In order to calculate the average buffer width, estimate the width of buffer on each side of the wetland to a maximum of 50m and divide by the number of sides, e.g. the average buffer width of a wetland with buffers of 100m, 50m, 0m and 0m would be calculated as follows: abw =(100 + 50 + 0 + 0)/4 = 37.5A wetland with buffers greater than 50m on all sides would have an abw>50m and would score 7 points. For very large wetlands or wetlands with unusual shapes there maybe multiple "sides" and it may be difficult to measure, determine, or obtain access to all of the sides of the wetland. In this situation, the Rater may consider this question to provide a buffer continuum from very narrow to wide and assign the points associated with the most appropriate category. Question 2b: Intensity of Surrounding Land Use This question asks you to evaluate the intensity of the predominant land uses in the areas outside the wetland and beyond the wetland’s buffer zone, i.e. more than 50m (164 ft) if the wetland has buffers greater than 50m on all sides. It asks you to generally characterize the type of land uses that are most common in the immediate vicinity of the wetland. Several examples are offered to aid in answering this question below. Example 1. Wetland is a deep (90cm), largely unvegetated (except for the canopy trees above it) vernal pool, located entirely within a large, contiguous patch of second growth forest. Upland forest extends from 100 to 300m on all sides of the wetland. Outside of the forest, the land use is agricultural row cropping. Score: the wetland is entirely surrounded by second growth forest and should receive a score of 7. Example 2. The wetland is deep, largely unvegetated (except for the canopy trees above it) vernal pool, located at the edge of a large, contiguous patch of second growth forest. Outside of the forest, the land use is agricultural row cropping. The boundary of hydric soils extends from the current wetland edge into the agricultural field. Score: the Rater should double check “very low” (7) and “high” (1), and average the scores , (7+1)/2=4. Example 3. The wetland is a vegetatively diverse emergent marsh located in the floodplain of a State Scenic River. A mature forested, riparian corridor is adjacent to one side of the wetland; on the other side is a fenced pasture (Note: both sides of the river have a forested, riparian corridor). Score: the Rater should double check “very low” and “moderately high”, and average the scores, (7+3)/2=5. Example 4. The wetland is an isolated, depressional cattail marsh. On one side, the wetland has no buffer and is immediately adjacent to active row cropping. On the other three sides, the wetland is surrounded by a new fallow field. Score: the Rater should double check “moderately high” (3) and “high” (1), and average the scores, (3+1)/2=2. Example 5. The wetland is a depressional buttonbush swamp with forested margins. The wetland is bisected by a small, paved township road. The wetland has mature to young second growth forest on one side, a “shrubby” old field (probably >10 years old) on 2 sides, and is hydrologically connected to another buttonbush swamp on the fourth side but is separated from this other wetland by a 20 to 50 meter wide upland forested area. Score: the Rater should double check "very low" and "low" and average the scores, (7+5)/2=6.
Wetlands are areas transitional between upland and aquatic environments. They are sensitive to human disturbances, both directly and indirectly. Nutrient enrichment or eutrophication from stormwater inputs, urban runoff, or agricultural runoff can degrade wetlands. These are just a few ways that wetlands can be disturbed via humans. The questions in Metric 2 relate wetlands with a “buffer” zone. A wetland with a buffer zone, essentially a space or gap between the wetland and human land uses, are often less disturbed than wetlands without these zones. Wetlands that are located in places where human land use is more intensive are often subject to greater degrees of disturbance. Question 2a: Average Buffer Width Typically, a buffer could be forested or shrubby margin, prairie, streams or lakes, old fields, and in certain instances more managed landscapes like meadows or hay fields. Intensive human land uses should not be counted as buffers. These include active agricultural row cropping, fenced or unfenced pastures, paved areas, housing developments, golf courses, mowed or highly managed parkland, mining or construction sites, etc.