To determine net mitigation credit remaining and its credit dollar value from a debit/credit transaction, enter the information requested in each of the boxes below and press the calculate button.

ALTERNATIVE A - Example Credit / Debit Transactions at Four Operational Portland Harbor Mitigation and Conservation Banks

ALTERNATIVE B - Example Credit / Debit Transactions at Four Operational Portland Harbor Mitigation and Conservation Banks

ALTERNATIVE C - Example Credit / Debit Transactions at Four Operational Portland Harbor Mitigation and Conservation Banks

ALTERNATIVE D and E - Example Credit / Debit Transactions at Different HEA Amortized Time Loss Penalty Discount Rates and Mitigation Ratios

ALTERNATIVE F - Example Credit / Debit Transactions at 100-Year HEA Amortized Time Loss Penalty of 3% Discount Rates and Mitigation Ratios

ALTERNATIVE G - Example Credit / Debit Transactions at 100-Year HEA Amortized Time Loss Penalty of 3% Discount Rates and Mitigation Ratios

This is the amount of acreage of a given natural resource type (e.g., frequent emergent wetland, wetgrass prairie, vernal pool, snowy plover breeding habitat, etc.) that will be converted to alternative uses (e.g., housing sub-divisions, shopping malls, highway interchanges, etc).

This is the amount of acreage of a given parcel of land (often degraded farm land or open space) that will be converted to alternative uses (e.g., frequent emergent wetland, wetgrass prairie, vernal pool, snowy plover breeding habitat, etc.) to off-set the loss of the same or similar resources somewhere else.

This is an assigned number often representing the relative importance of a particular resource type. Resources assigned high importance values are assumed to require a proportionally greater number of acres to compensate for their loss. Factors that can affect the assignment of resource value include but are not limited to: 1) scarcity in the landscape relative to historical extent, 2) time periods required to reach a fully functioning condition, 3) importance to focal concerns (e.g., imperiled species, watershed TMDLs, aesthetic and recreational opportunity, 4) the relative capability of a habitat unit to provide life-cycle requirements for a species, etc.). The acreage of a given development site multiplied by its assigned development multiplier equals the amount of debit accrued by the development action and the amount of credit needed from the mitigation site to off-set the debit.

If the development site is equal to 10-acres and the Development Multiplier is 2, then the number of debits is 20 (10 x 2).

It should be noted here that mitigation "ratios" are often derived directly from ranking comparisons between development sites and compensatory mitigation sites.

For example if the relative value of the development site is 3 and the relative value of the mitigation site is 2, then the ratio applied to the mitigation action is 3/2 or 1.5:1. Under this principle it is also possible (and hopefully probable) that the development site may be lower value than the mitigation site after the mitigation action is complete and meeting its performance objectives. For example, if the relative value of the development site is 2 and the relative value of the mitigation site is 3, then the ratio aplied to the mitigation action is 2/3 or 0.67:1. Since ratios of < 1 result in a net loss of natural resource acres, many regulatory agencies have taken the option of imposing a minimum compensatory mitigation ratio of 1 (also represented as 1:1).

It is my intent that future versions of this web site will be connected to a relational database management system (RDMS), possibly Microsoft SQL Server, that will contain data, run queries, and generate reports that reflect known field conditions measured against both performance standard criteria and functional assessment criteria and which will in turn be used to inform compensatory mitigation ratios and to model compensatory mitigation outcomes.

This is an assigned number often representing the relative likelihood of mitigation success depending on the compensatory mitigation method(s) employed. Methods that have a low track record of failure are generally assigned low mitigation dividers and those with a demonstrated high risk of failure are typically given higher mitigation dividers. Also compensatory mitigation methods that result in 100% loss of resource acreage are often assigned higher mitigation dividers. The acreage of a given mitigation site divided by its assigned mitigation divider equals the amount of credit available at that mitigation site.

If the mitigation site is equal to 10-acres and the mitigation divider is 2, then the number of credits available is 5 (10 / 2).

The "price per credit" is generally a free-market determined decision often based on the sale prices of credits in the general area being "serviced" by a mitigation site. Factors such as the monetary cost of producing a credit (e.g., costs of land acquisition, site-preparation, maintenance, long-term endowments, etc.) combined with the prices of credits from competing mitigation providers have a relatively large influence on the price a credit is sold for. These prices tend to vary temporally and spatially depending on such factors as supply and demand, the strength of the economy, and proximity to major metropolitan areas.

The geographic area (e.g., species recovery unit or watershed) surrounding a conservation or mitigation bank where species and/or regulated aquatic resource debits (i.e., development actions) may be accrued against the credits generated by the conservation or mitigation bank

Note: A good way to use this web map application is to first make sure the area of interest within the Willamette Valley Ecoregion is included in the extent (top to bottom and sides) of the map area you are viewing and that you have opened the attribute table (tab at bottom middle of map view window). Then click on the tab of the bank you are interested in and highlight it by clicking on the gray bar left of the far left column. Next, double click on the record to zoom into the bank boundaries. Repeat these steps for the service areas (SA) of the respective banks of interest. You may want to clear your selections before moving on to the next bank of interest. If you want to see where a proposed project is located in relation to a given bank and / or its Service Area, just type in the project address or coordinates in the serarch box and select the search icon. Be aware that attribute table records are only enabled if their related spatial data are inside the extent you are zoomed to in the map view window. No guarantee is given as to the accuracy or completeness of these data. The data are updated without notice on a periodic basis.

Note: Within the Willamette Valley Ecoregion, fish use data become visible roughly at scales where 1-inch equals 1.5-miles. Attribute data can be viewed by left clicking your cursor on the data of interest to execute the opening of a pop-up window and scrolling through the layers using the arrows at the top of the pop-up window container. You can also view the attribute tables and peruse tabs for the data currently in your map view by selecting the attribute icon on the top left corner of the map viewer. The options drop-down arrow at the upper left corner of the attribute table allows you to export the data currently in the map view for each tab as a CSV file. The print icon in the upper left corner of the map viewer allows you to customize and print out a hard copy map of the spatail data currently in your map viewer window. No guarantee is given as to the accuracy or completeness of these data. The data are updated without notice on a periodic basis.

• Willamette Valley Mitigation and Conservation Banks - You must have Google Earth loaded on your computer to download this zipped kml data
• Wetland Mitigation Banks in the Willamette Valley. Oregon Ecoregion
• Oregon 2000 Draft Mitigation Banking Guidebook
• US Fish and Wildlife Service 1981 Mitigation Policy
• US Fish and Wildlife Service 2003 Conservation Banking Policy
• US Army Corps of Engineers and Environmental Protection Agency 2008 Final Mitigation Rule
• Oregon 2008 Interagency Guidance on Mitigation Banking Federal and State Policy Relationships to Public Funding
• Willamette Valley Ecoregion Hydrogeomorphic Assessment Methods for Riverine Impounded and Slope-Flats Wetland and Riparian Subclasses Volume 1A
• Willamette Valley Ecoregion Hydrogeomorphic Assessment Technical Manual for Riverine Impounded and Slope-Flats Wetland and Riparian Subclasses Volume 1B
• Oregon Rapid Wetland Assessment Protocol
• Focal Oregon Department of State Lands Mitigation Bank and In-Lieu-Fee Administrative Rules
• Oregon Department of State Lands Permittee Responsible Compensatory Mitigation and Mitigation Bank Credit Calculator
• Modified DSL Mitigation Bank Crediting Workbook
• Logic Testing for Portland Harbor Mitigation and Conservation Bank Credits and Debits (DSAYs)
• Side-by-Side Comparison of Two Calculations to Derive DSAYs Using Different Logic Theory


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• Draft Discounted Service Acre Years (DSAYs) Calculator for Portland Harbor Mitigation and Conservation Banks

Note: Execution of the above hyperlink requires that you have Google Earth downloaded onto your computer or cell phone