Storm Sewer Assessment for South Newport Subdivision Waterworks, LLC. Storm Sewer Assessment for South Newport Subdivision Crosby, Texas May 5, 2015

Project Limits Goal: Design a Storm Water management system. Cover the development south of Jolly Boat Drive and encompassed by Golf Club Drive and Broken Back Drive. Goal: Design a Storm Water management system. Lower risk of flooding. Use SCS method to estimate runoff volume. EPA SWMM to direct runoff to proposed area. DENISE Location of Outfall

Project Limits Subdivison in Crosby, Texas South of Jolly Boat Drive. Approximately 55 acre for single family homes Area slopes from the north west to the south east. JILLIAN Location of Outfall

Preliminary Design Procedures Existing elevations were determined from the LiDAR topographic map in AutoCAD Subcatchment areas were found using closed polylines and the “Area” command in AutoCAD once the allowable area for a 10-foot and 15-foot inlet were calculated using the Rational Method Pipe lengths were found by using the “Distance” command in AutoCAD Project conformed to the standards in City of Houston Infrastructure Design Manual A few velocities did not meet the 3 fps specification Backfill requirements were met, with a range of 3-5 feet

Proposed Design 22 Subcatchment Areas 25 inlets 22 15-foot inlets 3 10-foot inlets 12 additional junctions to accommodate transitions to RCPs Reinforced Concrete Pipes (RCPs) 3925 LF of 1-foot dia. 2965 LF of 1.5-foot dia. 1300 LF of 2-foot dia. Outfall located at the southeast corner of the development

Preliminary Cost Estimate Description Unit Qty Unit Cost Total Cost CLEARING AND GRUBBING: 1 Clearing and Grubbing AC 8 $3,000.00 $24,000 TRENCHING AND BACKFILL:   2 Excavation CY 3640 $3.50 $12,740 3 Backfill 1500 $35.00 $52,500 STORMWATER DRAINAGE SYSTEM: 4 12" RCP drain pipe LF 3925 $34.00 $133,450 5 18" RCP drain pipe 2965 $38.00 $112,670 6 24" RCP drain pipe 1300 $48.00 $62,400 7 10-ft Inlets EA $1,300 $3,900 15-ft Inlets 22 $1,500 $33,000 9 Manhole-Standard Depth 12 $1,800 $21,600 LANDSCAPING AND SURFACE RESTORATION: 10 Hydromulch Seeding $1,000 $8,000 11 Stormwater Pollution Prevention Plan $50,000 Subtotal $514,260.00 Contingencies (15%) $77,139.00 Engineering (15%) $88,709.85 TOTAL $680,108.85