Client Tarrant Regional Water District

Integrated Pipeline (IPL) Section 15-1

Rice, TX

The Integrated Pipeline (IPL) Program consists of more than 150-miles of raw water pipeline to connect several North Texas reservoirs in the Tarrant Regional Water District (TRWD) and Dallas Water Utilities (DWU) systems. The program represents a large scale collaboration between the two agencies in an effort to realize significant long term construction and operational savings for constituents.

Lockwood, Andrews & Newnam, Inc. (LAN) was selected as pipeline design engineer for Section 15-1 of the greater program, which includes more than 15-miles of 108-inch diameter raw water pipeline. LAN provided preliminary design, final design, and construction phase services for the $90+ million dollar project, which was the first component of the overall IPL program that went to construction. Design included consideration for both steel and concrete pipe (competitively bid) and both flowable fill and traditional granular bedding as part of efforts to promote competition and maximize value.

Section 15-1 included several notable design challenges, including short tunnel sections at large diameter high pressure petroleum pipeline crossings, TxDOT crossings and a Union Pacific Railroad crossing. In addition, Section 15-1 includes the crossing of TRWD’s 90-inch diameter Richland-Chambers Pipeline, which required design of a pressure reducing interconnect with maximum flexibility for future parallel installations.

On completion of design, a bid was accepted and awarded for roughly $93 million dollars, which was more than $30 million below the original construction budget.

At a glance

Competitive sealed proposals were solicited and received for Section 15-1 of the IPL program.

Competitively bidding two pipe materials with several bedding and backfill options helped generate savings for the owner. The awarded low bid was more than $30 million under the original budget.

On completion of the overall program, the IPL pipeline will have a capacity of 350 million gallons per day.

LAN exceeded the established diversity goal of 25%, achieving more than 30% through design phases.

Through preliminary and final design, no budget was exceeded and every scheduled milestone was met by the LAN design team.

Design considered long term corridor access requirements, including incorporation of stabilized low water crossings of several small creeks.

The Richland-Chambers interconnect facility included design of two 78-inch diameter isolation valves and four pressure reducing trains totalling 12 42-inch control valves and four orifice plates.

Cathodic protection of the steel pipe ultimately installed consisted of a sacrificial anode system with two 78-inch diameter monolithic isolation joints near the interconnection.

Features

The pressure reducing interconnection at the Richland-Chambers pipeline crossing was architecturally designed to mimic other above ground barns/structures in the area to blend with the landscape

Design efforts included proactive stakeholder engagement with local officials, including Navarro County, the Navarro County Electrical Cooperative and two local water supply corporations

Preliminary design included detailed evaluation of likely construction access routes, including consideration of load ratings for bridges needed to deliver goods

Development of the Richland-Chambers interconnection site required design of improvements to an unpaved county road to ensure all weather access could be provided

The awarded contractor elected to utilize three pipe laying crews during construction, cutting construction from a budgeted 24 months to roughly 15

Services

Design

Pipeline Design, Assessment & Rehab

"This LAN team's project execution has been top-notch. Their flexibility to adjust in evaluating design alternatives or respond to urgent submittals has proven invaluable to the timely delivery of this project. I would recommend and would use them again."

Highlighted by ASCE's Civil Engineering for their online edition in October 2014.