Little Leading Creek Sediment Study

A project co-funded by the Ohio Department of Natural Resources

and Ohio Environmental Protection Agency

Co-PI with G. Riefler and B. Stuart

Introduction

Little Leading Creek, a tributary to Leading Creek, drains a twenty-four square mile watershed located primarily in Scipio and Rutland Townships, Meigs County, Ohio. A large portion of the streambed has been inundated with residual sand from hundreds of acres of abandoned strip-mined land, upland erosion from agriculture, and stream bank erosion. Sediment has significantly impacted fish and macro invertebrate habitat and has reduced the flow capacity of the channel, apparently increasing the frequency of road flooding in the area. The lower portion of Little Leading is inundated with up to several feet of sand. The frequency of flooding has increased in Rutland to the point that many homes have been raised or removed through FEMA. Although many residences are now protected, road flooding continues to be an issue.

The Leading Creek Improvement Plan (LCIP), completed in 1999 by Don Cherry et. al., indicates that the most negative environmental impacts in Little Leading Creek are due to past mining and poor agricultural practices, which would include high sediment depth in the channel, intermittent sediment toxicity, and high concentrations of metals. The LCIP ranks Little Leading Creek as the top priority in restoration of the main Leading Creek tributaries. Sedimentation is likely the strongest variable that prevents the stream from attaining Warm Water Habitat level.

The accumulation of sand in Little Leading Creek appears to have had a significant impact on the aquatic life in the creek, particularly fish. Excess sediment in the water column damages delicate gill tissue reducing the amount of oxygen intake into the body and reduces the fish's ability to see and catch food. Settled sediment fills the spaces between gravel and cobbles particles. This may destroy the habitat of bottom dwelling organisms which fish rely on for food, smother spawning gravels which kills eggs and fry in the gravel, and reduce sheltered areas which young fish need to survive. Bed substrate over most of Little Leading Creek is entirely composed of sand providing very poor habitat for macroinvertebrates and fish.

It is unclear where the sands that are constricting the lower portions of Little Leading Creek are originating from. Eroding land in the headwaters impacted from past surface mining may be a continuing source of sand to the creek. However, because mining operations have ceased and several reclamation projects have been completed, sediment sources from the abandoned mine lands (AML) may no longer exist. Rather, sediment in the channel and floodplain accumulated during the active surface mining that occurred in the 1950s may not yet be flushed from the watershed. Accumulation of sediments in the channel may have caused movement of the channel location, spreading sediment widely across the floodplain, raising the ground elevation and reducing the creek gradient. Even though the sediment sources may be eliminated, there are likely erosion and deposition zones within the creek, as the accumulated sediment continues to be redistributed throughout the creek. Further, cattle grazing directly along the creek banks may be adding significant quantities of sediments to the creek. All of these hypotheses will be tested in this study to determine where sediment is currently accumulated, where current erosion and deposition zones exist, what watershed sediment sources exist, and what the original source of accumulated sediment was. These results will be incorporated to understand sediment transport in Little Leading Creek, to predict future sediment movement, to determine sediment impact on flooding and fish habitat degradation, and to propose corrective actions.

One difficultly in understanding the movement of river sediment is the transient, random nature of sediment transport. It is estimated that 70% of sediment transport in rivers occurs during storm events (Yang, 1996), yet sampling during storm events is problematic. Each storm event has different characteristics that affect transport, so generalizations are difficult to make. Further, significant storms are difficult to predict, can be of short enough duration to limit the extent of sampling over an entire watershed, and sediment transport may vary significantly both in total load and particle distribution from the initial first flush of the storm to the time to concentration in the watershed. In this study, samples will be collected both during normal stream flow and several storm events to characterize the sediment sources and transport trends under a variety of flow conditions.