McGee Creek Cut-off, Unit B: Importance of Flood Connection
Over the last 100 years we have transformed Swampeast Missouri into today's widespread agricultural landscape. In so doing, we have largely disconnected the water from the land. Only during large rain events like the one we had this weekend are we reminded of this often underrated connection. The linkage between water and land is vastly important to wetland areas like Duck Creek. The flood frequency, timing and duration are what makes these areas so productive.
One of the goals of the renovation is to restore or mimic historic hydrologic regimes. One way to do this is to identify areas where we can reconnect to the watershed. Over the past few months we've met with biologists of various backgrounds (forestry, wildlife, waterfowl, private lands, fisheries and hydrology) within our agency and outside to discuss our options. One place where we all agree that a reconnection can be made is on the south side of Unit B. The old stream channel of McGee Creek runs through this portion of the area. On the northern end of the channel, a levee separates it and any flow from the current channelized portion of McGee Creek, which drains into Ditch 2. Two-thirds of the way down this old, cut-off slough, a road with a culvert pipe intersects the channel. The lower third of the old McGee Creek cut-off also runs into a road; however, it does receive some backwater flooding a couple times a year when Ditch 2 gets up.
Although the slough is largely disconnected from the watershed by levees and roads, it does capture water from rainfall and run-off from the immediately adjacent land. So at times, it does hold water and provides habitat for some animals to take advantage of. Last week, we sampled the cut-off slough in order to get an idea of the animal communities that are currently using it and how our renovation activities might impact them. We used a couple different sampling gears to do this (mini-fyke nets and seines).
What we found was a bunch of tadpoles (mostly chorus frogs) along with six different species of fish (primarily chain pickerel and slough darters), two turtle species (common snapping turtle and red-eared slider), two additional amphibian species (mole salamander larvae and central newts) and a slew of invertebrates (fingernail clams, dragonfly and beetle larvae and crayfish, to name a few).
First off, this was kind of cool to see critters using the slough even though the function (hydrologic connection) has been impaired for at least 60 years. Secondly, you often don't find certain amphibians (salamanders and newts) in the same habitat as fish because they usually end up being dinner for the fully aquatic predators, such as pickerel. Where we found the abundance of species was also interesting. Most of the fish (83 of the individuals) we caught were in the lower section of the slough that occasionally receives some backwater flooding. In the upper portion that is disconnected by the levee and the road, we caught only 18 fish.
Our findings confirm our past deliberations. Removing parts of the road and levee blocking the old channel will help restore a connection to this old channel during flood events. This connectivity will allow fish greater access and allow flood waters to spread out on public land, which will reduce the chance of flooding elsewhere on private land.
Many of our rivers and streams have been altered in order to manage the land more efficiently. Levees have been built to prevent flooding along these drainage networks. However, flooding is part of the natural system. By recognizing this reality and identifying locations where levees can be notched, we can dissipate floodwaters, which can potentially cause damage elsewhere. Small steps like these give nature a little room to breathe and private landowners a safety valve during these large rain events. Overall, strategically reconnecting water with the land allows the system to function better and helps everyone out in the long run.