The goal of the proposed project is to test the hypothesis: geochemical and physical properties of sedimentary aquifers are correlated to facies. A consequence of the hypothesis is that property heterogeneity must be related to the distribution of facies. If this hypothesis is correct, facies mapping can provide quantitative information about the spatial structure of physical and chemical transport properties of sedimentary aquifers. Additionally, a facies-based approach will yield insight into relations between permeability and reactivity. The proposed project seeks to test the hypothesis at one site - the Borden sites. The representative geochemical and physical aquifer properties selected for quantification are the sorption coefficient (Kd) for a model hydrophobic organic chemical (HOC), which provides a measure of reactivity, and the permeability (k). The specific objectives of the proposed project are to determine:
1. the significance of facies in explaining the variance (. i.e. heterogeneity) of k and HOC KD;
2. the spatial properties of, and spatial coffelation between, k and HOC KD;
3. Relationships between these two properties and fundamental sediment properties of each facies;
4. the accuracy of a mapped facies distribution in predicting the distributions of k and Kd.
A major contribution of this work is that the geology of the system - the basic materials which make up sediments and the processes which transport and deposit them - provides the framework for understanding chemical property heterogeneity. This project will produce quantitative information on the basic relationships between sedimentary facies and geochemical and physical hydrologic properties. It is one part of a larger sequence of studies designed to assess the variability of chemical properties of sedimentary aquifers. We anticipate that the results will transform the way that hydrogeochemical property heterogeneity is conceptualized for sedimentary aquifers.
d.
