Senior Design PP section

Abee, Benifield, Campbell, Damron, Manley

XY Engineering

Daylighting Town Branch

Phase 1

Problem Statement

The project team must daylight a portion of Town Branch stream and make the safely accessible to the public within the given project area.

Town Branch

Water Resources

Task Manager: Chase Campbell

Base Flow

Source: StreamStats, USGS

Storm Flow & Management

Source: "Hydrology, Storm Water Manual 2009." Lexington Fayette County Urban Government, 2009. Web.

Storm Flow Cont.

• “The time of concentration shall be determined using the method described in Technical Release No. 55 published by the U.S. Department of Agriculture, Natural Resources Conservation Service (2009 Storm Manual, 10).

Source: "Hydrology, Storm Water Manual 2009." Lexington Fayette County Urban Government, 2009. Web.

Storm Flow Cont.• The NRCS technical release dictates that the time of

concentration is calculated by the summation of variable travel times (sheet, shallow, open-channel).

Segment , XY Length, ft Elevation X, ft Elevation Y, ft SlopeAB(Sheet) 154 1045 1040 0.032468BC(Shallow) 1730 1040 1036 0.002312CD(Channel) 13912 1036 922 0.008194AD 15796 1045 922 0.007787

Source: Calculated using ArcGIS

Storm Flow Cont.Sheet Flow:

Segment ABSurfce Description Dense GrassManning's (n) 0.24Flow Length, ft 1542yr-24hr rain, in 3.02Land Slope 0.03Tt, hr 0.25

Shallow Flow:Flow Length, ft 1730Land Slope 0.002Avg. Velocity, ft/s 1Tt, hr 0.48

Channel FlowX-sec Area, ft^2 26.5Wetted Perimeter, ft 24.7Hydraulic Radius, ft 1.07Channel Slope 0.007Manning's (n) 0.02 ConcreteV, ft/s 6.5Flow Length, ft 15796Tt, hr 0.68Tc, hr 1.41 85 min

Source: "Technical Report- 55." NRCS, 1989. Web. 14 Oct. 2015.

Storm Flow Management Options

Source: David, Allen, and Bernadette, DuPont. "REVISION OF THE RAINFALL-INTENSITY DURATION CURVES FOR THE COMMONWEALTH OF KENTUCKY." Kentucky Transportation Center, 1 Mar. 2000. Web. 14 Oct. 2015.

• Sediment Pond• Floodplain• Detention Basin• Culvert

Stream Channel Alternatives• Alternative #1: Wetland Mitigation Bank with a

Sediment Pond coupled with Floodplain (High levels of vegetation)• Considers:

• 10year-24 hour storm• Water quality

• Alternative #2: Meandering Stream with a Detention Basin connected to a Culvert• Considers:

• 100year-24 hour storm • High safety

Steam Alternative Considerations• Where feasible, the streambank side slope shall be cut back to 3:1 slope or

flatter and overhanging bank edges shall be removed. • The buffer shall consist of a two zones. Zone #1 has a minimum distance of

15ft, and Zone #2 20ft, measured perpendicular from the waterbody

Source: "Streambank Stabilization and Restoration, Storm Water Manual 2009." Lexington Fayette County Urban Government, 2009. Web.

Floodplain calculated to be approximately 115 ft.

Stream Alternative Example

Storm Management Design Considerations

Graphical Method: 10-yr 100-yrDrainage Area, mi^2 2.12 2.12Runoff CN 80 80T.O.C, hr 1.41 1.41Rainfall Distribution II IIFrequency 10 100Rainfall, P, in. 4.34 6.5Initial Abstraction, Ia, in. 0.5 0.5Ia/P 0.12 0.08Unit Peak Discharge, qu, csm/in 300 350Runoff, Q, in 2.89 4.2Pond/Swamp Factor 1 1Peak Discharge, cfs 1838 3116

Other Daylighting Projects

• Benefits Obtained from other Daylighting Projects:• Provides reference for similar sized watersheds• Provides reference for similar flow rates• Shows range of project expenses• Provides team an idea for reasonable budget• Helps provide scope for various objectives & features

Source: Pinkham, R. (2000). Daylighting: New Life for Buried Streams. Retrieved October 6, 2015.

Design Phase Recommendations