Aberdeen Airport Drainage Study. Todd Yerdon, PE Al Erickson, PE

Transcription

1 Aberdeen Airport Drainage Study Todd Yerdon, PE Al Erickson, PE

2 INTRODUCTIONS

3 Project Background In 2009, HDR was hired to provide a drainage study for the Aberdeen Airport as part of an Environmental Assessment (EA) that was being developed by Helms & Associates. In the EA, potential wetlands were being identified for removal from the airport property due to wildlife hazards.

4 Project Background Wetland Removal Impacts to Drainage Natural Detention Will Be Removed Natural Channel Characteristics Will Be Modified Peak Flow Rates Leaving the Area Will Increase. A drainage study needed to be developed to prevent adverse impacts to neighboring properties due to wetland removal.

5 2009 Drainage Study Develop Existing Peak Flow Rates for the Airport. Existing peak flow rates refer to the flow rates leaving the airport at the time of the study in The study does not look at flow rates prior to Identify Wetland Storage Volumes. Provide Storm Water Control Alternatives

6 2013 Drainage Study and Design Develop Viable Alternatives for Storm Water Control Mitigate Impacts Due to Removing Wetland Areas Develop Preliminary Design for Storm Water Control Features

7 US 12 Study Area Study Area = 2,370 Acres MELGAARD RD. Minimal Channel Slope RUNWAY 17/35 JOBEE ACRES 392 ND AVE. 7 Outlet Points 390 TH AVE. Runway 13/31 is the Dividing Point for Flows 135 TH ST. Grassland and Agricultural Land Use

8 Hydrology US 12 8 Drainage Basins Defined 390 TH AVE. MELGAARD RD. 392 ND AVE. SCS Curve Number Method Used to Generate Flows 100-year 24-hour Storm Event Used for all Analysis The 100-year storm event is an event that has a 1% chance of happening during any given storm. 135 TH ST.

9 STORM WATER CONTROL

10 Storm Water Control Design Controlling Factors for the Final Storm Water Control Design: Peak Flow Discharges from the Proposed Design will not Exceed Historic Peak Flow Discharges for the 100-year 24- hr Design Storm. Required Drain Time for Detention Facilities. Cost for Storm Water Control Facilities.

11 Storm Water Control Benefits Eliminates Airport Wildlife Hazards Storm Water Control Facilities will be Designed for the 100- year Storm Event. Smaller Storm Events will have Minimal Releases to Neighboring Properties Due to the Large Design Capacity for the 100-yr Event. Pumping Options Increase the Availability of Detention after Each Event. Storm Water is Directed around Neighbors rather than Through Neighbors.

12 Solutions for Storm Water Control Four Storm Water Control Options Identified for Replacement of the Wetlands 1. On-site Above Ground Detention 2. On-site Below Ground Detention 3. Off-site Detention 4. Pump to Major Drainage Channel

13 On-site Above Ground Detention Above Ground Detention Not Viable Solution by Itself Current Topography does not Allow for Gravity Draining of the Pond in a Timely Manner. Pond Most Likely Would Become a Wetland if not Drained in a Timely Manner

14 On-site Below Ground Detention Below Ground Detention Not Viable Solution by Itself Cost for Detention Cost for Pumping

15 Off-site Detention Off-site Detention Not Viable Solution at This Time FAA Requirements for Offsite Detention Partnering Options are Limited Pumping and Forcemain Costs Land Costs for Detention Area

16 Pump to Major Drainage Channel Option Requires Pumping Storm Water Would be Pumped to a Local River Moccasin Creek James River

17 Pump to Major Drainage Channel Airport James River Moccasin Creek

18 Pump to Major Drainage Channel Airport James River Proposed Forcemain Alignment (Assuming Publicly Owned ROW)

19 Pump to Major Drainage Channel Pumping to Major Drainage Channel is a Viable and Preferred Solution Combine Basins to One Pumping Source Above Ground Detention Required 5 to 7 Miles of Forcemain 3 Possible Pumping Layout Options

20 Pumping Option 1 US 12 Open Grass Channel Open Concrete Channel Gravity Pipe Forcemain Detention 390 TH AVE. MELGAARD RD. Lift Station 392 ND AVE. 135 TH ST.

21 Pumping Option 1 Lift Station Located at the South End of Runway 13/31 Pump Station Required 5.8 Miles of Forcemain to James River 8,200 ft of Gravity Storm Sewer Pipes Along Runway 13/31

22 Pumping Option 2 US 12 Open Grass Channel Open Concrete Channel Gravity Pipe Forcemain Detention 390 TH AVE. MELGAARD RD. Lift Station 392 ND AVE. 135 TH ST.

23 Pumping Option 2 Lift Station Located Between Runways at the Detention Pond Pump Station Required 6.9 Miles of Forcemain to James River Two Culvert Crossings on Runway 13/31

24 Pumping Option 3 US 12 Open Grass Channel Open Concrete Channel Gravity Pipe Forcemain Detention 390 TH AVE. MELGAARD RD. Lift Station 392 ND AVE. 135 TH ST.

25 Pumping Option 3 Lift Station Located West of Runway 17/35 at the Low Point of the Airport Pump Station Required 7.5 Miles of Forcemain to James River Two Culvert Crossings on Runway 13/31

26 Conclusion Develop a Design that will Do No Harm to Neighboring Properties Pumping to the James River is the Most Viable and Preferred Option 3 Alternative Pumping Layouts Available Design Alternatives Provided are Conceptual and Many Design Elements Still Need to be Evaluated

27 Discussion and Questions