Principles of Stormwater Management

Roger D. Griffin

• Publisher: CRC Press
• Year: 2018
• Print ISBN:
  9781138093621
• eBook ISBN:
  9781351113731
• Topic: Tecnología e ingeniería
• Subtopic: Gestión medioambiental

This book presents of all aspects of storm water management: the hydrologic cycle, sources of contaminants, standards applicable to discharges, regulatory issues, atmospheric deposition, best management practices, and health/environmental impacts. It includes technical details of the modern treatment of stormwater, the emerging issues of atmospheric deposition, run-on, and snow melt, the Epidemiologic Model, and field data on discharge concentrations of a variety of contaminants. The principles explained in this book will enable students, contractors, developers, and engineers to grasp the most important field elements which must be included for construction projects impacting stormwater.

1

Introduction to Stormwater Management

All the rivers run into the sea; yet the sea is not full; unto the place from whence the rivers come, thither they return again.

Soloman, Ecclesiastes 1:7

∼950 bc

Water

It has been the lifeblood of civilization for thousands of years. Civilized man has traveled the world’s oceans since the very beginning. The earliest known written document (the book of Job) refers to water in its various forms over two dozen times: snow, ice, dew, rain, hail, clouds, storms, tempests, and floods. In the histories of over 200 ancient civilizations worldwide, there are accounts of the Great Flood; in its aftermath are the records of these cultures managing water resources. Civilization has always been dependent on finding water, particularly fresh water, both for drinking and for crops. Wars have been fought over the ownership and use of fresh water; even today, great bodies of legislation exist which attempt to allocate scarce water sources in arid lands.

The challenge—both then and now—has been to take what literally falls from the heavens and distribute those flows to the survival and benefit of all.

The Water Cycle

The basic concept necessary to our understanding is the Water Cycle (Figure 1.1).

Figure 1.1Depiction of the water cycle.

Water in the biosphere travels through a grand circle, starting from its primary source, the oceans. It passes into the atmosphere via evaporation and is ultimately deposited via condensation and precipitation onto the earth’s surface. Water passes through a number of intermediate steps, interactions, and pathways in making its journey.

Key Steps

The sources of water in the water cycle are the earth’s oceans. Thermal evaporation drives water vapor into the atmosphere where it begins its journey.

The earth’s oceans have a volume of 1.33 billion cubic kilometers (300 million cubic miles). The Pacific accounts for about half of all ocean area and about one-third of the entire surface of the earth. Heat energy enters the oceans from solar radiation and subterranean sources. Since there are about 40,000 active volcanoes beneath the Pacific Ocean, the latter are a significant source of thermal energy and water evaporation to drive the cycle.

Subsurface volcanoes, “black smokers,” and the 10 ton/second contribution from meteoric sources provide minor amounts of additional water to the oceans, but also add trace elements, gases, and particulate matter to the mass balance. Additional minor contributions come from soil surface moisture and evapotranspiration from plants. Streams and other bodies of water such as lakes, rivers, and ponds have minor roles.

Once in the atmosphere, water vapor is transported worldwide where it becomes the major greenhouse gas thereby affecting climate along the way. Ultimately, it will condense into the liquid state—where it begins adsorbing atmospheric gases and particulate matter.

Precipitation is the next step in the process. Water molecules consolidate around condensation nuclei, give up their heat of condensation to other gases in the vicinity, and form a liquid film on the surface of the developing droplet. From that point a number of phase changes occur as the droplet moves about in the atmosphere. These changes include the formation of fogs or clouds, solid masses (hail), and rain drops. Depending on the temperature regimes through which these droplets pass, they may grow further in diameter, shrink, sublime back into the gas state, consolidate with ices, or form snowflakes.

Deposition on the earth’s surface is the fourth phase of the water cycle prior to returning to the oceans. This is the phase in which we are interested. The pathways “en route” will vary from straight rainfall to fluvial transport, or to possible storage (as ice and snow with later melting) and/or infiltration into groundwater regimes.

Contaminant Entry Into Water Cycle

Of particular concern are the phases at which contaminants enter the water cycle. Figure 1.2 illustrates the contaminant entries into the water cycle. Water—being the universal solvent—picks up contaminants throughout the cycle as seen therein.

Figure 1.2Contaminant entry into the water cycle.

Water bodies continually accumulate various contaminants from subsurface volcanoes, black smokers, riverine injection, and aquifer infiltration. The oceans become the ultimate “sink” or reservoir for pollutants. They include reduced sulfur gases, a multitude of hydrocarbon compounds, methane, soils, silts, salts, and man-made chemicals. Evaporation drives off vapors, primarily water.

Once in the atmosphere condensing water droplets absorb anthropogenic gases (NOx, SOx, and particulate matter—primarily from fuel combustion), salts from sea spray, mineral dusts, and salts from transcontinental soil movement. Figure 1.3 shows a cloud of soils and dust from the Sahara Desert moving toward South America.

Figure 1.3Transcontinental soils from the Sahara Desert.

Precipitation—with the associated contaminants—is deposited in both solid and liquid phases.

Solid phase precipitation (i.e., ice, hail, and snow) becomes a large repository of natural and man-made dustfalls throughout the winter months. In the high latitudes of the United States and developed countries there is also the addition of snow melt chemicals, salts, and sands for road safety. These become a problem when spring arrives melting ice and snow and releasing these materials.

The liquid phase begins collecting contaminants during rainfall upon various surfaces and runoff from roofs, roads, fields, fens, factories, fences, and farms. During river and stream flows, natural and crustal soils from surface erosion add salts and silt to discharges.

The contaminants include elements (most of the metals in the periodic chart), various natural organic compounds such as metabolic breakdown compounds from decaying tissues, humic substances, tannins, crustal soils, and man-made chemicals such as pesticides. These are the contaminants of concern as they impact water resources used for drinking, bathing, crops, recreation, fisheries, and their habitats.

Ancient Times

Earliest Efforts at Managing Water

The ancient civilizations of the Middle East and Asia appeared following the Ice Age. Dating back to about 3000 bc, these include the lands of Sumer, Akkad, ancient Egypt, Babylon, the Harappan civilization of the Indus valley, and those of the Yangtze and Yellow River valleys. These civilizations all struggl...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Contents
• Preface
• Acknowledgments
• Author
• Chapter 1: Introduction to Stormwater Management
• Chapter 2: Nature and Impacts of Stormwater Quality
• Chapter 3: Markers and Measures of Water Quality
• Chapter 4: Stormwater Sources and Contaminants
• Chapter 5: Stormwater Laws and Regulations
• Chapter 6: Management of Point Sources
• Chapter 7: Management of Construction and Temporary Sources
• Chapter 8: Urban and Area Source BMPs
• Chapter 9: Stormwater Treatment Systems
• Chapter 10: Emerging Issues in Stormwater Quality
• Glossary
• Appendix
• Index