The Clardy Fox pump station has a rated flow capacity of 665 cubic feet per second — 300,000 gallons per minute — or in other words, about an 8.5-foot-deep swimming pool the size of a college basketball court moved per minute. It included approximately 4,000 linear feet of channel shaping and lining and approximately 3,700 linear feet of storm sewer conduit and associated inlets.

The storm sewer conduits ranged from 42-inch diameter pipe to 120-inch diameter pipe and concrete boxes of varying sizes. Additionally, there were five road crossings with culverts involved in the channel work. These crossings involved the construction of box culverts and some unique headwalls in order to remain within the designated right-of-way. Hydrologic and hydraulic computer modeling of the storm sewer, culverts, and channel were performed using THYSYS and WSP-2.

Parkhill coordinated with the City of El Paso as the project owner, the Texas Department of Transportation (TxDOT), the Bureau of Reclamation, and the International Boundary and Water Commission (IBWC) during the project. The pump station and much of the storm sewer were situated on TxDOT right-of-way, a future Bureau of Reclamation irrigation canal right-of-way was crossed by the pump station’s 120-inch diameter discharge pipeline, and this same discharge pipeline had to penetrate the IBWC’s river flood control levees. Therefore, all of these entities were involved in the review and approval of the project.

Project Leadership

Paul McMillen, PE, CFM

Northwest Lubbock Drainage Improvements Phase 2 is an extension of the Northwest Lubbock Drainage Improvements Phase 1/1a project. This phase focused on relieving intermittent yet long-term flooding at Maxey Park. A hospital at that location experienced a significant loss of accessibility during flood events. Large numbers of residences were also built below the playa overflow elevation and had suffered from long-duration flooding. Reducing flooding benefitted residents, hospital district employees and visitors, and the traveling public.

Parkhill designed Phase 2 of the Northwest Lubbock Drainage Improvements and served as Engineer of Record. This project, 10,700 LF of storm drain at depths up to 47 feet, had four tunnels with a total length of 3000 LF. The contract documents were written to allow the contractor a great deal of flexibility in choosing the best materials and installation methods, which provided the best value for the community.

The project design allowed the contractor to choose fiberglass reinforced pipe or concrete box or pipe. Fiberglass pipe was chosen in 96″ and 90″ sizes. The contract documents required single-pass tunneling as the standard. The contractor elected to use a hand mining process. Parkhill specified fiberglass manholes as an option, in addition to the concrete manholes used in previous Lubbock deep storm sewer projects.

Route selection for this project was a key element of the design. Parkhill worked closely with the City of Lubbock and various stakeholders to identify, avoid or adjust for numerous anticipated construction issues. An easement on Texas Tech University property was acquired for a portion of the route, but other portions had to be constructed below roadways, some of which were narrow residential streets. The route passes under and through the sorority and fraternity area on Greek Circle. Concerns for traffic and student safety resulted in contract provisions for scheduling work to avoid busy times in that area and for additional security on the 45-foot trench. The route needed to cross Marsha Sharp Freeway, and more than one location was considered. The best route still had to pass closely between two freeway support piers, and the tunnel also passed under a constructed wetland.

Parkhill coordinated with the firm selected for construction management services, expediting reviews to avoid any delays related to communications.

Parkhill provided Engineer of Record Services during construction. At that time, Parkhill converted the design hydraulic and hydrologic model to ICPR version 4 in preparation for final record documentation and model creation upon construction completion.

Awards  

TSPE South Plains – Trailblazer Award

Project Leadership

René Franks, PE, CFM

Phases 1 and 1A of the Northwest Lubbock Drainage Improvements Project consisted of 13,686 linear feet of 15-foot-by-7-foot, 10-foot-by-10-foot, and 8-foot-by-7-foot concrete box, as well as 950 linear feet of 78-inch, reinforced concrete pipe. Parkhill served as the engineer of record and oversaw all construction during Phases 1 and 1A.

Construction of Phases 1 and 1A stretched from Yellowhouse Canyon through the Arnett-Benson neighborhood and along the Erskine Corridor to where Quaker Avenue intersects Texas Tech Parkway. More than 1,200 linear feet of pipe was installed by two-pass tunneling at key intersections along the project route. All other pipe was installed by open-cut excavation. No more than 200 linear feet of open-cut trench was exposed at any given time, ensuring residents were inconvenienced as little as possible during the project.

The design of the NWLDIP called for gasketed, reinforced concrete boxes to be installed. The trunk line has a maximum operating pressure of 11 psi, and the gaskets at each joint must be water-tight during operation. Parkhill supervised a proof-of-design process that was completed by the contractor (Utility Contractors of America) prior to any construction at the project site. Precast box sections were joined, buried, and pressurized to simulate field conditions. Additional box sections were placed on top of the buried pipe to account for backfill loads, and the apparatus was required to maintain an operating pressure of 11 psi but not more than 13 psi for 48 hours.

Parkhill worked with the City of Lubbock and the contractor to reach out to community stakeholders along the project route. Through clear communication, the project schedule was constantly adjusted to accommodate school bus routes, Texas Tech move-in weekend, resident home access, and other City of Lubbock construction projects.

Phases 1 and 1A often involved open-cut trenching from curb to curb. With depths of up to 47 feet below natural grade, worker and public safety were a very large concern during this project. The contractor submitted plans for trench safety boxes that were used to protect workers from potential sidewall failures during open-cut trenching. Public safety was addressed with a site security fence installed at the end of construction each day. To ensure worker safety within tunnels, clean air was pumped into the tunnel, and a ventilation conduit was installed.

With such deep excavations and the volume of required backfill, quality control was stressed at every stage of this project. Nuclear density gauge testing was performed for every 12-inch vertical lift per 500 linear feet of backfill installed. In practice, this resulted in five nuclear density gauge tests performed for every 50 linear feet of backfill. The location of each nuclear density gauge test was plotted and tracked for uniformity by Parkhill’s engineering team. This ensured the quality of soil density for trench backfill and roadway subgrade. Parkhill also tracked the ultimate strength quality of the concrete, asphalt, and tunnel grout used on the project.

The City of Lubbock approved the contractor to submit payment applications for materials on hand. The construction management team at Parkhill tracked the payment for materials on hand, as well as materials installed on a monthly basis. The contractor carried a materials-on-hand surplus of over $1 million for 21 months and reached a maximum of $3.5 million materials-on-hand surplus. Each pay application submitted to the City included a materials-on-hand summary, a materials-installed summary, and a total project completion percentage.

Project Leadership

René Franks, PE, CFM

In 2014, the City of Midland selected Parkhill for on-call engineering services regarding the city stormwater master plan. Since then, Parkhill has performed many tasks for the city under this contract. 

Parkhill worked with the city to prepare final contract documents to upgrade five city-owned industrial permits to meet the latest TCEQ standards. Parkhill trained city staff on best management practices for the city’s municipal storm sewer system, drafted a new stormwater ordinance, and updated and implemented new stormwater programs. This included preparing Notice of Intent forms, coordinating with city staff to create and document the updated stormwater management program summary, and helping the staff maintain a schedule of activities for the five-year permit cycle. 

Parkhill also prepared citywide maps related to thoroughfare, utility, and drainage plans. The firm assisted with the city’s community rating system and updated the city floodplain management ordinance. 

Project Leadership

• Eric West
• René Franks

Stormwater drainage is usually a hot topic among West Texas residents and specifically in Lubbock, Texas. Urban growth in the city of Lubbock and the steady increase of an elevated water table lengthened the period of time for urban lake levels to recede after receiving runoff. 

The lakes naturally drain by lake-bottom seepage and evaporation or will overflow from one to the other, gradually transferring water overland along their natural drainage pattern. These shallow lakes become the receptors of urban precipitation runoff as communities develop. An increased frequency of flooding near lake boundaries and in lake overflow regions has been seen over the last 20 years with less lake storage available for holding runoff within a reasonable time frame. This significantly affected residential and commercial areas across the city. Man-made improvements have been the only way to significantly help aid the reduction of water levels in lakes. 

Parkhill, in association with Hugo Reed and Associates Inc., recommended a subsurface pipeline drainage system as the best option after a feasibility study was completed that included public involvement from neighborhood associations. The design team reviewed city maps and analyzed 33 alternatives and alignments to develop a practical route with the least existing utility conflicts for a gravity pipeline storm drainage relief system.

The 11 lakes drain 19.5 square miles and are now connected by subsurface pipelines that discharge floodwater into the Brazos River. The project spans the entire east-west limits of Lubbock and is in an entirely urban-developed area. It involved very deep installation depths, 13.6 miles of pipe, and reaches the Brazos River through a 5-mile long segment of 72-inch pipe.

The project required the use of extensive computer simulation, aerial photography, digital terrain model development, surveying, geotechnical investigation, ground-penetrating radar survey, tomography, and the development of extensive plans and specifications.

Awards

• National Finalist – Engineering Excellence Awards, American Council of Engineering Companies
• Gold Medal Winner – Engineering Excellence Awards, Texas Council of Engineering Companies

Project Leadership

Edwin “Butch” Davis, PE