Id Gaffe Hilary Brugger Stephen Kelly Anastasia Nugent Joseph Roberts

Design storm water runoff system for a 1 hour, 100 year storm as specified by the College Station Unified Development Ordinance. Using the Rational Method to determine a conservative calculation for the excess runoff: Design intensity for a 1 year, 100 year storm is 4.41 in/hr Design runoff coefficient for undeveloped and grassy areas is.355 Design runoff coefficient for impervious surfaces is.945 Level of Service Measures

Estimate Demand Runoff Pre-Development cy Post-Development cy Change (Storage needed) cy cy is equivalent to 48.4 acre-feet. A pond with a maximum depth of 6 feet would be a 10 acre pond.

Alternative 1: Enlarge Spearman Lake

Alternative 2: Creation of a Storm Water Detention Pond

ObjectQuantity Pipe (18”)72690 LF Pipe (24”) LF Excavation for Pipe.161 M CY Excavation for Pond.078 M CY Drains2467 Manholes243 Quantity Estimates ObjectQuantity Pipe (18”) LF Pipe (24”) LF Excavation for Pipe.158 M CY Excavation for Pond.078 M CY Drains2467 Manholes243 Alternative 1Alternative 2

Capital Cost Estimate Alternative 1Alternative 2 ObjectTotal Cost Pipe (18”)$ M Pipe (24”)$.303 M Excavation for Pipe $.597 M Excavation for Pond $.294 M Dewatering$ 13,185 Drains$.593 M Manholes$.227 M $4.26 M ObjectTotal Cost Pipe (18”)$ M Pipe (24”)$.496 M Excavation for Pipe $.606 M Excavation for Pond$.294 M Drains$.593 M Manholes$.227 M $4.45 M

Operating Estimates OperationCost Pipe Maintenance$.528M / yr OperationCost Pipe Maintenance$.536 M / yr Alternative 1Alternative 2

Overall Cost Estimate Alternative 1 Alternative 2 ObjectTotal Cost Pipe (18”)$ M Pipe (24”)$.303 M Excavation for Pipe $.597 M Excavation for Pond $.294 M Dewatering$ 13,185 Drains$.593 M Manholes$.227 M $4.26 M Maintenance$.528 M / yr ObjectTotal Cost Pipe (18”)$ M Pipe (24”)$.496 M Excavation for Pipe $.606 M Excavation for Pond$.294 M Drains$.593 M Manholes$.227 M $4.45 M Maintenance$.536 M / yr

We will be paying for this via municipal bonds and grants. The grants that we believe we can receive will cover 20% of the capital cost. The other 80% will be covered using bonds with a 7% interest rate. How Will We Pay For It?

Alternative BAlternative A Interest:0.07 Terms:20 Present Value$4,693,800$4,260,000 Payment:$443,062$402,114 Net Taxable Property Value (College Station, calculated using.43 per $100 tax rate) ~$25,000,000 Alternative BAlternative A Tax Rate:$ per $100K value Taxable Value With Alternatives: $25,443,062$25,402,114 Net Tax Increase Per Household (per $100k value of land)$9.83$9.50 Cost Per Household

Questions?