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Highly resolved data from the Borden research site provide a unique opportunity to study the horizontal spatial bivariate correlation of hydraulic and reactive attributes affecting subsurface transport. The data also allow quantitatively relating this correlation to the hierarchical sedimentary architecture of the aquifer. The data include collocated samples of log permeability, Y, the log of the perchloroethene sorption distribution coefficient, Ξ, and lithologic unit type. The horizontal Y and Ξ autosemivariograms and the Ξ-Y cross-semivariogram have the same underlying correlation structure (shape and range in the rise to a sill). The common structure is not due to Ξ-Y point correlation or in-unit spatial correlation. The common structure is defined by how the proportion of lag transitions crossing different unit types (i.e., the cross-transition probability structure) increases with increasing lag distance. The common underlying cross-transition structure contains two substructures with different correlation ranges corresponding to two scales of unit types within the sedimentary architecture. For each substructure, a large standard deviation in the length of units relative to the mean length gives rise to an exponential-like shape and the proportions and mean length of units define the ranges. The horizontal Ξ-Y spatial cross correlation is primarily defined by the larger-scale substructure and the differences in mean Ξ and Y between larger-scale unit types. [ABSTRACT FROM AUTHOR]

The Fool Creek watershed at the Fraser Experimental Forest, Colorado was harvested using a pattern of alternating clearcut and forested strips in 1956. Today, with almost 30 years of postharvest record, subtle impacts on the hydrology of the watershed can be detected that were not significant in the past. In addition to the depositional increases in the snowpack in the openings, average peak water equivalent over the entire watershed has been increased (9%). Long-term, postharvest, climatic records now available show a strong correlation between estimated increases in flow and winter and melt period precipitation. Much of the annual variability in increased flow, now explained by precipitation, was formerly attributed to regrowth or time. Peak discharges, advanced 7.5 days following harvest, have also been increased 20%, with the largest effect occurring in the wettest years. Increases in peak water equivalent, annual flow, and date of peak flow occurrence all appear to be returning to preharvest levels at a very slow rate. [ABSTRACT FROM AUTHOR]