Sediment Transport in Stream Assessment and Design July 31 August 4, Logan, Utah

Transcription

1 DEPARTMENT OF WATERSHED SCIENCES Sediment Transport in Stream Assessment and Design July 31 August 4, Logan, Utah This course is intended for those who wish to understand and apply the principles of sediment transport to alluvial channel assessment and design. Principles of open channel flow and sediment transport are combined with watershed-scale, hydrologic and sediment source analysis to place channel assessment and design in the appropriate context. Threshold and alluvial channel design methods are presented along with guidelines for assessing and incorporating uncertainty. The course balances advance reading, lecture, field work, and handson exercises for estimating sediment supply, calculating sediment transport rates, and forecasting channel response to water and sediment supply. This course is intended for participants who are familiar with basic principles of river geomorphology.

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3 Agency 4 Industry 6 Student 4 Geomorphologist 8 Biologist 1 Civil Engineering 6

4 Cache Valley Heber Valley

5 Cache Valley (Monday Thursday) Summit Ck (Tuesday) Merrill Cazier Library (Thursday) Logan R (Wednesday) Logan R (Monday)

6 Heber Valley (Friday) Provo R (Friday) G G

7 Exit Strategy (Friday) Logan SLC

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9 Given: Flow duration Upstream sediment supply Objective of a dynamic channel supporting a trout population With: Start and finish points & existing topography Use: Spreadsheet tools HEC RAS To Develop: Channel layout and geometry to transport supplied sediment with available flow 1 d hydraulic model of design to contain design discharge Sediment mass balance for channel dynamics

10 What is the supply of water and sediment? What is the supply of water and sediment to a stream & what do you want to do with it? I. How often does sediment move? Discharge Q Bed material D Channel Geometry Hydraulics Incipient Motion II. What is the sediment balance? Discharge Q Sediment Supply Q s & D Channel Geometry Flow COMpetence Transport CAPacity vs Sediment Supply Hydraulics Transport Capacity Q s & D Input + Storage = Output Surplus or Deficit? Stored sediment is the real geomorphic and restoration topic! What do you want to do with it?

11 Estimate sediment sources, sinks, flux Build 1d flow model Assess critical discharge for incipient motion Estimate transport rates & evaluate channel change Design channel to transport sediment supply & maintain dynamics

12 Design steps 1. Develop flood series, specify flood frequency Design Q. 2. Estimate sediment supply: develop supply sediment rating curve [Monday, Wednesday] 3. Planning phase: What slope S will transport the sediment supply with the available flow? Calculate (b, S) combination {S and valley slope determine sinuosity} [Thursday] 4. Develop flow duration curve 5. Design phase: Develop trial design, w/ desired channel geometry &composition. Use 1-d model to route sediment through the design reach over the flow duration curve. {Build 1-d hydraulic model for trial design. Calculate cumulative transport over flow duration curve at each section; evaluate sediment continuity.} [Tuesday, Thursday] Slope Transport Rate (tons/day) Discharge 1 = 15.0 Discharge 2 = River RD Midway Casperville Does not include transport samples <200g for the >16mm size class No meaasured transport in this size range at White Bridge Discharge (cfs) Slope Case 1 Slope Case 2 Depth Case 1 Depth Case 2 > 16 mm Sed Supply 1 = 954 kg/hr Sed Supply 2 = 2862 kg/hr Channel Width (m) Depth (m) 6. Bottlenecks or blowouts? Adjust for sediment continuity [Thursday]

13 Materials pdf color slides of presentations Paper print of some presentation slides Paper copies of field assignments Electronic copies of assignments, spreadsheets, readings Wireless Find Bluezone Sponsored Access Sponsor Code: nebixugu (Group Name: Sediment Workshop)

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15 Depart MTW: NR Parking Lot Dinner Wed: NR Atrium Workshop 101 Merrill Cazier Library Tyler Allred Patrick Belmont Peter Wilcock Dinner Mon 7p: 1624 Sunset Dr

16 Golf Course Golf Course Dinner Mon 7p: 1624 Sunset Dr 20 min walk from campus

17 Friday Morning I 80 Exit 146, US 40 toward Heber, Vernal, Provo Pass Jordanelle Reservoir on left, head down into Heber Valley Right at first stop light, onto River Road Right into Provo River Restoration Project Office PRRP Office