EVALUATING STREAM COMPENSATION PERFORMANCE: Overcoming the Data Deficit Through Standardized Study Design Kenton L. Sena (EPA VSFS Intern), Joe Morgan, Brian Topping, Palmer Hough, and Jenny Thomas

Context  Rising utilization of compensatory mitigation for stream impacts  Lack of data regarding performance of compensation sites  Need to evaluate compensation program as a whole  Identify strengths and weaknesses  Provide direction for future improvement Source: 2015 Mitigation Rule Report

Borrowing from Wetland Mitigation  Team developed standardized approach for evaluating wetland mitigation performance  While comparing precondition to post-mitigation condition would be ideal, pre-mitigation data are rarely available  As an alternative, the wetland team recommended comparing mitigation wetland data to ambient wetland condition (NWCA)  Here, we recommend a similar approach to evaluating stream compensation performance. Source: “Towards a National Evaluation of Compensatory Mitigation Sites: A Proposed Study Methodology”

PROPOSED STUDY DESIGN COMPONENTS

Goals:  Metric selection  Broad enough to be utilized on a national scale  Flexible enough for application to specific regional needs  Comparable methods and metrics to National Rivers and Streams Assessment (NRSA)  Time- and Cost-effective  Apply at a pilot scale

Site Selection and Sampling Methods:  Apply NRSA site-selection protocol:  Random and representative selection of mitigation sites  Establish 5 transects above and below x-site for sampling (11 transects total)  Needs:  Repeated sampling over time  Spatial constraints to only mitigated reaches Source: National Rivers and Streams Assessment Field Operations Manual, 2009

Metrics:  Watershed: Urbanization, disturbance history, etc.  Channel morphology: Channel cross-section, bank angle, thalweg profile, riparian zone health  Habitat: Woody debris tally, pool/riffle/run, substrate characteristics  Hydrological: Discharge/flow estimate  Chemical: DO, temperature, conductivity, pH, grab samples for regionally-specific analyses  Biological: macroinvertebrate surveys and metrics

Research Questions:  Comparison to NRSA: national ambient condition  Ecoregional differences  Techniques/methods used (e.g., in-stream structure, natural channel design, etc.)  Impairment type  Permittee responsible mitigation/in-lieu fee/Mitigation banking?  Preservation/enhancement/rehabilitation/establish ment?

Challenges: moving forward  Statistical questions  Significant regional variation in methods, program size, program type, etc.  Difficulties with multiple techniques applied within the same reach  Funding  Pilot program

QUESTIONS?

References:  Institute for Water Resources. The Mitigation Rule Retrospective: A review of the 2008 regulations governing compensatory mitigation for losses of aquatic resources. October US Army Institute for Water Resources, Alexandria, VA R-03.  Environmental Law Institute Towards a National Evaluation of Compensatory Mitigation Sites: A Proposed Study Methodology. Washington, DC, available at nal_evaluation_of_compensatory_mitigation_0.pdf. nal_evaluation_of_compensatory_mitigation_0.pdf  USEPA National Rivers and Streams Assessment: Field Operations Manual. EPA-841-B U.S. Environmental Protection Agency, Washington, DC.

Metrics: Watershed-scale  Urbanization  % impervious surface  Land use/land cover database  Agriculture  Disturbance history  Mining  Forest harvesting  Construction  Hydrological constraints (e.g., impoundments)

Metrics: Morphological  Characterize stream channel  Thalweg profile  Channel cross-section  Bank angle  Characterize riparian zone  Plant community composition  Evidence of disturbance

Parameters: Habitat  Habitat characterization  Tally habitat type throughout reach (pool/riffle/run)  Tally and characterize woody debris  Characterize substrate embeddedness and size class

Metrics: Hydrological  Discharge/flow?  Useful information, but difficult to evaluate in a single site visit  Options:  Model flow from watershed data?  Use stream gages  Make discharge/flow an optional parameter  Settle for one-time flow data

Metrics: Chemical  In situ:  Dissolved oxygen  Temperature  pH  Conductivity  Grab samples (regionally specific parameters):  Metals (e.g., Fe, Mg, Ca, Mn)  Other ions (e.g., SO4)  Nutrients (e.g., NO3, PO4)

Metrics: Biological  Macroinvertebrate surveys  Kicknet sampling at each transect  Composite samples and identify to family/genus in lab  Calculate metrics (regionally specific)  (Optional) Fish  Characterize fish community and calculate fish IBI  (Optional) Microbial  Characterize microbial contamination (e.g., E. coli)  Characterize algal/biofilm communities