Code of Colorado Regulations
1000 - Department of Public Health and Environment
1002 - Water Quality Control Commission (1002 Series)
5 CCR 1002-61 - REGULATION NO. 61 - COLORADO DISCHARGE PERMIT SYSTEM REGULATIONS
Section 5 CCR 1002-61.49 - STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY, AND PURPOSE DECEMBER 2000 RULEMAKING - PHASE II STORMWATER PERMIT REGULATIONS

A. APPLICABILITY

These regulations apply to permits and permit application requirements for point source discharges of stormwater runoff including small municipalities (and interrelated discharges), industrial facilities owned or operated by municipalities, and small construction activity. They also apply to industrial facilities with no exposure of their industrial activities to stormwater.

B. REASON FOR AMENDING THE STATE PROGRAM

The State stormwater program is being amended to be compatible with EPA's amended federal stormwater regulation, 40 C.F.R. Parts 122, 123 and 124, which incorporates Phase II of the stormwater program. The changes were published in the Federal Register, Vol. 64, No. 235, on December 8, 1999.

These regulations are consistent with EPA's amended federal stormwater regulations. With a few specific exceptions, the State regulations have the same content as the federal regulations. Sections of the federal regulations were written in a "readable regulation" format that includes both rule requirements and EPA guidance that is not legally binding. In most cases, the Commission chose to omit the guidance sections from the regulation, and the Division will provide guidance on regulation implementation in separate documents. (At least one of these guidance documents will be in the form of Division policy, and will go through the public notice and comment process. See the section on Small Construction Activity, below.) Language that is derived from EPA guidance but is included as part of the State's regulation is legally binding.

The federal regulations also include several sections that are intended to allow the delegated states considerable flexibility in implementing the program. Further discussion on how the Commission has dealt with these sections is included below.

C. DISCUSSION OF AMENDED SECTIONS

Definitions, 61.2(79): Definition #79 addresses Non-standard Municipal Separate Storm Sewers Systems (MS4s), i.e., publicly owned systems for facilities that are similar to a municipality, such as military bases, and large education, hospital or prison complexes. The Commission elaborated on the definition provided by EPA. The State's definition includes a population criterion of at least 1000, which assumes that, in most cases, populations under that threshold have a low potential to pollute stormwater.

This was done to ensure that only systems that have a reasonable potential to impact stormwater quality will be regulated, and to provide more clarification to the regulated community on which facilities might initially need permit coverage, while keeping with the intent of the federal regulation. The Division can still designate facilities as requiring coverage (see section 61.3), even if they do not meet the threshold outlined here. Other criteria that could be used for evaluation include percent imperviousness area, total area, population density, land use, seasonality of population, and sensitivity of receiving waters (i.e., on the 303(d) list).

Definitions for Small Municipal Storm Sewer System and MS4 were also added, as per EPA's regulation.

Small Construction Activity - Waiver, 61.3(2)(f)(ii) - While the federal regulation allows for two different possible waivers for small construction activity, the Commission has elected to only include the waiver based on the Revised Universal Soil Loss Equation (RUSLE) (see below). One federal waiver is TMDL-based. The Commission believes that it would be difficult to administer, since the process involved in implementing a TMDL is lengthy and complex, and that it would produce a workload for the Division that is not commensurate with any savings afforded the permittee, in terms of both explaining and applying the waiver. Also, the Division believes that it makes little sense to allow an otherwise regulated activity to discharge, without controls, to a stream that is known to be impaired for sediment, when that discharge produces sediment.

The other potential construction waiver is based on the potential for erosion, using location, weather patterns, season, and duration. To apply the RUSLE Equation waiver, the rainfall erosivity (R-Factor) must be determined using a State Approved Method. The Division will propose the State Approved Method after this regulation has been finalized, but before the application deadline for small construction sites. The State Approved Method will be made an official State policy and go through a public notice and comment process before going into effect. The methodology used for determining the R-Factor under the State Approved Method will be finalized by a work group that will convene in early 2001. The State Approved Method will be based on methodologies in Chapter 2 of the U.S. Department of Agriculture's Agriculture Handbook Number 703, Predicting Soil Erosion by Water. A Guide to Conservation Planning With the Revised Universal Soil Loss Equation (RUSLE), pages 21-56, dated January 1997. The Division will ensure that the State Approved Method will not allow sites to be waived that would not have obtained the waiver based on the method allowed for in 40 CFR 122.26(b)(15)(i)(A).

Regulated Small MS4s, 61.3(2)(f)(v) - Small municipalities (<100,000) in urbanized areas have been brought into the municipal part of the stormwater program, but with simpler application and permit requirements than for the Phase I medium and large municipalities. Some municipalities will be required to have permit coverage, while others must be evaluated by the Division, using the designation criteria described below, to determine whether permit coverage is needed.

Designating Small MS4s based on TMDLs, 61.3(2)(f)(iii) - The regulation allows the Division to designate a small MS4 as needing permit coverage if it "contributes to a violation of a water quality standard or is a significant contributor of pollutants to state waters." The most likely situation where this authority would be exercised is when an MS4 discharge is to an impaired water or must be covered under a wasteload allocation as part of a TMDL.

A review of the draft regulation after it was published showed that the application and permit requirements for a small MS4 designated under these criteria were not clear, especially if the designation was based on discharge to an impaired water or on a TMDL, and occurred before March 10, 2003. Therefore, the designation language under Phase II was expanded to be consistent with the language under Phase I. The section on types of regulated small MS4s was expanded at 61.3(2)(f)(v)(A)(lll)(e) to add a reference to small MS4s designated under 61.3(2)(f)(iii). This was to ensure that the application and permit requirements for such designated small MS4s are consistent with other small MS4s.

Designation Criteria, 61.3(2)(f)(v)(A)(lll) - EPA's suggested designation criteria were amended slightly, as follows: discharge to sensitive waters, high growth or growth potential, population density, contiguity to an urbanized area, and/or significant contributor of pollutants to State waters.

Regarding discharge to sensitive waters, the Commission provided a definition for the purposes of this regulation, to include those receiving waters that are classified as either Aquatic Life Class 1, a Drinking Water supply, or are on the Division's most current 303(d) list (i.e., need a TMDL). Regarding growth, while EPA recommends using a rate of 10%/decade, this element can have widely varying impacts, depending upon the initial population. Therefore, the Division will consider other factors when evaluating growth, such as population size, population density (in effect, using the third element to help evaluate the significance of the second), area of the municipality, potential impacts from growth, number of construction starts, etc. The element of being a significant contributor of pollutants is difficult to define, therefore something would have to trigger this element, such as the Division receiving information to support such a claim. Further discussion of this issue will be included in the guidance document.

Review of MS4s is two tiered. The first tier is the evaluation of the MS4 against the first five criteria included in the regulation. The second tier involves the evaluation of the MS4's current programs to determine if the programs in place adequately address water quality concerns. That is, if an MS4 met one or more of the first five elements, then it could be designated, or have the option of providing verification to the Division that it is already implementing the applicable portions of the six minimum control measures. The burden of proof is on the MS4 to demonstrate to the Division that the MS4's program is acceptable.

An additional criterion is mentioned as having a high priority when the Division reviews other small MS4s: a combined permanent and seasonal population of over 10,000. This will address municipalities that periodically have large numbers of tourists, and thus have infrastructure in place to support a larger population than the number of permanent residents alone. This particular criterion was highlighted to indicate the Division's and Commission's concern for the stormwater pollution potential from these types of municipalities.

Municipal Waivers, 61.3(2)(f)(v)(A)(lll) - Two potential waivers for small municipalities located within an urbanized area are referenced in the federal regulation. The first waiver is for those municipalities with a population between 1000 and 10,000. The main criteria for this waiver are that: the Division has evaluated all State waters that receive a discharge from the MS4; the Division has determined that stormwater controls are not needed, based on an EPA-approved TMDL or an equivalent analysis of all of these State waters; and the Division has determined that future discharges from the MS4 do not have the potential to result in exceedances of water quality standards or other significant water quality impacts. Application of these criteria appears to be unachievable, as EPA staff have admitted, based on the difficulty in accurately predicting future runoff quality, as well as the work load inherent in a comprehensive evaluation and analysis of all receiving waters. Thus, the first waiver was not included in the proposed State regulation. The other waiver, for MS4s under 1000, was included as written in the federal regulation.

Original Industrial 'No Exposure' Exemption, 61.3(2)(e)(ii)(C), 61.3(2)(e)(iii)(J) and (K) - Paragraph 61.3(2)(e)(ii)(C) has been deleted, and categories (K) and (L) have been combined, based on the following. EPA's original Phase I regulation allowed a 'no exposure' exemption for industries under 40 CFR 122.26(b)(14)(xi), so-called 'light industry' or category (xi). In the State's regulation, category (xi) had been split into two categories. (K) was the category that listed the SIC codes for industries that did not need permit coverage if none of their industrial activities were exposed to stormwater. (L) was the category that listed the SIC codes from EPA's category (xi) where this exemption was not allowed (see 61.36.E.2, Statement of Basis and Purpose, 1993, for discussion). Paragraph 61.3(2)(e)(ii)(C) described the criteria for meeting the exemption. The Phase II federal regulation includes a 'no exposure' exclusion that has been broadened to include all industrial categories except construction, and so the original exemption, including the split into categories (K) and (L), is no longer needed.

New Industrial 'No Exposure' Exclusion, 61.3(2)(h): This regulation allows for industries with discharges composed entirely of stormwater to be excluded from permitting if there is 'no exposure' of industrial materials and activities to stormwater. As defined in the regulation, 'no exposure' means that all industrial materials and activities are protected by a storm resistant shelter to prevent exposure to precipitation, snowmelt, and/or runoff. It is anticipated that in most cases the shelter would be permanent; however, there are circumstances where permanent 'no exposure' of industrial activities or materials is not possible. Under such conditions, materials and activities may be sheltered with temporary covers such as tarps, between periods of permanent enclosure. However, under all circumstances the operator must ensure that there will be no exposure of pollutant sources to stormwater. Stormwater that has come into contact with industrial materials and/or activities is defined as a point source discharge requiring a stormwater discharge permit. If a point source discharge occurs from a facility which has submitted a 'no exposure' certification, the discharger would be in violation of the regulation, and permit coverage must be obtained.

The preamble to EPA's regulation provides further clarification on the definition of 'no exposure', in terms of which materials/activities are not included under the definition of 'industrial materials and activity':

* Drums, barrels, tanks, and similar containers may only be stored outside; that is, they may not be used while outside. The addition of material to or withdrawing of material from these containers while outside is deemed exposure, and as such, not allowed under the exclusion provisions.

* Adequately maintained vehicles used in material handling may be exposed to stormwater. This includes adequately maintained vehicles, and vehicles awaiting maintenance, such as trucks, automobiles, forklifts, pallet jacks, carts, dollies, or other such general purpose vehicles at the industrial site that are not industrial machinery, and that are not leaking contaminants or are not otherwise a source of industrial pollutants.

* Final products may also be stored outside without it being considered exposure; however, this only includes products that are not to be used in producing another product, even by another facility.

Time to Apply, 61.4(3)(a) - Consistent with the federal regulation, this regulation requires that industrial activities owned or operated by small municipalities (such as construction operations, gravel pits, and wastewater treatment plants with a capacity greater than 1 MGD), which have been under a permitting exemption, obtain permit coverage beginning in March 2003.

The Commission opted to change one of deadlines from the federal regulation. March 10, 2003 is the deadline for applications from small MS4s, and for municipal industrial facilities. The deadline for applications for small construction sites was changed from the March 2003 date to July 1, 2002. This was done to spread out the permitting workload, and to coincide with the expiration of the Division's existing Construction Stormwater General Permit, so that the new permit may incorporate the new provisions, if necessary.

For permitted facilities that qualify under the new industrial 'no exposure' exclusion, a no exposure certification may be submitted to the Division at any time following the promulgation of these regulations. (Qualifying permitted facilities may also opt to continue permit coverage.) For facilities currently covered by the original exemption described in paragraph 61.3(2)(e)(ii)(C), in accordance with paragraph 61.4(1)(a) a 'no exposure' certification or an application for coverage under a stormwater permit must be submitted to the Division within 60 days of this regulation's publication in the Colorado Register.

Application Requirements for Small MS4s, 61.4(3)(d) - The Commission and the Division strongly support cooperation between permit holders in complying with the six minimum control measures, or stormwater management programs, that will be required of the small MS4s. Thus, the federal language allowing for the possibility of MS4s applying jointly under a general permit, and the possibility of using a local qualifying program to satisfy one or more of the minimum control measures, is included in the State regulation. The Commission also included a provision allowing for co-permittees to apply for an individual permit. However, the final decision on this approach is within the Division's discretion, due to the extra resources that would be required to issue such a permit, potential complications for enforcement/compliance/liability, and the possibility of the co-permittees' goals being achieved under a general permit.

Permit Conditions, Minimum Control Measures, 61.8(11) - The minimum control measures required for small MS4s (public education, public involvement and participation, illicit discharge detection and elimination, construction site stormwater runoff control, post-construction stormwater management in new development and redevelopment, and pollution prevention/good housekeeping for municipal operations) are consistent with EPA's, except for the following changes.

* Public Education - This measure involves educating the public, including businesses, on the impacts of stormwater discharges and improper waste disposal on water bodies, and what the public can do to minimize these impacts. In the federal regulation, the section regarding businesses and improper waste disposal was located under the Illicit Discharges measure. It was moved here to combine the public education requirements under one section.

* Public Involvement - The public involvement minimum control measure was clarified to indicate that public notice is required for ail of the minimum control measures. EPA's regulation could have been interpreted to only require public notice for the public involvement minimum control measure. However, discussion in the preamble (both draft and final) indicates that EPA intended for the public notice requirement to apply to an MS4's entire stormwater management program. The Commission also clarified that the means of public notice should be effective, i.e., should attempt to reach a majority of citizens, through the use of a community publication or newspaper of general circulation.

* Illicit Discharges - This measure involves detecting and eliminating illicit discharges to the MS4. EPA's guidance language regarding some components that it recommended to be included in an MS4 program was added to this regulation: procedures for tracing the source of an illicit discharge; procedures for removing the source of the discharge, and procedures for locating priority areas likely to have illicit discharges. Some of the municipal members of the Task Force have had experience with illicit discharge detection programs, and believe that any valid program would necessarily include these components. Thus, the Commission has added this language to the regulation.

* Construction - This measure requires the MS4 to institute a program to reduce pollutants in stormwater runoff to the MS4 from construction activities that result in a land disturbance of one acre or more. There were no changes made from the federal requirements.

* Post-Construction The post-construction stormwater management measure addresses stormwater runoff from new development and redevelopment projects that disturb greater than or equal to one acre. As per the federal regulation, it includes a requirement for municipalities to 'ensure adequate long-term operation and maintenance of BMPs.' This requirement makes municipalities responsible for seeing that BMPs for new development and redevelopment are operated and maintained properly, even those that the MS4 does not own. Several municipalities have expressed concern that this requirement could be extremely difficult or impossible to meet.

The standard for permit compliance for this sub-section is that municipalities ensure maintenance and operation of BMPs to the maximum extent practicable (MEP). In determining if an MS4 has complied to the MEP, the Division may consider such factors as the adequacy of the MS4's post-construction program, its ability to require that the necessary actions be performed by the responsible parties, how the MS4 has carried out the post-construction program, and, if necessary, the MS4's ability to provide appropriate mechanisms to ensure such maintenance and operation.

It is expected that the MS4 will put into place procedures, ordinances or other regulatory mechanisms that will require, to the extent allowed by State and local law, that BMPs be appropriately designed and planned, and provide for enforceable operation and maintenance by the owner/operator. Factors such as the extent of the inspection/verification system, and the procedures in place and implemented for instances when BMPs are not operated and/or maintained, can be evaluated by the State to determine if the MS4's program meets the MEP standard.

* Municipal Operations -This measure involves an operation and maintenance program, including an employee training component, that is designed to prevent or reduce pollutant runoff from municipal operations. EPA's guidance language on the types of municipal facilities that should be addressed under the good housekeeping/pollution prevention measure was included as a requirement in the State's regulation. The Commission believes these types of operations have the potential for stormwater pollution, and listing them in the regulation provides clarity on what is required from the regulated MS4s. Those that are found by an MS4 to be a low risk in its particular jurisdiction can be considered to be already complying with the regulation by preventing pollutant runoff, and thus no additional work on those operations would be needed.

Qualifying Local Programs, 61.8(12) - As per the federal regulation, this section authorizes the Division to accept the requirements of a qualifying local erosion and sediment control program as satisfying the requirements of the Division's construction permit(s). The local program would be incorporated by reference into the Division's permit(s). Thus, while Division permit coverage by the construction operators or owners is still required, they will only have to comply with one set of requirements, not two.

PARTIES TO THE RULEMAKING HEARING