This paper describes the measurement and modeling of turbidity currents (TC) in the Congo Canyon and the application of that data to design of a telecommunications cable. There are few direct measurements of TCs largely because the measurement instruments are often damaged. Indeed, this is only the second set of measurements ever recorded in the Congo Canyon, and the only set that shows the propagation of TCs through multiple sites. Four moorings were deployed in 2013 along a 500 km stretch of the Canyon and measured roughly a dozen TCs during a 5-month period. The largest event reached 150 cm/s. Two-D and 3-D numerical models were set up and calibrated using the measurements. The 3-D model shows significant along-and cross-channel variations and these results were used to select optimal crossing locations. The models were then integrated with cable data to permit stress and fatigue analysis at selected cable installation locations, permitting both cable route and cable type to be evaluated.

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In 2000, the Gwinnett County Department of Public Utilities (DPU) completed a Watershed Protection Plan (WPP) in accordance with the Georgia Environmental Protection Division (EPD) permitting requirements for a new or expanded wastewater National Pollutant Discharge Elimination System (NPDES) discharge permit. The WPP recommended improving impacted areas and protecting streams by completing detailed Watershed Improvement Plans (WIPs).CH2M HILL completed a WIP for the Chattahoochee River tributaries in Gwinnett County. The Chattahoochee River Tributaries study area encompasses 106 square miles and approximately 614 stream miles. The overall goal of this project is to identify and implement actions that 1) enhance the aquatic integrity of impaired streams within each study area, 2) return these streams to their designated uses, and 3) remove them from EPD's 303(d) list.Within the framework of this goal, the objectives of this project are to: • • Evaluate existing stream conditions, determine causes of stream degradation, and identify opportunities for stream restoration. • • Identify riparian-floodplain areas and opportunities to expand these areas for habitat improvement, flood reduction, and sediment storage. • • Inventory existing storm water BMPs and identify retrofit or new BMP opportunities that would mitigate urbanization-caused changes in runoff volume and timing. • • Evaluate the benefits of watershed BMP and stream restoration projects.• • Estimate costs of each potential project.• • Prioritize projects using benefit/cost analysis, public input, and County resource availability. •• Assist with public education efforts.The first step toward justifying a dedicated funding source for storm water projects is to identify the scope and need for a comprehensive storm water program. The results of the WIP indicate the need for and expected costs of proposed projects essential to meeting multiple regulatory requirements. The total CIP costs for these study areas, combined with others in Gwinnett County, determine the range of expenditures needed to improve water quality and biotic integrity. 3026Because of the need to efficiently collect and manage large amounts of detailed information about conditions in the study areas, GIS and global positioning system (GPS) technologies were used. GIS tools combine database information with spatial information to help quickly visualize and quantify the location and extent of conditions in the study areas. Base data, such as watershed boundaries, infrastructure, political boundaries, and hydrology, were provided by the DPU and other County departments. These data were used to develop field plans and other new data needed for the fieldwork. These data were critical to the assessment and development of potential restoration and retrofit projects.Field teams were equipped with handheld GPS units to gather data at the specific location of each problem or condition identified during the stream walk or BMP inventory. The GPS unit was connected directly to a handheld computer, which r...

The Sweetwater Creek watershed is located in central Gwinnett County within the Ocmulgee River Basin. The study area is comprised of 26 square miles. A total of 153 projects were identified in the Watershed Improvement Plan (WIP) for Sweetwater Creek. Total cost of all projects was estimated at $15,044,500. Implementation of projects was broken down into two primary phases:• Phase I -Prioritization of the recommended projects in the WIP • Phase II -Project design and construction Project prioritization included a review of data from the Sweetwater Creek WIP to develop a short list of BMP and stream projects for implementation. This was accomplished by conducting limited field work to review short listed projects. The work also included a review of regulatory requirements for potential projects and preliminary discussions of land acquisition issues. The McDaniel Farm Park stream restoration project was the first step in bridging the gap between watershed planning and implementation. As a result of the Phase I study, the McDaniel Farm Park stream restoration project was the first project chosen for implementation for a number of reasons. 1) The project was identified in the WIP as providing reduction in TSS because of eroding banks along an unnamed tributary to Sweetwater Creek. 2) The project was located on County-owned land within an existing park and the project could be completed on County-owned property, avoiding land acquisition that could cost the County additional time and money for the project. 3) Because the project is located in a park there will be a number of opportunities to provide public awareness and education to citizens regarding the program. 4) There was a nearby road construction project that was going to impact a stream channel and as a result the Georgia Department of Transportation (GA DOT) needed mitigation credits to obtain a 404 permit for the project. The McDaniel Farm Park stream restoration project could be used to provide mitigation for the road project. GA DOT cost for mitigation for the road project was $1.6 million. The McDaniel Farm Park stream restoration project involved the restoration of a deeply incised stream channel (South Tributary) and the restoration of stream buffers along the 723 WEFTEC®.06

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