Watershed Indicators

START DATE: 01-APR-2001 

END DATE: 30-SEP-2005 

PROJECT NUMBER: 2454ACT 

STUDY OBJECTIVES:  

AMNET provides a taxonomically rich and spatially comprehensive invertebrate data set for assessment of community impairment, however, to properly meet future NJDEP management goals for watersheds throughout the state, it has been suggested that the assessment methodology needs some fine-tuning. Project objectives are to 

1. evaluate AMNET assessment methodology for possible insensitivities in specific scoring criteria that is currently based on family-level (RBP II) invertebrate taxonomy, 
2. evaluate impairment relative to existing surface-water quality standards and stream classifications, 
3. evaluate relations between AMNET scores and major controlling environmental factors, including a rigorous analysis of flow and GIS derived basin characteristics, 
4. evaluate those sites where New Jersey impairment scores (NJIS) have changed since the first round of AMNET for underlying factors that may account for that change, and 
5. based on information developed in a-d, assist the NJDEP in defining stream restoration goals that translate into viable management recommendations for 1-2 pilot areas in NJ. 

STATEMENT OF PROBLEM:  

Various questions arise on whether or not realistic stream restoration goals can be established with our current understanding of watershed indicators and major controlling factors of aquatic ecosystem health. New Jersey is fortunate to have one of the nation's better spatial networks for assessing stream biological impairment --the Ambient Biomonitoring Network (AMNET); however, over 500 of the 800 sites sampled have indicated impairment. Multiple factors such as water quality, habitat quality, and flow characteristics are likely significant contributors. Some impairment might simply be due to methodological limitations, such as variation in the level of taxonomic scoring, insensitivity of the method to controlling factors, the large range of moderately impaired scores, and the inability to account for natural environmental variability. An in-depth evaluation of scoring method criteria and the factors leading to real impairment is now possible and warranted. Evaluation of data at several levels of stratification within the statewide network is needed to better link watershed nonpoint sources with observed biological impacts. A rigorous assessment of the dominant environmental factors contributing to confirmed impairment needs to be addressed before development of realistic stream restoration goals statewide and at specific sites can be accomplished. Finally, an approach to translate findings into viable management options needs to be developed and piloted.  

STRATEGY AND APPROACH:  

State-of-the-art statistical, GIS, and hydrologic modeling approaches at multiple levels of data stratification will be extensively used to evaluate the AMNET assessment methodology (regression and multivariate statistics), major controlling factors (regression and multivariate statistics) including a rigorous analysis of flow characteristics (TOPMODEL and impervious area analyses), underlying factors for change and existing standards/classifications (regression and multivariate statistics). Develop this information to assist NJDEP in defining restoration goals that translate into viable management recommendations for 1-2 pilot areas. 

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