Officials from South Carolina Electric & Gas and the Saluda Shoals Park held a ribbon-cutting ceremony on Wednesday, July 27, 2011 to open a new display at the Saluda Shoals Environmental Education Center in Columbia. The center will show off archaeological artifacts found by S&ME’s Columbia office, on the river’s bank in recent years.

More than 37,000 artifacts have been found at a site near an abandoned tree house along the Saluda. Some tools found there are said to be among the oldest found in the U.S. and dating back 13,000 years.

SCE&G Saluda Shoals Exhibit Video

The project managed by Bill Green, Cultural Resources Manager and Principal Archeologist for the Columbia branch, involved data recovery excavations for client South Carolina Electric & Gas Company (SCE&G).

The excavations supported SCE&G’s relicensing of its Saluda Hydroelectric Project and dealt with mitigating effects of erosion on a part of the site located on private property. Green called the project a unique opportunity to investigate one of the state’s most important archeological sites containing thousands of artifacts dating from 13,500 to 700 years ago.

“Our excavations were among the largest, most comprehensive and deepest undertaken in the state,” Green said. The investigation required meticulous organization and problem-solving as many staff and specialists joined their skills to face multiple challenges, including a tropical storm that flooded excavations.

One challenge was to maintain superior standards of archaeological excavation and recording techniques, while complying with OSHA safety requirements. S&ME engineers and archaeologists jointly designed a plan allowing excavators to safely perform highly scientific investigations following both archaeological and engineering standards to complete one of South Carolina’s most complex archaeological projects.

Awards Won:
2011 NHA Outstanding Stewards of America’s Waterways Award

2010 Engineering Excellence Award judged tops in the Studies, Research and Consulting Engineering Services category in South Carolina.

S&ME Project Role

The power industry is challenged in managing coal combustion byproducts such as coal ash.  Traditionally, many power plants transport and manage coal ash by mixing it with water and sluicing it to ash basins.  Consistent with industry trends, Duke Energy (Duke) was transitioning from the ash basin approach to dry fly ash management at the Allen Steam Station in Belmont, North Carolina and needed a new landfill before start up of a new dry fly ash handling system.

Duke considered three locations for the landfill, two on-site and one off-site.  Major siting considerations included environmental impacts, engineering feasibility, economics, and community/regulatory acceptance.  The ideal location was a brownfield site adjacent to the steam station on a 65-acre ash basin retired in the 1970s.  However, this site posed numerous technical and regulatory challenges because the retired ash basin contained upwards of fifty feet of soft, wet, compressible sluiced ash.  The project was further challenged by intensified regulatory scrutiny imposed after the December 2008 failure of a Tennessee ash basin.

Duke awarded S&ME, Inc. (S&ME) a groundbreaking project to permit, design, and provide construction services for the new landfill over the retired ash basin.  S&ME permitting and design responsibilities included:

• • Conducting geologic/geotechnical site characterizations
• • Preparing a Site Study
• • Gaining a letter of Site Suitability from the North Carolina Department of Environment and Natural Resources (NCDENR)
• • Completing engineering design for the overall facility plan (landfill master plan)
• • Developing a detailed design for the first five-year development phase
• • Gaining the Permit to Construct.

Duke retained S&ME throughout project construction to prepare bid documents, solicit bids, and monitor, test, and document construction.  S&ME prepared construction documentation submittals to NCDENR gaining the facility’s Permit to Operate.

Other Consultants Role in the Project

S&ME subcontracted Perigon Engineering to provide electrical engineering design services and Pacific Engineering and Analysis to conduct site-specific, probabilistic seismic site response analyses.

Original and Innovative Application of New or Existing Techniques

Developing a new ash landfill over the retired ash basin posed numerous engineering and permitting challenges.  The retired ash basin covered approximately 65-acres and consisted of sluiced ash that was wet, compressible, and up to 50 feet thick.  The retired ash basin was bound by engineered earthen dikes and the site conditions were further complicated because it was located adjacent to the Catawba River.  This project illustrates innovative design in the engineering solutions developed to overcome the obstacles posed by the site.

One innovative solution was the settlement analysis.  North Carolina solid waste rules have strict requirements for post-settlement liner system slopes and vertical separation from groundwater.  Ordinarily, settlement is evaluated at a few locations of interest within the landfill.  S&ME developed a geographic information system (GIS) based settlement model that allowed us to evaluate settlement across the whole landfill footprint and optimize landfill grading design. S&ME combined classic geotechnical settlement formulas with detailed three-dimensional surfaces of the proposed landfill cover, liner, and subsurface stratigraphy using GIS to evaluate settlement on a one-foot grid spacing.  With the power of GIS software, we developed detailed surfaces showing post-settlement contours, slopes, and liner system separation from groundwater.

Settlement analysis results indicated settlement up to several feet.  To validate the settlement model and to better understand the settlement from overlying landfill construction, S&ME proposed an innovative, full-scale instrumented test fill program.  We designed a three-acre, twenty-foot tall test fill with redundant instrumentation to monitor settlement and groundwater response to loading.  Results revealed significant insight into the loading response indicating that: actual settlement was less than calculated; settlement occurred immediately and stopped after loading; and initial groundwater level increase dissipated shortly after loading.

S&ME’s ground-breaking settlement evaluation approach went far in alleviating regulatory concerns about developing over such challenging site conditions.

The project became the focus of greatly intensified scrutiny after the December 2008 failure of a Tennessee coal ash pond.  In response, S&ME conducted slope stability analyses and liquefaction potential evaluations to a level of detail far beyond that ordinarily required.  S&ME used site-specific, probabilistic, seismic site response analysis results for both seismic-slope stability analysis and to evaluate liquefaction potential.  Results indicated the proposed development would be stable and satisfied regulatory design criteria. Our approach was successful at gaining the approval of the NCDENR Dam Safety Section, which was retained by the Solid Waste Section to provide slope stability expertise.

In addition to the site’s challenging physical characteristics, the project posed regulatory challenges because such a facility had never been permitted in North Carolina and there was regulatory uncertainty related to developing and monitoring the new landfill separate from the underlying ash basin.  We overcame these regulatory challenges in part by designing a double-liner system allowing landfill monitoring separate from the underlying ash basin.  Double-liner systems are uncommon in ordinary landfill containment systems and provide a leak-detection zone to monitor leaking through the primary liner.

The double-liner system design required estimating a threshold action leakage rate to trigger regulatory response.  S&ME developed a two-step response action plan based on detailed engineering design analysis to calculate a threshold initial response leakage rate and a higher action leakage rate.  S&ME engaged regulators early and frequently during project design and we were able to negotiate an agreeable double liner system design approach and response action plan before design submittal.

Future Value to Engineering Profession

Our successful permitting, design, and construction of the new landfill over an existing ash basin established a significant North Carolina and Duke precedent. This design, consisting of a double-liner system located entirely over a brownfield site (retired ash basin) is a “first of its kind” in North Carolina and for Duke.  This project blazed a regulatory trail by successfully setting the permitting framework for similar developments.  This project blazed a technical trail by transferring ordinary and established design methods in a new and multifaceted way (GIS settlement model, full-scale test fill program, beyond-the-ordinary stability analyses, and novel double liner system design approach).

In fact, this project’s value to the engineering profession has been realized already since S&ME has successfully permitted and designed a second similar facility for Duke.  Furthermore, this project brings high value to the engineering profession because there is an increased need and responsibility to effectively manage coal ash in light of the December 2008 Tennessee ash pond failure and resulting proposed regulatory changes advocating dry ash disposal in landfills.

Social/Economic and Sustainable Design Considerations

This project represents a significant achievement in sustainable design because S&ME successfully redeveloped a 65-acre ash basin that was retired in the 1970s.  By overcoming major engineering and permitting obstacles, S&ME helped Duke re-use this site located very near the steam station and waste source.

Even the next best alternatives would have posed negative environmental, community, and economic impacts because they would have required developing greenfield sites, closer to neighbors, with increased development and operating costs due to the distance from the steam station and waste source.  Furthermore, the new landfill provides a significant collateral benefit as the landfill liner system provides a cover system for the underlying ash basin, effectively isolating it from the environment.

Complexity

This project was extraordinarily complex from an engineering design and regulatory permitting perspective.  S&ME successfully navigated the design complexities by demonstrating a high level of technical innovation.  The site conditions were extraordinarily complex due to the retired ash basin under the proposed ash landfill.  S&ME’s rigorous GIS-based settlement model demonstrated without a doubt that the liner system could accommodate anticipated settlements.  Results of S&ME’s innovative full-scale test fill program validated settlement models and further demonstrated estimated liner system performance.  S&ME conducted detailed slope stability analyses and liquefaction potential evaluations withstanding intense scrutiny and demonstrating design criteria were satisfied.  Design and construction of the double-liner system added further project complexities.

S&ME successfully navigated regulatory complexities by actively engaging regulators throughout the permitting, design, and construction process.  We met with NCDENR regulatory personnel regularly to communicate our plans, goals, and schedule; to identify and confirm regulatory issues and concerns; and to address and resolve them.  Through this interaction we successfully addressed regulatory requirements and design considerations before completing permitting and design submittals thereby streamlining agency review and approval.

Exceeding Owner/Client Needs

S&ME exceeded Duke’s needs by developing original and innovative design approaches, setting a valuable precedent with this first of its kind development, providing high value in sustainable design, and overcoming extraordinary complexities to deliver this project on time.  The S&ME design withstood intense regulatory scrutiny as S&ME personnel presented engineering design and analyses to regulatory agencies, laying the groundwork for agency review and approval.

S&ME worked with Duke to focus the construction efforts on the first of two landfill cells, completing the first cell and gaining the Permit to Operate just as the new dry fly ash handling system came on line.  Duke valued S&ME’s leadership and technical insight on the project.  In fact, S&ME has permitted and designed a similar project at another Duke facility.

Grant funds will be used to support design, planning, permitting, equipment purchases, contracting, installation, and other items directly necessary for the successful installation and operation of landfill energy systems, including landfill gas collection, gas conditioning, or end-use equipment such as boilers, generators, or turbines.

Edgecombe County, one of S&ME’s long-standing municipal solid waste clients, was awarded one of these grants with grant writing assistance from S&ME.

S&ME also completed Phase II evaluative testing of five archaeological sites that were determined potentially eligible for inclusion in the National Register of Historic Places (NRHP). Based on this testing, one site, the 18th/19th century house site of William Christian and Thomas Cloyd (44PU164), was determined eligible for the NRHP.

The Claytor Hydroelectric Project involved consultation with the Virginia State Historic Preservation Office, the Eastern Band of Cherokee Indian Tribal Historic Preservation Offices, the Virginia Council on Indians, and the Federal Energy Regulatory Commission. In addition, there has been ongoing consultation with the public in the form of public meetings and presentations.

The work conducted for the Claytor Hydroelectric Project demonstrates S&ME’s experience in performing a range of cultural resource services, including archaeological surveys and testing, and consultation with Federal and State agencies and Indian Tribes.

The expansion to TVA’s wind energy project included the construction of 15 turbines which are 260 feet tall, with 135 feet long blades. In addition to the turbines, a mountainous access roadway, substation, transformers and switch gear equipment and ancilliary maintenance/support buildings were constructed at the site. In order to construct the turbines, crane pads were required to be constructed at each of the 15 turbine sites.

S&ME’s geotechnical services included site reconnaissance, drilling exploratory borings, logging of the soil samples and bedrock cores, geotechnical laboratory testing of soil and rock samples, and providing geotechnical data reports for each turbine. Our construction materials testing services included proofrolling observations of the roadways and crane pads, density testing of the fill placed in the building and substation areas, concrete and grout sampling and compressive strength testing of cubes and test cylinders

Upon approval of the plans, personnel from four S&ME offices initially inspected over 390 substations to document evidence of mineral oil releases, and the presence of sensitive environmental receptors in the vicinity of the each substation. The inspection data were entered in a Geographic Information System (GIS) database that was developed, in-part, by S&ME, and used to prioritize substation assessments and remedial activities based on the magnitude of the releases and potential impact to sensitive receptors. Of the over 390 substations inspected, approximately 175 require remedial activities to address mineral oil releases to the ground. It is expected that the remedial actions will take a minimum of five years to complete.

S&ME’s responsibilities during remedial actions have been to oversee all contractors, conduct soil screening to ensure cleanup to State of Florida Risk Based Corrective Action criteria, manage soil and other debris according to the approved Management plan, and ensure that the substation is restored to operational conditions.

The work has included: installation of piezometers for evaluation of the extent of free product; removal of excessively contaminated soil and recovery of free product as IRAs; soilgas surveys; installation of soil borings and monitor wells; sampling of groundwater using push-type technology; sampling ground water, surface water, sediment and soils aquifer testing; potable water well inventories; ground penetrating radar surveys; preparation of contamination assessment reports; design of remedial systems and preparation of RAPs; bidding and construction management of remedial actions; and operation and maintenance of the remedial systems. The program sites have ranged from Callahan (northeast corner of Florida) to Turkey Point K (south of Miami) to Sarasota and Fort Myers. Five of these sites were located in the immediate vicinity of the Kennedy Space Center and include the Merritt Island Service Center, the Timsville Service Center, the Cocoa Service Center, the Port Orange Service Center and the Ormond Beach Service Center.

For this project, S&ME also completed data recovery excavations, analysis, and reporting of the Tree House archaeological site located along the Lower Saluda River. This is one of the oldest, most important archaeological sites in Southeast and more than 37,000 artifacts ranging from 13,500 to 800 years ago were recovered. Public information in the form of a glossy, color booklet and artifact/interpretive displays at three local venues were also produced.

The Saluda Hydroelectric Project has involved extensive consultation efforts with the State Historic Preservation Office; the Catawba and Cherokee Indian Tribal Historic Preservation Offices; the Federal Energy Regulatory Commission; the South Carolina Department of Natural Resources; the South Carolina Department of Parks, Recreation, and Tourism; the Irmo-Chapin Recreation Commission; and the South Carolina Institute of Archaeology and Anthropology. In addition, there has been ongoing consultation with the public in the form of quarterly public meetings, and periodic meetings of the Cultural Resource Conservation Group.

The work conducted for SCE&G demonstrates S&ME’s experience in performing a wide range of cultural resource services, including archaeological and architectural surveys, testing, and data recovery excavations; preparation of an HPMP; and consultation with Federal and State agencies and Indian Tribes.  The project has also won three awards:

• The National Hydropower Association Award for Outstanding Stewards of America’s Waters (2011)

• An Engineering Excellence Award from the South Carolina Chapter of the American Council of Engineering Companies (2011)

• A Corporate Stewardship Award from the Palmetto Trust for Historic Preservation (2009)

• Reviewed available geotechnical data for the Cross Generating Station site
• Planned, coordinated and performed an extensive field exploration
• Provided full-time engineering supervision of all field exploration and testing
• Planned and performed laboratory testing program for soil and rock samples
• Evaluated the field/laboratory test data to characterize the geotechnical conditions at the project site
• Performed a site-specific seismic study to develop alternative earthquake design information
• Provided geotechnical design recommendations, including: 1) axial and lateral capacities of drilled shaft and driven pile foundations, 2) lateral earth pressures for the design of below-grade/retaining walls, 3) allowable bearing capacities, elevations, etc. for the shallow supported structures, 4) suitability of on-site soils for reuse as structural fill, and 5) pavement thicknesses/allowable traffic volumes
• Provided recommendations for site preparation, controlled fill, and foundation construction
• Performed engineering observation and pile testing during construction of Unit 3

S&ME’s application of advanced technology such as cone penetration testing and multi-node resistivity testing, to this site resulted in a representative and accurate subsurface profile showing little or no evidence of karst features on which to base the foundation design. This, along with the results of our site specific seismic response analysis, indicated that driven pile foundations were a viable alternative to the originally planned drilled shaft foundation system. When compared to the estimated cost of a drilled shaft foundation system, the driven pile foundation system for Unit 3 resulted in a projected cost savings to the owner on the order of $7 million.