Climate Change Alert!!

Willamette Valley Wetland Mitigation and Conservation Banking

  • 1.Amazon Creek
  • 2 Bobcat Marsh
  • 3 Butler
  • 4 Camas Swale
  • 5 Dairy Creek
  • 6 East Fork Minnow Creek
  • 7 Evergreen Creek
  • 8 Fernhill
  • 9 Foster Creek
  • 10 Frazier Creek
  • 11 Garret Creek
  • 12 Half-Mile
  • 13 Long-Tom
  • 14 Marion
  • 15 Mid-Valley
  • 16 Mud-Slough
  • 17 Muddy Creek
  • 18 Oak Creek
  • 19 One Horse Slough
  • 20 Oregon Trail
  • 21 Riverbend North
  • 22 Santiam River
  • 23 Tualatin Valley
  • 24 Weathers
  • 25 West Eugene
  • WVMCBs
    1 / 25
    Amazon Creek Wetland Mitigation Bank Site
    2 / 25
    Bobcat Marsh Wetland Mitigation Bank Site
    3 / 25
    Butler Wetland Mitigation Bank Site
    4 / 25
    Camas Swale Wetland Mitigation Bank Site
    5 / 25
    Dairy Creek Wetland Mitigation Bank Site
    6 / 25
    East Fork Minnow Creek Wetland Mitigation Bank Site
    7 / 25
    Evergreen Creek Wetland Mitigation Bank Site
    8 / 25
    Fernhill Wetland Mitigation Bank Site
    9 / 25
    Foster Creek Wetland Mitigation Bank Site
    10/ 25
    Frazier Creek Wetland Mitigation Bank Site
    11/ 25
    Garret Creek Wetland Mitigation Bank Site
    12/ 25
    Half-Mile Fee-In-Lieu Creek Wetland Mitigation Bank Site
    13/ 25
    Long-Tom Wetland Mitigation Bank Site
    14/ 25
    Marion Wetland Mitigation Bank Site
    15/ 25
    Mid-Valley Wetland Mitigation Bank Site
    16/ 25
    Mud-Slough Wetland Mitigation Bank Site
    17/ 25
    Muddy Creek Wetland Mitigation Bank Site
    18/ 25
    Oak Creek Wetland Mitigation Bank Site
    19/ 25
    One Horse Slough Wetland Mitigation Bank Site
    20/ 25
    Oregon Trail Heritage Wetland Mitigation Bank Site
    21/ 25
    Riverbend North Wetland Mitigation Bank Site
    22/ 25
    Santiam River Wetland Mitigation Bank Site
    23/ 25
    Tualatin Valley Wetland Mitigation Bank Site
    24/ 25
    Weathers Wetland Mitigation Bank Site
    25/ 25
    West Eugene Area Wetland Mitigation Bank Site

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    Development Debit and Compensatory Mitigation Credit Transactions

    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.

    Mitigation Debit / Credit Transactions
    Development Acres:
    Mitigation Acres:
    Development Multiplier:
    Mitigation Divider:
    Price Per Credit:


    Development Acres

    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).

    Mitigation Acres

    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.

    Development Multiplier

    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.

    Development Multiplier Values
    High: 4 Medium-High: 3 Medium: 2 Low: 1
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    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.

    Mitigation Divider

    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.

    Mitigation Divider Values
    High: 4 Medium-High: 3 Medium: 2 Low: 1

    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).

    Price Per Credit

    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.

    View Willamette Valley Mitigation Banks

    Note: No guarantee is given as to the accuracy or completeness of data. These data may need to be updated without notice on a periodic basis.

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    Other Resources

    Code partially adapted from Marc Goodman's homework assignments and suggestions in 2012 Winter Term CIS 122 Software Design Class at Portland Community College and Lhoucine Zerrouki's 2015 Fall Term CSI-145 Web Design Course at Renton Technical College. Copyright [2014] [ESRI] Map Application Licensed under the Apache License, Version 2.0; you may not use the map file script except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

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    John Marshall
    2215 SE Miller Street Apartment 11
    Portland, Oregon 97202
    mobile: 503.913.1695
    Map Tool