Where Water Flows in the West
By Brett Bovee
()
About this ebook
Related to Where Water Flows in the West
Related ebooks
The World's Water 2008-2009: The Biennial Report on Freshwater Resources Rating: 0 out of 5 stars0 ratingsWACONOMICS: Redefining Water's Role in Our Economy Rating: 0 out of 5 stars0 ratingsThe Race to Protect Our Most Important Natural Resource: Water Rating: 0 out of 5 stars0 ratingsWater: The Elixir of Life Rating: 5 out of 5 stars5/5More Water, Less Meat? Rating: 0 out of 5 stars0 ratingsOn Water Rating: 0 out of 5 stars0 ratingsBoiling Point: Government Neglect, Corporate Abuse, and Canada’s Water Crisis Rating: 0 out of 5 stars0 ratingsBottled and Sold: The Story Behind Our Obsession with Bottled Water Rating: 4 out of 5 stars4/5Australia's Water Resources: From Use to Management Rating: 0 out of 5 stars0 ratingsThe Worth of Water: Designing Climate Resilient Rainwater Harvesting Systems Rating: 0 out of 5 stars0 ratingsWhose Water Is It, Anyway?: Taking Water Protection into Public Hands Rating: 5 out of 5 stars5/5The World's Water Volume 7: The Biennial Report on Freshwater Resources Rating: 0 out of 5 stars0 ratingsWinning the Water Wars: California can meet its water needs by promoting abundance rather than managing scarcity Rating: 0 out of 5 stars0 ratingsThe World's Water 2006-2007: The Biennial Report on Freshwater Resources Rating: 5 out of 5 stars5/5Water Markets: Priming the Invisible Pump Rating: 0 out of 5 stars0 ratingsPeak Water: How We Built Civilisation on Water and Drained the World Dry Rating: 0 out of 5 stars0 ratingsSustainable Water Management in Smallholder Farming: Theory and Practice Rating: 0 out of 5 stars0 ratingsYour Water Footprint: The Shocking Facts About How Much Water We Use to Make Everyday Products Rating: 4 out of 5 stars4/5Resilience Thinking: Sustaining Ecosystems and People in a Changing World Rating: 4 out of 5 stars4/5Water Resources Rating: 0 out of 5 stars0 ratingsThe State of the Earth: Environmental Challenges on the Road to 2100 Rating: 0 out of 5 stars0 ratingsHydrate the Earth Rating: 0 out of 5 stars0 ratingsWater 4.0: The Past, Present, and Future of the World's Most Vital Resource Rating: 4 out of 5 stars4/5Planet Water: Investing in the World's Most Valuable Resource Rating: 5 out of 5 stars5/5Water And Man An Inseparable Pair Rating: 0 out of 5 stars0 ratingsThe Fight for Conservation Rating: 0 out of 5 stars0 ratingsThe Practical Preppers Complete Guide to Disaster Preparedness Rating: 2 out of 5 stars2/5Water Ethics: Foundational Readings for Students and Professionals Rating: 0 out of 5 stars0 ratingsFrom Ground Water to Grass Roots: Two Small Towns —One Large Corporation Rating: 0 out of 5 stars0 ratingsCoastal Waters of the World: Trends, Threats, and Strategies Rating: 0 out of 5 stars0 ratings
Earth Sciences For You
I Contain Multitudes: The Microbes Within Us and a Grander View of Life Rating: 4 out of 5 stars4/5The Witch's Yearbook: Spells, Stones, Tools and Rituals for a Year of Modern Magic Rating: 5 out of 5 stars5/5Norwegian Wood: Chopping, Stacking, and Drying Wood the Scandinavian Way Rating: 4 out of 5 stars4/5Nuclear War Survival Skills: Lifesaving Nuclear Facts and Self-Help Instructions Rating: 4 out of 5 stars4/5Foraging for Survival: Edible Wild Plants of North America Rating: 0 out of 5 stars0 ratingsSAS Survival Handbook, Third Edition: The Ultimate Guide to Surviving Anywhere Rating: 4 out of 5 stars4/5Mother of God: An Extraordinary Journey into the Uncharted Tributaries of the Western Amazon Rating: 4 out of 5 stars4/5Rockhounding for Beginners: Your Comprehensive Guide to Finding and Collecting Precious Minerals, Gems, Geodes, & More Rating: 0 out of 5 stars0 ratingsBushcraft Basics: A Common Sense Wilderness Survival Handbook Rating: 0 out of 5 stars0 ratingsThe Finest Hours: The True Story of the U.S. Coast Guard's Most Daring Sea Rescue Rating: 4 out of 5 stars4/5The Rise and Fall of the Dinosaurs: A New History of a Lost World Rating: 4 out of 5 stars4/51 Dead in Attic: After Katrina Rating: 4 out of 5 stars4/5Five Acres and Independence Rating: 4 out of 5 stars4/5A Fire Story: A Graphic Memoir Rating: 4 out of 5 stars4/5The Phantom Atlas: The Greatest Myths, Lies and Blunders on Maps Rating: 4 out of 5 stars4/5Young Men and Fire Rating: 4 out of 5 stars4/5Being Human: Life Lessons from the Frontiers of Science (Transcript) Rating: 4 out of 5 stars4/5Answers to Questions You've Never Asked: Explaining the 'What If' in Science, Geography and the Absurd Rating: 3 out of 5 stars3/5The Pocket Guide to Prepping Supplies: More Than 200 Items You Can?t Be Without Rating: 5 out of 5 stars5/5Exploring the Geology of the Carolinas: A Field Guide to Favorite Places from Chimney Rock to Charleston Rating: 4 out of 5 stars4/5Rocks and Minerals Rating: 4 out of 5 stars4/5Southwest Treasure Hunter's Gem and Mineral Guide (6th Edition): Where and How to Dig, Pan and Mine Your Own Gems and Minerals Rating: 0 out of 5 stars0 ratingsSummary of Bruce H. Lipton's The Biology of Belief 10th Anniversary Edition Rating: 5 out of 5 stars5/5Devil's Gate: Brigham Young and the Great Mormon Handcart Tragedy Rating: 4 out of 5 stars4/5Infinity in the Palm of Your Hand: Fifty Wonders That Reveal an Extraordinary Universe Rating: 4 out of 5 stars4/5Mind of the Raven: Investigations and Adventures with Wolf-Birds Rating: 4 out of 5 stars4/5The Year Without Summer: 1816 and the Volcano That Darkened the World and Changed History Rating: 3 out of 5 stars3/5
Reviews for Where Water Flows in the West
0 ratings0 reviews
Book preview
Where Water Flows in the West - Brett Bovee
topic.
Chapter 1: The Science of Water Flows
A journey to understand water flow in the West must start somewhere, and this book starts with water in its natural state. It seems obvious to start here, and to understand the unobstructed conditions before one comprehends what we have done to modify the flow of water to meet our demands. The science of water flow provides a good foundation because although we have certainly made a lot of modifications, natural flows still describe a lot of what we see in the West. This chapter provides some of the basic ideas behind the movement of water; and if I had to summarize the science of water flow, it would simply be that water has a persistent desire to fall downhill.
Hydrologic Cycle
Rivers are one of nature’s most impressive and inspiring features. They are destinations for our travels, focal points of our memories, and subjects of our books. Rivers are also what most often come to mind when we think of flowing water; but the truth is that water is flowing all around us, under our feet and in the air. Rivers are only the most visible piece of a much larger cycle of water.
It is strangely comforting to be reminded that water on earth is not created or destroyed – it simply moves around¹⁸. Any standard hydrology textbook provides an illustration of the various parts of the ever-continuous hydrologic (or water) cycle, and a typical illustration is shown in Figure 1.1. To understand our relationship with water, it is helpful to divide this cycle into three categories: (1) water that we can see without effort, such as rainfall and river flows; (2) water that is visible if we go looking for it, such as groundwater and soil moisture; and (3) invisible water, such as water vapor in the air. We have managed and monitored the first category for a very long time, evidently since at least 3000 B.C¹⁹. We have done the same for the second category since about the middle of the 20th century (in the Western U.S. at least²⁰) and are continuing to get better at it. We have often considered the last category as lost
water, because we are fairly incapable of managing it even if great expense is made to monitor it.
The hydrologic cycle describes the movement of water between phases, with each phase representing either a relatively temporary or long-term state. Phases of the hydrologic cycle include rain, rivers, groundwater, water vapor and clouds, large water bodies, and others. Rivers are a temporary state for water, linking rainfall on the land surface with oceans and other large water bodies. When water is said to be lost, it has simply transformed into a different state within this overall cycle and is only lost to the extent that society cannot really utilize it anymore.
Although rivers and streams make up a relatively small volume (less than ten percent) of the total combined flow in the global water cycle, they remain the focal point of water use and management because they are the terrestrial portion of the cycle on which we are reliant. Rainfall over the world’s oceans is almost four times greater than rainfall over land, but rainfall over land creates rivers, which are a unique and vital resource for us living on the land.
Figure 1.1: Hydrologic Cycle
Comment: Figure from W. Brutsaert. Hydrology: An Introduction. Cambridge University Press. 2005. Notice the counter-clockwise circulation of water flow in the figure from water vapor in clouds to precipitation, to runoff & infiltration, to evaporation & transpiration, and back to clouds. This circulation represents the hydrologic cycle.
This chapter explores the natural flow of water from rainfall to river mouths and coastal estuaries. The exploration starts with why rain falls where it does in the West, follows the fallen rain as it takes one of several routes to become river flow or groundwater, and follows the flow downhill until it reaches the ocean.
Rivers are borne from precipitation, which is a term used to define all types of water falling from the sky, such as rain, snow, sleet, hail, and others. What is lacking in the Figure 1.1 illustration, and what creates water management and conflict hotspots in the West, is the spatial variability in this cycle, and in particular precipitation. Precipitation does not fall uniformly across land masses, creating rain forests in some areas and deserts in others. Most of the Western U.S. is considered semi-arid, meaning that it receives between 10 and 20 inches of precipitation per year. But variations in precipitation are as boldly evident in the West as they are elsewhere in the world. The green lush environment of the Pacific Northwest coast is so very different than the desert landscape of the Southwest.
For many reasons, precipitation can be viewed as a master feature of hydrology which defines the local environment. Plants, animals, cultures, and (long-term) economies are often dictated by how much rain falls at a given location. Figure 1.2 shows a map of average annual precipitation for the United States. This map explains so much of what we see on a cross-country road trip. The Eastern forests, great Midwest plains, Southern bayous, snowcapped Rockies, Western rangelands, and Southwest deserts are all explained, at least in part, by the amount of rainfall. Considering its significance to how rivers are born, and ultimately how much water is available, the next section will discuss climate patterns in the Western U.S. with a focus on precipitation.
Comment: Map produced by the Oregon Climate Service using PRISM data. Oregon State University. PRISM Climate Group. http://prism.oregonstate.edu/. PRISM is a precipitation mapping tool that stands for Parameter-elevation Relationships on Independent Slopes Model.. Some of the more interesting observations are found: (1) in the Midwest states going from 40 inches in the eastern parts to 15 inches in the western parts, which corresponds to the gradual rise in land elevation and rain shadow effects of the Rocky Mountains; (2) in mountainous states with over 40 inches at high elevations down to less than 10 inches at lower elevations; (3) in the coastal Pacific Northwest receiving around 100 inches; and (4) in the far Southwest receiving less than 5 inches.
Western Climate
For water science, climate is a critical subject because it helps explain rainfall amounts, and rainfall amounts largely explain the amount of water that nature provides for a given location. Climate science aims to explain why it rains 10 inches one year, and 30 inches the next year; or why one area of the West is a desert while another area is a rain forest.
To understand typical climate patterns, one first has to take a few thousand steps back and look at large air masses that exist in the atmosphere. An air mass represents a large pocket of air that sits in a particular location long enough to acquire the temperature and humidity properties of the surface at that location. Around North America, there are seven dominant air masses that affect climate. At the intersection of the polar air masses to the north and the tropical air masses to the south, patterns of air movement known as jet streams develop that drive dominant weather patterns in the Western U.S.
The jet stream is often discussed in weather reports, usually depicted as a superhighway for winter storms. A jet stream is a fast flowing current of air in the upper atmosphere that moves west to east in North America. Actually, most air currents in the continental U.S. move in a west to east direction, which itself explains a lot of the dominant precipitation patterns. The mid-latitude or polar jet stream typically moves across Canada in the summer months and dips down into the continental U.S. in the winter months. A separate sub-tropical jet stream is located south of the continental U.S. The jet stream pathway is sinuous, with ridges and troughs; and this pathway contributes to the formation and path of low pressure systems.
A basic principle of climate is that warm air rises and cool air sinks, due to density differences. On a large scale of hundreds of square miles, this principle leads to the formation of high pressure (cool air sinking) and low pressure (warm air rising) areas. Low pressure systems are the dominant weather driver in the continental U.S. The location and movement of these low and high pressure systems can be quite variable and are often shown on weather maps to describe the short-term forecast.
Although variations exist, a dominant trend in the winter season is for a low pressure system to develop in the Pacific Ocean off of the western coast of North America, and then to move into the mainland U.S. following the jet stream pathway. This low pressure system dissipates, or breaks apart, over the Rocky Mountains, and then reforms on the eastern side of the mountains and continues across the Midwest towards the Great Lakes. In the summer months, low pressure systems often develop at more northern latitudes near the Canadian border, and high pressure systems (associated with nice weather and a lack of rainfall) dominate much of the Western U.S. Figure 1.3 illustrates some dominant pressure systems for the winter and summer seasons.
A notable characteristic of this dominant low pressure movement track is its avoidance of the Southwest U.S., which has the effect of causing more arid conditions in this part of the country. You may have heard of a weather pattern called El Nino, and perhaps you have even heard of its opposite twin sister, La Nina²¹. These terms refer to the relative latitude (north / south position) at which winter low pressure systems form in the Pacific and move inland across the Western U.S. A strong El Nino signal means that the low pressure systems are expected to form at a more southerly latitude, roughly west of southern California, and move east into the U.S. over the Southwest. The more southern presence of these low pressure systems means that El Nino years bring more winter-time precipitation to the Southwest region. Just the opposite happens in La Nina situations. A strong La Nina signal means that the low pressure systems are expected to form at a more northerly latitude, and move into the West around the Seattle and Vancouver area. La Nina years usually produce more rain for the northern areas of the West, and drought conditions in the Southwest.
The reason that the location of low pressure systems is important is that weather fronts form where low and high pressure areas meet, and weather fronts often produce precipitation. Weather fronts form at the intersection of two air masses of different temperatures, often as a result of low pressure systems moving air masses around in a counter-clockwise direction. Frontal systems are characterized by the transition from one air mass to another and named after the incoming air mass properties. Cold fronts and warm fronts are often associated with precipitation events.
Unlike weather fronts, which cover a large area of usually several hundred square miles, thunderstorms can be localized and caused by small-scale convection (or rising) of air. Convective rain clouds are formed as warm, moist air from the land surface rises up and into the cooler atmosphere, causing water condensation and eventually precipitation. Convective precipitation is typically of short duration with rapidly changing intensity since the clouds have a limited spatial extent.
The same convective air movements that cause thunderstorms can also produce monsoon seasons, particularly in the Southwest. A monsoon condition is simply when the land surface is heated by the sun, causing warm air near the surface to rise, and then resulting in moist air from the ocean or other large water body to move inland to replace the lifted air. This moist air from the ocean causes widespread rain or more commonly localized thunderstorm development in July and August, particularly in the Southwest²².
The map in Figure 1.2 also shows that precipitation in the Western U.S. is largely defined by elevation. Higher elevation areas receive more precipitation than lower elevation areas because of orographic effects. Orographic rainfall effects simply mean that air cools and condenses as it rises, and if condensation is sufficient, then precipitation will occur. Higher elevations usually receive more rainfall because the air is cooler. Aspect, which refers to the cardinal direction, plays an important role when considering orographic effects. Air masses typically move west to east in the Western U.S. due to the dominant direction of the trade winds. When an eastern moving air mass encounters a mountain range, the air will lift, which in turn may cause condensation and precipitation on the western (or windward) aspect of the mountain range. As the air mass continues to move east, it has lost much of its water content, and dry conditions are often found on the eastern (or leeward) aspect of the mountain range. Figure 1.4 illustrates this orographic effect.
Figure 1.3: Typical Pressure Systems by Season
Comment: Low Pressure system follows the jet stream, dipping down into the U.S. during the winter and remaining high in Canada during the summer. El Nino conditions occur when the Low Pressure from the Pacific follows the more southerly track into the Western U.S.
Figure 1.4: Orographic Effects Causing Precipitation
Comment: Air cools and condenses as it rises over a mountain ridge, and the condensing water vapor forms rain clouds and precipitation. After the air has moved over the mountain, the air has lost much of its water vapor and is dry as it descends down the mountain. This process results in wet conditions on the windward (wind-facing) aspects of mountains and dry conditions on the leeward (downwind)