ORD-2013-036 Ordinance approving Budget Amendment #2-A and Upper Neuse River Basin Assoc. Funding Request

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Attachment A. Instructions for Preliminary, Screening-Level Cost Estimates and 4 Schedules The information you should use to develop your preliminary, screening-level cost estimates and schedules are provided below. The UNRBA technical steering committee does not expect those firms invited to provide qualifications to conduct an extensive project planning analysis as part of the qualifications package. The committee is requesting the development of preliminary, screening-level estimates using a minimum level of effort. However, these estimates should have some basis in how the firm will approach the task. That basis should be included as a 1-paragraph description with each upper and lower level estimate. Estimated costs maybe presented with a±10% contingency to reflect a higher level of confidence, and a f 15% contingency to reflect a lower level of confidence. Using the list of the 5 submittal components, information under item 5 should address the following: 5.a. Credit Development Low end estimate: Develop nutrient credits for sixteen (16)nutrient reduction measures as listed in Table A-1. The credits will be developed using data from existing studies and located in existing publically available databases. A measure of central tendency will be the basis of the removal credit recommendation assigned to each BMP. A project database will be created for this task. Sources of data and information may include but not limited to the International Stormwater BMP Database, the National Stormwater Best Management Practices Database,NC State University BMP Databases, Chesapeake Stormwater Network,the USEPA Green Infrastructure Case Studies, and other appropriate organizations or credit development processes. Table A-l. Practices for the Low-End Credit Development Estimates Over/Under-Sized Level Spreader/Filter Check Dam Grass Swale Green Roof(revision Bioretention Strip combined with requested to existing Swale nutrient credit values) Soil Amendments Volume-based Pond Infiltration Practices Street Sweeping /Restoration Retrofits Urban Tree Canopy Permeable Pavement Pond Retrofits/Upflow Check Dam Grassed (Diversified) Filter Swales Bio-Swales Filter Strips with Toe Leaf Litter Recovery Improved Rainwater Trenches Harvesting High end estimate: Similar to the low end estimate, develop recommended nutrient credits for fifty-five (55)nutrient reduction measures as listed in Table A-2. Credits will be developed using data from existing studies and located in publically available databases. Instead of a measure of central tendency as the basis for assigning credit, the service provider would be expected to use an analysis of the distribution of reported removal efficiencies to incorporate uncertainty and variability into the removal efficiencies. Table A-2. Practices for the High-End Credit Development Estimates Over/Under-Sized Level Spreader/filter Permeable Pavement Infiltration devices/ Flood plain Bioretention Strip combined with (Diversified) basins: permeable restoration Swale walkways,planters, infiltration trenches (Refine) Soil Amendments Pond Retrofits/ Check Dam Grassed Bio-Swales Filter Strips with /Restoration U flow Filter Swales Toe Trenches Leaf Litter Recovery Urban stream Riparian buffer Catch basin inserts Blue Roof restoration restoration(50-feet and vortex wide buffers) separators Constructed Sand filters Peak flow control Proprietary devices Impoundment of wetlands with for water quality urban,degraded various designs credits streams Enhancing or Land or forest Riparian buffer Increase tree canopy Cattle exclusion, repairing existing protection restoration with with and without riparian buffers varying width buffers Page 2 of 3