Download presentation
Presentation is loading. Please wait.
Published byNorman Warner Modified over 8 years ago
1
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
2
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
3
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”
4
PROPOSED STUDY DESIGN COMPONENTS
5
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
6
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
7
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
8
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?
9
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
10
QUESTIONS?
11
References: Institute for Water Resources. The Mitigation Rule Retrospective: A review of the 2008 regulations governing compensatory mitigation for losses of aquatic resources. October 2015. US Army Institute for Water Resources, Alexandria, VA. 2015-R-03. Environmental Law Institute. 2013. Towards a National Evaluation of Compensatory Mitigation Sites: A Proposed Study Methodology. Washington, DC, available at https://www.eli.org/sites/default/files/docs/towards_natio nal_evaluation_of_compensatory_mitigation_0.pdf. https://www.eli.org/sites/default/files/docs/towards_natio nal_evaluation_of_compensatory_mitigation_0.pdf USEPA. 2007. National Rivers and Streams Assessment: Field Operations Manual. EPA-841-B-07-009. U.S. Environmental Protection Agency, Washington, DC.
12
Metrics: Watershed-scale Urbanization % impervious surface Land use/land cover database Agriculture Disturbance history Mining Forest harvesting Construction Hydrological constraints (e.g., impoundments)
13
Metrics: Morphological Characterize stream channel Thalweg profile Channel cross-section Bank angle Characterize riparian zone Plant community composition Evidence of disturbance
14
Parameters: Habitat Habitat characterization Tally habitat type throughout reach (pool/riffle/run) Tally and characterize woody debris Characterize substrate embeddedness and size class
15
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
16
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)
17
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
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.