I-64 Embankment Study

Volkert, Inc. &Schnabel Engineering Consultants, Inc. for

the Rivanna Water & Sewer Authority

I-64 Embankment Study

• Hydrology/ hydraulic study

• Geotechnical evaluations

• Hazardous spill risk analysis

Site Location, Properties, Land Use

The Rocks LLC

City of C’ville

City of C’ville

Proposed Normal Pool

Existing Upper Dam Existing

Lower Dam

Proposed Dam

I-64 Drainage Areas & Flow Paths

Proposed Normal Pool

8’x8’ Box

Proposed Ped Bridge & Boom

8’ x 8’ Box Culvert Profile

683

675

683695

702

• Modeled 5 hydraulic conditions for 8-ft-by-8-ft box:– Existing– Repaired – 72-in liner with full reservoir– 72-in liner with low reservoir– Blocked

• All conditions acceptable

H&H - Summary

I-64 Embankment, South Side

Embankment Stability Analysis

Condition Calculated Required

Proposed Normal Pool Balanced 1.55 1.5 Acceptable

100-yr Flood Unbalanced

(Culvert Clogged)1.52 1.3 Acceptable

Rapid Drawdown 1.54 1.1 Acceptable

Seismic 1.31 1.1 Acceptable

Settlement

• Tendency for Heave– Resisted by > 100ft of overburden

• Predicted Settlement = 3½”– In line with previous evaluations– Occurs gradually (est. 3 yrs)– Minimal dif. settlement: gradual and uniform

Geotechnical - Summary

• Modeled I-64 embankment considering:– Stability– Settlement– Seepage– Seismic

• All conditions acceptable

Hazardous Spill

• Risk Mitigation analysis

• 2 steps recommended– Floating boom– Filter curtain

Boom

Curtain

Boom

Conclusion

With proposed upgrades, I-64 embankment and culvert will function safely and adequately in conjunction with the proposed dam.

QUESTIONS?