Interpreting the Results of Airport Water Monitoring (2017)

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1 Water-related issues are central to environmental programs at most airports. On a regular basis, airport staff make water management decisions to support permitting, regulatory compli- ance, development planning, infrastructure design, asset management, operations, and mainte- nance efforts. Making appropriate decisions often relies on the acquisition, interpretation, and application of water monitoring data. Water monitoring is described here as the process of quantifying physical and chemical characteristics of water, inclusive of observation, sampling, and analysis processes. While the term “sampling” is often used casually when referring to the process of acquiring data (e.g., “Sampling Plans” that include both sample collection and analytical procedures), the term “monitoring” is preferred and is used throughout this document to describe the entirety of the data acquisition and evaluation process. Use of “monitoring” to describe the overall process allows the field observations, sample collection, and analytical measurement elements to be better distinguished. In the context of this guidebook, use of the term “water” is primarily associated with storm- water runoff that discharges to surface waters, storm sewers, sanitary sewers, treatment facilities, or groundwater. Stormwater monitoring represents the vast majority of water monitoring at airports. Monitoring of receiving streams is considered an extension of stormwater monitoring and is specifically referenced in the guidebook. In some instances, airports may also monitor groundwater, sanitary wastewater, and drinking water. While the content of this guidebook is stormwater based, many of the concepts presented are applicable to monitoring of water other than stormwater. Reliance on any given set of water monitoring data can have significant legal, financial, sched- ule, and functional consequences. The general consequences are usually apparent to airport staff, resulting in questions such as “Is my monitoring data accurate?,” “Is the data set repre- sentative?” and “Do I need to monitor for more or different parameters?” While the questions regarding the appropriateness of the data set are often apparent, finding clear answers to such questions can be a significant challenge. This guidance document is intended to be used as a reference for the aviation industry. It serves to consolidate known information on water monitoring at airports with the aim of improving clarity to the process of obtaining and using water monitoring data. The guidebook provides information, including a suite of water monitoring considerations, for airport staff to use in improving their own site-specific water monitoring programs and plans. By apply- ing the guidebook contents to individual situations, users can increase their confidence in monitoring results and perhaps find new means for interpreting collected data when making decisions. Introduction

2 Interpreting the Results of Airport Water Monitoring To facilitate application of the guidebook contents to individual situations, the document is structured to address three fundamental aspects of water monitoring data: 1. Process of acquiring reliable monitoring data 2. Methods for interpreting data that has been acquired 3. Means for applying the acquired and interpreted data to various decision-making processes. Each step in this process is equally important if airport staff are to confidently use water monitoring data. Without a thorough process in place for acquiring water monitoring data, the interpretation and application of the data may be built upon a faulty or uncertain foundation. Even with a strong monitoring program in place, rigorously interpreting each acquired monitor- ing data set is essential to be confident in the accuracy and representativeness of individual data points. Successful interpretation of monitoring data also benefits from use of appropriate statis- tical techniques to effectively assess the meaning of the data set as a whole. Finally, it is important to recognize that appropriately applying an interpreted data set in the decision-making process depends on the specific application or question to be answered. The guidebook uses the framework of a water monitoring plan as the linchpin for linking the various monitoring activities an airport might encounter. In this introductory section of the guidebook, an outline for a typical water monitoring plan is presented. The water monitoring plan framework aligns with the structure of this guidebook. Both the monitoring plan framework and this guidebook have three primary chapters following the introduction. • Chapter 1: Acquiring Monitoring Data focuses on providing users with information to strengthen aspects of their water monitoring programs and plans dealing with initial acquisi- tion of water monitoring data. If the guidance in the chapter is followed, the representativeness and accuracy of monitoring data should be improved and more consistent. • Chapter 2: Interpreting Monitoring Data provides information on two main elements of inter- preting water monitoring data: (1) verifying the accuracy and representativeness of acquired data and (2) applying statistical methods to quantify the characteristics of the monitored data set as a whole. • Chapter 3: Applying and Responding to Monitoring Data discusses situations for which airport staff most typically use monitoring. The chapter includes common applications for monitoring data, such as addressing compliance issues and preparing for future permit modifications. Guidebook users are also encouraged to use the following supplemental materials: • A Field Data Collection Form (Appendix A) provides a framework for information that should be collected in the field monitoring process. The form emphasizes observations made and meta- data (data about the monitoring data) at the time that field-monitored data is collected. Individual users can use the form directly or adapt it to their site-specific situations. • Field Conditions Fact Sheets (Appendix B) provide guidance on how to make observa- tions on certain environmental issues (including odor, color, sheen, solids, biofilm, and toxicity) in water flows. The fact sheets are aligned with narrative permit criteria found in most permits. • Monitoring Case Studies (Appendix C) from three airports are provided as illustrations of unique application of monitoring programs. • Customizable Parameter Fact Sheet Tool (Appendix D, Quick Start Guide) is a Microsoft® Access™ database of selected fact sheets on individual monitoring parameters (e.g., phospho- rus) that may be of interest in specific situations. The fact sheets can be customized to include only the information needed by the user and to add site-specific effluent criteria for the individual parameters. The fact sheets include information on pollutant forms and sources, general environmental effects, common monitoring laboratory and field methods, detection

Introduction 3 range, reference concentrations, monitoring challenges, related parameters and parameter- specific sampling considerations. These customized fact sheets can be printed. • The Water Quality Data Analysis Tool (Appendix E, Quick Start Guide) is a Microsoft Excel™ spreadsheet that allows the user to enter monitoring data sets to produce a basic set of statistical information and graphs using advanced computational procedures to assist with interpretation of the data. To facilitate useful application of the guidebook, the following features appear throughout the text of the guidebook. • Terminology by Chapter. Following an introductory section, each chapter contains a list of key terms used in the chapter. Consistent and appropriate use of terms by teams associated with monitoring data promotes efficiency and reduces the likelihood of unintentional errors. • Hyperlinked Features. The portable document format (PDF) version of this guidebook includes hyperlinks that allow readers to jump quickly to locations of direct interest. Hyper- linked entry points include table of contents, quick reference guide (see following section), chapter outlines, and sidebars. • Sidebars and Text Boxes. This guidebook includes a series of sidebars and text boxes, as shown in Table 1, that highlight key information. I.1 Quick Reference Guides This guidebook is organized to provide a comprehensive and systematic approach for users to establish or improve an airport water monitoring program. The authors recognize that some guidebook readers may not be looking for comprehensive guidance on interpreting water moni- toring results, or may not have the time to read the guidebook from cover to cover, but may be looking for guidance related to a specific water monitoring concern. The quick reference guides Description Example References to: • Other Guidebook sections • Guidebook appendices • Tools from research project • Other ACRP documents • Non-ACRP documents Individual lessons learned regarding monitoring, derived primarily from airports Use tables or forms that can be copied and taken into the field to define monitoring activities. Lists of key considerations on specific topics Topical Tips • Parameters • Field observations (visual, olfactory) Summaries of key points from major guidebook sections Key Takeaways • Add commonly encountered drivers.… • Summarize key regulatory drivers…. For more information about identifying monitoring drivers, see: 1.3 Identifying Drivers and Objectives for Monitoring Typical Monitoring Requirements Prescribed in Discharge Permits Writing Monitoring Plan Introduction Table 1. Description of sidebars and text boxes used in this guidebook.

4 Interpreting the Results of Airport Water Monitoring were designed to provide users looking for focused guidance on the following specific situations with easy access to the material that might be useful: • Responding to an unusual observation at an outfall • Tracing contaminant sources • Making improvements to a monitoring plan • Choosing the appropriate statistical analysis • Responding to exceedance of a numeric limit or benchmark • Proposing/establishing new permit conditions and monitoring requirements For each situation, a hierarchical quick reference graphic is provided in the following sections. For each level, links are provided to applicable guidebook sections, appendices, and tools. I.1.1 Responding to an Unusual Observation at an Outfall When airport staff make field visits to permit compliance locations, observations of par- ticular conditions are typically required by permit. Staff can use the guidebook either to improve their ability to make and document field observations or to get additional informa- tion after observations have been made. Guidebook sections, appendices, and tools appli- cable to field observations are listed in Figure 1. Click on the applicable line to be directed to the relevant area. I.1.2 Tracing Contaminant Sources When the potential for contamination of water discharges is discovered, a series of activities can be initiated to trace the contaminant source. Personnel associated with the investigation can use this guidebook to find information and techniques on the process for identifying the source of the contamination. Guidebook sections, appendices, and tools applicable to tracing Appropriately Document Field Conditions • 1.7.2 Documentation of Field Conditions • Appendix A: Field Data Collection Form Determine Cause or Source of Unusual Observation • Appendix B: Field Conditions Fact Sheets • 3.3.4 Conduct Source and Root Cause Investigations Respond to a Regulatory Compliance Issue • 1.8.3 Understanding Requirements for Reporting Results • 3.3 Application 1: Responding to Regulatory Compliance Issues Conduct Effective Public Outreach • 3.6 Application 4: Stakeholder Communication and Public Outreach Update Monitoring Plan Based on Lessons Learned • I.2.3 Monitoring Plan Section 1: Monitoring Data Acquisition; Monitoring Execution • I.2.3 Monitoring Plan Section 1: Monitoring Data Acquisition; Reporting • I.2.3 Monitoring Plan Section 1: Monitoring Data Acquisition; Recordkeeping • I.2.5 Monitoring Plan Section 3: Application of Monitoring Data; Program Review and Revision Figure 1. Quick reference guide for unusual observation at an outfall.

Introduction 5 contaminant sources are listed in Figure 2. Click on the applicable line to be directed to the relevant area. I.1.3 Making Improvements to a Monitoring Plan There are several reasons that an airport may choose to make improvements to their monitor- ing plan. Users looking to develop a monitoring plan for the first time can start with Section I.2: Developing a Monitoring Plan to Effectively Coordinate and Implement Monitoring Activities. Those users interested in improving their existing plans may also benefit from reviewing Section I.2. Guidebook sections, appendices, and tools applicable to writing or improving monitoring plans are listed in Figure 3. Click on the applicable line to be directed to the relevant area. I.1.4 Choosing the Appropriate Statistical Analysis Selecting the statistical analysis method that is appropriate for the monitoring data set can be a challenge. Personnel responsible for interpretation of the monitoring data can use the infor- mation in this guidebook to support their analysis. Guidebook sections, appendices, and tools applicable to choosing the appropriate statistical analyses are listed in Figure 4. Click on the applicable line to be directed to the relevant area. I.1.5 Responding to Exceedance of a Numeric Limit or Benchmark When managing an exceedance of a numeric limit or benchmark, airports may feel pressured to respond quickly and make decisions based on limited review of the data and an incom- plete understanding of the situation. A systematic approach to responding to the exceedance is recommended. Guidebook sections, appendices, and tools applicable to responding to an exceedance are listed in Figure 5. Click on the applicable line to be directed to the relevant area. Review the Existing Information • 2.3 Verifying the Accuracy and Representativeness of Raw Data Understand the Regulatory Implications • 1.8.3 Understanding Requirements for Reporting Results • 3.3 Application 1: Responding to Regulatory Compliance Issues Conduct a Source or Root Cause Investigation • 3.3.4 Conduct Source and Root Cause Investigations • 1.4 Defining Monitoring Parameters • C.1 Seattle-Tacoma International Airport • C.3 Victoria International Airport • Customizable Parameter Fact Sheet Tool • 2.4 Analyzing the Data Conduct Public Outreach • 3.6 Application 4: Stakeholder Communication and Public Outreach Update Monitoring Plan Based on Lessons Learned • I.2.5 Monitoring Plan Section 3: Application of Monitoring Data; Program Review and Revision Figure 2. Quick reference guide for tracing contaminant sources.

6 Interpreting the Results of Airport Water Monitoring Review Monitoring Plan to Confirm It Includes Appropriate Components • I.2 Developing a Monitoring Plan to Effectively Coordinate and Implement Monitoring Activities Make Updates to Improve Data Acquisition • 1.3 Identifying Drivers and Objectives for Monitoring • 1.4 Defining Monitoring Parameters • 1.5 Identifying Monitoring Locations • 1.6 Selecting Monitoring Frequency and Extent • 1.7 Executing Monitoring • 1.8 Collecting, Reporting, and Maintaining Data • Appendix A: Field Data Collection Form • Appendix B: Field Conditions Fact Sheets • Customizable Parameter Fact Sheet Tool Make Updates to Improve Data Interpretation • 2.3 Verifying the Accuracy and Representativeness of Raw Data • 2.4 Analyzing the Data Make Updates to Improve Data Application • 3.3 Application 1: Responding to Regulatory Compliance Issues • 3.6 Application 4: Stakeholder Communication and Public Outreach Figure 3. Quick reference guide for making improvements to a monitoring plan. Summarizing Water Quality Concentrations at a Site • 2.4.1 Uses of Statistical Analyses of Water Monitoring Data • 2.4.2 Descriptive Statistics • 2.4.3 Graphical Data Analysis • Water Quality Data Analysis Tool and Quick Start Guide (Appendix E) Appropriately Handling Nondetects • 2.4.7 Censored Data (Nondetects) • Water Quality Data Analysis Tool and Quick Start Guide (Appendix E) Comparing Data Sets (Paired and Unpaired) • 2.4.3 Graphical Data Analysis • 2.4.4 Comparative Data Analysis and Hypothesis Testing Assessing Changes Over Time • 2.4.5 Trend Analysis • 2.4.6 Hydrograph Analysis Evaluating the Performance of a Stormwater Best Management Practice • 2.4.3 Graphical Data Analysis • 2.4.4 Comparative Data Analysis and Hypothesis Testing Figure 4. Quick reference guide for choosing the appropriate statistical analysis.

Introduction 7 I.1.6 Proposing/Establishing New Permit Conditions and Monitoring Requirements Although it is the regulator’s responsibility to establish or modify permit conditions, many airports play an active role in permit condition development. Airports may choose to provide the regulator with data to support development or modification of specific permit conditions. Sometimes airports have difficulty meeting monitoring requirements due to hazards or physical or logistical constraints at the required monitoring location. They may also be concerned about the accuracy or representativeness of monitoring results obtained using the parameters and methods prescribed in the permit. Providing this feedback to a regulator may allow for discus- sion of modification of monitoring requirements to support more accurate and representative collection of data. Guidebook sections, appendices, and tools applicable to the water monitoring that support establishing permit conditions and monitoring conditions are listed in Figure 6. Click on the applicable line to be directed to the relevant area. I.2 Developing a Monitoring Plan to Effectively Coordinate and Implement Monitoring Activities A water monitoring plan is recommended for both routine and situation-specific water moni- toring activities. The plan can provide the following benefits: • Serve as the linchpin for linking monitoring activities • Provide a common point of reference for all staff and outside entities engaged in the monitoring Define the Issue • 3.3.1 Define the Issue • 2.3 Verifying the Accuracy and Representativeness of Raw Data Review Related Information to Further Understand the Issue • 3.3.2 Review Related Existing Information to Further Understand the Compliance Issue • 2.4 Analyzing the Data Communicate and Coordinate with the Regulator • 1.8.3 Understanding Requirements for Reporting Results • 3.3.3 Communicate and Coordinate with the Regulator Conduct Root and Source Cause Investigations • 3.3.4 Conduct Source and Root Cause Investigations Collect Additional Data to Confirm Compliance • 3.3.5 Collect Additional Data to Confirm Compliance Conduct Effective Public Outreach • 3.6.2 Handling Non-compliance Incidents Update Monitoring Plan Based on Lessons Learned • I.2.3 Monitoring Plan Section 1: Monitoring Data Acquisition; Reporting • I.2.4 Monitoring Plan Section 2: Monitoring Data Interpretation; Data Analysis • I.2.5 Monitoring Plan Section 3: Application of Monitoring Data; Program Review and Revision • I.2.5 Monitoring Plan Section 3: Application of Monitoring Data; Regulatory Coordination Plan Figure 5. Quick reference guide for responding to exceedance of a numeric limit of benchmark.

8 Interpreting the Results of Airport Water Monitoring • Help develop a level of consistency in techniques and methodologies as monitoring activities progress over time • Improve the accuracy of the data • Improve the representativeness of the data • Allow decisions made on early activities to be influenced by the “end-game.” For example, understanding the statistical analyses that will be used can influence the decision made on the number of samples collected. A framework for a water monitoring plan is presented in this section to promote clearer connection to the information in Chapters 1, 2, and 3. I.2.1 Typical Components of a Water Monitoring Plan While each airport monitoring plan should be specific to situational needs at individual air- ports, certain components should be considered for inclusion in any airport monitoring plan. The components in Figure 7 make up a framework for a typical monitoring plan. The remainder of this introduction describes the components of the framework in more detail. It is recom- mended that airports use the framework to develop a monitoring plan template that contains core elements applicable to most monitoring situations. The template can be adapted to meet situation-specific needs. I.2.2 Monitoring Plan Introduction: Focus on the Purpose and Objectives of Monitoring The introductory section of the Airport Monitoring Plan Framework lists items that provide background information on the monitoring effort needed to inform monitoring stakeholders. This section should include a general site overview and a general reference to the focus area of the monitoring (e.g., Drainage Basin 1, Little Run Stream), including figures showing key site To promote consistency in the monitoring process, the airport should develop a monitoring plan template specific to itself in order to provide a framework for all individual monitoring plans. Consider Modifications to Enhance the Accuracy and Representativeness of Monitoring Data • 1.4 Defining Monitoring Parameters • 1.5 Identifying Monitoring Locations • 1.6 Selecting Monitoring Frequency and Extent • 1.7 Executing Monitoring Use Monitoring Data to Support Proposal to Modify Permit Conditions • 1.8.3 Understanding Requirements for Reporting Results • 3.4 Application 2: Using Data in Establishing Permit Conditions • C.1 Seattle-Tacoma International Airport • 1.3.1 Regulatory-Required Routine Monitoring • Customizable Parameter Fact Sheet Tool Update the Monitoring Plan with Changes • I.2 Developing a Monitoring Plan to Effectively Coordinate and Implement Monitoring Activities Figure 6. Quick reference guide for proposing/establishing new permit conditions and monitoring requirements.

Introduction 9 Introduction Airport Overview Drainage Areas and Outfalls Industrial Activities and Pollutant Sources Control Measures Regulatory Background Permit Effluent Limits Benchmarks Monitoring Purpose and Objectives Terms Section 1: Monitoring Data Acquisition Monitoring Responsibilities Responsibilities for Staff and External Entities Involved with Monitoring Internal Communication Protocols Training Safety Procedures Personal Protective Equipment Monitoring Execution Monitoring Locations (include reference to stormwater pollution prevention plan map or other figure) Protocol for Initiating Monitoring Activities Qualifying Circumstances for Conducting Monitoring Qualifying Circumstances for Suspension of or Waiver from Monitoring Requirements Field Condition Documentation Procedures Monitoring Parameters Sample Collection Type Monitoring Type Monitoring Method Monitoring Frequency Monitoring Extent Calibration Protocols Maintenance of Equipment Maintenance of Monitoring Locations Reporting Standard Reporting Procedure Reporting of Exceedances Recordkeeping Record Retention Policy Data Compilation Procedures File Naming Conventions Budget Capital and Operating Costs for Monitoring Activities Section 2: Monitoring Data Interpretation Data Analysis Procedures for Evaluating Sampling Errors Procedure for Confirming Quality of Laboratory Analytical Data Statistics Used for Data Interpretation Protocol for Determining Need for Additional Data Collection Compliance Assessment Comparison of Monitoring Data to Standard Criteria Figure 7. Framework for airport monitoring plan. (continued on next page)

10 Interpreting the Results of Airport Water Monitoring features. Descriptions should be provided of relevant current and historical activities occurring on airport areas associated with the monitoring that may contribute to stormwater pollution. The introduction should also summarize control measures, like oil–water separators or infiltra- tion basins, if monitoring is used to evaluate performance of control measures. The introduction should identify applicable federal, state, and local requirements and any relevant effluent limits or benchmarks. A detailed replication of regulations and permit condi- tions is not needed, but applicable requirements and documents should be referenced, and a brief summary of the regulatory elements that directly influence this particular monitoring plan should be provided. The most important element of the introductory section of the monitoring plan is a summary of the drivers, purpose, and the objectives for conducting monitoring. As will be discussed in Chapter 1: Acquiring Monitoring Data, careful consideration should be given to the risks, ben- efits, and costs associated with monitoring. Documentation of these items is critical because they directly affect the basis for the monitoring decisions such as monitoring extent and frequency. If the airport has any globally applicable drivers or objectives, those can be included in the air- port’s monitoring plan template, with situation-specific drivers and objectives added for each new monitoring circumstance. Section 3: Monitoring Data Application Defining Applications for Which Monitoring Data Will Be Used Analyses to Support Investigations of Contaminant Source Triggers for Conducting an Investigation, such as Root Cause Analysis Regulatory Coordination Plan Planned Activities Requiring Coordination with Regulator Protocol and Staff Responsibility for Contacting Regulators Public Outreach Strategy External Communication Protocols Program Review and Revision Procedure for Review and Revisions to Monitoring Plan Log of Revisions Tables Summary of sample collection type, monitoring type, monitoring method, monitoring frequency, and applicable limits or benchmarks for each parameter. Summary of required equipment, including containers, preservation techniques, and hold times, for field activities. Figures Stormwater pollution prevention plan map or figures illustrating potential pollutant sources, drainage area boundaries, and monitoring locations. Appendices Sample Collection Procedures Field Data Collection Form Sample Chain of Custody Field Equipment Operations and Maintenance Manuals Applicable Permit or Regulation References and Excerpts Contact List Stormwater Pollution Prevention Plan or Stormwater Pollution Control Plan Spill Prevention Control and Countermeasures Plan Copies of Laboratory or Consultant Agreements Regulatory Reporting Schedule Flow Chart for Root Cause Analysis Figure 7. (Continued).

Introduction 11 The monitoring process can also greatly benefit by adding and defining key terms in the moni- toring plan. This enhances communications, reduces errors, and improves efficiency. Practitio- ners can use the applicable terms and definitions provided in this guidebook as a starting point. Key Takeaways Writing Monitoring Plan Introduction • Add commonly encountered drivers and objectives to the monitoring plan template. • Summarize key regulatory drivers from permits, consent orders, notices of violations, etc. • Clarify ambiguous regulatory requirements with the regulators. • Identify risks associated with monitoring and limitations on monitoring. • Document decisions to limit monitoring based on considerations such as costs, accessibility, safety. I.2.3 Monitoring Plan Section 1: Monitoring Data Acquisition Section 1 of the Airport Monitoring Plan Framework, entitled “Monitoring Data Acquisi- tion,” is typically the longest and most detailed section of a monitoring plan. This section should detail everything that monitoring personnel would need to successfully conduct monitoring. A summary of key elements of the monitoring data acquisition section is provided in the following subsections. Section 1 of the framework is also the focus of Chapter 1 of this guidebook. Data Acquisition Responsibilities The monitoring plan should clearly define data acquisition responsibilities for airport and outside staff. This includes personnel conducting field activities, outside laboratories or consul- tants, and management that may need to provide consultation or approval for certain decisions. Contact information should be provided for applicable parties. The monitoring plan should clearly identify the responsibilities of each staff member, including expectations for coordina- tion among staff and protocols for contacting outside entities. The monitoring plan should also identify any required training such as on-airport vehicle driving or confined-space entry training needed to collect samples. For monitoring programs, frequency of training and refreshers should be specified. Any requirements for personal pro- tective equipment for field personnel or other safety requirements should be identified in the plan, along with the location of the personal protective equipment. Finally, emergency contact information should be included in the plan’s contact list. Monitoring Execution Monitoring locations should be clearly defined within the plan. The most effective way to identify monitoring locations in the plan is a site map. Ideally, this map should indicate not only monitoring locations, but also the boundaries of the drainage area contributing runoff to that monitoring location as well as the industrial activities, potential pollutant sources, and the control measures within that drainage area. Plan developers are encouraged to be as specific as possible in describing the location from which samples are to be taken. Including photographs or coordinates for each monitoring location in the plan may help ensure monitoring data is col- lected from consistent locations. For more information about selecting monitoring locations, see: 1.5 Identifying Monitoring Locations

12 Interpreting the Results of Airport Water Monitoring The protocol for initiating monitoring activities should be described. If the permit contains specific language describing the circumstances required to initiate monitoring (e.g., probabil- ity of precipitation greater than some quantity), that language should be included in the plan. Otherwise, the airport should consider the purpose for monitoring and determine which cir- cumstances best meet monitoring objectives and describe those in the plan. This could include monitoring to capture the first flush, monitoring to capture average concentrations, or dry weather monitoring. Additionally, if there are circumstances defined in the permit, or defined by the airport, that would trigger temporary suspension of monitoring activities such as lightning, inundation of monitoring locations, freezing, or other hazardous conditions, those circum- stances should be clearly outlined in the plan. Procedures for monitoring field conditions should be clearly defined in the plan. Utiliz- ing a form to collect field condition data facilitates consistent collection and tracking of such conditions. The monitoring plan should also clearly define the sample collection type (grab, com- posite, continuous), monitoring type (test kit, handheld, online, or off-site), monitoring method (analytical method), and monitoring frequency for each monitoring parameter. The clearest way to define this information may be in tabular form. Monitoring extent, or the total number of locations or data points to be collected, should also be discussed in the plan. For ongoing regulatory-required monitoring, this may be the total number of monitoring events per year. For other non-routine monitoring drivers, defining monitoring extent may be more complex. Finally, the monitoring execution section of the monitoring plan should address quality. Proper calibration and maintenance of monitoring equipment is key to acquiring quality monitoring data. Calibration procedures and maintenance requirements for all monitoring equipment should be defined. The location of equipment operations and maintenance manuals should identified or, if possible, included as an appendix to the plan. Frequency for calibra- tion and maintenance activities should also be clearly defined in the plan. In addition, quality control procedures should be included in the plan. This could include a procedure for the field personnel to count sample bottles and double check specific items on the chain of custody. Including a sample completed chain of custody in an appendix is a good way to make sure they are filled out correctly. Lastly, proper maintenance of monitoring locations allows for safe access and facilitates collection of monitoring data. This typically includes mowing, and brush and debris removal. Reporting The procedure for regulatory reporting should be identified in the plan. If the regulator requires a specific form, an example completed form will facilitate proper completion of the form. If annual reporting is required, the contents of the annual report along with data analysis procedures and summary formats should be specified. In all cases, the staff responsible for com- pleting forms, developing reports, and reviewing regulatory submittals should be identified in the plan. It may be helpful to develop a schedule for completing regulatory submittals, particu- larly if development will require compilation of information from multiple sources and review by management and/or legal counsel. Procedures for required reporting of exceedances should be identified in the plan. Often reporting procedures are prescribed in permits, and there may be a time frame within which a report must be made once an exceedance is discovered. Specific information may also be required, and a list of the required information should be included in the plan so that it can be prepared in advance of making a call to a regulator. Use tables or forms that can be copied and taken into the field to define monitor- ing activities to eliminate incomplete collection of monitoring data. For more information about collecting field condition data, see: 1.7.1 Field Activity Execution Appendix A: Field Data Collection Form For more information about selecting monitoring parameters, and monitoring frequency and extent, see: 1.4 Defining Monitoring Parameters 1.6 Selecting Monitoring Frequency and Extent Failing to calibrate instru- ments or improper calibra- tion is one of the primary sources of monitoring error. For more information about reporting monitoring data, see: 1.8.3 Understanding Requirements for Reporting Results

Introduction 13 Recordkeeping Good recordkeeping can be a time saver when managing monitoring data and also a means of improving accuracy when historical data sets are used. A record retention policy, and procedures for where and how to save data, including original laboratory reports, compiled records, and summary statistics, should be clearly defined in the plan. Clearly defined file naming conven- tions also facilitate easy retrieval of data at a later date. Budget Clearly defining all of the specifics related to monitoring activities previously discussed should facilitate development of the monitoring budget. The budget should include capital costs for purchasing and installing monitoring equipment. Operating costs should include regular main- tenance and calibration, laboratory expenses, chemical supplies, specialty software subscriptions, as well as labor for conducting field activities and interpreting and reporting data. If decisions are made to limit field monitoring based on budgets, the decisions should be documented along with the means for filling in the data gaps through measures such as modeling, assumptions, or data extrapolations. For more information about compiling and managing monitoring data, see: 1.8.2 Compilation and Management of Results to Support Interpretation of Data For more information about cost saving, see: 1.7.5 Monitoring Efficiently to Reduce Costs and Save Time Key Takeaways Writing Monitoring Plan Section on Monitoring Data Acquisition • Clearly define team members’ roles and responsibilities to avoid execution gaps and conflicts. • Use site maps showing features such as monitoring locations, drainage areas, locations of key industrial activities, and access points to facilitate understanding and execution. • Detail procedures for the quality assurance (QA) and quality control (QC) processes; if detailed QA/QC procedures are executed by others (e.g., labora- tory analyses), reference this in the plan. • Provide detailed direction on recordkeeping responsibilities, content, and platforms (e.g., databases, spreadsheets, etc.). • Document the means for addressing data gaps if considerations such as budget, logistics, safety, or ability to collect representative samples affect the monitoring extent, frequency, location, or parameters. I.2.4 Monitoring Plan Section 2: Monitoring Data Interpretation Section 2 of the Airport Monitoring Plan Framework describes the data verification and sta- tistical analysis tools used to help interpret the acquired monitoring data set. This section of the water monitoring plan aligns with Chapter 2: Interpreting Monitoring Data. Data Analysis The monitoring plan should include a procedure for reviewing sampling and analysis data to confirm that it is accurate and representative of conditions monitored. The monitoring plan should identify statistical analyses that will be used to help interpret monitoring data. The plan should draw from potentially applicable statistical analyses, describe evaluations conducted using the data, and identify any programs that may be used to conduct detailed analyses. For more information about statistics and data analysis, see: 2.4 Analyzing the Data For more information about verifying accuracy and repre- sentativeness of monitoring data, see: 2.3 Verifying the Accuracy and Representativeness of Raw Data

14 Interpreting the Results of Airport Water Monitoring Compliance Assessment Airports may wish to define the procedures for how the acquired monitoring data will be compared to target criteria such as effluent limits, benchmarks, or performance standards in the monitoring plan. Key Takeaways Writing Monitoring Plan Section on Data Interpretation • Review the acquired data for errors and representativeness even if a sound process is in place for minimizing errors in field data collection and laboratory analyses. • Define, to the extent possible, statistical analyses that will be used to evaluate the data before the sampling is executed. • Select the statistical method based upon the extent of data collection and the anticipated distribution of the data as discussed in Chapter 2: Interpreting Monitoring Data. • Seek assistance from internal or external experts on statistical methods to help identify the methods most applicable to the airport’s situation. I.2.5 Monitoring Plan Section 3: Application of Monitoring Data Section 3 of the Airport Monitoring Plan Framework addresses how the monitoring data that is acquired will be applied to address the situation-specific issues. Acquisition of accurate and representative data, in addition to appropriate data analysis and interpretation, positions an airport to use monitoring data to inform decisions regarding response to compliance issues, future permitting, stormwater management practice design, ongoing stormwater control sys- tems, tracking of progress, and coordination with regulators. Key aspects of this section are summarized in the following subsection and discussed in detailed in Chapter 3: Applying and Responding to Monitoring Data. Defining Applications for Which Monitoring Data Will Be Used The monitoring plan should list and discuss the specific applications for the monitoring data. In simple terms, it should describe how the monitoring data will be used. The plan should be as specific as possible regarding the decisions that will be affected by the monitoring data. The eventual uses of the data impacts monitoring type, location, extent, and timing. The plan should be as specific as possible regarding which regulatory activities the data will be used for and whether the data will be presented to the regulators or used for internal evaluation. Consider both short-term and potential long-term uses of the data. Documenting Analyses to Support Investigation of Contamination Sources If there is a sudden unexplained increase in concentration of a specific parameter, or if unusual characteristics are noted in stormwater, a process should be described in the plan for investigating the source or cause of the unusual characteristics. In some cases, it may be possible to define the techniques to be used to investigate the source before data collection begins. In other cases, the decision on the investigation technique needs to be made after the initial data has been collected and evaluated. In either case, the methodology to be used to evaluate the con- taminant source, such as a root cause investigation, should be documented in the monitoring plan. The airport should also decide if the results of the investigation should be documented in For more information about conducting a root cause investigation, see: 3.3.4 Conduct Source and Root Cause Investigations Even if a formal root cause analysis is not completed, document potential contrib- uting factors to the effluent limit or benchmark exceed- ance in the monitoring plan.

Introduction 15 the monitoring plan. This has the advantage of providing a single document to encapsulate all information associated with the monitoring program. Regulatory Coordination Plan Regardless of the degree of interaction planned with regulators, the triggers for coordination between the airport and regulator should be documented. Specific staff should be identified that will handle all regulatory correspondence. A process for hiring an outside consultant to assist with regulatory coordination should be in place, should that become necessary to help facilitate understanding of an issue. If the objective of monitoring is to support development of permit conditions, a protocol should be described in the monitoring plan for which data will be pro- vided to the regulator, and when it will be required. Consider if it would be beneficial to ask the regulator to review the monitoring plan in advance and provide input on monitoring activities that would best support monitoring objectives. Public Outreach Strategy Often, airport water monitoring data is collected without significant consideration of its impacts. At times, however, public access to historical data is requested or required. When water monitoring data is documented, filed, and reported, it is important that how that data may be interpreted in the future be considered. Documenting the context for the acquired data can help avoid misinterpretation and misunderstanding in the event of a public data request. Program Review and Revision The monitoring plan can also be used as a vehicle for documenting lessons learned and poten- tial improvements to be included in future monitoring plans. Ideally the monitoring plan is a living document that is regularly updated to reflect changes at the airport. At a minimum, monitoring plans for ongoing regulatory compliance monitoring should be updated annually. Monitoring program review should include review of any compliance issues or root cause analyses that have occurred since the last review. Consider if changes need to be made to moni- toring methods or analysis procedures if hold times were missed. Determine if sample event coordination procedures should be updated if a sampling event was missed, or reporting pro- cedures updated if a non-compliance event was not appropriately reported. Consider any needs for additional monitoring personnel or training. Review current monitoring methods and loca- tions and determine if they still meet monitoring objectives and will result in representative data collection. Also include lessons learned associated with data management. A budget review should be conducted comparing actual costs to budget and determining if changes should be made to the monitoring budget. Any changes to regulatory requirements, including changes to limits, benchmarks, monitoring locations, monitoring parameters, moni- toring frequency, or reporting requirements should be updated in the plan. If the airport plans to make changes to monitoring execution, like adding automatic samplers, hiring a consultant, or training staff to collect samples, description of a plan for implementing these changes and the costs should be incorporated into the monitoring plan. For more information about regulatory coordination, see: 3.3 Application 1: Responding to Regulatory Compliance Issues 3.4 Application 2: Using Data in Establishing Permit Conditions For more information about effective public outreach, see: 3.6 Application 4: Stake- holder Communication and Public Outreach Key Takeaways Writing Monitoring Plan Section on Data Application • Define how the monitoring data will be used. • Be specific regarding the decisions to be made using the data. • If known, document the methods used to help support the decision-making process, such as a root cause analysis.