powerpoint presentation · stormwater engineer city of lubbock r. paul mcmillen, p.e., cfm project...

6/9/2014

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2014 TFMA Annual Spring Conference

Project Team

Michael Keenum, P.E., CFM

Stormwater Engineer

City of Lubbock

R. Paul McMillen, P.E., CFM

Project Manager

Parkhill, Smith & Cooper, Inc.

Jason L. Swofford, P.E.

V.P. Engineering

Hugo Reed and Associates, Inc.

What is a playa lake?

Naturally occurring, broad, shallow,

roughly circular depression

Approximately 1 per square mile

Non-riverine

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How do playa lakes function?

Catch runoff that collects in low spots

Naturally restore capacity by

evaporation or infiltration – slow process

Some overflow to the next downstream

playa in larger rainfall events

Some lakes do not overflow even in a

0.2% chance annual rainfall event

City of Lubbock Storm Sewer

Projects

South Central Lubbock Drainage

Improvements Project (SCLDIP) – 1995-

2003

South Lubbock Drainage Improvements

Project (SLDIP) – 1999-2009

Northwest Lubbock Drainage

Improvements Project (NWLDIP) –

2006-present

South Central and South

Lubbock Drainage Projects

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Northwest Lubbock Study Area

Northwest Lubbock Drainage Project

Catalyst for “recent” projects

October 1983 Storm Event

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June 1999 Storm Event


September 2008 Storm Event


July 2010 Storm Event

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Storage Restoration

Install storm sewer networks to drain down lakes

to pre-rain condition

Migrate from reliance on evaporation and

percolation to restore lake storage

Establish initial Water Surface Elevation (WSE) at

lakes

Evaluate draindown times and recovery process

for each lake

Design appropriate pipe network to meet goals

Design Considerations

Based on recovery of playa lake storage

within a reasonable time period to

prepare for the next rainfall event

Design basis – single day (24 hour)

event precipitation, “official” and

accepted method

Design Considerations

Basis for single-event precipitation is the

Flood Insurance Study 24-hour

precipitation depths based on probability

of occurrence in any given year:

• 10% probable event (10 Year) 4.60 inches




• 0.2% probable event (500 Year) 8.38 inches

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Design concept for projects

Infeasible to capture and collect storm event to

offer significant protection

Evaluated draindown time concept vs. standard

design storm

Ensured available storage and draindown times

Utilized 30-day draindown time for ultimate

designs for largest storage-capacity lakes

Most lakes recover 90% of available storage in 10

days or less

Other design considerations

Route (right-of-way) availability

Available grades to outlet point

Existing utilities

Subsurface obstacles (i.e., drill shaft retaining wall

at IH-27 for SCLDIP)

Archaeology at outlets

Environmental sites (i.e., LPST)

Corps of Engineers Permit (all projects under

NWP 26)

Draindown Effects April-June 1999 SCLDIP

L019 (Casey/K-Mart)April - June 1999

3195

3200

3205

3210

3215

3220

24-Apr 24-May 23-Jun 23-Jul 22-Aug 21-Sep

Date

Sta

ge (

ft)

Overflow Low Floor No Project Alt 2E Int 1 Int 2 Alt 2A

Estimated Low Floor Elev. = 3215.5

Lake Overflow Elev. = 3214

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L021 (Clapp)April - June 1999

3185

3190

3195

3200

3205

3210


Date

Sta

ge (

ft)


Estimated Low Floor Elev. = 3200

Lake Overflow Elev. = 3208.6


L023N (Trinity)April - June 1999

3214

3215

3216

3217

3218

3219

3220

3221

3222

3223

3224


Date

Sta

ge (

ft)





L037 (McAlister)April - June 1999

3252

3254

3256

3258

3260

3262

3264

3266

3268


Date

Sta

ge (

ft)




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Maxey Park Draindown Single Event NWLDIP

Rush Park Lake Draindown Single Event NWLDIP

Project Costs

South Central Drainage Project (SCLDIP)

$39 million

South Lubbock Drainage Project (SLDIP)

$55 million

Northwest Lubbock Drainage Project (NWLDIP)

$80 million (estimated)

Total Costs

$174 million

Feasibility Study preceded each project

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Financing Approach

Stormwater Utility Fee – created in 1993

Currently flat fee based on number of water meters

City Council elected to fund all of the projects with utility fee

20 and 30 year bonds to fund projects

Additional debt service added through 2018

First debt roll-off scheduled in 2021

Remapping Efforts

SCLDIP – Playa Lake System E

SLDIP – Playa Lake System G

NWLDIP – Playa Lake Systems B,C,D

SCLDIP Remapping

Playa System E

Reduction of Base Flood Elevations at all

lakes except Lakes 20, 23N, 31

665 structures removed from SFHA

98 structures added to SFHA

567 net structures removed from SFHA

Estimated structure removal value - $76.5

million

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SCLDIP Remapping Lakes 23, 24,

and 25 Playa System E

SCLDIP Remapping Lakes 27 and 31

Playa System E

SLDIP Remapping

Playa System G

Reduction of Base Flood Elevations at all

lakes except Lakes 84, 87, 91 and 92

465 structures removed from SFHA

86 structures added to SFHA

379 net structures removed from SFHA

Estimated structure removal value - $71

million

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SLDIP Remapping Lakes 94, 95 and 133

Playa System G

NWLDIP Anticipated Remap Structure

Removal Arnett-Benson Area

NWLDIP Anticipated Remap

Structure Removal

Structure Removal Count at Arnett-Benson

Structures to be Removed from Special Flood Hazard Area

Residential 770

Business 43

Church 6

Education 9

Municipal 1

Total Structures 829

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NWLDIP Anticipated Remap Structure

Removal Maxey Park

NWLDIP Anticipated Remap

Structure Removal

Structure Removal Count at Maxey Park

Structures to be Removed from Special Flood Hazard Area

Residential 400

Business 33

Total Structures 433

Conclusion

Remapping completed and FEMA

accepted for System E

Remapping efforts for System G

awaiting FEMA approval – anticipate

Draft maps in summer 2014

Capital Project to remap systems

impacted by Phase 1 of NWLDIP

scheduled for FY 2014-15

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2014 TFMA Annual Spring Conference

Project Team

Michael Keenum, P.E., CFM

Stormwater Engineer

City of Lubbock

R. Paul McMillen, P.E., CFM

Project Manager

Parkhill, Smith & Cooper, Inc.

Jason L. Swofford, P.E.

V.P. Engineering

Hugo Reed and Associates, Inc.

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Playa Lakes

Naturally occurring, broad, shallow,

roughly circular depression

95% of the world’s playas are located on

the South Plains

There are approximately 22,000 playas

located across the Llano Estacado

Playa Lakes

The Construction Process

Three major projects

South Central Lubbock Drainage Improvements Project (SCLDIP)

South Lubbock Drainage Improvements Project (SLDIP)

Northwest Lubbock Drainage Improvements Project (NWLDIP)

All are deep Installations

Up to 55 feet below grade to storm sewer invert

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Project Costs

South Central Drainage Project (SCLDIP)

$39 million

South Lubbock Drainage Project (SLDIP)

$55 million

Northwest Lubbock Drainage Project (NWLDIP)

$80 million (estimated)

Total Costs

$174 million

SCLDIP Statistics

Connects 12 playa lakes

13.6 miles of storm sewer pipeline

Depths ranging from 15 to 50 feet

Over 32,000 linear feet of tunnel

Pipe diameters from 24 – 72 inch

Retrofit through urban area

SCLDIP Permissible Materials

Precast reinforced concrete pipe (RCP)

Fiberglass reinforced mortar pipe

(FRMP)

Cast-in-place non-reinforced concrete

pipe (CIPNRCP)

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SCLDIP at Outlet 72” RCP

SCLDIP CIPNRCP 72” Dia.

SCLDIP CIPNRCP 72” Dia.

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SCLDIP Rock Trencher on Avenue W

SCLDIP TBM Retrieval 50’ Below Grade

40th Street at IH-27

SCLDIP “Stair Step” Lake Inlet

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SCLDIP “Stair Step” Lake Inlet

SCLDIP “Tower” Inlet

Cofferdam protected

construction at Lake 31

Completed tower inlet at Lake 24

SCLDIP 72” Diameter Outlet

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SLDIP Statistics

Connects 12 playa lakes

19 miles of storm sewer pipeline


Over 10,000 linear feet of tunnel

Pipe diameters from 24 – 54 inch

SLDIP Permissible Materials



(FRMP)

SLDIP Construction Train

In unpaved right-of-way

In paved thoroughfare

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SLDIP Deep Installation

Construction in thoroughfare

Deadweight prevents FRMP flotation

when installing cement stabilized

backfill

SLDIP Lake Inlet Under Construction

SLDIP FRMP Stockpile

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SLDIP Outlet 54” Diameter

NWLDIP Statistics

Connects 6 playa lakes and 1 retention

basin

8 miles of storm sewer pipeline


Over 8,200 feet of tunnel

Pipe sizes from 24-inch diameter to

10’x10’ box with short segment of 15’x7’

box

NWLDIP Permissible Materials

Precast reinforced concrete box (RCB)



(FRMP)

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NWLDIP Plan & Profile at Outfall - Why it

gets deep so quickly

NWLDIP Precast Box Manufacture

10 x 10 box reinforcement cage

and post-casting touchup

NWLDIP 15’ x 7’ RCB Stockpile

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NWLDIP 10’ x 10’ RCB Stockpile

NWLDIP Placing 15’ x 7’ Boxes at Outlet

NWLDIP Placing Articulated Block

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NWLDIP Placing Articulated Block

NWLDIP RCB Cast-in-place Transition

15’ x 7’ to 10’ x 10’

NWLDIP Trenching Uphill from Outlet

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NWLDIP First Major Bend 10’ x 10’ RCB

Prior to Trench Box Reset

NWLDIP Screening Operation

NWLDIP Tunnel Shaft at Railroad

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NWLDIP Tunnel Shaft at Railroad

NWLDIP Tunnel Liner Plate Under Railroad for

10’ x 10’ RCB – 230 linear foot drive

NWLDIP Tunnel Jacking Machine

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NWLDIP Lowering 10’ x 10’ Box at Railroad

Tunnel Shaft

NWLDIP Construction Train in Residential

Neighborhood

NWLDIP Gantry Crane Operation

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NWLDIP Cement Stabilized Backfill

NWLDIP Density-Controlled Backfill Compaction

NWLDIP Work Zone in Residential Area

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NWLDIP 10’ x 10’ One-Pass Tunnel in

Knoxville Avenue – 330 Linear Feet Run

NWLDIP Lake 52 Inlet Structure

NWLDIP Paving Operations in Residential

Neighborhood

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Conclusion

2 Major projects already completed

SCLDIP in 2003

SLDIP in 2009

Phase 1 of third project completed

NWLDIP in May 2014

Projects tested by record rainfall events

in 2008 and 2010

Most recent test of systems May 2014

powerpoint presentation · stormwater engineer city of lubbock r. paul mcmillen, p.e., cfm project...

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