RESOLVING OBSTRUCTIONS

In pre-settlement years, early explorers and trappers had many fewer treefalls to contend with than we see in some of our creeks and rivers today. Rivers were more stable because the prairies absorbed most of the rainfall. Bank erosion was much less pronounced, and rivers and creeks were not downcut or incised into the surrounding landscape as deeply as today. Invasive tree and shrub species were not present, and seasonal prairie fires kept box elders, cottonwoods, and large willows out of the headwater creeks entirely. Unfortunately treefalls are a management issue today if a creek or river is to be used for a water trail. Once the significant task of cleaning treefalls out of a heavily laden creek or river system is accomplished, yearly maintenance is much easier. But occasional treefalls were nonetheless part of the habitat in presettlement times and did create habitat structure for macroinvertebrates, fish, and other animals. A water trail should be designed with the involvement of aquatic habitat specialists so that habitat value is retained, since high quality habitat is one of the best experiences to be gained from paddling a creek or river in the first place.

Beaver are probably here to stay, and their dams should not be unexpected on a paddling trip in smaller creeks. Beaver dams are usually not very high, but do demand some portaging experience as they occur unexpectedly and in locations where normal portaging on the creek bank may be difficult due to bank steepness or shrub growth. In most cases, these dams are very strong and can be stood upon to pull a canoe up and over. On small creeks used often by school or local neighborhoods, beaver dams should be removed.

Construction crews at highway bridges often place large rock in the creek below in order to create a rapid that prevents silt deposits from forming. Illegal dumping of rock and rubble into streams also occurs. Generally, a minor repositioning of the rocks to allow canoe or kayak passage is all that is needed, but permits from regulatory agencies or the road jurisdiction may be required. Rocky riffles and rapids have important benefits in creating habitat for macro-invertebrates and fish. In channelized creeks and rivers, these rock and rubble areas may be the only habitat structures in many miles for many fish species.

In general, creeks are deeper for a longer period of time in the spring when more rainfall events occur. Normal rainfall tapers off in August through October, so this is the seasonal low-flow period. Almost every creek in Northwest Indiana will rise rapidly after a thunderstorm or multi-day rain event, no matter what the season, because the landscape has been so drastically altered to drain rain rather than infiltrate it. Shallower creeks in the upper portion of any sub-watershed that may be excellent for paddling when water is seasonally higher, may not be useful during the seasonal low flow. This doesn’t mean they shouldn’t be considered part of a water trail system. It simply means that they are seasonally available.

Farther downstream, a creek with a high-quality natural structure (geomorphology) will have a continuous series of pools and riffles (shallows and deeper spots), which greatly increase fish diversity. With seasonal low flows however, paddlecraft passage is much more difficult – whereas a channelized creek with the same water flow might be available throughout the summer and fall.