# Presentation: 200115

## Slide 1

## Wadeable Streams Assessment

- Overview of Findings
- San Jose 2006

## Wadeable Streams Assessment

- First statistically-valid report on the condition of the Nation’s streams
- Baseline from which to track changes over time
- Collaboration among EPA, states, tribes and other partners

*Wadeable streams are streams, creeks, and small rivers that are shallow enough to be sampled using methods that involve wading in the water.*

## Objectives of Assessment 

- Objectives of Assessment

- Assess the biological condition of streams nationally and regionally
- Determine the proportion of streams that fall in three condition classes (good, fair, poor)
- Assess the extent of streams affected by key stressors
- Describe associations between stressors and biological condition

## Indicators of Biological Condition

- Index of biotic integrity (IBI) incorporating 6 metrics of benthic community health
- Taxa loss based on comparison of taxa observed in sample to taxa expected at site
- Why benthic macroinvertebrates?
- Used by most states as indicator of biological condition
- Integrate the effects of stressors over time
- Important food source for game and non-game fish

**Notes:**
Taxa is used to refer to unique groups of organisms, for WSA these are usually genus level identification but include some family-level groups.

IBI multi-metric index 
Combines metrics of benthic community structure and function into a single index for each region.  
Thresholds for defining condition classes are developed for each of the 9 WSA ecological regions based on the condition at the best available regional reference sites.  
Good (least disturbed) stream resources are most similar to reference condition.
Fair (intermediate) IBI scores worse than 75 percent of reference.
Poor (most disturbed) streams score worse than 95 percent of reference.
O/E predictive model 
Estimates taxa loss
Calculates ratio of observed to expected taxa  
Expected taxa is based on taxa found at least-disturbed reference sites with similar environmental attributes.  
Scores around 1 indicate site is similar to reference.  
Scores of .9 represent a 10% loss in expected taxa.
Each 0.1 reduction represents another 10% loss

## Stressors in Streams

- WSA looked at key indicators of stress
- Nitrogen
- Phosphorus
- Salinity
- Acidification
- Streambed sedimentation
- In-stream fish habitat
- Riparian vegetation cover
- Human influence in riparian zone
- WSA evaluated the relative risk of stressors to biological condition

## Assessment at Multiple Scales

## Approach

- Sampled 1392 random sites using standardized field and lab protocols
- Implemented rigorous QA program
- Trained and audited all crews
- Revisited 10% of sites
- Reprocessed 10% of biological samples
- Supported state enhancements to extend use of survey
- State scale surveys
- Additional biological indicators
- Methods comparability studies

## National Assessment

- 1,392 sites

## Key Findings

- The WSA found that
- 28% of stream length is in good shape.  Results vary geographically
- The stressors with the greatest impact are nitrogen, phosphorus, and excess streambed sedimentation.

**Biological Condition of Streams**
**(Index of Biotic Integrity)**

## Bug Index of Biotic Condition

**Figure 2-1. Biological condition of streams based on Macroinvertebrate Index of Biotic Condition. **

**Bug Index of Biotic Condition**

## Bug Taxa Loss

**Figure 2-2. Macroinvertebrate taxa loss as measured by the Observed/Expected (O/E) Ratio.  ****The O/E predictive model displays the loss of taxa from a site compared to reference for that region. Scores 0.1 lower than reference represent a 10% loss in taxa.**

**Bug Taxa Loss**

## Total Nitrogen 

- The WSA found that 53% of stream miles have higher levels of nitrogen than reference.

**Notes:**
Change legend to say low, medium, high rather than least disturbed...
Change legend to say low, medium, high rather than least disturbed...

## Ranking of Stressors to Biological Condition

**Notes:**
Consider changing names to reflect negative/poor condition?
Excess total nitrogen
Excess total phos
Poor instream habitat

## Relative Extent

**Figure 2-11. Relative extent of stressors (i.e., proportion of stream length ranked in ****poor category for each stressor).**

## Relative Ranking of Stressors

**Figure 2-12. Relative extent of stressors and relative risk for Macroinvertebrate Index of Biotic Condition and macroinvertebrate taxa loss.  **

## Total Phosphorus 

**Figure 2-3. Total phosphorus concentrations in U.S. streams. **
**This is the percent of stream miles with low, medium, and high levels of phosphorus based on regionally relevant thresholds derived from the best quality regional reference sites.  Low concentrations are most similar to reference condition.  Medium concentrations are higher than the 75th percentile of reference condition.  High concentrations are higher than the 95th percentile.**

- Total Phosphorus

## Figure 3-2. WSA survey results for the Northern Appalachians ecoregion.

**Figure 3-2. WSA survey results for the Northern Appalachians ecoregion.**

## Figure 3-9. WSA survey results for the Western Mountains ecoregion. 

**Figure 3-9. WSA survey results for the Western Mountains ecoregion. **
**Bars show the percentage of stream length within a condition class for a given indicator. Lines with brackets represent the width of the 95% confidence interval around the percent of stream length. Percents may not add up to 100 because of rounding.**

## Challenges Before Next Assessment

- Addressing protocols for different system types (e.g. low gradient streams)
- Calibrating for different quality reference sites
- Blending other “subpopulations” of interest
- Combine with assessments for other “flowing waters”

## Success Due To:

- Sampling Teams
- State & Tribal partners
- Academic partners
- Agency partners
- Working groups

## Slide 22

## Reach Layout for Sampling

## Reference Population

- Reference Distribution

## IBI versus PCA Factor 1, by ECO-9 region. 

**IBI versus PCA Factor 1, by ECO-9 region.**
- Instead of smooth curves, use simple linear regressions

**If a regional regression is significant, then the ‘best’ reference conditions for that region are found near the left end of the region’s regression line.**
- We used this idea to model the ‘best’ reference distributions for IBI.

## PCA Factor 1 score

- Option 2A – Use 25%ile of
- Factor 1 score instead of 5%ile,
- to locate IBI reference distribution
- along a disturbance gradient.

- ‘Option 2a’ – Suggested modification of the PCA-correction method for reference
- distributions of IBI, as applied to the Western Mountains region.

**5 %ile**

**25 %ile**

## Biological   Condition

* *

**Biological   Condition**

*** ******Aquatic Life Use Workgroup: Conceptual Model ***
***(adapted from Cairns 1993)***

***--- Historical ---***

**Time****               **

*** ******Natural***

***Severely***
***Altered***

***existing condition (hypothetical)***

**Notes:**
This model shows the domain of the CWA and the domain of assessment, monitoring and criteria.  CWA “restore and protect the physical, chemical and biological integrity of nation’s waters”.
The ovals are the “TIERS” in tiered aquatic life uses and they are the condition tiers in the Biological Condition Gradient
Purpose of assessment is to determine where a given waterbody is in relation to that goal.  Criteria are ways to quantify how close to the goal you are.
WQ stds differ greatly- “no harm to aquatic life”- but where is harm?

Tiered aquatic life uses partition the information into more refined bins- are some conditions still very close to natural? (Tier 1-2)  Is most of the state uniformly altered down to Tier 3-5?  Are some locations really terrible?

The BCG provides descriptive content to the 6 circles on the gradient.
It is a conceptual foundation “behind” or underneath all the approaches to quantify biological condition like IBI, RivPacs, RBP; multivariate analysis.  It provides a common yardstick- “ballpark” bin.   

##  The  Biological Condition Gradient – Tiers

* *

**Biological Condition**

*** *****The  Biological Condition Gradient – Tiers**

** **

**                       ****Increasing Levels of Stressors   **

***Natural structure & function of  biotic community maintained***

***Minimal changes in structure & function***

***Evident changes in structure and minimal changes in function***

***Moderate changes in structure & minimal changes in function***

***Major changes in structure & moderate changes in function***

***Severe changes in structure & function***

**1**

**2**

**3**

**4**

**5**

**6**

**Notes:**
Background notes:  This figure is a generalized representation of the BCG.  In your handout you have the detailed BCG model.  (Handout: BCG slide above, next, and matrix – Table 2.2  p 21 in the document)

The gradient of biological responses spans a range of condition - from natural, undisturbed conditions to severely y disturbed.   There are 6 tiers, or increments of  biological change, along the gradient.   

Key Points: 

1.   It is intended to be uses as the starting point for States and Tribes to think about how to more accurately describe the condition of a waterbody and to establish appropriate goals;  the 6 tiers represent  incremental, measurable changes along this gradient; it is up to the States and Tribes to determine number of tiers and where thresholds established.  

2.   The model is applicable to different places (geography); different methods; across political boundaries (incorporate into existing State and Tribal programs).