1. Integrated Reports Classified Use Support Evaluation
Compiled, Evaluated, and Written by
R. W. Parachini
Genesis high level overview of the status of CO water quality management was at and future challenges.
“The most important thing to consider in water quality management is the classified uses and their support and protection”.
Very prominent in the federal and state regulatory frame but is not regularly evaluated and then used in various decision making actions.
Comparison of the 2012 and 2016 Integrated Reports.
Identified a little bit of what I already knew, but raised several more questions about the status of Colorado’s classified uses.

2. Background Information
Federal Level
Clean Water Act
State Level
Colorado Water Plan
Colorado Water Quality Forum
Water Quality Control Division
Clean Water Act Background
Attainment status of all surface waters according to the five classified use categories adopted by the Colorado Water Quality Control Commission.
Colorado Water Plan Background
The Water Quality Control Commission strategic water quality goal is: By 2050, Colorado’s waters will fully support their classified uses, which may include drinking water, agriculture, recreation, aquatic life, and wetlands.
Colorado Water Quality Forum Background
Concept of developing a process to better identify potential forum and work group efforts that balance standards development and standards implementation actions.
WQCD 2027 Roadmap
Primary platform for this effort over the next 10 years.
Effort may be better served at a state-wide or river basin scale rather than only at the pollutant level to address water quality issues.

3. Classified Use Support Change Across Basins & Over Time?
Can classified use support be evaluated at statewide and individual river basin scale?
Available IR data
River/stream miles and lake/reservoir acres in each classified use category
Calculations and evaluation methodology
R/S miles and L/R acres calculated as the respective percentage of the total statewide assessment miles and acre values.
State wide and basin level evaluation within IR periods and over time.
Compared to applicable WQCD/CW program goals.
Question to be answered?
Is data available to turn into information?
Is evaluation methodology available and understandable?

4. Statewide Classified Use Support
2010 to 2012
All river/stream miles CUS decreased.
Lakes/reservoirs acres more variable.
2016 to 2018
River/stream miles and lake/reservoir acres for agriculture, all aquatic life, and recreation CUS show consistent increase.
Evaluate % change in various use classifications of river/stream miles and lake/reservoir acres over time.
2010 to 2012
This decrease may have been caused by WQCC actions such as additional classified uses, a classified use upgrade or downgrade, or increased available data and assessment and a change in assessment methodologies between periods.
This increase may have been caused by WQCC actions such as removal of a classified use or a classified use downgrade.

5. Basin River/Stream Miles Classified Use Support
Fully supporting - great variability across basins over time.
Some uses supporting - variability over time; decreasing across all basins over the last 10 years.
Insufficient data/not assessed - variability across basins over time, except Rio Grande at low 20% range.
Insufficient data - M&E list - limited time period; limits any trend observations.
TMDL completed and approved, impaired-no TMDL necessary, impaired naturally/impairment not caused by pollutant - data limitations.
Impaired; TMDL necessary - variability across basins over time.
Fully supporting –
Some use supporting –
Insufficient data/not assessed –
Insufficient data - M&E list –
TMDL completed and approved, impaired-no TMDL necessary, impaired naturally/impairment not caused by pollutant –
Impaired; TMDL necessary -

6. Basin Lake/Reservoir Acres Classified Use Support
Fully supporting - greater variability over time within some basins than in others.
Some uses supporting - variability over time for majority of basins decreasing; remainder increasing.
Insufficient data/not assessed - variability over time with four river basins showing a negative trend and three showing a positive trend.
Insufficient data - M&E list - - limited time period; limits any trend observations.
TMDL completed and approved, impaired-no TMDL necessary, impaired naturally/impairment not caused by pollutant – data limitations.
Impaired; TMDL necessary - general positive decreasing percentage across time for all basins.
Fully supporting –
Some use supporting –
Insufficient data/not assessed –
Insufficient data - M&E list –
TMDL completed and approved, impaired-no TMDL necessary, impaired naturally/impairment not caused by pollutant –
Impaired; TMDL necessary -

7. Conclusions Statewide level Basin level Two tier evaluation approach
Low classified use protection status percentage
Potential causes?
Basin level
Two tier evaluation approach
Relatively easy and useful method.
Causes of both statewide and basin level trends?
Conclusions
Statewide level - determine potential causes such as standards development and other actions.
Basin level - determine potential causes such as site-specific standards development actions, and standards implementation such as discharge permit issuance and TMDL completion activities.
Two tier evaluation approach
Useful and successful means to identify important water quality issues that affect applicable classified use support.
Causes of these trends may prove useful.

8. Next Steps Evaluation methodology
Focused application?
State wide and river basin level?
WQCC 2050 water quality goal?
Additional refinement of cause/effect relationship
Evaluation methodology
Potential method to observe progress Colorado Nutrient Management Plan and 10-Year Water Quality Roadmap.
Evaluate state wide and river basin level classified use support in general.
Simple high level method to evaluate progress towards the WQCC 2050 water quality goal.
Additional refinement of cause/effect relationship between standards development and implementation and classified use support ratio over time needed