New Approaches for Getting from Wetland Scores, to Wetland Ratings, to Credits and Debits Paul Adamus, Ph.D Adamus Resource Assessment, Inc. Corvallis, OR Hans Ehlert CH2M Hill Bellevue, WA In collaboration with: Southeast Alaska Land Trust, Juneau, AK U.S. Fish & Wildlife Service, Alaska Office

Wetland Function Assessment Methods Developed & Field-calibrated by Adamus et al.

Detailed Accounting of Wetland Functions and/or Values, Scored & Grouped by WESPAK-SE Water Storage Carbon Sequestration Water Quality: Sediment Retention, Phosphorus Retention, Nitrate Removal Fish: Anadromous Fish, Resident Fish Aquatic Support: Aquatic Invertebrate Habitat Stream Flow Support Organic Nutrient Export Water Cooling, Water Warming Aquatic Habitat: Amphibian Habitat Waterbird Feeding Habitat, Waterbird Nesting Habitat Terrestrial Habitat: Songbird, Raptor, & Mammal Habitat Native Plant Habitat Pollinator Habitat Social:Native American Subsistence Public Use & Recognition

Some Options for Combining Function and Value Score 1.Average each pair (=FVindex) Function score= 5, Value score=7  so 6 or 2. Use the greater of function or value (=Max Score) so 7 or 3. Use function score unless FV is greater. Then use FV. F=5, V=2, so 5

Some Options for Rolling Up Into an Overall Score 1. Average the individual function or FV scores. 2. Do a weighted average of the function or FV scores. 3. Use whatever function a wetland is “best at” to represent the wetland. (i.e., MAX function or MAX FV) 4. Use: (Average + Maximum)/2 5. Convert scores to ratings (H, M, L = 3, 2, 1). Then do any of above.

Score distributions vary by function: Carbon SequestrationAnadromous Fish Habitat Convert to ratings using “natural breaks” in score distributions. Do NOT manipulate models or category break-points so they give “an even distribution” of ratings.

For Southeast Alaska’s in-lieu fee program: Categorical Option: 3: 1 mitigation ratio for higher-rated wetland (based on function-value, NOT wetland type). For that ratio, use 1.0 credit or debit/acre. 2: 1 ratio for moderate-rated wetland. To get that, use credit or debit/acre (0.666 X 3:1 = 2) 1.5: 1 ratio for lower-rated wetland = 0.5 credit or debit/acre. To get that, use 0.5 credit or debit/acre (0.5 X 3:1 = 1.5). Numerical Alternative: Debit = Desired ratio x FV score x acres Preservation = Debit/FV (of the credit wetland) = acres of credit Both Options: Always compensate with equal or greater FV. Also consider : Wetland Risk (Threat, Sustainability) when selecting in-lieu fee mitigation sites. (WESPAK-SE partially quantifies that). Distance from debit site to credit site. Time Lag (wetland loss vs. credit site acquisition)

Conclusion s 1.Score roll-ups should be transparent and as statistically unbiased as possible. Science does not support any particular algorithm for roll-ups of scores or credit/debit calculations. 2.Break points for establishing rating categories (e.g., H-M-L, or I-II-III-IV) should not be based on some predetermined percentile cutoffs, but by using “natural break points” (calculated using Jenks Optimization). 3.Scores from a reference data set should be normalized at each step of the calculations (e.g., spread out to fill a 0-10 scale). Contact: Reports: people.oregonstate.edu/~adamusp