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 Primary Biotype Metrics Germane to Hi or Lo Index High or Low Elevation MMI MMI Score (0-100)
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) Yellow Zone Midpoint=44 Lower Bound (-6)
Initial Thresholds Initial Thresholds for Aquatic Life Use Classification High Mountains (biotype 2) Mountains (biotype 1) Colorado Biotype (MMI Group) High elevation, steeper slopes, moist Mid-elevation, flatter slopes, moderate precipitation MMI Index Threshold MMI score Impaired Attainment High <38 >50 High <34 >46 Mountain Edges (biotype 3) Transition (biotype 4) Plains and Xeric (biotype 5) Mid-elevation, steeper slopes, drier Low elevation, flatter slopes, drier Low elevation, flatter slopes, drier High <26 >38 Low <22 >34 Low <16 >28
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 50 38 Attainment Threshold 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 MMI Score of 20.0 Impairment Threshold
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?
RIVERS AND STREAMS NUTRIENT CRITERIA UPDATE Sabin Room--CDPHE 1:30pm--August 19, 2009
BACKGROUND 2001 304(a) Criteria Colorado s use-based approach to numeric nutrient criteria for rivers and streams Recreation 150 mg/m 2 Chla (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
MMI Scores COLORADO S AQUATIC LIFE USE LINKAGE Nutrient (ug/l)
TABLE VALUE STANDARDS Nutrient criteria will be adopted into the Basic Standards (Reg. 31) via numeric table value standards (TVS) Nutrient Criteria for Rivers and Streams Total Phosphorus (ug/l) Total Nitrogen (ug/l) Cold water biota AA BB Warm water biota CC DD
RIVERS AND STREAMS 304(a) CRITERIA Summary of the 2001 304a Nutrient Criteria for Rivers and Streams by Subecoregion That Would be Applicable to Colorado EPA Ecoregion Designation Xeric Wyo Basin Plateau (III.18) Xeric Colo Plateau (III.20) Xeric Az/NM Plateau (III.22) Mountains So Rockies (II.21) So Great Plains W High Plains (V.25) Great Plains SW Tablelands (IV.26) Portion of Colorado Total Phosphorus (ug/l) Total Nitrogen (ug/l) Chlorophyll a (ug/l) Turbidity (FTU) westslope, north 21.87 368 1.78 4.2 westslope, west 20 553 1.78 2.79 westslope, south 15 228 1.78 5.13 central mountains 6.34 90 1.08 0.8 eastern plains, northeast 90 840 2.5 9.01 eastern plains, southeast 25 450 3.4 4.96
CURRENT NUTRIENT 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
MMI Score INITIAL RESULTS 100 Total Phosphorus 90 80 70 60 50 40 30 20 10 0 0.01 0.1 1 10 TP (mg/l)
MMI Score INITIAL RESULTS 100 Total Nitrogen 90 80 70 60 50 40 30 20 10 0 0.02 0.2 2 TN (mg/l)
MOVING TOWARDS NUMERIC CRITERIA 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 EXAMPLE (f = 0.8)
MMI Score 100 Total Phosphorus 90 80 70 60 50 40 30 20 10 0 0.01 0.1 1 TP (mg/l)
ATTAINMENT THRESHOLD EXAMPLE
NEXT STEPS 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
QUESTIONS AND COMMENTS Blake W. Beyea blake.beyea@state.co.us 303.692.3656
BREAK
WQ Impacts of High Chlorophyll Transparency ph DO demand Cyano-toxins DBPs Fish species
Secchi Depth, m Chlorophyll and Transparency Transparency high only at low chlorophyll Transparency also may be reduced by factors other than chlorophyll 0 1 2 3 4 5 6 7 8 Warm Lakes 9 1 10 100 1000 Chlorophyll, ug/l
ph Chlorophyll and ph ph>9 much more likely when chlorophyll >30 10.5 9.5 At low chlorophyll, 8.5 high ph values are from shallow lakes 7.5 with abundant macrophytes 6.5 0.5 1 2 4 8 16 32 64 128256512 Chlorophyll, ug/l Warm Lakes
Trophic State and Fishery Type Trophic State (OECD) Chlorophyll, ug/l Secchi Depth, m Oligotrophic <2.5 >6 Mesotrophic 2.5 8 6 3 Eutrophic 8 25 3 1.5 Hypereutrophic >25 <1.5 Salmonids do better in low productivity lakes Transition to walleye Warmwater fishes in eutrophic lakes Highest productivity lakes dominated by carp and bullheads
General Strategy Balance potentially competing interests (high clarity for swimming vs. high yield for fishery) without compromising support for other uses Develop meaningful thresholds for non-toxic constituents Focus on algal abundance (chlorophyll concentration) as the response variable with direct impact on uses Support with data from Colorado lakes
Swimming and Chlorophyll Perceptions When is it too green? Texas user surveys: Recreational experience diminished when chlorophyll approaches 30 ug/l Other states with plains lakes Iowa: 25 ug/l (and Secchi of 1.0m) Minnesota: up to 30 ug/l severe nuisance bloom = 30 ug/l nuisance bloom = 20 ug/l Instantaneous vs. summer average thresholds
Standard Deviation, ug/l Linking Blooms and Averages After Walker (1985) Capitalizes on lognormal distribution: std deviation increases with mean Defines exceedance frequency of grab sample based on summer avg 250 lake-years of data from Colorado 1000 100 10 1 0.1 y = 0.3043x 1.2184 R² = 0.8547 0.1 1 10 100 1000 Seasonal Average Chlorophyll, ug/l
Warm Lakes Overview Summer average 20 ug/l Optimal for warmwater game fish - eutrophic Prevents hyper-eutrophic conditions Exceedance frequency once in 5 yrs Bloom threshold 30 ug/l Link with Walker s method Exceedance frequency <15% when avg < 20 ug/l Acceptable risk of cyano-toxins (> 50 ug/l once in 6 weeks)
Cold Lakes Overview Summer average 8 ug/l Optimal for most salmonids Similar to cold water fishery thresholds in other states MN: 6 ug/l VA: 10 ug/l Exceedance frequency once in 5 yrs May need site-specific for lake trout Bloom threshold 20 ug/l Exceedance frequency ~1% when summer avg < 8 ug/l (i.e., 1 day in summer) No risk of cyano-toxins (no measurable risk of chlorophyll >50 ug/l)
80% Summer Avg Chl, ug/l Link Chlorophyll to Phosphorus 1000 100 y = 0.7894x 0.7331 R² = 0.8839 10 1 1 10 100 1000 80% Summer Average Phosphorus, ug/l 13 lakes with sufficient data (multiple years) Compare 80 th percentile summer averages Strong linkage
80% Summer Avg Chl, ug/l Link Chlorophyll to Nitrogen 1000 100 y = 0.0021x 1.3364 R² = 0.9969 10 1 100 1000 10000 80% Summer Average Nitrogen, ug/l 6 lakes with sufficient data (multiple years) Compare 80 th percentile summer averages Strong linkage
80% Summer Avg Chl, ug/l N and P from same set of lakes 1000 100 TP TN y = 0.5512x 0.777 R² = 0.9784 10 1 y = 0.0021x 1.3364 R² = 0.9969 1 10 100 1000 10000 80% Summer Average Nutrients, ug/l
Summary and Comparison Ecoregion EPA 304(a) Nutrient Criteria Table Values for Lakes Spectrophot. Chlorophyll (ug/l) Total Phosphorus (ug/l) Calculated Total Nitrogen (ug/l) Mountains, So Rockies (II.21) 1.7 15 180 Xeric, Wyo Basin Plateau (III.18) 1.4 10 380 Xeric, Colo Plateau (III.20) 1.4 3 150 Xeric, AZ, NM Plateau (III.22) 2.0 15 230 Plains, So Great Plains (V.25) 2.4 24 500 Plains, Great Plains (IV.26) 1.2 20 390 Classification Initial Table Values: Nutrient Criteria for Lakes Recreation 1 Aquatic Life 2 Chlorophyll (ug/l) Chlorophyll (ug/l) Total Phosphorus (ug/l) Total Nitrogen (ug/l) Cold water biota 20 8 24 490 Warm water biota 30 20 82 960 1 85 th percentile of summer measurements 2 80 th percentile of summer average
Previous presentations are on the website
Domestic Water Supply 31.13(1)(d) These surface waters are suitable or intended to become suitable for potable water supplies. After receiving standard treatment (defined as coagulation, flocculation, sedimentation, filtration, and disinfection with chlorine or its equivalent) these waters will meet Colorado drinking water regulations and any revisions, amendments, or supplements thereto.
Necessity of proposed changes 31.6(1)(e) Classifications should be for the highest water quality attainable. Must protect the most sensitive use. Nutrient criteria based on protection of aquatic life may not be protective of public health.
Proposed Regulatory Revisions 31.13 STATE USE CLASSIFICATIONS (1) Classifications (d) Domestic Water Supply These surface waters are suitable or intended to become suitable for potable water supplies. After receiving standard treatment (defined as coagulation, flocculation, sedimentation, filtration, and disinfection with chlorine or its equivalent) these waters will meet Colorado drinking water regulations and any revisions, amendments, or supplements thereto. (i) Class DUWS Direct Use Water Supply. A plant intake is located on these lakes and reservoirs in order to provide raw water directly to a water treatment facility..
Proposed Regulatory Revisions (cont.) 31.5 DEFINITIONS (31) Plant Intake means the works or structures at the head of a conduit through which water is diverted from a source (e.g., river or lake) into the treatment plant. Note: This is the same definition as contained in the Colorado Primary Drinking Water Regulations (5 CCR 1003.1).
How are these reservoirs different? Most are off channel Highly managed, both inputs and outputs Aquatic life and recreation are not the driving factors for use protection Human health consequences for non-attainment
What water treatment managers really care about: compliance and customer satisfaction Taste and odor Disinfection byproducts Filter clogging algae Release of metals from anoxic sediments Contaminants of concern/pharmaceuticals
304(a) criteria, 1-2 µg/l transparency, 5 µg/l disinfection byproducts, 5 µg/l Chlorophyll a dissolved oxygen, 6 µg/l prevalence of bluegreen algae, 10 µg/l taste and odor, 10 µg/l ph, 25 µg/l
Initial Proposal Table Values for Direct Use WS Chlorophyll a = 5 ug/l Annual average 1 in 5-yr allowable exceedance frequency DUWS sub-classif ication would be applied by the WQCC on a case -bycase basis
Next Steps Averaging period Monitoring concerns Discussion
Future Meetings September 21, 2009 Reservoir DO Antidegradation (WQCD) Economic Reasonableness (Regulated Community) Update on thresholds as they are refined October 19, 2009 Antidegradation (others) Temperature issues Discharger Specific Variance Update on Thresholds as they are refined
Future Dates November 9, 2009 IFH November 16, 2009 Implementation issues December 16, 2009 January 15, 2010 Proposals due to WQCC office
More meetings on Aq Life or Nutrient Criteria? Intensive refresher on Bioassessment Tools? Focus on Lake Nutrient Criteria? Focus on Rivers and Streams Nutrient Criteria? You need to tell us what content would be helpful