The Effect of Channelization on Factors of Habitat Quality in Big Chico Creek
Bobby and Gracie
gbirdwell@csuchico.edu
rbbanta-green@csuchico.edu
Channelization of streams has become a trend in cities and agricultural areas where human involvement is altering the landscape, and therefore the quality of the habitats it provides. The artificial narrowing of stream channels can have impacts on the sediment distribution, available oxygen, and acidity of the water. Organisms relying on these habitats can be sensitive to changes in these factors, which is why it’s important to understand how human interaction can have an impact.
Channelization can include narrowing, straightening, and embanking streams in order to control the behavior of rivers and streams for the benefit of humans. Cities may channelize streams as they see fit for the convenience and benefit of those living there. While there are benefits for humans, the altering of streams and rivers can have major impacts on the health and status of wildlife. This is crucial to consider as certain species rely heavily on their specific environment. Shifts in dissolved oxygen, acidity, and sediment distribution can affect how animals find food, interact with predators and/or prey, and more. Changing these things has been shown to have detrimental impacts on some species that if lost, may cause much more grief for humans than we realize. In fact, certain species are already endangered. Many stream and river fish, like salmon and trout, are very economically important to the fishing industry. Once they are lost, those species can never be recreated and we have lost that resource forever. As these trends continue, it could lead to the losses both on a greater economic level and individual level for the many that rely on fishing for their livelihoods.
Aquatic animal species require certain levels of available oxygen to stay healthy long enough to reproduce. Too much oxygen can allow for harmful algae to bloom and kill endangered fish. While an environment that lacks oxygen makes survival an impossibility. Different animals require different amounts of oxygen. Fish require an highly oxygenated environment compared to other aquatic animal and plant species, making them especially sensitive to environmental change. Oxygen availability is not the only determinant of aquatic habitat health. Human behavior has also increased aquatic acidity, which has a dramatic effect on the health of important fish species such as trout and salmon.
Aquatic acidity change is one of the greatest threats to commercial and endangered fish species such as trout and salmon. An increase in acidity hurts these important and endangered fish at all stages of their life. An increase in acidity decreases the survival rate of eggs and young fish. This leads to a significant population decrease over time. An increase in aquatic acidity also kills many of the aquatic insects that commercial and endangered fish species rely on for food. Changes in aquatic acidity overtime lead to a decrease in the survival of commercial fish at all levels of their development, leading to hardship for people and economies that rely on these endangered species to survive. Channelization also has an effect on the health creek bed habitat.
Aquatic animals, especially shellfish and young trout and salmon, require a diversity of stream bed habitat to move up and down stream and reproduce. Channelization increases water velocity, in turn washing larger sediments such as cobble and boulders downstream, which animals use as spawning grounds and resting areas. Fish require larger sediment types to protect them as they fight the current to reach their spawning grounds. A decrease in available protective habitat can lead fish to run out of energy and die before they are able to reproduce. And a lack of proper sediment diversity leads to trout and salmon eggs being washed downstream and consumed before they can hatch. We used these environmental factors to assess the current habitat health of a channelized urban creek in rural California.
To further understand the effects of human impact, we decided to investigate how channelization affects the habitat quality of Big Chico Creek in Chico, CA. Over the course of several days we measured dissolved oxygen levels, pH levels, and sediment distribution of the creek. Collecting this data for sites upstream and downstream from the channel, as well as within the channel allowed us to assess the impact of this structure on the creek. We found that the channel does cause a shift in the important aspects of stream health detailed above. Therefore, the channelization of Big Chico Creek makes it a lower quality habitat for aquatic species. This is important to recognize because the valuable biodiversity of Northern California relies on delicate habitats like this, which can be changed so greatly by human interference.