Hendrickson Marsh is more than just the water of the marshland. It has a combination of highlands or grasses and various food plots planted each fall and winter specifically for use in the wild.
The 8,000-hectare catchment area contributes to the runoff that is fed into the basin. The area is managed by the Iowa DNR Wildlife Bureau, with offices at the Boone Research Station in Ledges State Park. Joshua Gansen is the conservation biologist who oversees this area and many other natural areas in central Iowa.
Hendrickson Marsh is not a massive wetland complex compared to other state sites in north central Iowa. However, it is an important ‘step up’ every spring and autumn when the migration of shorebirds and waterfowl takes on a new accent. It is a matter of timing for these migratory birds to find a stopping point to rest and eat before continuing their journey.
This 851-acre area is owned by the state of Iowa. It is located in the extreme southeast corner of Story County and a small portion of the southwest corner of Marshall County. This landform site has its geological origins as a result of the last glacial maximum, the Wisconsin System, in which a lobe of the Wisconsin Glacier penetrated into north central Iowa.
At the eastern edge of this glacial ice, the lateral moraine, a large segment of an ice block that separated from the glacier about 15,000 years ago during its retreat (melting phase). On the bet card, look for the small dot next to what is now Hendrickson Marsh.
This block of ice, filled with rocks, silt, soil and crushed glacial ice into pre-soil mixtures, remained stranded and away from the rest of the retreating glacial ice. However, it was not separated from the meltwater outflow from the glacier and from the ice block itself.
What geologists theorize that happened is that this large block of ice was stranded to just sit there and melt into place. As it melted, all kinds of debris came out of the ice to surround it and in the process left a ring of parent material soils around the ice block.
Finally, when all the ice melted, a shallow depression was left with plenty of shallow standing water. For a long time, a natural outlet was found through the water. That eventually joined and became what we now know as Clear Creek.
A little more about the PPR – Prairie Pothole Region – is in order. It covers a vast area of southern Canada, parts of Montana, North and South Dakota, western Minnesota, and north central Iowa. Many shallow wetlands are characteristic of this landscape.
Some are ephemeral wetlands and others are small to medium-sized lakes. These lands also have an icy history of soil deposits on which prairie grasses grew in the deep, rich soils, the foundations for some of North America’s most productive farmlands.
During years of abundant rainfall, many of these former wetland depressions in the landscape refill with temporary and in some cases permanent water. If that happens during waterfowl migration, the stage will be set for many wetland sites for wildlife to use.
Hendrickson Marsh is a management challenge. The large catchment area can and contributes to abundant watering if sufficient rainfall occurs. The other side of this coin is drought-like drier years.
Biologists try to retain the water at different levels by operating the gate openings at the control structure and the dam. If the idea is to lower the water in the basin to grow aquatic plants and emerging vegetation, a lack of rain or too much rain can spoil administrators’ plans.
But sometimes the rainfall and good timing coincide to provide the right mix of water levels. Fall waterfowl hunters look for those opportunities where there is just enough water left for duck boats to use, and the water is still shallow enough to grow emerging vegetation that feeds ducks and geese.
Hendrickson Marsh was purchased by the State of Iowa (Conservation Commission) in the mid-1960s. Prior to the acquisition, the area was known locally as Kimberly Marsh. The natural wetland habitats brought hunters to the area.
Once purchased by the state, a dam and water control gate system was designed and construction was completed in 1968. The area was given its new official name because of George Hendrickson, a professor of wildlife management at Iowa State University. On June 13, 1970, a dedication ceremony was held to officially name the area Hendrickson Marsh.
Plans for an improved water gate and drainage installation have been established for decades. Due to funding issues, those updates were never released. If these improvements were made, the water levels at Hendrickson could be better managed with suction capacity from above rather than below.
Those large metal gates now in place, when opened, take water out of the bottom, an undesirable situation, allowing shaggy fish to enter the basin as well. Rough fish can be a huge problem as they disturb the bottom of the lake as they feed, creating murky water, which in turn doesn’t let sunlight through.
Rough fish cause water quality problems. Natural drought conditions sometimes favor managers with little to very little water, killing unwanted fish populations. One thing about wetland complexes is that there will be years of too much rain – just the right amount or too little. Those natural cycles have to be fought year after year.
During this summer, a kayak or canoe adventure can be arranged in Hendrickson if you prefer. An excellent boat ramp and parking lot are located southwest of the County Line Bridge on Arney Avenue.
From Rhodes, head west for two miles on the E-63 state road, then turn north onto Arney Ave approximately half a mile. The parking lot will be on the west side of this provincial road. Discover and enjoy.
Summer season is here, arrived a few days ago on June 21st. Long day lengths mark this time as our Earth’s northern hemisphere is tilted toward the sun. This allows maximum and more direct solar radiation to penetrate the atmosphere.
In the southern hemisphere, the exact opposite happens, but it is our summer season when the maximum photosynthesis takes place by all kinds of plants. Those plants use carbon dioxide to live and thrive, and they return oxygen to the air mix we breathe.
Our longest days were from June 18-24 at 15 hours and 15 minutes. From now until December 21, the day length will gradually shorten, a fact that you no doubt already know. As one travels north in the Northern Hemisphere, the maximum day length gets longer and longer until one gets to the Arctic Circle, a point on the Earth’s curvature where the sun never sets below the horizon, but only touches it briefly. Our friends who lived and worked in Fairbanks, AK, had a daylength of 22 hours and 2 minutes on June 21.
The sunrise was at 2:53 AM and the sunset was 55 minutes past midnight. Reading a book or newspaper outside at midnight in Fairbanks is common.
For us Earthlings, summer is picnic time, outdoor adventure, carnival time, camping or fishing and time for visits to pools in local communities. The heat of summer is the opposite of heady cold and snowy winter conditions.
So while summer is here, adapt to it, enjoy it and relax. Take a vacation to one of the four corners of Iowa to learn what Mother Nature has to offer. Don’t forget to save a campfire-cooked hot dog for fido the dog.
Garry Brandenburg is the retired director of the Marshall County Conservation Board. He is a graduate of Iowa State University with a BS degree in Fish & Wildlife Biology.
Contact him at:
PO Box 96
Albion, IA 50005