Tiered Aquatic Life Use Model Christy Pickens, Physical Research Scientist Water Quality Control Division Colorado Dept. of Public Health and Environment 30 July 2003

Purpose of Model The tiered aquatic life use framework is a conceptual model predicting the response of aquatic communities to increasing human disturbance. The conceptual model is a draft framework for using biological assessment information to refine designated aquatic life uses. www.brainybetty.com

Purpose of Model EPA developed the TALU model for a nationally consistent approach. Scientifically defensible benchmarks Common framework for communication and evaluation- public, stakeholders, across political boundaries Protection for excellent quality waters Achievable goals for incremental restoration Nationally consistent approach. Example- 305(b) reports. 305(b) reports are sometimes not consistent when compared across the nation… Scientifically defensible benchmarks- We all know the credible data issues… www.brainybetty.com

Purpose of Model National ALUS Workgroup Biological Condition Gradient (BCG) focus of workgroup in 2001. Human Disturbance Gradient (HDG) focus of workgroup in 2002. Workgroup recommendations going forward to EPA this spring with the conceptual models, implementation options, case examples. The first step EPA took to develop guidance on use of biological assessments to help refine designated aquatic life uses was to build upon the expertise and practical experience of existing State and Tribal water programs. A workgroup was established for this purpose and includes representation from States and Tribes that have strong, well established biological assessment programs and have adopted numeric biological criteria into their water quality standards. www.brainybetty.com

TALU Model Basics Bioassessments help states develop expectations for acceptable biological conditions. This is accomplished through the technical process of developing aquatic life goals, aquatic life uses (ALUs). Biological assessments allow various levels of ALUs. Using several types, or tiers, of ALUs allows states and tribes to allocate limited resources to waterbodies in proportion to their need for protection. www.brainybetty.com

ALUS Integrity ALUS is determined by assessing: Response variable (biological condition) to determine impairments and full support Stressors (physical and chemical conditions) to determine impairment The assessment of these variables is where the BCG and the HDG come into play. www.brainybetty.com

TALU Conceptual Model www.brainybetty.com

TALU Model Basics The tiered system of use designations provides for different levels of protection and reflects the choices implicit in reconciling the “ideal” (represented by least impacted reference conditions) with the “reality”, the ongoing effects of two centuries of intensive human use of the state’s land and water resources. www.brainybetty.com

TALU Model Basics Key Points to Emphasize: Framework is conceptual Number of tiers to be determined by State “Best Fit” approach recommended The framework may be quantitatively defined by many possible methods BCG is a quality gradient, not a classification Framework is conceptual- it does not replace existing use classifications or categories in State and Tribal WQS. It is intended to be used as guidance to assist States and Tribes in thinking how to use biological assessments and criteria to refine their designated ALU. There is no expectation for States and Tribes to establish 6 tiers. The purpose of the number of tiers is to provide a highly resolved biological condition gradient as guidance to the States and Tribes. The ultimate number and content of the tiers is a State determination. The list of attributes is intended to organize and record the current state of our understanding and observation concerning changes in key characteristics of an aquatic community in response to increasing levels of human disturbance. It should not be thought of as a check list. The workgroup will be developing recommendations for methods for determining “best fit” of data- weighing the importance of and signal-strength of the different attributes as they pertain to a specific waterway. Again, this is a conceptual model- it is not constrained to any one method. Needs to be applicable to programs that use RBPs, IBIs, RIVPACS, etc… The biological condition gradient is a quality gradient- the upper end of the scale reflecting “natural conditions” corresponding with the CWA integrity objective. The BCG is not a model for classification of natural systems such as ecoregions or bioregions. The BCG would only be applied to waterbodies once they have been appropriately classified; e.g. the first tier characterizes the natural expectations for a waterbody unimpacted or minimally impacted by human activities. If the natural expectation for a stream includes naturally low dissolved oxygen concentrations and high suspended sediment load, then that would be the top tier (tier1) for that waterbody www.brainybetty.com

TALU Model Basics Human Disturbance Gradient (HDG) Biological Condition Gradient (BCG) The 2 components of the model… www.brainybetty.com

TALU Model Basics From Karr… www.brainybetty.com

TALU Model Basics www.brainybetty.com

Human Disturbance Gradient TALU Model Basics Human Disturbance Gradient www.brainybetty.com

TALU Model Basics HDG Layout Six tiers (A-F) Six major stressor classes Habitat Structure Flow Regime Water Quality Toxics and Bioengineered Chemicals Energy Sources Biotic Interactions Look at handout marked TALU 201. From Bob Hughes, Dynamac Corp. A HDG for permanent, unconstrained, desert streams and rivers. www.brainybetty.com

TALU Model Basics HDG Layout Six major disturbance classes Landscape Character Riparian Condition Barriers Channel Morphology (map scale) Atmospheric Deposition Biotic Interactions www.brainybetty.com

TALU Model Basics HDG Rationale Essential for determining reference sites and minimal disturbance Necessary for metric and index development and evaluation Often represents half the variability in biological response scores Easier to assess than large suite of stressors Assists in diagnosing stressors Source of most manageable stressors Critical for stream protection, BMPs and restoration Self explanatory HDG is also very useful for selecting candidate metrics that are responsive to the major stressors Often, such simple variables such as %urban land use can incorporate half the variability in a biological response If general patterns are deemed important, it is often much easier to assess land use than to attempt to assess all possible chemical, physical, and biological stressors. For ex. Published studies on many areas of N. America show that 10-30% urbanization or 15-50% agriculture results in marked declines in IBI scores. Knowledge of land use helps us screen particular disturbances that are useful for diagnosing possible stressors, or the effect of the proximity of those disturbances. It may be easier and more direct, to mange land use, instead of multiple stressors separately. www.brainybetty.com

Draft Model Tiers – 6 levels TALU Model Basics Draft Model Tiers – 6 levels Natural structure and function of biotic community maintained Minimal changes in structure and function Evident changes in structure and minimal changes in function Moderate changes in structure and minimal changes in function Major changes in structure and moderate changes in function Severe changes in structure and function From the biological response to the HDG levels of disturbance, the workgroup derived these 6 basic tiers, or levels of the conceptual model. www.brainybetty.com

TALU Conceptual Model www.brainybetty.com

TALU Conceptual Model www.brainybetty.com Tiers in depth. Remember that we can have more or less. www.brainybetty.com

HDG Concepts Human disturbance gradient does not necessarily imply degradation. Human disturbance gradient addresses two basic questions: What is the departure from expected condition as a result from human activities? What is the impact of this departure from expected condition on the biotic community? BMPs will need to be incorporated into the framework. Scale issues need to be addressed (temporal and spatial). www.brainybetty.com

Biological Condition Gradient TALU Model Basics Biological Condition Gradient www.brainybetty.com

TALU Model Basics www.brainybetty.com

Biological Condition Gradient (BCG) TALU Model Basics Biological Condition Gradient (BCG) BCG is a quality gradient, with the upper end of the scale reflecting “natural conditions” corresponding with the CWA integrity objective. BCG is not a model to be used for classification of natural systems, such as ecoregions. BCG would only be applied once they have been appropriately classified. BCG provides consistency among states using different approaches. As previously mentioned… www.brainybetty.com

Biological Condition Gradient (BCG) TALU Model Basics Biological Condition Gradient (BCG) The first tier of the model characterizes the natural expectations for a waterbody unimpacted or minimally impacted by human activities. The subsequent tiers show the response of the biological community to increasing human disturbance. As previously mentioned… www.brainybetty.com

TALU Model Basics 10 Major Attributes BCG Layout Taxonomic composition and tolerance Attributes I-V Regionally Endemic through Tolerant Non-Native taxa Attribute VI Organism condition Attribute VII Ecosystem function Physical-biotic interactions Attributes IX-X See handout marked TALU 101, Greg Pond – Kentucky Division of Water. Within each of the 6 tiers of biological condition, these attributes are laid out. www.brainybetty.com

BCG Attributes www.brainybetty.com

BCG Attributes www.brainybetty.com

BCG Attributes www.brainybetty.com

BCG Attributes www.brainybetty.com

BCG Attributes www.brainybetty.com

BCG Attributes www.brainybetty.com Development of BioAxis is on-going - always evolving based on evolving science www.brainybetty.com

BCG Attributes EX www.brainybetty.com

ALUS Tiers Provide Consistency the various state/tribal assessment and analytical approaches illustrate OBSERVATION AND MEASUREMENT- constrains the development of precision accuracy and knowledge if EPA were to attempt to standardize at level of ‘METHODS’--Thus BioAxis serves as a common backdrop illuminating the basic theory behind why the various methods work Standardization - common language of biological conditions- so that a BioAxis ‘B’ in Kansas can be related to a BioAxis ‘B’ in Oregon- regardless what methods are used to do the assessment and quantitative work-up. Management context is state-specific- the number of quantitatively distinguishable management tiers is a function of 1. the level of rigor of the methods and the overall size and quality of the state database. States/tribes NOT obliged to quantitatively manage for all 6 tiers!! But should be able to relate individual site or reach conditions to any one of the 6 tiers by expert judgement following BioAxis decision rules and to relate management categories to positions on the gradient. a 1 b 2 c 3 d 4 e 5 f 6 Natural Degraded Susan P. Davies, MDEP

TALU Model Thinking ahead… How can we transition from describing what we see to establishing thresholds? www.brainybetty.com

Designated Aquatic Life Uses in Vermont natural/ minimally altered 1 Class A1: Excellent - Biota within the range of the natural condition Threshold criterion A1 2 Class B1: Very Good - Minor changes to structure and function; tolerant/intolerant forms within the range of reference condition. Biological Condition Threshold criterion B1 Class B2/3: Good - Moderate changes in the relative proportions of tolerant, intolerant, taxonomic and functional components. 3 Threshold criterion B2/3 Biocondition Gradient Tiers 4 5 Non-Support: Fair-Very Poor highly altered Not meeting CWA 101a uses for protection & propagation of aquatic life 6 Human Disturbance Low High

This slide illustrates some of the distinctions we wish to keep in mind during the reference condition courses. In some regions, we might find places where human disturbance is relatively minor or minimal, and we might use data from these places to describe a reference condition that approximates biological integrity. In these places we might want to set goals that approximate biological integrity (i.e. uses that meet the objective of the CWA). In other regions, we might find no places with minimal human disturbances; we might use data from places that are least disturbed to describe a reference condition that we expect to be attainable, at the upper end of existing conditions, meeting the goal of the CWA. In still other regions, human disturbance might be so extensive that we might want to describe a reference condition that falls outside the range of existing condition; the condition at least disturbed sites might not be acceptable. Establishing a reference condition outside the range of existing conditions might require approaches other than the use of reference sites in that region.