So it was with some trepidation and amusement that I began to read Hruby's latest publication, Update on Wetland Buffers: The State of the Science, Final Report. Relative to genuinely professional work about risk assessment and/or fate and transport, it's still amateurish ... but nevertheless ... it isn't completely wrong. Let's review a couple of the good things about this mediocre report.
- For water quality, Huby admits that the effectiveness of buffers depends on site-specific factors. He says that recent research has increased our understanding of the many different factors that control the effectiveness of a buffer at trapping pollutants, and then he names width, slope, type of vegetation, type of pollutant, geochemical and physical properties of the soil, infiltration rates of the soils, sources of pollutants, concentration of pollutants, path of surface water through the buffer, and for phosphorus, the amount of phosphorous already trapped by the soil.
- For habitat, Hruby admits that studies do not show minimum buffer distances needed to protect species, but only show how far species roam from wetlands. He also says that there is very little research correlating plant diversity in wetlands with buffer width.
Furthermore, we have all heard the Department of Ecology and Dr. Adamus proclaim that amphibians can be found hundreds of feet away from a wetland; therefore, buffers should be hundreds of feet wide to accommodate their roaming. Hruby admits that this "roaming data" is not related to buffer width. Stated another way, there is no science that explains how the distribution of wetland dependent species varies with buffer width. Amphibians may roam hundreds of feet away from a wetland regardless whether the buffer is hundreds of feet, tens of feet, or nonexistent. We do not know how, or even whether, changing buffer width affects species distribution. Anyone who has found tree frogs in their window boxes, for example, knows that tree frog wandering does not seem to depend on buffer size.
There are other good admissions in this report. Key Point #4 on page 30 says "Several researchers have recommended a more flexible approach that allows buffer widths to be varied depending on site-specific conditions." On page 10, the report says, "Site-specific factors (vegetation density and spacing, initial soil water content, saturated hydraulic conductivity, and sediment characteristics) are so important in determining the effectiveness of a buffer that simple designs that do not account for these factors can fail to perform their protective functions."
And lastly, this report discusses the Meyer and Zhang papers, both of which have been the topic of intense discussion at various Planning Commission and County Council meetings over the past two years.
We'll save our substantial criticisms of the report for the next post, but for now, take some heart in the fact that even a blind Department of Ecology can find a nut once in a while.