Lazy summer, lazy river

T-R PHOTO BY GARRY BRANDENBURG The Iowa River courses through Marshall County for about 29 miles from the Hardin County line south and southeastward past Three Bridges County Park before crossing into Tama County. iewed today is only one small portion of the river between Timmons Grove and the highway 330 bridge (top) and the future bike trail bridge (bottom). Low river flow levels all summer have allowed many sand bars to become exposed, some long enough for green vegetation to grow on them.Canoeists and kayakers should find the river at this time as a fun place to paddle from put-in point to a designated take-out destination.

The IOWA RIVER just keeps poking along, steadily and silently giving an outlet to surface water runoff and ground water table seepage. Granted, this summers lack of significant rain has not added appreciable amounts of runoff water. From its headwaters at Crystal Lake in Hancock County to the mouth of the Iowa River 323 miles later near the City of Oakville at the Mississippi River, the watershed adds numerous tributaries small and large adding water to the system. The size of the river channel gradually grows in response to all of the additional water sources, a natural by product of physics that gets tested every time big rainfall events put too much water on the land.

In Marshall County there are three man-made dams across the Iowa River to note if you are a canoeists or kayaker. The first one in a low head dam at North Center Street at the river bridge. It is visible now due to low water flow. Standing on the bridge sidewalk, you can look down and view a flat concrete structure that is somewhat broken but still intact enough to hold a small head of water above it. At present there is a narrow slipway where a canoe or kayak can easily pass … if the people in the watercraft know how to properly steer the craft. If not, the flat dam top can make an easy point to pull along side for a portage.

I’ll make this observation about low head dams: Never assume them to be safe, just dangerous at a different level. Canoeists or kayakers enjoy the water and leisurely paddles. But if you make a mistake, river water may kill you for your lack of respect to its current and power. However, as water levels rise, their power increases exponentially way beyond the muscle power of even the strongest person. Low water flows may appear sublime and tempting and yes it is safer. Know what you are doing and know how to stay safe.

The second dam is at the northeast edge of Riverview Park. Here a few decades ago, a large 30 inch diameter pipe peppered with 4 inch holes was laid across the channel. Then large rip-rap rocks were placed above, and along both sides of the pipe. Its purpose was and is a part of the treatment plant operation and improved ammonia dispersal. The result is a small white-water dam when the river is low. Paddlers should automatically assume a portage of this dam, using the south edge to walk you watercraft around the rocks.

A third dam, or what is left of it, is at Three Bridges County Park. A long time ago there was a limestone rock dam here built by pioneers. It deflected water to the south and past two huge water wheels of a mill. Water power turned the wheels which spun huge timber frame axles and gears to move concrete mill stones. Farmer’s grains added to the mill stones was ground into flour-like size particles. The mill building has been long gone. What is left are a few of the foundation remnants and the twin arches where water from the river entered the mill. The mill foundation can easily be seen if one parks your car near the south end of the old river bridge. A walk onto the bridge lets you look down at the rapids, water bubbling over the limestone bases of the former dam. This set of rapids can be safely passed by canoe or kayak. The exit boat ramp is only 100 yards downstream on the south shore.

I’ll mention one other “dam”, actually it is a natural bedrock ledge or series of shallow bedrock exposures. It’s location is upstream from the Liscomb river bridge, or downstream from the Hardin County line about one-half mile. For canoeists gliding along with the current, you will hear the water bubbling over the rocks, you will see the small white-water effect, and you will look for a shallow “v” shape in the water flow to point the canoe into. This is usually the deepest water sufficient to allow the canoe hull to pass over. I learned of this bedrock ledge from Soil Conservation Scientist Norm Helzer way back in the 1980’s when an update to the Marshall County Soil Survey was being tabulated.

During moderate to high flow times when the river is moving fast, all of these dams may disappear at the surface. Their power below the foot of each dam has not disappeared. It lingers and retains its power to grab and hold onto things including people. Now that the river flow is very low, all of these dams are visible. Check them out carefully of course. Enjoy your summer time river adventures.

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Have you ever heard of a shore bird species called the BAR-TAILED GODWIT? Neither had I until this weekend. Avid birders from Iowa and the entire United States were taking note of a sighting of this species at Lake Red Rock’s mud flat area known locally as Pinchey Bottoms. This is in Marion County. OK, next question is so what? Well folks, this bird is way off its usual course and migration route. How far off? Well let’s say only half a world off.

Here are the facts. This species of shore bird nests along the western coastline of Alaska. Then each fall, when it decides to begin its migration, it will fly south southwest for over 7,000 mile across the open Pacific Ocean for a non-stop flight all the way to New Zealand. This species does so without any breaks or rest times, no sleep and no additional food. Incredible! The journey takes eight days. It never seems to get lost … until one bird shows up at Lake Red Rock.

The Bar-tailed Godwit is an efficient user of its energy supply, way more efficient than any aircraft designed and built by man. Professor of Ecology Anders Hedenstrom of Lund University calculated that this species consumes 0.41 percent of its body weight each hour during the long flight. Incidently, this is low compared to other migrating birds. The Bar-tailed Godwit has the right ratio of body weight to size to be able to pull off this extraordinary feat of travel. An from an aerodynamic standpoint, the bird’s body shape allows for fast flight.

When its stay in New Zealand is over, and the time to return to Alaska nears, the migration route is not the same straight line route it took last fall. Instead it island hops, or should I say continent hops, first to Australia in March, then between April and early May will over Borneo on its way to southern Japan and Korea. May to June will see its migratory path continue along the coast of Siberia before arriving back to nesting sites in western Alaska.

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DEER licenses for resident Iowans went on sale Aug. 15. Statewide there are more than 700 vendors that sell licenses for fall DNR hunting seasons. Marshalltown City will also cooperate in its tenth year for urban archery deer hunting within the city limits. Qualified and certified archers will soon be taking a new proficiency test, obtaining a 2017-18 hunting permit from Parks and Recreation, and making purchases for in-city bow hunting. All across Iowa many large and medium cities have been active in urban deer hunts. It is a record of safety and a record of good response to help control urban deer populations. It works and works well.

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“There is no such thing on earth as an uninteresting subject; the only thing that can exist is an uninteresting person.”

— G. K. Chesterton,

writer and critic


Garry Brandenburg is a graduate of Iowa State University with BS degree in Fish & Wildlife Biology. He is the retired director of the Marshall County Conservation Board. Contact him at P.O. Box 96, Albion, IA 50005.