Water Resources of Michigan

Simulated Effects of Pumping Irrigation Wells on Ground-Water Levels in Western Saginaw County, Michigan

US Geological Survey Water-Resources Investigation 01-4227
Lansing, Michigan 2001

By: C.J. Hoard and D.B. Westjohn

Accessible Web version is available in Web (HTML) format at:
http://mi.water.usgs.gov/WRIR/WRIR01-4227/WRIR01-4227LW.php

Contents

• Contents
• Figures
• Tables
• Conversion Factors, Vertical Datum, and Abbreviations
• Glossary

Contents:

FIGURES

Figure 1. Location of study area and selected wells in Saginaw County, Michigan.

Figure 2. Potentiometric surface of the Sainaw aquifer and location of Saginaw Lowlands in the central Lower Peninsula of Michigan (Modified from Barton and other, 1996.).

Figure 3. Distribution of saline and fresh water in the Saginaw aquifer and locatio of Saginaw Lowlands in the central Lower Peninsula of Michigan (Modified from Westjohn and Weaver, 1998.)

Figure 4. Increase of chloride concentration as a function of time at two public-supply wells in western Saginaw County, Michigan.

Figure 5. Depth to water in the Marion Springs monitoring well for selected years, October through September, western Saginaw County, Michigan.

Figure 6. Depth to water in the Marion Springs monitoring well and the USGS MW, September 2000 through August 2001, western Saginaw County, Michigan.

Figure 7. Depth to water at USGS MW, June throught September 2001, western Saginaw County, Michigan.

Figure 8. Example of model discretization for axisymmetric flow simulations. (From Reilly and Harbaugh, 1993.)

Figure 9. Simulated drawdown at approximately one-half mile from a pumping well in the Saginaw aquifer, western Saginaw County, Michigan.

Figure 10. Simulated drawdown at different distances from a single irrigation well after 3 months pumping with a 12-hour pumping cycle, western Saginaw County, Michigan.

Tables

Table 1. Well location, pumping rate, and aquifer for irrigation wells used for model calibration

Table 2. Model parameters used for simulations

Table 3. Simulated drawdown compared to observed drawdown used for model calibration

Table 4. Summary of predicted drawdown after one month and three months of pumping, at selected distances

Table 5. Factors that can contribute to insufficient water supply at residential wells

Conversion Factors, Vertical Datum, and Abbreviations

For use of readers who prefer the International System of Units (SI), the conversion factors for terms used in this report are listed below.

Sea level: In this report "sea level" refers to National Geodetic Vertical Datum of 1929 (NGVD of 1929), a geodetic datum derived from a general adjustment of the first-order level nets of both the United States and Canada, called Mean Sea Level of 1929.

Glossary

Aquifer

A water-bearing unit of rock or sediment that will yield water in a usable quantity to a well or spring.

Basal lodgment till

A mixture of unsorted sediments (in this case mostly clay) plastered directly on land surface by overriding glacial ice.

Bedrock

A general term for consolidated (indurated) rock that underlies soils or other unconsolidated surficial material.

Confining unit

A layer of rock or sediment having very-low hydraulic conductivity that impedes the movement of water into and out of an aquifer.

Drawdown

The reduction in water level at a point caused by the withdrawal of water from an aquifer. For this report, water-level declines caused by pumping of a well.

Glaciofluvial

Material moved by glaciers and subsequently sorted and deposited by streams or overland flow of water from melting ice.

Ground-water gradient

Change in water level per unit distance measured in the direction of the steepest change.

Hydraulic conductivity

The capacity of a rock or sediment to transmit water. It is expressed as the volume of water at the existing kinematic viscosity that will move in unit time under a unit ground-water gradient through a unit area measured at right angles to flow.

Lacustrine sediment

Stratified materials deposited in ponded or still-standing water, usually fine grained (typically silt to clay) due to low-energy nature of sedimentary environments.

Recharge

Inflow of water to a ground-water reservoir from the surface. Infiltration of precipitation and its movement to the water table is one form of natural recharge. Also, the volume of water added by this process.

Storage coefficient

The volume of water released from storage in a unit volume of aquifer when the head is lowered a unit distance.

Citation:

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