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Nashville Zoo at Nashville Zoo at GrassmereGrassmere
Stream and WaterStream and Water Quality ImprovementsQuality Improvements
Littlejohn Engineering Associates, Inc.Littlejohn Engineering Associates, Inc.
Civil & Environmental Consultants, Inc.Civil & Environmental Consultants, Inc.
Stream ImprovementStream ImprovementObjectivesObjectives
Bank Stabilization Opportunities Limited
Re-establish Stream at Location of Lower End Pond
Exotic Plant Control (privet, honeysuckle, et. al.)
Re-establish Native Vegetation Habitat Amendments (slab rock, log
drop structures for crayfish)
Project SiteProject Site
Phase V –Construct middle wetland
Phase I –Construct and line pond, construct water quality forebays
Phase II –Construct upper wetland
Phase III -Construct/install water recirculation system
Project SiteProject Site
Phase IV -Options:• Convert existing pond into wetland• Re-establish stream, remove pond
Phase II -Options:• Construct lower off-line wetland
Line Existing Water Quality Pond to Retain Water
Water Quality Improvements - Water Quality Improvements - Upper EndUpper End
Raise Height of Existing Weir to Increase Pond Capacity
Construct Water Quality Forebay for Storm Water from Adjacent Business Park
Upper Wetland Adjacent to Storm Water Retention Pond, 1.5± Ac.
Construct/Install Recirculation System to Supply Water from Retention Pond to Upper Wetland and to the Stream
Construct/Install Catch Basins and Piping to Direct Storm Water from Upper Parking Lot to Forebay on East Side of Water Quality Retention Pond
Construct/Install Pump and Force Main to Remove Water from Lower End of Stream and Pump to Retention Pond and Upper Wetland
Middle Wetland Adjacent to Pond, 0.25± Acre
Water Quality Improvements – Water Quality Improvements – Middle Middle
Improve Flow Through Pond to Reduce Algal Growth
Lower Wetland adjacent to stream, 1.0± Acre
Water Quality Improvements – Water Quality Improvements – Lower End Lower End
Possible Stream Restoration (300 feet) and Elimination of Existing Pond
Possible Wetland Creation/Restoration of Existing Pond
Mitigation Credits EarnedMitigation Credits Earned
Consider Project as a Whole to Earn Maximum Credits
Overall Ratio Expected to be 4:1 2,580± Feet of Stream Generates 645
Credits at $200/foot or $129,000 Wetlands Creation Credited at 4:1 Ratio;
4 Acres of Wetlands Generates 1 Acre of Credit or $25,000
Total Credit Dollars Earned $154,000
Conceptual Plan Conceptual Plan Opinion of Probable Opinion of Probable Construction CostConstruction Cost
Construct Retention Pond and Forebays $225,000
Water Quality Upgrade of Parking Area $80,000
Water Recirculation (force main with pump) $110,000
Construct/Create Upper Wetland $45,000
Conceptual PlanConceptual Plan Opinion of Probable Opinion of Probable Construction CostConstruction Cost
Construct/Create Middle Wetland $20,000
Construct/Create Lower Wetland $30,000
Alternate Stream Reconstruction/ Restoration (300 feet) $48,000
Bank Stabilization/Habitat Amendments $50,000
Exotic Plant Control/Re-establish Native Vegetation $30,000
Total of Opinion of Probable Construction Cost $638,000
Conceptual Plan Conceptual Plan Opinion of Probable Opinion of Probable Construction CostConstruction Cost
Phase I - $225,000 Construct Retention Pond and Forebays
Phase II - $75,000Construct Upper and Lower Wetlands
Phase III - $190,000Water Quality Upgrade of Parking Lot and Water Recirculation
Phase IV - $98,000Stream Restoration, bank Stabilization/ habitat Amendments
Phase V - $50,000Construct Middle Wetland and Exotic Plant Control/
Re-establish Native Vegetation
Opinion of Probable Opinion of Probable Construction Cost Construction Cost Breakdown by PhaseBreakdown by Phase
Nashville Zoo at Nashville Zoo at GrassmereGrassmere
Open DiscussionOpen Discussion