August 19, 2009 Agenda Aquatic Life Use Refinement Nutrient - PowerPoint PPT Presentation

August 19, 2009

Agenda  Aquatic Life Use Refinement  Nutrient Criteria – Rivers and Streams  Nutrient Criteria – Lakes and Reservoirs  Nutrient Criteria – Direct Use Water Supply Res  CMA issues

Recap – rivers and streams  Refined Aquatic Life Uses (and Nutrient Criteria for Rivers and Streams) depend on bioassessment tools and biocriteria  Bioassessment tools  methods of quantifying the biological condition of an aquatic community  Biocriteria  Describe the biological condition that must be present to support the use  Serve as the threshold against which assessment results are compared

Bioassessment Tools  How to describe the condition of the elephant height weight temperature blood pressure

Bioassesment Tools  A method of quantifying the biological condition of an aquatic community

Multi-Metric Bioassessment Tool  Statistical analysis of stressed and reference sites  Select metrics that discriminate well between the good and bad sites  MMI  Macroinvertebrates  Recalibration complete (see website for report)

Biocriteria Setting thresholds Are any of these elephants “ impaired ” ?

Longterm view…  Embarking on new territory  Incremental Progress  Refinement in the years to come

 The thresholds we are about to discuss are the Division’s preliminary thresholds.  We are still in the process of checking our math and making sure the logic and concepts are sound.  The thresholds will change.

August 19, 2009

Topics  Terminology  WQCC Policy 2010-1  Tool Limitations  Determining MMI Score  Threshold Development  Decision Framework Approach  Next Steps

Terminology  Reference and Stressed  The ID of reference and stressed was a scientific exercise using anthropogenic influences.  Attained and Impaired  The ID of attained and impaired is a regulatory exercise based on direct measurement of aquatic community.  Biotype  Refers to the conceptual biological groupings defined by cluster analysis.  Class  Refers to Aquatic Life Use Classifications Cold and Warm I and II.

WQCC Policy 2010-1  Division will not propose revisions to the aquatic life use classification descriptions in the Basic Stds.  The Division’s proposal will be made in WQCC Policy 2010- 1 titled “ Aquatic Life Use Attainment, Methodology to Determine Use Attainment for Wadeable Rivers and Streams”.  This document will:  Provide a description of methodology  Record the WQCC’s policy decisions for MMI thresholds for use attainment

Tool Limitations  The Division is defining “wadeable streams” as streams with a natural drainage less than 7,000 km 2 or 2,700 mi 2 .  The limit on stream size is driven by practical concerns related to:  Sampling methodology  Data treatments in MMI development (“limitations of the model”)  Examples:  South Platte River at Waterton = 2,621 mi 2  Arkansas River at Canon City = 3,117 mi 2

Tool Limitations cont.  The MMI tool was calibrated and validated with data treatments for consistency in analysis.  Therefore, not all samples will match this data treatment.  Tool Usage Criteria:  Drainage area must be less than 7,000 km 2 or 2,700 mi 2  Sample must include 150 or more total individuals 1  Sample must include 10 or more taxa 1 1 Target sub-sample size is 300 individuals.

Determining MMI Score “Ingredients to Determine MMI Score” Metrics Germane to Hi Primary or Lo Index Biotype High or Low MMI Score Elevation (0-100) MMI

Initial Threshold Development  Thresholds for each biotype developed based upon the reference dataset distribution of MMI scores.

Step 1  Example – Biotype 2 (Reference Sites):  25 th percentile=66, IQR=14.4  Midpoint = 66 – 1.5 x 14.4  Midpoint = 66 – 21.6 = 44.4 or 44 Inter-Quartile Range 25 th Percentile

Step 1 Illustrated Midpoint=44

Step 2 Upper Bound (+6) Midpoint=44 Yellow Zone Lower Bound (-6)

Initial Thresholds Initial Thresholds for Aquatic Life Use Classification Threshold MMI score MMI Colorado Biotype (MMI Group) Index Impaired Attainment High Mountains High elevation, steeper High <38 >50 (biotype 2) slopes, moist Mountains Mid-elevation, flatter slopes, High <34 >46 (biotype 1) moderate precipitation Mountain Edges Mid-elevation, steeper High <26 >38 (biotype 3) slopes, drier Transition Low elevation, flatter slopes, Low <22 >34 (biotype 4) drier Plains and Xeric Low elevation, flatter slopes, Low <16 >28 (biotype 5) drier

Decision Framework Approach  The distinction between Class 1 and Class 2 relies on the phrase “a wide variety of warm/cold biota including sensitive species”.  The Division proposes using a decision framework approach that relies upon auxiliary metrics that measure diversity and sensitivity.

Example of Class 1 Water Attainment Threshold 50 38 Impairment Threshold

Example of Class 1 Water MMI Score of 46.5 Attainment Threshold 50 • 38 Impairment Threshold

Example of Class 2 Water 38 Impairment Threshold

Example of Class 2 Water MMI Score of 46.5 • 38 • Impairment Threshold MMI Score of 20.0

Next Steps  The Division is still investigating auxiliary metrics and their potential thresholds.  The Division is still examining the issue of secondary biotype membership and will be assessing its implications for threshold development.  The Division will start exploring other options for streams/rivers that don’t meet the Tool Usage Criteria.

Questions?

R IVERS AND S TREAMS N UTRIENT C RITERIA U PDATE Sabin Room--CDPHE 1:30pm--August 19, 2009

B ACKGROUND  2001 304(a) Criteria  Colorado’s use -based approach to numeric nutrient criteria for rivers and streams  Recreation — 150 mg/m 2 Chl a (attached)  Based on recreational user surveys ( http://www.umt.edu/watershedclinic/algaesurveypix.htm )  Aquatic Life — numeric values to be determined  Based on Colorado’s Multimetric Index (MMI) thresholds and Total Phosphorus/Total Nitrogen

C OLORADO ’ S A QUATIC L IFE U SE L INKAGE MMI Scores Nutrient (ug/L)

T ABLE V ALUE S TANDARDS  Nutrient criteria will be adopted into the Basic Standards (Reg. 31) via numeric table value standards (TVS) Nutrient Criteria for Rivers and Streams Total Total Phosphorus Nitrogen (ug/L) (ug/L) Cold water biota AA BB Warm water biota CC DD

R IVERS AND S TREAMS 304(a) C RITERIA Summary of the 2001 304a Nutrient Criteria for Rivers and Streams by Subecoregion That Would be Applicable to Colorado EPA Portion Total Total Chlorophyll a Turbidity Ecoregion of Phosphorus Nitrogen (ug/L) (FTU) Designation Colorado (ug/L) (ug/L) Xeric westslope, 21.87 368 1.78 4.2 Wyo Basin Plateau north (III.18) Xeric westslope, 20 553 1.78 2.79 Colo Plateau west (III.20) Xeric westslope, 15 228 1.78 5.13 Az/NM Plateau south (III.22) Mountains central 6.34 90 1.08 0.8 So Rockies mountains (II.21) So Great Plains eastern plains, 90 840 2.5 9.01 W High Plains northeast (V.25) Great Plains eastern plains, 25 450 3.4 4.96 SW Tablelands southeast (IV.26)

C URRENT N UTRIENT DATABASE  + 51,000 total phosphorus records  +35,000 total nitrogen records  911 MMI Scores (Colorado EDAS)  Includes data from  Storet  NWIS Riverwatch   23 other 3 rd party sources

I NITIAL R ESULTS Total Phosphorus 100 90 80 70 MMI Score 60 50 40 30 20 10 0 0.01 0.1 1 10 TP (mg/L)

I NITIAL R ESULTS Total Nitrogen 100 90 80 70 MMI Score 60 50 40 30 20 10 0 0.02 0.2 2 TN (mg/L)

M OVING T OWARDS N UMERIC C RITERIA  Explore various statistical methods to define the linkage between biological thresholds (MMI) and nutrient concentrations in order to develop numeric nutrient TVS  LOWESS  Change-point analysis  Break-point analysis  Quantile regression  Conditional probability http://n-steps.tetratech-ffx.com/statisticalTool-method.cfm

LOWESS E XAMPLE (f = 0.8)

Total Phosphorus 100 90 80 70 MMI Score 60 50 40 30 20 10 0 0.01 0.1 1 TP (mg/L)

A TTAINMENT T HRESHOLD E XAMPLE

N EXT S TEPS  Data  Complete nutrient database  Pair remaining EDAS MMI sites and nutrient data  Process 3 rd party macroinvertebrate data  Table Value Development  Explore methods for use in defining linkage between biological community and nutrients  Develop thresholds for nutrient concentrations  Propose numeric nutrient table values

Q UESTIONS AND C OMMENTS Blake W. Beyea blake.beyea@state.co.us 303.692.3656

B REAK

WQ Impacts of High Chlorophyll  Transparency  pH  DO demand  Cyano-toxins  DBPs  Fish species

Chlorophyll and Transparency  Transparency high 0 1 only at low 2 chlorophyll Secchi Depth, m 3  Transparency also 4 may be reduced by 5 6 factors other than 7 chlorophyll Warm Lakes 8 9 1 10 100 1000 Chlorophyll, ug/L