IOWA - Portrait of the Land - Water: A Life-Giving Cycle

iris
Blue flag iris

Water:
A Life-Giving
Cycle

Bottle gentian

Tree frog

Whether it comes from a sprinkle, a downpour, or a blizzard - a river, a lake, or an underground aquifer - water gives us life.

We might think first of water as an essential liquid that we must drink. Without it, we die. It's a critical, yet sometimes inconspicuous, part of our air, our land, our bodies. Likewise, our crops must have water to grow. And water drives the weather cycles: the winds, the rains, the storms, the clouds, the ever-changing warmth and cold that affect nearly everything we do.

This amazing little molecule, just one oxygen atom bonded with two hydrogen atoms, is priceless yet free. It falls from the sky for anyone to capture and use. Iowa annually receives about thirty-two inches of precipitation, enough to average two and one-half feet of water spread over the entire state, or enough to provide about 11 million gallons per person.

But where does all that water go? About two inches of our moisture evaporates from trees and plants before it can even reach the earth; it returns almost immediately to the atmosphere. Surprisingly little water, only about four inches of our total rain and snowfall, runs directly into our rivers and lakes. Another two inches soak into the groundwater system. The vast majority, about twenty-four inches or three-fourths of the water that falls, lingers temporarily in the soil where it sustains our bountiful crops and lush, green vegetation. Like living pumps, the plants draw the moisture from the soil, pull it through the roots, stems, and leaves, and process it into growing cells. That liberal water supply, along with our temperate climate, rich soil, and favorable slope of land, makes Iowa one of the most productive places on Earth.

Photo by Photographic Services, University of Iowa.

Photo by Photographic Services, University of Iowa.

Photo by Michael Bounk.

Water takes many forms,
such as gathering storm clouds,
rising water vapor, and dripping
cave stalactites.

Left: The chemical compostion
of cave formations provides clues
to past climatic conditions in Iowa.

To maintain the cycle, our land and atmosphere constantly recirculate and reuse that water. It rises into the air, through a thunderstorm, and back to earth. It is stored in shallow lakes and rivers and deep rock aquifers, soaked up by plants, gulped down by animals, season after season. We humans may interrupt the process as we borrow water for our own uses: drinking, sewage treatment, industry, recreation, and irrigation. But eventually the water cycle continues.

Our water resources also shape and beautify our landscape. Two of the nation's mightiest rivers, the Mississippi and Missouri, embrace Iowa's land. The giant watercourses run nearly 500 miles along our borders, covering more than 200,000 acres. Their history - of geologic spectacles, Indian cultures, early explorers, abundant wildlife, and industrial development - mirrors Iowa history. We revere those waters and the scenic valleys where they flow. But we also ask much of these places, for they sustain cities and industries; provide biological habitats; attract suburban developers; host greenbelt recreationists; yield sand, gravel, rock, and groundwater resources; and provide space for overflowing rivers.

We recognize, too, the way we've rebuilt those rivers for our own purposes. On the Mississippi, locks and dams, frequent dredging, and diversion dikes now maintain a passage deep enough for barge traffic. We have built a series of artificial pools joined by regulated channels, replacing the maze of wild chutes and sloughs that once wandered across the valley between the bluffs. Still, the Mississippi Valley remains rich in fish and waterfowl resources. Tourists seek its scenery and history. Boaters explore its islands and backwaters.

On the Missouri, however, engineers saved less of the original river. They built huge reservoirs to capture upstream snowmelt and straightened the meandering channel into a rock-lined canal. Now the Missouri, which once swelled across the bottomlands in the spring and slithered among sandbars in the summer, marches uniformly past our western border. Its water level rises and falls not so much with the upstream precipitation as with the computer-operated gates of dams in the Dakotas and Montana.

Between these two giants on Iowa's east and west coasts flows an incredible network of tributaries - more than 70,000 miles of tiny creeks, winding streams, and robust rivers. These valleys served as pathways for Indian travelers and fur trappers and European settlers. Railroads, highways, recreational trails, and greenbelts still follow the corridors. Cities have grown from the villages that first sprouted along the riverbanks. Through the decades, Iowans have plied the inland rivers in steamboats and harnessed their waters for power. Enterprising pioneers built more than 1.000 water-driven mills to grind wheat and saw lumber. We've dipped our drinking water from these streams, dumped our wastes into them, and fought their floods. We've straightened, dammed, canoed, and fished them. We've also built more than 25,000 bridges across them.

The water that feeds our streams also fills our lakes. In some of the forty-eight remaining glacial lakes, water lilies bloom in the shallows. Beds of aquatic plants often grow from the clear depths. Walleyes and perch sometimes prowl the gravel bars. Glacial boulders may ring the shorelines. More than 32,000 acres of water trace their origin to ice sheets that gouged these lake basins more than 12,000 years ago.

Not satisfied with the natural lakes, people have impounded another 148,000 acres of water to fill large reservoirs and artificial lakes built for recreation. These structures may have earthen dams, rip-rapped shorelines, and mud bottoms, but we're still fascinated by bodies of water. We love to swim and fish in them, to sail and ski upon them, and to build our houses beside them.

Drinking water from underground aquifers is used by 78 percent of Iowans. Photo by Paul VanDorpe.			Water sometimes cycles from the atmosphere back to Earth with a dramatic counterpoint. Photo by Photographic Services, University of Iowa.
		In its continuing cycle, water stops temporarily to encase a bittersweet vine in ice. Photo by Lowell Washburn.

Everybody likes lakes, it seems, but wetlands are another matter. Shallow marshes once teemed with birds, animals, and plant life, however their rich basins also became some of the richest cropland on Earth. And now, virtually all of the countless tiny ponds and potholes that once dotted Iowa have been drained and farmed. We've slowly come to recognize the value of wetlands, however. Marshes can slow floods, store water, provide wildlife habitat, neutralize pollutants, digest wastes, and trap sediment. To reap those benefits, government agencies and private landowners have built nearly 30,000 acres of artificial or restored marshes in recent years, doubling the acreage of remaining natural wetlands.

These aquatic ecosystems have an abundant array of plant and animal life. Algae drift in the water or cling to the rocks and submerged logs. Rooted plants sway in the current, reaching for the sunlight. Snails and caddisflies forage in the gravel. One-celled protozoans become food for water fleas, which in turn are eaten by dragonfly larvae, which are food for fish, which can be eaten by herons or by people.

Still, beneath all the marshes and land and lakes and rivers, seeping through gravel and rock, flows yet more water - Iowa's groundwater. It's mostly hidden from view, but groundwater from wells supplies the drinking water for 78 percent of Iowans. The rest drink surface water from lakes and streams. Groundwater occasionally bubbles up at springs or flows from artesian wells, such as the public well in Benson Park just west of Clarion. We drill wells to tap groundwater, and surface waters ever-so-slowly recharge it. Although often buried far underground, it's still vulnerable to pollution and much harder to clean up than water exposed to air and sunshine.

Focused as we are on the quantity of our water resources, Iowans must protect the quality as well. Before we began to exploit our landscape by plowing prairies, draining wetlands, grubbing out forests, straightening rivers, and developing lakeshores, our waters usually ran clear. Fish, mussels, aquatic birds, water-loving animals, and plant life thrived. Underground aquifers stored pristine water, and springs gushed with pure flows that had been filtered through layers of soil and rock.

But the purity of the water can be only as good as the integrity of the watershed, the land from which it flows. As we've changed the surface of the land, is it any wonder that people have muddied those waters? Where rainfall used to slowly ooze into marshes or trickle through prairie vegetation, the water now falls on crop ground across two-thirds of the state. Too often, the runoff rushes into rivers and streams, carrying with it topsoil and agricultural chemicals. Silt chokes fish and other aquatic life, clouds the water, and reduces the sunlight that reaches algae and submerged plants.

Iowa farmers annually apply more than 3 billion pounds of chemical fertilizers and 45 million pounds of pesticides to their corn and soybean fields. Should we be surprised, then, to learn that agricultural pesticides can be detected in nearly every sample of rainfall taken during the growing season and that the chemicals show up in 26 percent of groundwater samples and 78 percent of surface waters sampled? Scientists may differ on the impacts of agricultural chemicals on human health or the environment, but few dispute their wide dispersal.

Nitrogen from farm and lawn fertilizers, livestock manure, and municipal and industrial wastes also enter our land and rivers and eventually travel down the Mississippi River system. The accumulated discharges of these pollutants into the Gulf of Mexico have reduced the amount of oxygen there, causing the hypoxic zone, an area in the Gulf with very little aquatic life. Researchers have calculated that Iowa may contribute nearly 25 percent of the nitrates that the Mississippi delivers to the Gulf. Studies continue on the exact sources of the excess nitrogen, the long-term impacts, and strategies to reduce the nitrogen problem.

These waters contrast sharply with the confined flow and straightened channel of the Little Sioux River in Monona County. Photo by Clay Smith.

Natural meanders and oxbow lakes form riparian wetland habitat along the East Fork Des Moines River, in Kossuth County.
Photo by Lynn Betts.

Fortunately, our land has a tremendous capacity to filter out, neutralize, and recycle sediment and other effluents before they reach the water. Our water ecosystems also can purify many pollutants, but we must not overload these natural sanitation systems. For example, livestock manure can fertilize and enrich our farms. If the waste is spread too heavily on the land, however, or if it does not have time to decompose before rains wash it downstream, it can poison our streams. Discharges from factories, municipal sewage and private septic systems also may enter rivers, either intentionally or by accident.

Many Iowa streams and lakes fail to meet federal clean water standards. Problems range from silt to fertilizer to agricultural chemicals to industrial wastes to algae to sewage to livestock manure. We can't expect our waters to return to prehistoric purity, but how dirty is too dirty? In an agricultural state, how much can we minimize siltation? Should we tolerate some level of pollution from farm chemicals or manure? Shouldn't we be equally concerned about lawn chemicals and oil from vehicles that run off city streets, parking lots, or suburban lawns? Can our industries use our water, then return it to a river even cleaner than they found it? What if pollutants enter our groundwater supplies? How can we clean up those vital, vulnerable aquifers? And will we have enough pure water in the future? Can we use and reuse our precious water, then leave it clean and plentiful enough for others to use?

As we ponder these questions, we also should consider this reality - water, clean water, truly is our lifeblood.

Dark Sky - Canvasbacks � Maynard Reece

WHAT'S YOUR WATERSHED ADDRESS?

Essay by Larry A. Stone

Where do you live?

Besides having a street or county road address, we each live in a very distinct watershed. The land, like the back of a duck, sheds water. Rainwater and melting snow from the land around us run downhill. The water follows a specific path, flowing into a series of lakes, wetlands, and streams, in an ever-expanding link - ultimately to the sea.

Thus, the quality of our watershed determines the quality of our water. Larger watersheds will move more water. Certain soils filter water more completely, or erode more easily, than others. Steep slopes or paved parking lots speed runoff. Wetlands, forests, and farmland conservation retard the flow and reduce flooding.

We need to ask questions about the land that funnels our water to us. On its way, does our water flow through a park or a feedlot or a prairie or a housing development? How carefully do upstream neighbors dispose of their sewage, use pesticides, or recycle toxic wastes?

What about the water that leaves our property? Do we consider downstream friends when we maintain sewers or septic tanks, plant crops, fertilize lawns, dump garbage, wash cars, or discard household chemicals? Clean water starts with the small decisions we make in our own communities - in our watersheds.

Photo by Gary Hightshoe, Iowa State University		Photo by Roger Hill

Water is stored on the landscape in natural lakes, such as the rounded shores of Big Spirit, Marble, and Hottes, in Dickinson County (left) and by constructed embankments that form farm ponds (right).


Disastrous loss of property and life can occur when people live in a river's natural space. A river's timetable for large floods can overreach human life spans. Left photo by Lynn Betts and right photo by John Walkowiak.