Extracts from: Manual for the Wetland Ecosystem Services Protocol (WESP) version 1.3 October 2016
by: Paul R. Adamus, Ph.D. Oregon State University. Available at https://www.researchgate.net/publication/352383733_Manual_for_the_Wetland_Ecosystem_Services_Protocol_WESP_version_13
The WESP-AC protocol includes separate scores for Functions and for Benefits. The Draft LSA for Sandy Lake Study Area makes no mention of Benefit Scores. Below are some extracts from Manual for the Wetland Ecosystem Services Protocol (WESP) version 1.3 pertaining to the benefits of wetlands in regard to Water Storage, Sediment Retention & Stabilization, and Phosphorus Retention.
The brown highlighting of selected text is added to indicate features which apply to wetlands in the Sandy Lake Study Area and that, if Benefit Scores were calculated, would contribute towards high scores.
A.1 WATER STORAGE & DELAY (WS)
Function Definition: The effectiveness of a wetland for storing water or delaying the downslope movement of surface water for long or short periods and in doing so to potentially influence the height, timing, duration, and frequency of inundation in downstream or downslope areas.
Scientific Support for This Function in Wetlands Generally: Moderate to High….
WS Benefits Model
The Benefits score is the average of two factors. One concerns whether buildings or infrastructure within 5 km downriver or downslope from the wetland have been damaged or are in a mapped floodplain. The other is the average of 3 indicators — the extent of unvegetated upslope surfaces (more impervious or semi-pervious proportional surface indicates more opportunity for downslope wetlands to influence flood peaks), lower position in a regional watershed, and the potential for runoff to be transported to a wetland as related to steeper slope and decreasing vegetation in its contributing area.
A.4 SEDIMENT RETENTION AND STABILIZATION (SR)
Function Definition: The effectiveness of a wetland for intercepting and filtering suspended inorganic sediments thus allowing their deposition, as well as reduce current velocity, resist erosion, and stabilize underlying sediments or soil.
Scientific Support for This Function in Wetlands Generally: High…
SR Benefits Model
If water quality data indicates that contamination (within 1 km upstream) has occurred with metals and other substances that readily adsorb to sediment, this counts for half the score.
Otherwise, the Benefits scores increases if a tributary enters the AA, or a large proportion of the wetland contains surface water, or if the average of scores for several indicators is large: increased presence of recent erosive land use activities upslope from the wetland, greater amounts of impervious surface and less natural cover in the wetland’s contributing area, steeper slopes surrounding the wetland, large water level fluctuations.
A.5 PHOSPHORUS RETENTION (PR)
Function Definition: The effectiveness for retaining phosphorus for long periods (>1 growing season) as a result of chemical adsorption and complexation, or from translocation by plants to belowground zones or decay-resistant peat such that there is less potential for physically or chemically remobilizing phosphorus into the water column.
Scientific Support for This Function in Wetlands Generally: High…
The Benefits model (as opposed to the function model) addresses only the opportunity to perform this function, not its potential positive or negative effects on ecosystems, which are too difficult to estimate with a rapid method…
PR Benefits Model
This function is considered most valuable if a wetland has greater opportunity to perform it. The score is calculated by taking the larger of four indicators: a score for phosphorus load, known presence of a nutrient problem above or below the wetland, presence of a tributary, and the group average for several indicators of increased phosphorus delivery to the wetland, such as buffer slope, upland erodibility, lack of undisturbed upland cover.