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The purpose of the study to obtained water well screens opening size and gravel packs size, and to access within the groundwater inter through the aquifer to the well screen and prevent running sand from entering the well. The use of properly designed screen and gravels are important and this paper is an important reference for the design of groundwater wells. In this study, the purpose of the circle method is to design water well and the benefits of sand control. The determination of screen slot size and its variation in the opening is often a major aim of hydrogeological studies. However, measurement of hydraulic conductivity (K) at a high spatial resolution in sedimentary aquifers is a challenge. One commonly used approach is to estimate slot size from grain size analysis. The objectives of this study are to compare between curve of grain size analysis, bar graph and circle method used applied different formulas for the determination of slot size from grain-size data and to evaluate how well this method predicts slot size and gravel pack. Correlation between the mechanical analysis curve, bar graph and the circle methods were found for the used applied different formulas. Based on circle results, the applied circle formulas appear to be suitable for an initial assessment of aquifer properties. However, considering the difference in calculated aquifer parameter values, results are smaller significantly and reliable for the high analysis of aquifer materials.

The well screen is the component of a well which provides an opening through which water enters the well casing from the aquifer, as well as stabilizing the material in the “near-well zone” and preventing it from entering the well. Screens may be constructed with a variety of different materials and designs, as appropriate to the design of the well and its aquifers. Typical types of screen are:

As a water well ages, the rate at which water may be pumped (commonly referred to as the well yield, flow or performance) tends to decrease, especially in wells that were not properly developed when first drilled. This fact sheet briefly describes common well problems and discusses prevention and rehabilitation measures.

Water Well Maintenance

Water wells require regular maintenance to ensure adequate water flow and continued drinking water safety. To ensure water quality, well water should be tested annually for total coliform bacteria and E. coli bacteria by a state accredited testing laboratory.

Every three years, additional testing is recommended for pH and total dissolved solids as well as tests related to land uses occurring or expected to occur within sight of the well. Additionally, if there are obvious stains, tastes, or odors in water, seek testing that will help identify the source of these symptoms.

Get the well professionally inspected by a water well contractor every ten years. Keep all records related to the water well including:

Water well completion report or log (if you have it) which should include information such as water well depth, date drilled, construction (including casing specifications, grouting and screen), and water well yield or flow rate in gallons per minute (gpm)

Water quality test reports

Past inspection reports

Invoices from work done by water well contractors (including pump replacement)

Water treatment equipment warranties, invoices and manuals

To find some of this information you can check with the Pennsylvania Department of Conservation and Natural Resources (PA DCNR) Pennsylvania Groundwater Information System (PaGWIS) or contact a local well driller.

Well Performance

As a water well ages, the rate at which water may be pumped (commonly referred to as the well yield, flow or performance) tends to decrease, especially in wells that were not properly developed when first drilled. A drop or complete loss of water production from a well can sometimes occur even in relatively new wells due to a lowered water level from persistent drought or over-pumping of the well which can dewater the water-bearing zones. More often, reduced well yield over time can be related to changes in the water well itself including:

Incrustation from mineral deposits

Bio-fouling by the growth of microorganisms

Physical plugging of "aquifer" (the saturated layer of sand, gravel, or rock through which water is transmitted) by sediment

Sand pumping

Well screen or casing corrosion

Pump damage

This fact sheet briefly describes these common problems and discusses alternative prevention and rehabilitation measures.

Water Well Rehabilitation

Measures taken to correct these problems are referred to as well rehabilitation or restoration. A successful well rehabilitation will maximize the flow of water from the well. The chances for successful rehabilitation are dependent on the cause(s) of poor well performance and the degree to which the problem has progressed.

Upon noticing loss of performance in your well have a professional water well contractor inspect your well, preferably with a downhole camera.

A common measure of the delivery of water by a water well is referred to as the "specific capacity" which is defined as the pumping rate (gallons per minute) divided by the drawdown or increased depth to water during pumping (in feet).

Generally, a decrease of 25% or more in well yield indicates that rehabilitation is in order. Delaying rehabilitation procedures can significantly increase costs and in some cases make rehabilitation impossible.

To detect deterioration of well performance, you must have a point of reference. Often this reference is the original well construction and pump test data which are normally supplied to you by the well driller on a well completion report or well log when the well is installed. However, even if you do not have this information, significant changes in your well are also a warning sign. 

The principal means used for rehabilitation of chemical incrustation problems involves the use of strong acid solutions to dissolve incrusting materials.

Once loosened or dissolved, the incrusting materials are pumped from the well with the acid solution for disposal.