Limitations to Each Approach Sample Clauses

Limitations to Each Approach. The use of the air permeameter approach in a laboratory setting to estimate field- scale saturated hydraulic conductivity is limited by the disturbance of soil samples. The structure of the soil as it exists in the field is difficult, if not impossible, to reproduce for laboratory samples. Non-uniform soil samples can result in voids in the air permeameter cylinder. These voids allow preferential pathways for the air to flow through and thus produce higher air conductivity estimates. In general, the shortcomings of this type of testing procedure arise from disturbed soil samples and non-uniform soil structure. Density, porosity, soil structure, and packing play a significant role in both water and air conductivity. When these parameters are mechanically altered, small-scale effects are lost. There are limitations in determining infiltration based on soil texture as well. Although soil texture can provide good insight into the potential infiltration rate of a soil type, site-specific characteristics also influence the actual infiltration rate. Specific site characteristics that should be considered when infiltration potential is estimated include flow direction, heterogeneity of the soil formation, depth from the bottom of the pond to the water table, and impermeable surfaces in the subsoil. Soil texture alone does not incorporate these other factors. Another consideration is that infiltration rates of soils with the same textural classification can still differ because of structure and packing.