EP 1110-1-27
27 Jan 00
b. Use of power data. Within a pump circuit, changes in amperage draw can be used to spot worn
motors, or pumping system problems such as a clogged or perforated discharge line. As with the
hydrologic data, the longer and more complete the records, the more likely that valid trends can be
charted.
3-7. Video for Historical Comparison
When properly used, downhole video provides a direct view of conditions within wells. Video documents
the as-built condition and timing of subsequent well damage and deterioration. Types of clogging
conditions can be identified visually with some background. A progression of videos in any particular
well, especially from the original construction condition, provides a direct way to watch changing
conditions in the well (e.g., progressing screen corrosion or biofouling development). A video can also be
used for comparison to file records where file records are suspect or incomplete.
3-8. Piezometric Maps
Existing interpretation aids available on typical HTRW projects can be used to assist in performance
analysis. Piezometric or water table maps provide information on "regional" head data that influence
specific capacity, and help to illustrate anomalies around pumping wells. Depths of water-bearing
formation exposure and evidence of pumping centers can also provide insight into well-clogging
oxidation occurrence in a well field.
3-9. Geologic Regime
a. Information on geologic maps. Geologic maps and cross-sections provide information on the
influence of stratification and particle and geochemical types on well performance and degradation, and
how effective original well designs were. Trouble-causing situations such as long, large-particle-size filter
packs in variable stratified aquifers can be identified. Expected well treatment problems such as
overdeveloping clay lenses can be predicted. Good geology and geophysical data relevant to the well's
location are essential for proper well design.
b. Problems with too little geologic information. Well systems are often designed based on too
little geologic site information. Problems that crop up often have a basis in a well being designed for a
generic site condition, sometimes based on single borings, instead of well-site specific data. Files reveal
when this is the case when multiple wells on a site will have identical depths, screen slot sizes, and filter
packs. Results include screens and filter packs that are too fine or too coarse for the formation material
and generally poor hydraulic efficiency.
c. Preserving original information. Because interpretations of geologic data over time may be
distorted or simplified, it is recommended that original field notes be preserved for reference. Good data
collection and analysis save operational money in the long term by aiding good well design that improves
the capability of facility operators to maintain well systems. It is important that facilities maintain an
archive that remains available and accessible despite management changes for use by future technical
oversight or advising personnel (Section 4-3).
3-10. Maintenance Logs for Individual Wells
a. File elements. Section 2-10 reviews major file elements for well system maintenance. While
general site information such as piezometric maps can be held centrally, files should be kept for
individual wells to record their specific O&M histories.
3-3