Deicing Planning Guidelines and Practices for Stormwater Management Systems, second edition (2020)

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3 This report offers guidelines to assist airports and aircraft operators in identifying and select- ing best management practices (BMPs) for controlling aircraft and airfield deicing runoff. Air- craft operators are included in this target audience because of their role as key participants and stakeholders in any decisions that may affect aircraft safety or operations. This introductory section presents background on the origins and drivers behind this research project, describes the purpose and objectives of this document, and explains the structure of the planning guidance. Subsequent sections present guidelines for developing integrated deicing runoff management systems (Chapter 2), guidance for evaluating and selecting individual practices (Chapter 3), and fact sheets describing each of the practices (see Chapter 4). In addition, the electronic Deicing Runoff Management Decision Support Tool is available on the TRB website by searching for ACRP Research Report 14, second edition, to facilitate the identification of deicing runoff management system components that have potential applicability to an airport’s specific situation. For the purposes of this guidance document, BMP is used in the most expansive sense and includes source reduction, collection, containment, storage, and treatment/disposal/recycling practices and technologies. Because the selection of deicing runoff management measures for each airport will be based on site-specific considerations and factors, the term should not be interpreted to mean that a particular practice identified in this document is the best for all situ- ations. Instead, the collective group of practices identified generally is considered to represent potentially viable alternatives of managing deicing runoff. Other situation-specific practices or solutions outside the scope of this document also may be viable in certain situations. Background Deicing aircraft and airfield pavement is critical to ensuring safe flight operations during winter weather. FAA’s clean aircraft concept and associated guidance require that all critical surfaces of an aircraft be free of contamination at takeoff. Transport Canada (TC) Canadian Aviation Regulations (CARs) and Standards Part VI subpart 602.11 states, “No person shall conduct or attempt to conduct a take-off in an aircraft that has frost, ice or snow adhering to any of its critical surfaces.” Achieving and maintaining these critical conditions during winter weather requires deicing—removing frost, snow, and ice—sometimes followed by anti-icing—preventing the development of further accumulations for a limited period of time (that is, holdover time). These processes are accomplished with a combination of physical removal techniques and application of specialized deicing and anti-icing products. Similarly, airfield pavement surfaces must provide sufficient friction for safe landings, taxiing, and takeoffs during winter weather conditions. Approaches for deicing and anti-icing airfield C H A P T E R 1 Introduction

4 Deicing Planning Guidelines and Practices for Stormwater Management Systems pavement surfaces are distinctly different than those for aircraft, with physical removal play- ing a more prominent role and different deicing products being used. For simplicity, unless there is a reason to make a distinction, the term deicing in this document includes both deicing and anti-icing. Deicing products and practices are standardized and implemented with the overriding pri- ority of safe public travel. FAA and TC standards for aircraft deicing and anti-icing include the use of products that meet stringent performance specifications defined and published by the Society of Automotive Engineers (SAE) Aerospace Council. To ensure deicing practices are appropriately and consistently implemented, they are described in an aircraft operator’s FAA-approved Ground Deicing and Anti-icing Program, guidelines that are provided in FAA Advisory Circular (AC) 120-60 or in Canada guidelines provided in TP 14052 Guidelines for Aircraft Ground-Icing Operations. Reflecting the paramount focus on safety, pilots also have the discretionary power to demand supplemental deicing or anti-icing beyond the formal requirements if they believe it is needed. FAA AC 150/5200-30 provides comparable guidance to airport operators in developing a snow and ice control plan, conducting and reporting runway friction surveys, and establish- ing snow removal and control procedures. These plans are required for all Part 139–certified airports and recommended for other airport operators. Guidance for airfield pavement deicing products is provided in the form of recommendations that they meet applicable SAE specifica- tions. ACRP Report 123: A Guidebook for Airport Winter Operations is a useful reference for planning and implementing an effective winter operations program. Unfortunately, all of the SAE-certified aircraft and airfield pavement deicers have potential environmental implications when mixed with airfield runoff and discharged in airport storm- water. Concerns over these implications have led to regulation of deicing discharges under provisions of the Clean Water Act (CWA) and the Canadian Environmental Protection Act (CEPA) in Canada. In the United States, this regulation is typically accomplished through a National Pollutant Discharge Elimination System (NPDES) permit authorizing deicing stormwater discharges and requiring that controls on deicing runoff be implemented. This situation can result in airports and aircraft operators facing the dual demands for flight safety and environmental compliance. Ultimately, flight safety cannot be impaired, and compliance with environmental laws must be maintained. Environmental requirements on deicing runoff discharges vary from state to state or province to province and from airport to airport and may be driven by local environmental concerns associated with deicing pollutants (see “Environmental Concerns” in Chapter 2). ACRP Research Report 169: Clean Water Act Requirements for Airports describes the regulations and permitting programs that apply to regulating the environmental impacts on airport storm water discharges containing deicers. In Canada, discharges of storm water containing deicers from federal airports are regulated under the Glycol Guidelines in the CEPA (P.C. 1994-106, January 20, 1994). The core require- ment under the guidelines is that the discharge of (ethylene, diethylene and/or propylene) glycols into surface water resulting from aircraft de-icing and anti-icing activities at a federal airport does not exceed a concentration of 100 mg/L. Non-federal Canadian airports are not subject to the Glycol Guidelines per se. However, both federal and non-federal airports use the guidelines as an indicator of how well deicing run off measures are performing, and also are regulated under federal, provincial, county, and/or municipal environmental regulations intended to protect receiving waters. Ultimately, each airport has to manage its deicing runoff to comply with water quality requirements deter- mined by the combination of regulations or bylaws that apply to its specific discharges.

Introduction 5 Purpose and Objectives The purpose of this document is to provide practical planning guidance describing BMPs for managing airport deicing runoff. The following objectives guided the development of this document: • Develop the document as a practitioner’s handbook that is useful to airports, aircraft opera- tors, their consultants, and relevant regulatory agencies; • Provide information and practical guidance to assist airports and aircraft operators in decid- ing what types of practices may be appropriate to meet their particular requirements and constraints (funding, operations, setting, etc.); • Provide a Decision Support Tool that airports can use to identify and prioritize practices and technologies that are potentially suitable for their situation and provide the foundation and direction for subsequent detailed engineering feasibility analyses and design. • Present the guidance and Decision Support Tool in a way that overlaps or overlays with the principal compliance considerations of the NPDES permit program and the CWA. The purpose of this guidance is to assist airports and aircraft operators in gaining a basic understanding of the technical issues, screening the spectrum of deicing practices to identify those that may have potential benefits at their airport, and guiding the development of a deicing runoff management program. The guidance and information in this document are not intended to be a substitute for site- specific planning, permitting, engineering analysis, design, cost estimation, or operational pro- cedures. Each airport presents a unique combination of physical, climatological, operational, funding, environmental, and regulatory characteristics that must be evaluated as a whole when an effective deicing runoff management program is being developed. Rather, this document is intended to serve as a starting point. It is important to recognize that the technical and regulatory landscapes surrounding aircraft and airfield deicing are evolving, which may necessitate that this document be updated periodically to remain current. Guidance Structure The structure of the information in this document is top down, beginning with discus- sions of the issues and principles for developing integrated deicing runoff management sys- tems, followed by overviews and guidance for selecting currently available deicing practices by category, and ending with a compilation of fact sheets that describe specific characteristics of each practice. The Deicing Runoff Management Decision Support Tool is available as a down- loadable file from the TRB website.