Salt Lake County June 2010 Flooding and Restoration Little Cottonwood (LCC) and Big Cottonwood (BCC) Kade Moncur, PE, CFM Salt Lake County Engineering August 10 th - 12 th SLCo Symposium 2011
August 10 th - 12 th SLCo Symposium 2011
Cause of the June 2010 Flooding Cool temperatures during early to mid Spring, which delayed snowmelt runoff from LCC and BCC June rainfall along with rapidly increasing temperatures for several days in a row Resulting in higher than average spring runoff of LCC and BCC August 10 th - 12 th SLCo Symposium 2011
LCC & BCC Peak Flows Drainage Area FEMA FIS Q100 June 2010 Peak Q June 2011 Peak Q Flooding Source (sqmi) (cfs) (cfs) (cfs) Little Cottonwood Creek 46 A bo ve Wheeler F arm D ebris B asin - 1,400 913 965 B elo w Wheeler F arm D ebris B asin - 1,050 800 821 Big Cottonwood Creek 50 1,230 786 788 Overbank flooding of Little Cottonwood Creek below the Wheeler Farms Debris Basin will start around 700 cfs The 1983 flood peak runoff for LCC was 1,135 cfs. August 10 th - 12 th SLCo Symposium 2011
Emergency Response Efforts and Costs 2010 & 2011 Emergency Response Efforts 24-hr Flood Watch Sandbagging in Critical Areas Placement of Riprap Along the Channel Banks Clearing of Debris Blocking Culverts and Bridges 2010 Flood Response Cost: 2011 Flood Response Cost: $571,840.00 Agency Agency Total Unified Fire Authority $382,339.02 Unified Police Department $43,966.00 Midvale City $46,205.86 Sandy City $17,500.00 Murray City $2,457.00 Salt Lake City $702.00 VECC $2,198.28 August 10 th - 12 th Total: SLCo $492,889.68 Symposium 2011
Disaster Relief No Relief from FEMA Needed Approximately 2.9 million in Damage to Public Infrastructure. Funding from NRCS under National Emergency Watershed Protection Program (EWP) 3.3 million for 2010 Maybe 3.3 million more in 2011 SLCo will match funding to 25% EWP funds will not be used for any of the following: Increase the pre-disaster capacity of a channel by constructing a new channel, enlarging the old channel or relocating the stream. Modifying the channel based upon regional curve data which maintains the same channel capacity upstream and downstream, and is necessary to stabilize the channel, is allowable. Sediment and debris removal is not considered new construction. August 10 th - 12 th SLCo Symposium 2011
Wasatch Resort August 10 th - 12 th SLCo Symposium 2011
3700 E to 4000 E Above Wasatch Blvd August 10 th - 12 th SLCo Symposium 2011
Upper Rails Debris Structure Below Wasatch Blvd. August 10 th - 12 th SLCo Symposium 2011
Cobble Canyon Lane to Willow Creek Drive August 10 th - 12 th SLCo Symposium 2011
LCC at Crestwood Park August 10 th - 12 th SLCo Symposium 2011
Through Union Park Ave & Fort Union Blvd August 10 th - 12 th SLCo Symposium 2011
LCC Wheeler Farm August 10 th - 12 th SLCo Symposium 2011
LCC Murray Pk tovine Street August 10 th - 12 th SLCo Symposium 2011
August 10 th - 12 th SLCo Symposium 2011
August 10 th - 12 th SLCo Symposium 2011
Elevation (ft) LCC Flood Damage Assessment Upper Reach Structure Capacity (Flood Insurance Study Model) 4805 4800 4795 4790 4785 Little Cottonwood Creek Plan: Little Cottonwood Creek 8/18/2010 Will ow Green Ci rcle.085.04.085 4780 0 50 100 150 200 Station (ft) August 10 th - 12 th SLCo Symposium 2011 Legend EG 500-year WS 500-year Crit 500-year EG 100 ENC EG 100-year WS 100 ENC WS 100-year EG 50-year WS 50-year EG 10-year Crit 100-year Crit 100 ENC WS 10-year Crit 50-year Crit 10-year 2 ft/s 4 ft/s 6 ft/s 8 ft/s 10 ft/ s Ground Levee Bank Sta Encroachment
LCC Flood Damage Assessment Upper Reach Structure Capacity August 10 th - 12 th SLCo Symposium 2011
LCC Flood Damage Assessment Field Reconnaissance August 10 th - 12 th SLCo Symposium 2011
LCC Flood Damage Assessment Damage Classification -- Debris August 10 th - 12 th SLCo Symposium 2011
LCC Flood Damage Assessment Damage Classification -- Erosion August 10 th - 12 th SLCo Symposium 2011
LCC Flood Damage Assessment Damage Classification -- Scour August 10 th - 12 th SLCo Symposium 2011
LCC Flood Damage Assessment Damage Classification Riprap and/or Rock Displacement August 10 th - 12 th SLCo Symposium 2011
LCC Flood Damage Assessment Damage Classification Structural Damage August 10 th - 12 th SLCo Symposium 2011
LCC Flood Damage Assessment Damage Classification Gabion Damage August 10 th - 12 th SLCo Symposium 2011
LCC Flood Damage Assessment Damage Classification -- Deposition August 10 th - 12 th SLCo Symposium 2011
LCC Flood Damage Assessment Damage Assessment Parameters Public infrastructure impact Pre-existing conditions contributing to damage Private encroachment Restoration work sites August 10 th - 12 th SLCo Symposium 2011
LCC Flood Damage Assessment Damage Prioritization High priority Debris pond deposition Structural damage Total gabion failure Severe undercutting Threat to adjacent home, infrastructure, etc. August 10 th - 12 th SLCo Symposium 2011
LCC Flood Damage Assessment August 10 th - 12 th SLCo Symposium 2011
LCC Flood Damage Assessment August 10 th - 12 th SLCo Symposium 2011
1 3700 E to 4000 E Channel Repair
1 3700 E to 4000 E Channel Repair - Flood
1 3700 E to 4000 E Channel Repair - Post Flood
3 3700 E to 4000 E Channel Repair - Construction
4 3700 E to 4000 E Channel Repair - Construction
Upper Rails Access Road and Repairs Site 2 & 3 Access Road Upper Rails Repairs
2 & 3 Upper Rails Access Road and Repairs
2 Upper Rails Access Road Repairs - Construction
2 Upper Rails Access Road Repairs - Construction
2 Upper Rails Access Road Repairs - Construction
3 Upper Rails Repairs Pre Flood
3 Upper Rails Repairs Pre Flood
3 Upper Rails Repairs Flood
3 Upper Rails Repairs Construction
3 Upper Rails Repairs Construction
4 Cobble Canyon Ln. to Willow Creek Dr. Channel Repair
4 Cobble Canyon Ln. to Willow Creek Dr. Channel Repair
4 Cobble Canyon Ln. to Willow Creek Dr. Channel Repair
4 Cobble Canyon Ln. to Willow Creek Dr. Channel Repair -Flood
4 Cobble Canyon Ln. to Willow Creek Dr. Channel Repair -Flood
4 Cobble Canyon Ln. to Willow Creek Dr. Channel Repair -Flood
4 Cobble Canyon Ln. to Willow Creek Dr. Channel Repair -Construction
4 Cobble Canyon Ln. to Willow Creek Dr. Channel Repair -Construction
5 Highland Drive Gabion Repairs
5 Highland Drive Gabion Repairs
5 Highland Drive Gabion Repairs - Construction
5 Highland Drive Gabion Repairs - Construction
6 Waterside Cove Concrete Wall Repair
6 Waterside Cove Concrete Wall Repair
6 Waterside Cove Concrete Wall Repair - Flood
6 Waterside Cove Concrete Wall Repair - Flood
6 Waterside Cove Concrete Wall Repair - Construction
6 Waterside Cove Concrete Wall Repair - Construction
7 1300 E Gabion Repair
7 1300 E Gabion Repair - Post Flood
7 1300 E Gabion Repair - Post Flood
7 1300 E Gabion - Construction
7 1300 E Gabion - Construction
8 Wheeler Farm Dredging
8 Wheeler Farm Dredging
8 Wheeler Farm Dredging - Flood
8 Wheeler Farm Dredging - Flood
8 Wheeler Farm
9 900 E Gabion Repair
9 900 E Gabion Repair
9 900 E Gabion Repair Flood
9 900 E Gabion Repair - Construction
9 900 E Gabion Repair Construction
9 900 E Gabion Repair Construction
10 Murray Park Channel
10 Murray Park Channel
10 Murray Park Channel Flood
10 Murray Park Channel Flood
10 Murray Park Channel Post Flood
10 Murray Park Channel Construction
10 Murray Park Channel Construction
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