# Unsaturated Hydraulic Conductivity in Composite Porous Media
## 3 Results and Discussion  
The \(k_{s}\) values obtained using the conventional constant inversion experimental model and the automated permeameter for the three types of materials are shown in Table 4. During the constant head test in the conventional permeameter, the \(k_{s}\) values register hydraulic height changes at speed slow enough for granular dominance to be absolute in all reconstituted prototypes. Figure 5: Graph cumulative infiltration vs. square root of the time. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Material** & & & & \(h_{o}\) **(cm)** & & \\ \hline  & \(-1\) & \(-2\) & \(-3\) & \(-4\) & \(-5\) \\ Guamo sand & A & A & A & A & A \\  & 2.40 & 1.73 & 1.24 & 0.89 & 0.64 \\ Guamo sand + Diat. & 3.89 & 3.91 & 3.93 & 3.95 & 3.98 \\ Guamo sand + Fe\({}_{2}\)O\({}_{3}\) & 3.89 & 3.91 & 3.93 & 3.95 & 3.98 \\ Guamo sand + CaCO\({}_{3}\) & 3.89 & 3.91 & 3.93 & 3.95 & 3.98 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Values of Van Genuchten parameter A for different types of soils. For the first approach of the granular beds with percentages of diatoms, the permeability characteristics of the Guamo sand were considerably limited, although the data acquisition for this particular set considers the highest \(k_{s}\) results. From 0.02416 cm/s as the \(k_{s}\) characteristic of the granular system to 0.00081 cm/s with a dependence of 40% of fossilized microalgae, the reduction covers about 99.7% using a data convergence scale forced to 0 (Table 4). The addition of diatoms to the base material clearly reduces the saturated permeability coefficient because it has a finer PSD, which allows diatom particles to locate between the pores of the Guamo sand. Likewise, the standard deviation was calculated in the \(k_{s}\) values obtained by the conventional permeameter and KSAT methods. In most cases, the normal distribution showed that 90% of the values are within one standard deviation. Regardless of the method used to estimate the value of \(k_{s}\), there is parity in the values, and most fluctuate close to the mean (Table 4). The above also applied for \(k_{u}\) results from the MDI. The permeability values in saturated conditions coincide with previous studies that have been fully validated in the literature, where the sand under study is considered a medium-sized grain, highly permeable. Similarly, when the additions are included, the soil begins to change, in terms of its PSD, towards fine-grained sand and silly sand. This aspect influences the reduction in \(k_{s}\). The effects described are collinear with those recorded in several studies, where the values are in similar positions and can be consulted in [47; 53; 54; 55; 56; 57; 58]. This behavior responds to the pedogenetics and composition of diatom soils, corresponding to fossilized remains of freshwater unicellular photosynthetic algae with silica skeletons. Within the literature, there are extensive studies on how pedogenetics influences the material's current mechanical and hydraulic behavior and even the anisotropy and heterogeneity of depositional soils such as diatomic [59; 60; 61; 62; 63; 64; 65; 66]. The \(k_{s}\) value of Guamo sand is an intrinsic property of the porous medium, so it remains constant during all tests. This mechanism is observed in the three coupling scenarios, where a stable average permeability is defined throughout the experimental phase. In the second approach, which considers the inclusion of synthetic components derived from mixtures of two or more elements in a pure state, such as calcium carbonate (CaCO\({}_{3}\)) and iron oxide (Fe\({}_{2}\)O\({}_{3}\)), the digital mapping of soils is seen subjected to amplification in smaller diameters, reducing the micro and macroporous spectrum of the Guamo sand. Consequently, the permeability is much lower in the core than in the first approach. On the other hand, when the liquid reaches the sample top during the constant head test, the overestimation of the hydraulic gradient can be neglected by ignoring the gravity within the sample.