Winnick Drain Revisited:Winnick Drain Revisited:

Flamingo Wash Flamingo Wash at the Imperial Palaceat the Imperial Palace

byby

Douglas B. Blatchford, PEDouglas B. Blatchford, PE

OverviewOverview

““Revisited” again since 1994Revisited” again since 1994Complex project driven by Las Complex project driven by Las

Vegas MonorailVegas Monorail Involved under-grounding the Involved under-grounding the

Flamingo Wash at the Imperial Flamingo Wash at the Imperial Palace Palace

BackgroundBackground

Flamingo Wash flows across the Las Flamingo Wash flows across the Las Vegas Valley from west to eastVegas Valley from west to east

Crosses Las Vegas Strip at the Imperial Crosses Las Vegas Strip at the Imperial PalacePalace

Day-lights (Day-lights (not!not!) in the casino’s parking ) in the casino’s parking garagegarage

Major storm flows pass through the Major storm flows pass through the parking garage and onto Winnick parking garage and onto Winnick AvenueAvenue

Existing ConditionsExisting Conditions

Flamingo Wash day-lights under Flamingo Wash day-lights under casino parking garagecasino parking garage

4000 cfs drains east to Winnick4000 cfs drains east to Winnick2500 cfs intercepted by a hydraulic 2500 cfs intercepted by a hydraulic

weirweirWinnick carries remainder as Winnick carries remainder as

surface flowsurface flow

Design objectiveDesign objective

Owner desired to underground Owner desired to underground systemsystem

Involved phased construction:Involved phased construction:Phase I involved placement of 2 –11’ x Phase I involved placement of 2 –11’ x

7’ RCB’s7’ RCB’sPhase II involved construction of system Phase II involved construction of system

in parking garage, demolition of weirin parking garage, demolition of weirPhase II not feasiblePhase II not feasible

Phase I DesignPhase I Design

Placement of 2- 11’ x 7’ RCB’sPlacement of 2- 11’ x 7’ RCB’sComplex utility relocationsComplex utility relocationsColumn supporting Imperial Palace Column supporting Imperial Palace

Station placed on weirStation placed on weirCritical path for permittingCritical path for permitting

Phase I DesignPhase I Design

Placement of 2- 11’ x 7’ RCB’s Placement of 2- 11’ x 7’ RCB’s necessary because:necessary because:Existing downstream capacity limited Existing downstream capacity limited

to 2-11’ x 7’ RCB’sto 2-11’ x 7’ RCB’sIP Station prevented future IP Station prevented future

constructionconstructionPlacement of column within ramp Placement of column within ramp

or on weir not permitted at firstor on weir not permitted at first

Phase I DesignPhase I Design

Utilities complex:Utilities complex:6” water line, 4” gas relocated6” water line, 4” gas relocatedWater vault protected-in-placeWater vault protected-in-place48” storm drain tie-in48” storm drain tie-in8”, 18” and 24” sewer lines relocated8”, 18” and 24” sewer lines relocatedOverhead power under grounded to Overhead power under grounded to

conduit below 2-11’x7’ box culvertsconduit below 2-11’x7’ box culverts

Imperial Palace

Winnick Avenue

Winnick Drain

Alley

Weir

Grate

Phase I Design – Column Phase I Design – Column PlacementPlacement

Required close coordination with Required close coordination with Clark CountyClark County

Only one location to support straddle Only one location to support straddle bent for IP Station: on the weirbent for IP Station: on the weir

County allowed for reconstruction of County allowed for reconstruction of barrier rail barrier rail

Cross-sectional area remained the Cross-sectional area remained the samesame

Phase II DesignPhase II Design

Underground the system in the IP Underground the system in the IP Parking garageParking garage

Demolition of the weir and intakeDemolition of the weir and intakeTie-in to Phase I 2-11’ x 7’ RCB’s Tie-in to Phase I 2-11’ x 7’ RCB’s Parking garage construction not Parking garage construction not

feasiblefeasible

Phase II DesignPhase II Design

Footings for IP parking garage Footings for IP parking garage columns set on shallow calichecolumns set on shallow caliche

Footings close together, columns Footings close together, columns support casinosupport casino

Underground utilities such as Underground utilities such as sewer and water in parking garagesewer and water in parking garage

Phase II DesignPhase II Design

Grate type intake not feasible given Grate type intake not feasible given large flows and clogginglarge flows and clogging

Downstream limited to 2500 cfsDownstream limited to 2500 cfsCould raise the parking garage floor Could raise the parking garage floor

for traffic, allow storm flows to exit for traffic, allow storm flows to exit as isas is

Probably solved if/when casino is Probably solved if/when casino is taken downtaken down

T-t-that’s all folks!T-t-that’s all folks!