Determining the potentiometric surface of an area is essential for the preliminary planning of any type of construction, land use, environmental investigations, or remediation projects that may influence an aquifer.
5.1.1 The potentiometric surface in the proposed impacted aquifer must be known to properly plan for the construction of a water withdrawal or recharge facility, for example, a well. The method of construction of structures, such as buildings, can be controlled by the depth of the ground water near the project. Other projects built below land surface, such as mines and tunnels, are influenced by the hydraulic head.
Monitoring the trend of the ground-water table in an aquifer over a period of time, whether for days or decades, is essential for any permanently constructed facility that directly influences the aquifer, for example, a waste disposal site or a production well.
5.2.1 Long-term monitoring helps interpret the direction and rate of movement of water and other fluids from recharge wells and pits or waste disposal sites. Monitoring also assists in determining the effects of withdrawals on the stored quantity of water in the aquifer, the trend of the water table throughout the aquifer, and the amount of natural recharge to the aquifer.
This guide describes the basic tabular and graphic methods of presenting ground-water levels for a single ground-water site and several sites over the area of a project. These methods were developed by hydrologists to assist in the interpretation of hydraulic-head data.
5.3.1 The tabular methods help in the comparison of raw data and modified numbers.
5.3.2 The graphical methods visually display seasonal trends controlled by precipitation, trends related to artificial withdrawals from or recharge to the aquifer, interrelationship of withdrawal and recharge sites, rate and direction of water movement in the aquifer, and other events influencing the aquifer.
Presentation techniques resulting from extensive computational methods, specifically the mathematical models and the determination of aquifer characteristics, are contained in the ASTM standards listed in Section 2.
1.1 This guide covers a series of options, but does not specify a course of action. It should not be used as the sole criterion or basis of comparison, and does not replace or relieve professional judgment.
1.2 This guide summarizes methods for the presentation of water-level data from ground-water sites.
Note 18212;As used in this guide, a site is meant to be a single point, not a geographic area or property, located by an X, Y, and Z coordinate position with respect to land surface or a fixed datum. A ground-water site is defined as any source, location, or sampling station capable of producing water or hydrologic data from a natural stratum from below the surface of the earth. A source or facility can include a well, spring or seep, and drain or tunnel (nearly horizontal in orientation). Other sources, such as excavations, driven devices, bore holes, ponds, lakes, and sinkholes, which can be shown to be hydraulically connected to the ground water, are appropriate for the use intended.
1.3 The study of the water table in aquifers helps in the interpretation of the amount of water available for withdrawal, aquifer tests, movement of water through the aquifers, and the effects of natural and human-induced forces on the aquifers.
1.4 A single water level measured at a ground-water site gives the height of water at one vertical position in a well or borehole at a finite instant in time. This is information that can be used for preliminary planning in the construction of a well or other facilities, such as disposal pits.
Note 28212;Hydraulic head measured within a short time from a s......
Copyright ©2024 All Rights Reserved