lake kirby dam repairs

8/11/2019 Lake Kirby Dam Repairs

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Abilene City Council

LAKE KIRBY DAM REPAIRS

September 25, 2014

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AGENDA

LAKE KIRBY DAM REPAIRS

Items of Discussion:

1. Issues With Lake Kirby Dam

2. Recommended Improvements

3. Questions and Discussion

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ITEM 1

ISSUES WITH LAKE KIRBY DAM

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Lake Kirby Dam

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Main Embankment: 4,200 ft long

earthen embankment with rock

riprap upstream slope protection

Service Spillway: 520 ft wideearth/rock spillway channel

at east end of dam

West Levee (Emergency Spillway):

6,000 ft long earthen embankment


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ISSUES WITH LAKE KIRBY DAM

A Dam Safety Regulations

(TCEQ Regulations in Title 30 TAC Chapter 299)

Classified as IntermediateSize& High Hazard Dam

Regulation: dam & spillways pass at least 81% of PMF

Existing dam and spillways only pass 73% of PMF

Pass 81% PMF - raise dam 0.7 feet (minimum)

Pass 100% - raise dam 1.6 feet (recommended)

B Erosion of Dam / West Levee and Restricted Drainage

Erosion of upstream slope (water side)

Erosion of west levee (emergency spillway) Erosion of downstream slope

Vegetation restricting drainage around toe of dam

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Erosion of Upstream Slope

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Downstream Slope - Vegetation

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Vegetation

restricting drainage

around toe of dam


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ISSUES WITH TRAFFIC ACCESSING

LAKE KIRBY

A Traffic Issues on West Side of Dam

TxDOT requested closure of two access points on

east side off Highway 83/84

B Traffic Issues on East Side of Dam

Inadequate and poorly defined roadway

Roadway floods when Lake Kirby is spilling

C Traffic Issues Across Dam

Non-standard, narrow roadway with inadequate end

transitions.

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Traffic Issues on West Side of Dam

Closure of Access Points off Hwy. 83/84

West Side

Cut-Through

ExistingDriveway

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Traffic Issues on West Side of Dam

West Side Cut-Through

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West Levee Roadway


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Traffic Issues on East Side of Dam

Service Spillway/East End of Dam

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Inadequate and poorly

defined roadway that floods

when Lake Kirby is spilling


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Traffic Issues Across Dam

Existing Dam Crest Roadway Not Suitable for Public Traffic

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Soft, thin

shoulders

Non-standard,

narrow roadway, withinadequate end

transitions.


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RECOMMENDED IMPROVEMENTS

Clear vegetation along dam, west levee, & toe-of-dam

Repair erosion on dam and west leveeRaise dam with compacted fill to meet 100% PMF

Resulting crest width of 15 feet

Implement new traffic control plan

Motorized vehicle access to east & west sides of lake

No unauthorized motorized vehicles on dam crest

Dam crest is accessible to pedestrians and bicycles

Work with TxDOT to close Hwy. 83/84 access points

Extend west levee roadway to Spur 707

Fencing to restrict access downstream of dam

Cost $3,869,00015


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Future Dam Crest View

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Traffic Control for Lake Kirby

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East Turnaround,

Gated at boatramp

with no motorized

vehicular access to

spillway and dam

West Turnaround, Gated at

turnaround with no motorized

vehicular access to dam

Install new flexible

base roadway andnew traffic driveway

at east Spur 707

Eliminate existing

traffic driveway andcut-through at

Highway 83/84

Only non-motorized vehicular

traffic, pedestrians, and

authorized maintenance

vehicles on dam & spillway


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Segment 1 Roadway

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Construct new

flexible base

roadway

Eliminate existingtraffic driveway at

Highway 83/84

Install new traffic

driveway at

East Spur 707


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IMPROVEMENTS - SUMMARY

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Proposed Improvement

Dam Safety Issues

Raise dam to meet 100% PMF

Upstream slope repairs

West levee repairs

Downstream vegetation removal

Access Issues

Remove existing access points to Hwy. 83/84

New fence to restrict downstream access

Extend new road to Spur 707

No Public Motorized Traffic on dam crest roadway

Cost $3,869,000


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ITEM 3

QUESTIONS AND DISCUSSION

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lake kirby dam repairs

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