Carter and Burgess has developed a comprehensive, easy-to-use, GIS-based permit compliance system (GISPCS) for NPDES storm water compliance activities. This system has been successfully deployed in Florida Department of Transportation District 5 and variations on the system are currently being developed for other municipalities. New ArcView extensions such as Spatial Analyst extend the power of the system to more traditional storm water management tasks such as hydrologic modeling. This paper details the development of the permit compliance system and highlights its potential application for other municipal storm water managers.

The 1987 amendments to the Clean Water Act required the U.S. Environmental Protection Agency (EPA) to incorporate storm water permitting requirements into its existing National Pollutant Discharge Elimination System (NPDES) permitting program. In 1990, EPA published its NPDES permitting program for storm water runoff. The initial program focused on so-called Phase I dischargers. Phase I dischargers included most municipal separate storm sewer systems (known by the acronym MS4 - serving populations exceeding 100,000), construction activities over 5 acres in size and most industries.

For MS4's, EPA established a two-part permit application process. Part 1 of the application required cities to provide EPA with detailed information regarding the components of their storm water system and existing storm water program. Part 2 of the application required cities to provide EPA with a detailed storm water management program designed to improve the quality of storm water runoff in their city. In most instances, regulated cities submitted their completed permit applications during the period from 1991-1993. Since the regulations required cities to map key components of their storm water system, many cities opted to use geographic information systems (GIS) as a tool for application development.

EPA (or the delegated states where EPA had delegated NPDES permitting authority) processed the permit applications and began issuing 5-year NPDES permits in 1995 (some delegated states, such as California, issued NPDES permits earlier). Although many cities are still awaiting permits, a significant percentage of regulated cities now have NPDES permits for their storm water discharges.

The 5-year permits require a wide variety of compliance activities, most of which are well suited to use of a GIS-system for tracking, analysis, and reporting tasks.

Most municipal NPDES storm water permits require the performance of certain basic tasks that can be summarized as follows:

• Dry and wet weather sampling
• Tracking of system maintenance activities
• Tracking of illicit discharges and city enforcement activity
• Tracking of development and construction activity
• Tracking of industrial dischargers
• Tracking of public involvement activities and citizen complaints
• Annual reporting of compliance activities

Although other requirements exist in most permits (most require the development of specific storm water control ordinances or the development of storm water best management practices - BMP=s ) the majority of the tasks involve the cataloguing and analysis of data by spatial location - a perfect task for a Geographic Information System.

The heart of the GISPCS is ArcView 3.0, developed by Environmental Systems Research Institute (Esri) of Redlands, California. ArcView 3.0 was chosen for the GISPCS application for the following reasons:

• Defacto industry standard desktop GIS
• AVENUE scripting language allows application customization
• Most base data available in Esri ArcInfo format
• Relatively low cost
• Compatible with low cost PC hardware
• Extensions incorporate hydrologic analysis functions

Although ArcView represents the heart of the GISPCS system, other application development systems can be used to enhance the base capabilities of ArcView. For example, although ArcView and its AVENUE scripting language allow customized data input through the use of message boxes, the message boxes require the user to employ an input format which may be different from the normal input format that the user would employ on a standard paper form. For that reason, the DELPHI application development language was selected as a front-end to ArcView. In addition, ArcView is limited in its capabilities for report quality tabular and printed output so Crystal Reports Pro was selected as a report generation module for the GISPCS.

The pilot application developed for the Florida Department of Transportation (FDOT), District 5 used extensive base GIS coverages available from various state and local resource agencies including the St. John's River Water Management District, the South Florida Water Management District, Orange County, and the City of Orlando. These base coverages were supplemented with extensive field data gathered by Carter and Burgess for key storm water compliance features including storm water outfalls, industries, and storm water management ponds. A photographic inventory was taken of these features and added to the GIS database for ready determination of field conditions from the FDOT office location. Data was generated for over 500 major outfalls, 100 storm water management ponds, and 1250 drainage connection permittees (adjacent commercial and industrial activities).

The various components of the GISPCS were integrated with almost 10,000 lines of AVENUE scripting. The AVENUE scripts provide customized data input through DELPHI forms, custom query capabilities from within ArcView, specific spatial analyses, links to the report generation software, customized map production, and a simplified and customized ArcView graphical user interface (GUI).

Figure 1 shows the various components of the GISPCS in block format.

In the early development stages of the GISPCS, ArcView message boxes were used as the data input vehicle for the system. Although suitable for small forms, the application quickly exceeded the capabilities of the ArcView message input boxes. Based on similar work that Carter and Burgess was performing for the North Carolina Department of Transportation, the decision was made to use the forms capability of DELPHI application development software as the database front-end for ArcView. DELPHI allowed the development of forms that had the same look and feel as paper forms already in use by the department. The DELPHI-based forms also allowed the system to incorporate data input integrity checking. For example, one of the forms contained in the system allows the user to input data for EPA-mandated field screening of storm water outfalls. The paper version of the form provides a multiple-choice type of selection for certain parameters. Specifically, the form requests the user to input a selection for the visual appearance of the field-screening sample. Specific terminology (such as clear, muddy, green, etc.) is to be used by the field inspector. The DELPHI form, through a pull-down menu, prompts the user for the specific requested response, rather than allowing the user to input a response that is inconsistent with the remainder of the database entries. Radio buttons and other types of pull down lists are also used in the DELPHI forms to ensure data integrity and prompt user input. Forms were developed for outfall inspections, industry inspections, and storm water facility inspections for the FDOT application. The DELPHI forms were linked through AVENUE scripts to attribute tables associated with the shape file coverages. Figure 2 shows an example of one of the DELPHI forms used in the GISPCS application.

ArcView=s native capabilities allow extensive querying of resident datasets. However, the query capabilities of ArcView do require at least some knowledge of the program and the underlying data. To ease use of the system for a storm water manager, Carter and Burgess developed a set of AVENUE scripts that simplify the query process. Enhanced query capabilities built into the GISPCS system include the following:

• A location query menu selection allows the user to zoom in on industries, ponds, and outfalls based on pull down lists
• An inspection query menu selection allows the user to locate past outfall, pond, or industry inspection records based on user specified criteria
• An image viewer menu selection allows the user to view multiple images of pond, outfall, or industrial photographs or scanned images of pond construction plans
• Many of the query menu selections are duplicated on the GUI button bar

Figures 3, 4 and 5 illustrate the query capabilities of the GISPCS.

Although the native capabilities of ArcView 3.0 are somewhat limited for spatial analysis tasks, ArcView's Spatial Analyst extension provides tremendous flexibility for the performance of analyses required by the storm water manager. The hydrologic analysis AVENUE requests contained in Spatial Analyst have been added as menu selections in the GISPCS. These hydrologic analysis functions and the basic analysis capabilities of Spatial Analyst provide the storm water manager with the following GISPCS capabilities:

• Watershed delineation and runoff parameter estimation
• Pollutant loading analysis based on land use data
• Illicit discharge analysis based on field screening results
• Rainfall analysis based on station data
• Watershed prioritization based on discharge characterization and sensitivity of receiving waters

Figures 6 and 7 show two examples of the use of the GISPCS and Spatial Analyst for storm water analysis.

Although ArcView 3.0 has excellent map production capabilities, its capabilities for production of tabular and text-based reports are somewhat limited. Carter and Burgess incorporated a sophisticated report generator into the GISPCS using the Crystal Reports Pro software package. The report generator is called from an icon on the button bar, an associated AVENUE script, and once called, the report generator provides all of the flexibility of the Crystal Reports software. All attribute tables contained within the GISPCS may be used as input to report production. Using the report generator, NPDES compliance reports can be produced in any number of formats incorporating tabular data, integrated explanatory text, images and appropriate titles. Examples of NPDES reports which can be produced using the GISPCS and the report generator include field screening reports, industrial inspection reports, construction site inspection reports, wet-weather sampling reports and storm drainage maintenance activity reports. Figure 8 shows a report in development, and Figure 9 shows a completed report.

ArcView also allows export of tabular data to Excel spreadsheet format for users who are more familiar with the capabilities of that program for production of tabular reports.

EPA's NPDES storm water permitting program places a tremendous burden on public officials charged with storm water permit compliance. The NPDES program amounts to an unfunded mandate, and most cities are forced to use existing personnel - personnel who are usually unfamiliar with the capabilities of GIS - to cope with the myriad of requirements contained in their permits. The GIS-based Permit Compliance System (GISPCS) provides an easy to use, relatively low cost NPDES compliance solution for municipal storm water managers. Using the ArcView 3.0 engine and readily available application software, the GISPCS provide the storm water manager with extensive storm water system mapping, data input, analysis and report generation tools.

Steven Veal, P.E. (Primary and Presenting Author)

Vice-President

Carter and Burgess, Inc.

3880 Hulen Street

Fort Worth, Texas 76107

Phone: (817) 735-6161

Fax: (817) 735-6118

E-Mail: vealSC@c-b.com

Franziska Brun

GIS Specialist/Environmental Scientist

Carter and Burgess, Inc.

3880 Hulen Street

Fort Worth, Texas 76107

E-Mail: brunFE@c-b.com