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Slide 2 Preliminary Design of Galvez Estates Subdivision Slide 3 Summary of Topics Introduction General Site Information Sanitary Sewer Design Design of Subdivision Hydrologic Analysis Traffic Impact References Slide 4 General Site Location LA 42 Slide 5 General Site Information Development Site: Tracts A & B Development Size: 47.9 Acres Lot Size: 70x150 Minimum Number of Lots: 100 Land Cost: $30,000/acre Construction Cost: $450/linear foot of street Profit Goal: >$2.5 million Slide 6 Sanitary-Sewer Design Pipe Size Design Based on: Peak Flowrate Mannings with PVC Pipes Flowing Half-Full Q peak = 1.69 cfs Diameter = 1.7 ~ 2 Per EBR: Minimum Pipe size = 8 Slide 7 Sanitary-Sewer Design Velocity Requirements Minimum Velocity = 2 fps Maximum Velocity = 10 fps Mannings with PVC Pipes Flowing Half-Full V = 2.4 fps Slide 8 Sanitary-Sewer Design Slide 9 Design of Subdivision Slide 10 Lot size of 70x 150 Lot frontage along Curved Right of Ways held to 70 at building line Building Lines held to 25 122 lots Curb and gutter with subsurface drainage Slide 11 Design of Subdivision Road Design 12 feet utility servitude outside 50 ft right-of-way Surfaced with 3asphalt cement over 12 soil cement sub base Road designed above Base Flood Elevation of 18 Minimum road slope of 0.4% Slide 12 Road Cross Section Slide 13 Preliminary Earthwork CUTFILL POND96,500 C.Y.------- ROADWAYS8,700 C.Y.1,900 C.Y. LOTPADS--------T.B.D. Slide 14 Drainage Design Site Conditions Topography Soil Types Flood Zone Pre-Development Drainage Post-Development Drainage Fill Mitigation Design Storm Slide 15 Soil Types Calhoun Silt Loam 81.1% of Site Deerford-Verdun Complex 17.9% of Site Olivier Silt Loam 1% of Site Predominately Hydrologic Group D Slide 16 FEMA F.I.R.M. FIRM Panel# 2205C0035E Flood Zones AE & X BFE=18.0 Slide 17 Pre-Development Slide 18 Catchment Area 1Discharge Rational Method Weighted Runoff Coefficient, C = 0.32 Intensity, I = 4.0 in/hr (EBR Drainage Manual) Area, A = 47.2 Ac (Includes 7 Ac of adjacent land) Pre Development Discharge, Q = 60.4 Slide 19 Post Development Slide 20 Fill Mitigation Not an Issue Majority of Site is above Base Flood Elevation 1,100 C.Y. of Storage Loss due to Fill Pond Normal Pool Below B.F.E. B.F.E.=18.0 Normal Pool = 13.75 Potential for >30,000 C.Y. of Storage Offsets Loss due to Fill Slide 21 Design Storm 10 yr, 24 hr Event Total Rainfall = 8.5 (EBR Drainage Manual) Modeled in HydroCAD SCS - Type III Event Slide 22 Post-Development Hydrograph Slide 23 Current Site Conditions Route: LA0042 milepoint: 19.61 station: 205510 Year ADT 2007 12566 Route: LA0933 milepoint: 0.82 station: 205530 Year ADT 2007 - 5684 Slide 24 Traffic Impact Analysis (Per Institute of Transportation Engineers Trip Generation Model) Slide 25 Design Vehicle S-Bus36 Minimum Design Turning Radius = 38.9 Centerline Turning Radius = 34.9 Minimum Inside Radius = 23.8 Slide 26 Galvez Boulevard @ La 932 La 932 Galvez Boulevard Slide 27 Permits Lousiana DOTD Right Of Way Permits Highway Access, Utilities, Vegetation Department of Health And Hospitals Sanitary Sewer, Onsite Treatment Ascension Parish Subdivision Permit Slide 28 References East Baton Rouge Parish Unified Development Code Trip Generation Institute of Transportation Engineers - 6 th Edition Google Maps www.DOTD.Lousiana.gov AASHTO Guide for Design of Pavement Structures