Water Resource Management Issues

Basic Principles and Applications

Louis Theodore, R. Ryan Dupont

• Publisher: CRC Press
• Year: 2019
• Print ISBN: 9780367183851
• eBook ISBN: 9780429590207
• Edition: 1
• Topic: Biological Sciences
• Subtopic: Hydrology
• Index: Biological Sciences

Drinking Water Safety: Basic Principles and Applications, examines the technical and scientific, as well as regulatory, ethical, and emerging issues of pollution prevention, sustainability, and optimization for the production and management of safe drinking water to cope with environmental pollution, population growth, increasing demand, terrorist threats, and climate change pressures. It presents a summary of conventional water and wastewater treatment technologies, in addition to the latest processes.

Features include:

Provides a summary of current and future of global water resources and availability.

Summarizes key U.S. regulatory programs designed to ensure protection of water quality and safe drinking water supplies, with details on modern approaches for water utility resilience.

Examines the latest water treatment technologies and processes, including separate chapters on evaporation, crystallization, nanotechnology, membrane-based processes, and innovative desalination approaches.

Reviews the specialized literature on pollution prevention, sustainability, and the role of optimization in water treatment and related areas, as well as references for further reading.

Provides illustrative examples and case studies that complement the text throughout, as well as an appendix with sections on units and conversion constants.

Section II

Water Resources

9	Water Resources of the United States

9.1 INTRODUCTION

The present outlook of water resources in the United States affects each and every citizen living today and each generation to come. As in any engineering undertaking, the concern associated with water resources must be identified and understood. The most basic question this chapter tries to address is the current and future projected discrepancy between water supply and water demand within the United States, and what practices will need to be implemented to ensure sustainable water resources in the future.

There are two major categories of water sources that are used in the United States. Surface water and groundwater both contribute to the national supply and are used in different proportions that varies by state. Trends in past usage and analysis of present issues creates a picture of what water resources will be available in the future.

One important metric to determine is if present water supplies will meet demands in the near future. Another equally important issue pertaining to present water resources is maintaining water quality standards. It could be argued that the quality issue is becoming increasingly more important in the face of increasing urbanization and population growth. Obviously, drinking water consumed by humans needs to be of the highest quality, ensuring health and vitality to all U.S. inhabitants.

In addition to studying water quality, water use and sustainable reuse methods are considered in this chapter. In the presence of increasing demands, more and sustainability efforts should be implemented in the United States. The feasibility and benefits of several types of reuse methods are discussed, and hopefully developing nations will continue to learn and emulate sustainable water practices in the developed world, making the overall future global water outlook a brighter one.

This chapter summarizes the state of water resources in the United States and addresses surface water, groundwater, quality of water resources, and water use and sustainable reuse methods. An application section provides three Illustrative Examples related to the general subject of water resources in the United States.

9.2 SURFACE WATER

Surface water consists of streams, lakes, and reservoirs. It should be noted that surface water contains both fresh and saline resources. Several coastal states resourcefully use saline surface water for industry and other uses. Two factors must be understood to establish what the most important surface water concerns are: the largest sectors of current water resource usage, and the trends in usage in these sectors.

The usage of fresh surface water has declined since 1980 and has actually decreased approximately 25% between 2005 and 2015. The decline in total withdrawals in 2015 was primarily caused by significant decreases (28,800 MGD) in thermoelectric power water use because of increased efficiency and closures of plants with once-through cooling systems and accounted for 89% of the decrease in total withdrawals. Between 2010 and 2015, withdrawals decreased in all categories except irrigation (2% increase), mining (1% increase), and livestock (no change). Both fresh surface-water withdrawals (198,000 MGD) and saline surface-water withdrawals (38,600 MGD) were 14% less than corresponding values in 2010 (Dieter et al. 2018). Considering the continuing increase in the U.S. population over time, significant strides are being made in surface-water use efficiency (Figure 9.1). Total surface-water withdrawals were estimated to be 237,000 MGD, or 74%, of total withdrawals. About 84% (198,000 MGD) of total surface-water withdrawals were freshwater.

FIGURE 9.1 Trends in groundwater and surface water withdrawals and U.S. population, 1950–2015. (From Dieter, C.A. et al., Estimated Use of Water in the United States in 2015, Circular 1441, U.S. Geological Survey, Reston, VA, 65 p, 2018.)

In 2015, more surface water than groundwater was withdrawn for all categories of use except domestic, livestock, and mining; however, irrigation was nearly evenly split between surface water and groundwater. Thermoelectric power accounted for about 48% of the total fresh surface-water withdrawals and irrigation accounted for about 31%. The largest surface-water withdrawals were in Texas, Idaho, Florida, California, New York, and North Carolina, cumulatively accounting for about 29% of total surface-water withdrawals for all categories nationwide. Large quantities of fresh surface water were withdrawn for thermoelectric power in Texas, Illinois, Michigan, and Alabama. Large saline surface-water withdrawals for thermoelectric power occurred in Florida, New York, Maryland, and New Jersey, which cumulatively accounted for 61% of the national total saline surface-water withdrawals.

Based on the present population distribution and large industrial uses of water; the usage rates discussed should be expected to at least be maintained, if not decrease in coming years. Efforts should be focused on sustainable methods that use water more efficiently, especially in the irrigation and thermoelectric power sectors. These two industries literally feed and power the nation and currently represent the largest water consumption sector in the United States, making up 78% of total water withdrawals in the United States in 2015. Significant reductions in water use in the thermoelectric power sector have recently been achieved as discussed. Irrigation withdrawals steadily increased from 1950 to 1980, when they peaked (150,000 MGD) and then have remained relatively steady from 2005 (127,000 MGD) through 2010 (116,000 MGD) to 2015 (118,000 MGD). The trend toward using more efficient irrigation systems has continued over time, with 10% more irrigated lands using sprinkler systems (including micro-irrigation) and 11% less land area using surface (flood) irrigation systems in 2015 than in 2010, but even with these improvements, water use for irrigation has increased over time. Given the large percentages of surface and groundwater consumed by both of these industries, they would be the largest leverage points in water conserving efforts and implementing reuse strategies.

With regard to trends in streamflow, there seems to be mixed results reported in the literature. Anderson a...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• Preface
• Authors
• SECTION I Overview
• SECTION II Water Resources
• SECTION IV The Future
• Appendix A
• Appendix B
• Index