Read Me for Grain Size Data:

These files contain grain size data from samples collected throughout a 
managed aquifer recharge system. 

The file 0_GrainSizeSampleMetadata contains details on each sample. This file
has four columns. The first contains the sample name, which corresponds with
files containing grain size data for each sample. The second contains the year
during which the samples were collected (13 = 2013, and so on). The third contains
the depth below ground from which the sample was collected (if applicable). The
fourth contains a description of where the sample was collected.

Each data file contains one line with the sample name.
Below that are three columns of a distribution of grain size data.

The first is the average grain size in the given bin, in micrometers. 
The second is the percent by volume of the sample that falls in that bin.
The third is the lower limit of grain size in the given bin.

Each row represents one data bin, and the data bins grow exponentially larger. 