Guidelines for Evaluating and Selecting Modifications to Existing Roadway Drainage Infrastructure to Improve Water Quality in Ultra-Urban Areas (2012)

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20 Various state and federal regulations are the basis for high- way water quality retrofits. However, retrofit mandates vary significantly among individual DOTs. This section describes the regulatory triggers for BMP retrofits and DOT experi- ences and practices with BMP retrofits. This information is relevant for understanding the regulatory drivers that cur- rently and potentially affect DOTs, and secondly, for drawing on DOT experiences and approaches for addressing retrofit requirements. 3.1 Regulatory Drivers of BMP Retrofits Regulatory drivers are the main impetus for most BMP retrofits. Historically, water resources regulations affecting highway projects have mainly focused on construction and post-construction BMPs associated with new highway con- struction. However, there is an increasing trend in environ- mental regulations for protection and enhancement, and retrofitting requirements are expected to receive greater con- sideration in future USEPA stormwater rulemaking (USEPA, 2009). A number of federal regulations can provide the basis for retrofit mandates, including the: • Clean Water Act, • NPDES Permitting Program, • Water quality impairments and TMDLs, • Endangered Species Act, • Underground injection controls regulations, and • State and local requirements. 3.1.1 Clean Water Act The USEPA regulates water quality under the CWA, also known as the Federal Water Pollution Control Act. Enacted by the federal government in 1972, and significantly amended in subsequent years, the CWA is designed to restore and main- tain the chemical, physical, and biological integrity of waters of the United States. The CWA provides the legal framework for several water quality regulations that can impose BMP retrofit requirements. 3.1.2 National Pollutant Discharge Elimination System Permit Program Section 402 of the CWA authorized the NPDES per- mit program. Under this program, a permit is required for facilities that discharge pollutants from point sources into waters of the United States. Phase I of the program regulated medium and large MS4s that serve areas with a population of 100,000 or greater, and Phase II expanded coverage to small MS4 in urbanized areas. NPDES permits are also required for point discharges from DOT-owned industrial facilities and construction activities. Most states are authorized to administer the NPDES permit program, but the USEPA remains the permitting authority in a few states and territories. Delegated authorities have a certain amount of discretion in permitting approaches and conditions. As a result, NPDES permit requirements vary among permit- ting agencies and EPA regions, as well as in response to specific receiving water issues. Thus, a variety of NPDES permitting strategies are applied to state DOTs. Within Phase I and Phase II coverage areas, an NPDES permit may be issued to state DOTs and DOT districts, or DOTs may be co-permittees with local municipalities. In some states, DOTs are issued DOT-specific Phase I NPDES permits with statewide coverage. These permits are tailored to DOT activities, and often are more prescriptive with expanded requirements. NPDES MS4 permits can explicitly mandate DOTs to implement specific water quality retrofit requirements, such as stand-alone retrofits, retrofits associated with highway improvement projects, or retrofit evaluation studies. Exam- ples include Phase I permits issued to the North Carolina DOT and the Washington State DOT (WSDOT). In the case S e c t i o n 3 Retrofit Drivers and Practices

21 of WSDOT, recent litigation has expanded retrofit require- ments in the Puget Sound region. Highway BMP retrofit requirements are expected to extend to more DOTs with the increasing trend toward more DOT-specific MS4 permits, as well as greater consideration of retrofitting requirements in the USEPA stormwater rule- making (USEPA, 2009). In addition, TMDLs and CERCLA contaminated sediment efforts will likely result in retrofit requirements in subsequently issued NPDES permits and/or USEPA- or state-issued orders. 3.1.3 Water Quality Criteria, Impairments, and TMDLs In accordance with the CWA, the USEPA developed national water quality criteria (National Toxics Rule, or NTR) that are designed to protect the aquatic health of water bodies. The CWA requires state water quality programs to designate uses for all state waters, establish water quality criteria to meet those uses, and institute an antidegradation policy for waters that meet or exceed criteria for existing uses. The state water quality criteria must include both numeric standards for quantifiable chemical properties and narrative criteria or criteria based on biomonitoring. Some states have adopted the NTR criteria, while others adapted the NTR criteria or developed their own criteria (e.g., the California Toxics Rule [CTR]). Section 303(d) of the CWA requires the states to prepare a list of water bodies that are compromised or “impaired” by water quality based on an assessment and determination of meeting water quality objectives. The 303(d) list is prepared every 2 years and submitted to the USEPA for approval. Once a water body has been deemed impaired, a TMDL must be developed for the impairing pollutant(s). A TMDL is an esti- mate of the total load of pollutants from point, non-point, and natural sources that a water body may receive without exceeding applicable water quality standards (plus a “margin of safety”). Once established, the TMDL allocates the loads (waste load allocations) among current and future pollutant sources to the water body. The TMDL includes an implemen- tation plan for achieving the waste load allocations. TMDLs are a major driver of BMP retrofits. Due to their linear nature, urban highways cross numerous watersheds and many of these watersheds will have approved TMDLs, especially in urbanized areas where anthropogenic impacts are more profound. DOTs may literally have hundreds of waste load allocations for numerous pollutants and receiving water bodies, even in cases when highways are not significant sources of impairing pollutants. The waste load allocation can be expressed in terms of loads (e.g., zero trash loads) or in terms of concentration limits. To meet waste load allocations, DOTs may need to implement BMP retrofits to address load- ings from existing highway facilities. For example, Caltrans and DCDOT are researching and implementing BMP retro- fits to address trash TMDLs. In the Lake Tahoe Basin, BMP retrofits are required as part of the TMDL. Applicable TMDL requirements must be incorporated into NPDES permits as they are renewed. 3.1.4 Section 401 Water Quality Certification and Section 404 Permits Section 401 of the CWA requires that any applicant for a federal permit that may result in a discharge of pollutants into waters of the United States must obtain a state water quality certification that the activity complies with all appli- cable water quality standards, limitations, and restrictions. No permit may be issued by a federal agency until certifica- tion required by Section 401 has been granted. A state-issued Section 401 water quality certification is needed for DOT projects that require a federal permit, for example, highway improvement projects that require a Section 404 permit (see next paragraph). The certification process differs from state to state, and some states may be involved early in the proj- ect’s development to affect BMP selection and design. Thus, the water quality certification can potentially impose condi- tions on the project, including retrofit treatment, which will become a part of the federal permit. Section 404 of the CWA establishes a program to regulate the discharge of dredge and fill material into waters of the United States, including wetlands. These permits regulate dis- charges that alter substrate elevation or contours, suspended particulates, water clarity, nutrients and chemical content, current patterns and water circulation, water fluctuations, and salinity gradients. Regulated activities include fills for devel- opment, water resource projects, infrastructure development (such as highways and airports), and conversion of wetlands to uplands for farming and forestry. The USEPA and the US Army Corps of Engineers (USACOE) jointly administer the program. The USACOE oversees day-to-day administration of the program, including issuing individual or general permits. DOT projects that result in construction and stormwater management adjacent to or across waters of the United States may be required to obtain a Section 404 permit. The permit may have requirements for stormwater treatment and discharge activities, potentially including retrofit treat- ment requirements that are developed as part of the water quality certification. 3.1.5 Endangered Species Act The ESA of 1973 provides a means to protect endangered and threatened species and the ecosystems upon which they depend. The US Fish and Wildlife Service (USFWS) has juris- diction over terrestrial and native freshwater species, and the

22 National Marine Fisheries Service (NMFS) is responsible for listings of marine species or anadromous species. The USFWS and NMFS determine the critical habitat for the maintenance and recovery of endangered species, and require that the impacts of human activities on species and habitat be assessed. If the biological assessment finds that the endangered species may be affected by the proposed project, then the DOT must work with the USFWS or NMFS to develop mitigation mea- sures for the project, which can potentially include retrofit treatment of existing highway infrastructure. The mitigation measures may potentially include requirements for retrofit treatment of existing highway facilities associated with the project. This is the case for many DOT projects in the Pacific Northwest, where critical habitat for endangered salmon spe- cies occurs in numerous watersheds that are traversed by high- ways, including watersheds in dense urban centers. Ultimately, the ESA may result in stricter water quality goals than state water quality standards. 3.1.6 Underground Injection Control Program and the Safe Drinking Water Act Underground injection controls (UICs) are subsurface distribution and fluid disposal systems. There are five types of UICs based on USEPA classification. Class V UICs are for the disposal of non-hazardous fluids, such as on-site waste disposal systems and stormwater disposal systems such as dry wells and soakage trenches. The USEPA defines a Class V well as any bored, drilled, or driven shaft or dug hole that is deeper than its widest surface dimension, or an improved sinkhole, or a subsurface fluid distribution system (an infil- tration system with piping to enhance infiltration capabili- ties). Stormwater disposal in dry wells is the most common stormwater management practice in regions with favorable geology. Thousands of dry wells are in operation throughout the country, including DOT-operated facilities. The UIC program is a federal program under the Safe Drinking Water Act (SDWA) and Title 40 of the Code of Fed- eral Regulations (CFR) Parts 144-148, designed to prevent groundwater contamination from injection wells. The UIC program is administered by the USEPA, but many states are delegated permitting authorities. Because of the potential to contaminate drinking water supplies, the USEPA imple- mented new rules for Class V injection wells in 1999. The UIC rules include a number of prohibitions on the use of UICs and require all Class V UICs to be registered and regulated through rule-authorization or area-wide permits. Depending on the location and number of UICs and applicable permit requirements, UIC owners can be required to develop and implement stormwater management programs, conduct UIC evaluation studies, and conduct UIC monitoring programs. In addition, UIC owners, including DOTs, can be required to construct pretreatment retrofits of existing UICs to ensure compliance with drinking water standards prior to injection. 3.1.7 Comprehensive Environmental Response, Compensation, and Liability Act The Comprehensive Environmental Response, Compensa- tion, and Liability Act of 1980 (CERCLA), commonly referred to as Superfund, is a federal law that provides broad author- ity to clean up sites that are contaminated with hazardous substances such as contaminated groundwater and contami- nated sediments. Remedial actions under CERCLA require the control of potential upstream sources of recontamina- tion, for example, groundwater flows, overland flow, and riverbank erosion. Contaminants in stormwater are also a potential source of contamination and recontamination, but NPDES-permitted stormwater dischargers have not his- torically been subject to CERCLA liability under the feder- ally permitted releases exemption. A recent ruling, however, found that WSDOT was liable for CERCLA cleanup costs because WSDOT “arranged for the disposal” of stormwater by designing drainage systems for the three highways that dis- charge to a Superfund contaminated sediments site. Although the ruling is under appeal, it has implications for implement- ing effective treatment of highway stormwater discharges to Superfund sites, potentially through BMP retrofitting of high- way facilities. 3.2 DOT Retrofit Experiences There is a range of retrofit practices and policies among state DOTs reflecting differences in regional water quality issues and regulatory requirements by permitting agencies. DOT retrofit practices and policies fall into three general categories: • No documented retrofit policies. Many DOTs have not developed formal retrofit practices in their stormwater manuals, hydraulic design manuals, or management plans, but retrofit projects may be implemented on an individual project basis. • Developing retrofit policies. Some DOTs have initiated retrofit evaluation studies and development of retrofit pri- oritization procedures. • Established retrofit program and requirements. A few DOTs have established stormwater retrofit practices that are documented and formalized through policy and pro- grammatic procedures. Washington State DOT: WSDOT has an established storm- water retrofit program. WSDOT’s Phase I NPDES permit

23 requires three categories of stormwater retrofits: (1) capital improvements funding for stand-alone stormwater retro- fits; (2) project-triggered stormwater retrofits, implemented in conjunction with highway improvement projects; and (3) opportunity-based retrofits. Recent modifications to the NPDES permit resulting from a settlement agreement will expand stormwater project-triggered retrofit requirements in the Puget Sound region. WSDOT has implemented more than 65 stand-alone stormwater retrofit projects since 1995, and project-triggered retrofit requirements are routinely imple- mented on highway projects (WSDOT, 2008b). WSDOT has established programmatic retrofit procedures that are integrated into the state’s Highway Runoff Manual (WSDOT, 2008a). The procedures are used to determine min- imum cost-effective retrofit requirements associated with project-triggered highway projects, including assessment of off-site retrofits. For stand-alone and opportunity-based retrofits, WSDOT initially developed an outfall prioritiza- tion scheme based on numeric scoring procedures (WSDOT, 1996; Barber et al., 1997). The highest priority outfalls were found to be concentrated in urban areas that discharge to small streams. To achieve more consensus on the procedures, WSDOT updated the outfall prioritization procedure based on collaboration with the Washington State Department of Ecology, National Oceanic and Atmospheric Administra- tion (NOAA) Fisheries, and the USFWS. A tiered approach is used. The first screen uses geographical information systems (GIS) and existing information to identify high scoring areas. The second stage is based on field assessment and coordina- tion with local area biologists to identify problem areas and recovery strategies. Coordination and upfront buy-in with the regulatory and resource agencies was a programmatic breakthrough for retrofit prioritization. North Carolina DOT: The North Carolina DOT (NCDOT) Phase I NPDES permit requires implementation of 14 stand- alone stormwater retrofits per year, and development of a prioritization process. Retrofit prioritization is based on assessment of high ADT roads and sensitive waters, and on field assessments to identify constraints and opportunities. NCDOT has identified retrofit opportunities at rest areas, which tended to be hotspots; at interchanges near shellfish waters; and in watersheds with TMDL waters. It has also partnered with municipalities in developing off-site retrofits. NCDOT has constructed 43 stand-alone retrofit projects, with another 23 in the planning stages (NCDOT, 2008a). They have implemented a variety of conventional BMPs including dry and wet ponds, bioretention, sand filters, infil- tration basins, swales wetlands, and catch basin inserts. NCDOT actively coordinates with researchers, contrac- tors, and maintenance personnel to assess and improve ret- rofit activities. NCDOT has a strong partnership with North Carolina State University and sponsors research on BMP development and evaluation, including bioretention, bio- filtration, and permeable friction overlays. They coordinate with contractors to work out design issues and seek feedback from maintenance crews on BMP maintenance practices and issues. Ongoing coordination advances NCDOT’s retrofit program by expanding the knowledge base on effective BMP selection, efficient BMP design and construction, and practi- cal BMP maintenance. Caltrans: The California Department of Transportation (Caltrans) routinely implements stormwater retrofits in conjunction with major redevelopment projects (Caltrans, 2008). In addition, Caltrans implements stand-alone storm- water retrofits to comply with NPDES permit requirements, to comply with court orders or state water resources board orders, or to meet watershed-specific requirements [e.g., TMDLs, Lake Tahoe Environmental Improvement Program (EIP), Areas of Special Biological Significance (ASBS), and the California Ocean Plan (COP)]. Caltrans also has an active retrofit pilot test program for evaluating alternative BMPs. The program is designed to study and evaluate all aspects of stormwater retrofits for high- way facilities, including design and construction, capital and maintenance costs, treatment effectiveness, and operations and maintenance (O&M) requirements. The program is also used to support BMP certification. The ongoing program has produced a number of pilot test data reports on a wide vari- ety of BMP types. Caltrans conducted a comprehensive BMP retrofit pilot study for highway infrastructure (Caltrans, 2004). This study evaluated a wide range of BMPs that were installed as retro- fit applications along freeways and in Caltrans facilities. The study included cost information tracking, performance mon- itoring assessments, and information about maintenance practices (Currier and Moeller, 2000; Currier et al., 2001).