5 Colo. Code Regs. § 1002-73.16
Sections 25 8 202 and 25 8 205, C.R.S., provide the specific statutory authority for adoption of the revisions to this regulation. The Commission also adopted, in compliance with Section 24 4-103(4), C.R.S., the following statement of basis and purpose.
BASIS AND PURPOSE
The Commission has adopted changes for this regulation, which include the addition of revised and new definitions, recognition that the margin of safety in the total maximum annual load equation is not an implicit margin of safety, adjusting the wasteload allocations for total phosphorus based on nonpoint source to point source trades and a reallocation within the Chatfield Watershed, identifying how reclaimed wastewater applies to the wasteload allocation, recognizing four new wastewater treatment facilities, directing the Authority and the Division to coordinate review and actions on trade applications, clarifying that the Division shall consider the Authority's decisions on trades in rendering its final decisions on such trades, incorporating an opportunity for public comment on trades, noticing that the Division's decisions on trades are subject to an adjudicatory process, identifying the Authority as the monitoring and reporting authority, identifying the quality assurance project plan as the mechanism to identify data collection, compilation and transfer protocols, recognizing that the Authority is responsible for the development of an implementation program of best management practices, specifying that the Authority will implement a nonpoint source management program, identifying additional components of the annual report including trades and modeling efforts, and adding a revised watershed map with all point sources located.
Several minor typographical errors were corrected throughout the regulation, such as the spelling of "Dillon."
In section 73.2 , the following definitions were modified or added. A new figure 1 was added to the regulation reflecting an updated watershed boundary and the location of all wastewater treatment plants. The definition for the Authority was revised to recognize the existing and potential members of the Authority. The Authority is a water quality management agency within the areawide planning process of the Denver Regional Council of Governments. A phrase was added to the definition of "nonpoint source" to recognize that runoff from significant wildland fires, such as the Hayman burn, is classified as a nonpoint source and is accounted for in the wasteload allocation process as part of the background allocation. A new definition of "regulated stormwater" was added since Douglas and Jefferson Counties have stormwater management programs. Jefferson County is a new phase II stormwater permittee. As a point of clarification, the regulation notes that current stormwater permit holders (Douglas and Jefferson Counties) are not subject to the point source total phosphorus wasteload allocation in section 73.3 . A definition of the Authority "Trading program" was added to the regulation, which identifies the Authority as the entity administering the trading program within the Chatfield Watershed. A new definition of "wastewater treatment facility" was added to the regulation, which identifies wastewater operations subject to the point source wasteload allocations in section 73.3.
The Commission recognizes that the Authority has an active nonpoint source to point source trading program as defined in its trading guidelines. This trading program allows for a trade ratio reduction in specific nonpoint source trade projects. This trading program results in the net reduction of annual pounds of nonpoint source total phosphorus within the Chatfield Watershed. This poundage reduction alters the total phosphorus allocations defined in the adopted "total maximum annual load or TMAL" . However, the trades do not change the adopted TMAL, which remains as a flow dependent calculation of 59,000 pounds of total phosphorus at a total reservoir inflow volume of 261,000 ac-ft/ year. The trades effectively reduce the amount of total phosphorus assigned to the background allocation category within the Chatfield Watershed distribution by 351 pounds of total phosphorus per year. The assigned total phosphorus background allocation is reduced from 20,312 to 19,961 pounds. The trades result in an increase to the point source allocation within the Chatfield Watershed distribution from 7,358 to 7,533 pounds of total phosphorus using a 2:1 trade ratio. These trades do not affect the total allocation assigned to the "Upper South Platte Watershed".
The Commission recognizes the value of the Authority-maintained long-term data record to quantify the distributions of total phosphorus as inputs into Chatfield Reservoir. The Authority uses monitoring data to measure the response of chlorophyll productivity to the total phosphorus loading. The control regulation total phosphorus allocations reflect a data-driven predictive and monitoring strategy that better defines the limnological response of the reservoir to total phosphorus loading. A new footnote was added to 73.3(1) (b) that recognizes how the total phosphorus trades in the Chatfield Watershed can alter the wasteload allocations. It was noted that the margin of safety defined in the control regulation is not scientifically defined as an "implicit" margin of safety, so the term implicit was removed from the regulation.
A new footnote was added to the "Wasteload Allocation (point sources)" in the TMAL allocation table for point source discharge permit holders and stormwater permittees. This footnote states that dischargers or stormwater permittees in compliance with their permits will not have these limits modified prior to any future adjustment of classifications or standards by the Commission when attributable to factors such as wildland fires.
A new section is added to 73.3 (a) to clarify that the use of reclaimed wastewater (pursuant to regulation 84) is subject to the provisions of this regulation including trading provisions. As a result, the subsequent subsections and internal cross-references were re lettered.
In section 73.3 (2) (c), four new wastewater treatment facilities are added with the corresponding total phosphorus wasteload allocations. The existing Sacred Heart Retreat discharge system is assigned 15 pounds of total phosphorus from the reserve pool through 2010, which corresponds to the issuance period of the current wastewater discharge permit. The facility will develop a monitoring system and evaluate alternatives for a permanent wasteload allocation within the 5-year permit period. Three new treatment plants are scheduled to provide future wastewater service, and these allocations reflect approved trades being incorporated into this Control Regulation. The Authority applied a 2:1 trade reduction (nonpoint source: point source) for three projects in the watershed: the Ponderosa Retreat Center, the Centennial Water and Sanitation District and the Law Enforcement Training Facility, and the Jackson Creek Ranch. The Ponderosa and Centennial Water and Sanitation District allocations are supported by trades that convert nonpoint source total phosphorus to point source pounds through the closure of multiple septic systems. The Jackson Creek Ranch allocation is supported by an agreement for a point source to point source trade with the Roxborough Park Metro District and nonpoint source to point source trade reductions.
The Commission modified the Chatfield trading program in sections 73.3 to clarify the Division's authority to make final decisions on transfers, trade credits, and awards from the reserve/emergency pool to the dischargers in the Chatfield watershed. The Authority will continue to implement its historic application review and decision process on trade applications.
The Commission understands that the Chatfield Trading Guidelines (Guidelines) are acceptable to the Division and that the Division and the Authority are working to fine-tune the Guidelines to add a description of a coordinated review process. The Commission expects the Authority and Division to work expeditiously to complete this work and, in making revisions, encourages the Authority and the Division to consider the other basin trading programs in the State as possible models. Nevertheless, an applicant seeking approval of:
In reviewing an application, the Authority and the Division shall use the criteria outlined in the Chatfield Watershed Authority Water Quality Trading Guidelines, unless such Guidelines are modified without Division concurrence. If the Chatfield Watershed Authority Water Quality Trading Guidelines do not address an issue such as antibacksliding or antidegradation, then the Authority and the Division will defer to the Colorado Pollutant Trading Policy.
New sections 73.3 were added to require public notice of proposed trades and to provide that any person adversely affected or aggrieved by a Division decision on a total phosphorus trade may request an adjudicatory hearing before the Commission. These notices will provide an opportunity for third parties to review and comment upon proposed trades. The Authority has, and will continue, to provide notice of its meetings, including agendas, where trades will be considered.
Upon the effective date of the revisions to the regulation, any trades that have been approved by the Authority but have not been incorporated into a permit or are not reflected in a new or increased wasteload allocation in section 73.3 will be subject to Division approval under the aforementioned process.
Because trades may affect effluent limits and wasteload allocations in discharge permits, approved trades must be incorporated into permits. To encourage trading and to avoid duplicative appeals of trades, the Commission endorses the process for Chatfield Watershed discharge permits proposed by the Authority and Division to authorize trading and to incorporate approved trades as minor modifications in the permits. The Division and Authority presented evidence that, for new permits - during the initial issuance process and for existing permits - during a reopening and amendment process, language indicating that any future Division-approved trades would be incorporated into the permit as a minor modification would be included in the new/amended permit and subject to public notice and comment. Accordingly, after the period for appeal of a Division-approved trade has passed, the adjustment to the wasteload allocation and/or concentration limit for phosphorus, as appropriate, would be made as a minor modification of permit limits for phosphorus without further public notice.
In section 73.5 , the Authority is identified as the responsible entity for the monitoring and reporting program. Clarification was added to section 73.5 to note that the data collection, compilation, and transfer protocols are defined in a quality assurance program plan maintained by the Authority and subject to review and acceptance by the Division. All data collected by the Authority will be transmitted electronically to the Division annually. In section 73.6 , the Authority is identified as the responsible entity for implementing a nonpoint source management program. The Authority implementation program is subject to review under this control regulation. The Authority is responsible for providing strategies consistent with section 73.6 for those entities with land use powers to manage the 33,361 total phosphorus nonpoint source pounds assigned to the Chatfield Watershed.
The Authority, in cooperation with the Division and the Coalition for the Upper South Platte (CUSP), contracted for a special review of nonpoint source load assumptions contained in this Control Regulation. The independent review did not recommend that the existing wasteload allocations be adjusted, but rather was conducted to determine the validity of nonpoint source load assumptions used to allocate total phosphorus between the Chatfield and the Upper South Platte River Watersheds as defined in this control regulation and part of the adopted TMAL. The two goals of the review were:
This review required evaluation of the original assumptions used to establish the TMAL using the Woodward Clyde Report (1992), water quality data of the Authority, the control regulation, original Clean Lakes Study and information provided by the Authority, WQCD and CUSP. The review provided specific comments in the form of a technical memorandum addressing the TMAL assumptions and distribution of the total phosphorus allocations contained in the control regulation. The special study summary, conclusions and recommendations are in a technical memorandum. (Stednick, March 31, 2005). The special evaluation concluded that the Authority should revise the original model, underlying assumptions, load variability, runoff coefficients, impacts from the Hayman Wildfire, and the relationship of total phosphorus and chlorophyll in the reservoir based on the long-term available data. The evaluation further determined that the Authority reached a reasonable conclusion on the distribution of total phosphorus pounds between the Upper South Platte River and Chatfield Watersheds. The special study did not see the need to readjust these watershed distributions of total phosphorus as listed in the control regulation. The Commission finds that the assumptions and nonpoint source watershed distributions of 40,894 pounds of total phosphorus for the Chatfield Watershed and 17,930 pounds of total phosphorus for the Upper South Platte Watershed are supported by ongoing monitoring data, are reasonable. The study did note that the proposed expansion of the Chatfield Reservoir may affect water quality and any new operational plans should consider water quality concerns.
Based on these observations from the Stednick special review, the total phosphorus allocations between the Chatfield Watershed and the Upper South Platte Watershed remain reasonable and are supported by the ongoing water quality monitoring data. Additionally, the data collected and analyzed by the Chatfield Authority supports the watershed distributions of 40,894 pounds of total phosphorus for the Chatfield Watershed and 17,930 pounds of total phosphorus for the Upper South Platte Watershed.
The Commission recognizes that the Authority and the Division do not agree on all of the findings of the Stednick study and directs both parties to work together cooperatively to examine the TMAL and underlying assumptions. With the understanding that implementation of the existing controls is resulting in attainment of the water quality standard for phosphorus and the goal for chlorophyll a for Chatfield Reservoir, the Commission directs the Division and the Authority, subject to available resources, to examine the TMAL and its underlying assumptions. The Authority and Division will report to the Commission at the next triennial review on progress made towards developing a plan, obtaining funding, and a schedule of future activities for such study.
The Commission is aware that the Colorado Water Conservation Board is leading an effort to increase the amount of storage volume and storage allocation in Chatfield Reservoir. In that regard, in support of the Environmental Impact Statement being prepared for the project, consultants working on behalf of the U.S. Army Corps of Engineers are developing a water quality model to assist in the evaluation of the project's potential to impact the water quality of the reservoir. To the extent that evaluation of the aspects of the increased water storage can dovetail with this TMAL evaluation process, the Commission encourages the Authority and the Division to coordinate with the EIS team on any common elements that may assist in the development of models or approaches to evaluate water quality.
PARTIES TO THE RULEMAKING
5 CCR 1002-73.16