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Well Log Scans
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and Interpretation Maps
Project investigations into the ground water produced several new GIS
layers as well as maps resulting from queries on the data. For example
the Well layer can be displayed in many ways depending of which attributes
are queried and assigned symbology and color.
Here the wells are ranked and colored by the year they were installed. A surface of influence was calculated to aid in visualizing trends in drilling location. It becomes clear that few new wells have been drilled in the vicinity of available public water. Areas of recent growth and new drilling are easily seen.
Bored wells, as opposed to drilled wells, are of a much larger diameter and usually only reach shallow depths. This study found 188 bored wells ranging from 24-inches to 44-inches in diameter with an average of 38-inches. Their average depth is 56-feet. Most were installed prior to the 1990s. They appear to be fairly well distributed across the County even when filtered by install date.
A number of things become apparent by viewing the distribution of well yields. We see greater average yields in the Coastal Province. Theses higher yields are more evenly distributed than in the Piedmont Province where areas of high yield are concentrated. A very important finding is the degree to which the yield correlates with the geologic structure, particularly in the Piedmont Province.
Here the yield distributions are split into two time periods. We calculated a number of these time period views to see if any changes were apparent with time. Yields and yield patterns appear to be stable and consistent through the 25-year time frame of the data.
A look at the the averages across the Coastal Province show minimal changes over time. The shallow bored wells are both included and excluded to illustrate the affect they can have on the statistics. Prior to 1983 we have too few well records for averages to have meaning.
A look at the the averages across the Piedmont Province also shows minimal change over time. The shallow bored wells are both included and excluded to illustrate the affect they can have on the statistics. Prior to 1983 we have too few well records for averages to have meaning.