Credit Quantification Quantify Credits/Debits Calculation of credits and debits will incorporate functionality and the spatial dimension (e.g. acreage or linear feet) of the impact and mitigation site. Value scores not be used in credit quantification. Three remaining options are being discussed. Highest Function—Points Summed Functions—Percent of maximum Highest Function—Percent of maximum

Policy Overview – Credits & Debits Credits represent gains at the mitigation site Debits represent losses at the impact site Calculated as functional unit * areal unit Functional unit must represent net change in function Debits and credits need to match to achieve replacement

Function Level Matching Model, Highest Function, % of Max Function Group Impact Site Function Scores Mitigation Site Function Scores Hydrologic Water Quality Aquatic Support Highest Score Points 0.3 Function Acres Debits0.3Credits0.3 Acres 1.0 Highest Score—Points Function Level Matching Model Impact SiteMitigation SiteSite Comparison ABCDEFGH Grouped Function Max Scoring Function Max Function Score (Funct Imp) Corresponding Value Score (Value Imp) Matched Function Mitigation Function Score (Funct Mit) Mitigation Value Score (Value Mit) Funct Mit- Funct Imp Value Mit- Value Imp Hydrologic Function Water Storage and Delay Water Storage and Delay Water Quality Group Sediment Retention & Stabilization Sediment Retention & Stabilization Aquatic Support Organic Matter Export Organic Matter Export Crediting Rules Scores are binned and converted to points. Highest score is converted to points based on Jenks breaks for that group. H-bin =.3; M-bin =.2; L-bin =.1 for a 3-bin system Multiply by acres. Note: Terrestrial Support and Fish Support Services are not shown for improved presentation purposes.

Highest Function, Percent of Maximum Summed Functions, Percent of Maximum Function Level Matching Model, Summed Function, % of Max Function Group Impact Site Function Scores Mitigation Site Function Scores Hydrologic Water Quality Aquatic Support Sum of Scores Percent of Max (Score/30) Function Acres Debits0.52Credits0.61 Acres Function Level Matching Model, Highest Function, % of Max Function Group Impact Site Function Scores Mitigation Site Function Scores Hydrologic Water Quality Aquatic Support Highest Function Percent of Max (Score/10) Function Acres Debits0.73Credits0.77 Acres Crediting Rules (Highest Score) Only the highest score is selected. Score is divided by 10 to make a percentage of maximum potential score. Multiply highest score by acres to get credits and debits. Crediting Rules (Summed Scores) Scores are added, then divided by maximum potential score (30 used for demonstration). Multiply by highest score point by acres to get credits and debits. Note: Terrestrial Support and Fish Support Services are not shown for improved presentation purposes.

Credit Quantification Methods—All Options Considered Criteria Highest Function, Point Model Summed Functions, Percent of Maximum Model (no points) Highest Function, Percent of Maximum Model (no points) Results in resource replacement (H,M,L) Med Carrying highest function is good for replacement of that function. Truncates range of trade ratios by using point system. Med Summing allows resulting credits to reflect all functional groups. Summing can obscure outliers, including high scoring functions. High High standard for replacement for one function group; depends on function fingerprint matching to assure replacement of other groups. Transparency & simplicity (H,M,L) Med Add steps. Points conversion could be confusing or unclear since there are different bin breaks for each grouped function. Med/High Summing adds a step, but fairly straightforward. High No points, no summing, no averaging. Practicable (H,M,L) Med Most sites are likely to have a score in the highest point bin but points tend to obscure high-functioning outliers. Points system results in a limited number of potential ratios and provides a level of predictability. Med Summing helps dilute highest functions, which can make it more practicable than highest function models Low Most sites are likely to have a score in the highest point bin. A low lift wetland mitigation site can result in large trading ratios if impact site has a high-scoring function. Trade ratios are not limited so can be less predictable. Consistently applied between wetland/ streams, across mitigation type, and within agencies No There is not enough data to define defensible bins for streams. Yes