Regulatory Activity

• In June 2009, the WQCC will hold a rulemaking hearing regarding temperature standards for the South Platte River. Click here to download the latest documents presenting the Authority’s position.  Updated information on all Rulemaking hearings is always available on the WQCC web page, http://www.cdphe.state.co.us/op/wqcc/
• The Authority’s expert consultant, Dr. William Lewis, prepared the power point presentation in the pdf document that is available for downloading.  The presentation summarizes the Authority’s proposal and the scientific basis for the proposal. download
• 2008 Rulemaking Hearing
• The Water Quality Standards and Stream Classification defined in Regulation #38 can be found at http://www.cdphe.state.co.us/regulations/wqccregs/100238wqccsouthplattenew.pdf and Regulation #73 can be found at: http://www.cdphe.state.co.us/regulations/wqccregs/100273wqccchatfieldreservoirregnew.pdf
• On November 10th, 2008 the Water  Quality Control Commission took the following action regarding Regulation #73.
  "In 2008, the WQCC held a rulemaking hearing to consider revisions to water quality standards and goals in the Chatfield Basin, specifically, Regulations #38 and #73. The rulemaking hearing began on November 11th 2008. As part of that hearing, the record was reopened and parties were invited to submit additional testimony. Because a quorum was not available for the Water Quality Control Commission (Commission) December meeting, the rulemaking hearing was continued until January 12th 2009.
  
  As part of the October 2007 triennial review hearing, the Commission directed the Authority and Water Quality Control Division (Division) to work together cooperatively towards continued improvement of water quality in the Chatfield watershed and jointly review the 23 years of data collected by the Authority. Beginning in September of 2007 through April of 2008, the WQCD conducted a series of presentations to the Authority, describing concepts and approaches to the review.
  
  Initially, the WQCD pursued a translator approach where models would be developed or adjusted to reflect the relationships between both phosphorus load and in-lake phosphorus; and between in-lake phosphorus andchlorophyll. The proposal finally submitted to the WQCC indicates that the translator approach was abandoned and is replaced by a probabilistic one. Instead of using the data to describe relationships between components of the ecosystem, the data is used to describe the likelihood of standards being attained based on past performance.
  
  At the conclusion of the rulemaking hearing, in January 2009, the WQCC, adopted a Total Phosphorus standard of 30 ug/L and a chlorophyll standard (changing the goal to a standard) of 10 ug/L with an exceedance standard of1 in 5 years. They adopted a new concept, a new approach, called an “assessment threshold” (a.k.a attainment criteria). They set the assessment threshold at 35 ug/L for phosphorus and 11.2 ug/L for chlorophyll. TheWQCC also adopted a revised Total Maximum Annual load of 19,600 lbs/yr at a median flow of 100,860 Acre-feet/yr. The WQCC adopted language about the development of aTMAL at some point in the future and that existing wasteloads would be in place until there is development of the revised TMAL. Activities to support the TMAL development would be based on the availability of funds."

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