INTRODUCTION

Historic use of Polychlorinated Biphenyl (PCB)-containing oils in equipment at a major steel manufacturing facility in southwestern Ohio ultimately led to PCB contamination in two small adjacent streams known as Dicks Creek and Monroe Ditch. Investigation and delineation by the facility’s contractors revealed numerous areas of stream sediment and floodplain soils with PCB concentrations ≥50 parts per million (ppm), requiring removal, management and disposal in accordance with requirements of the Toxic Substances Control Act (TSCA). Additional areas of elevated PCB concentrations in stream sediment below TSCA regulatory levels were also identified and required remediation. A Consent Decree became effective in 2006 and is the governing document for the permitted discharger to remediate, restore and monitor the streams. Remediation efforts, which included the dredge removal and disposal of sediment and floodplain soils over nearly four miles of stream, were completed in three phases during 2010, 2012, and 2013. Concurrent restoration activities involved both instream and riparian improvements were completed in November 2013.

The following provides a summary of remediation and restoration activities as well as presents the results from the first year of instream biological monitoring in Monroe Ditch and Reach 1 of Dicks Creek.

ACKNOWLEDGEMENTS

Jim Kemp, Louis Sanderson, Ken Cummings, James Fitzgerald, PJ Hilbert, Katie Jackson, Joe Vondruska, and Conrad Zack as well as the restoration design team of Biohabitats, Inc. for their assistance during this project.

STUDY AREA

• Dicks Creek and Monroe Ditch are small perennial streams in the Great Miami River watershed; largely urban/industrial land use.

• The Dicks Creek - modified, third order stream with a 1.88 km (1.17 mi) long monitoring reach and drainage area of 105.15 to 116.03 km2. Historic channelization had resulted in a wide, flat, flood-control channel within constructed levees/berms.

• The Monroe Ditch - modified, first order stream, 1.17 km (0.72 mi) long monitoring reach and drainage area of 6.73 to 7.90 km2. The stream had been relocated and straightened

CONCLUSIONS

The initial monitoring of Dicks Creek and Monroe Ditch suggests that the design objectives of the remediation and restoration have been met and are being maintained. It is expected that over time, additional improvements in the aquatic community will be observed.

REMEDIATION

• Pre-remediation delineation of the impacted areas and confirmatory sampling provided the opportunity to segregate, manage and dispose of removed wastes as TSCA vs. non-TSCA.

• Remediation and restoration were completed in three phases during calendar years 2010, 2012, and 2013.

INSTREAM MONITORING METHODS

• The fish and benthic macroinvertebrate communities along with aquatic habitat were monitored using Ohio EPA methods.

• Fish sampling involved wadeable electrofishing in 150-200 m zones.• Benthos were sampled with modified Hester-Dendy artificial

substrate samplers and qualitative samples.

Post Remediation and Restoration of Two Small Southwestern Ohio Streams Marty Sneen and Mary Lou Rochotte

EA Engineering, Science, & Technology, Inc., PBC and KEMRON Environmental Services, Inc.

RESTORATION

• Following remediation to pre-defined design surfaces and/or confirmatory sample-defined depths, restoration was completed to include placement of clean sediment and natural stream design elements.

• The restoration design had to work within the channelized footprint of the streams, which significantly limited the riparian corridor and ecological benefits.

• The stream was believed capable of building a natural channel over time. As was feasible, the restored channel was constructed to enhance sinuosity and support the natural restoration process.

• Sequences of pools and riffles were designed and installed using cross-channel large rock, braided berms, and woody debris.

• Invasive species were stripped out in the remediated floodplain and replaced with extensive plantings of native non-invasive species that are being aggressively managed via identification and removal of resurgent invasive plants.

Dicks Creek2014

After Remediation & Restoration

Monroe Ditch2014

DC1-4 DC2-1

MD2 MD3

RESULTSDicks Creek

• Based on the QHEI, habitat quality improved from Poor or Fair in 1987-2001 to Good or Excellent in 2014.

• Fish total species richness increased but not appreciably; however, notable compositional changes were observed:o Common carp among dominants 1987-2001; one individual in

2014.o Darters three species total 1987-2001; six species in 2014.o IBI and IWBmod historically Poor to Good; 2014 Fair to Very

Good.

• Benthos exhibited marked improvements:o Total taxa richness increased <50 taxa in1987-2001 to >70 taxa

in 2014.o EPT richness increased slightly but relative abundance increased

substantially.o Mean percent tolerant taxa decreased from 44% to 6%.o ICI scores increased from mostly Poor or Fair to Marginally Good

or Good.

Monroe Ditch

• QHEI scores improved from Fair or Good in 2006 to Excellent in 2014.

• Baseline fish and benthic data are not available; however, anecdotal observations by Ohio EPA and EA suggest the aquatic community within Monroe Ditch was historically very poor.

• IBI scores achieved an Exceptional narrative rating while ICI scores rated Good or Very Good.

Dicks Creek Reach 1 Average Pre and Post-

Remediation/Restoration Index Scores

Index 1987 – 2001 (n=10-14)

2014 (n=3)

QHEI 44.1 64.5

IBI 32 44

IWBmod 7.1 8.5

ICI 16 33

Dicks Creek2008

Before Remediation & Restoration

Monroe Ditch2006

DC1-4 DC2-1

MD2 MD3

During – 2012

Before - 2005

o Years 1 and 2: Dredging in the dry with by-pass pumping of impacted streams. Materials required discrete and separate management throughout remediation.

o Year 3: Dredging was conducted via hand-held small scale equipment, managed in GeoTubes®; deep water areas required use of certified divers. Low flow conditions mandated additional downstream check dams, sediment curtains and dredging methods modifications to achieve remedial objectives.

REMEDIATION (CONT.)

o In all, approximately 174,500 metric tons of sediment and floodplain soils were removed and properly disposed over nearly four miles of stream.

After - 2014

INSTREAM MONITORING METHODS (CONT.)

• Ohio EPA’s Qualitative Habitat Evaluation Index (QHEI) was used to assess aquatic habitat quality in each fish sampling zone.

• Analyses included the Index of Biotic Integrity (IBI) and modified Index of Well-Being (IWBmod) for fish and the Invertebrate Community Index (ICI) for benthos.

• Results were compared to existing ecoregional biocriteria as well as pre-remediation and restoration baseline data.