The wetland currency is linked closely with the Clean Water Act and implementation of the 404 programs for the US Army Corps of Engineers and Oregon Department of State Lands. Wetland credits are traded as functional acres and calculated using the Oregon Rapid Wetland Assessment Protocol.

Oregon Rapid Wetland Assessment Protocol (ORWAP)

ORWAP is a functions-based assessment developed by Paul Adamus and the Oregon Department of State Lands for use as a statewide rapid assessment for wetland conditions. It was not developed explicitly as a crediting metric. The Department of State Lands and the Army Corps of Engineers have approved ORWAP for use as a functional assessment. The Counting on the Environment project convened a wetlands focus group to assign rules for converting ORWAP scores into quantities of functional acres as tradable credits.

ORWAP computes a score for each of 16 wetland functions and their societal value. Although ecosystem services are considered to be the combination of a site’s functional capacity and its value, ORWAP currently does not specify a process for combining the function and value score into an “ecosystem service” score based on each pairing. These 16 functions are grouped into 5 functional groups with a score between 0 and 10.

Wetland Calculation Documents

Wetland Crediting Procedure
ORWAP Manual
ORWAP Supplemental Information
ORWAP Calculator