As neighborhoods grew in El Paso's northwest side, the city's Parks and Recreation Dept. sought to create a positive neighborhood influence near the West Hills housing development.
Working With Nature
Available land on the west side of the Franklin Mountain Range has become premium, but a 100-acre area of rainwater detention ponds held promise. Rains come infrequently in this desert environment, but when they do, water runs fast and flood control is a major issue. The city of El Paso challenged the design team of Schrickel, Rollins and Associates (SRA) to create a community park in this existing water detention basin without disturbing the ponds and drainage system created by the U. S. Army Corps of Engineers.
"It's one of the more innovative projects we've seen in a long time because it mixes so many different concepts in one spot," commented Victor Baxter, RLA, vice president with Schrickel, Rollins and Associates (SRA), the landscape architectural firm for the project. "The landscape architect's role was critical to the successful blend of maximizing the site's uses without altering the performance of the area's prime function — detention of flood waters."
Balancing Cut and Fill
The U.S. Army Corps of Engineers has a stringent requirement that does not allow changes in the earthwork quantities for on-site cut and fill operations. Any changes in the detention ponds' storage capacity would have terminated the project. Because USACE requirements prohibited bringing in outside fill, the project had to be designed with a balanced cut and fill within the park.
Results of site analysis were particularly critical. A team of civil engineers and hydrologists from Parkhill, Smith and Cooper (PSC) mapped the 50-, 75-, 100-year and spillway flood elevations within the site. By coincidence, that summer of 2006 was one of the wettest in El Paso's history, "perhaps equivalent to a 100-year flood," said Jose Reyes, P.E., a hydrologist with PSC. "This episode allowed hydrologists to observe water levels first hand."
The analysis revealed a narrow band of land along the east side of the park that was above the spillway elevation. Facilities were arranged according to their ability to withstand the various flood frequencies. Placed at the highest elevation and near the park's single entrance were the 30,000-square-foot recreation center and large picnic pavilion. A concession building serving the girls' softball fields was similarly placed. The remainder of the area was then broken into land uses, which range from green belt nature areas to children's play areas.
PSC engineers calculated approximately 33,000 cubic yards of cut and about 32,500 cubic yards of fill. Also calculated into the volume was 8 inches of base material and asphalt for the parking lots and the landscaping sod, according Reyes. Material could be removed from the job site, but not brought in.
SamCorp General Contractors of El Paso served as the prime contractor for the facility and subcontracted A.T.S.S. Inc. of Canutillo, Texas, for the earthwork. A.T.S.S. used traditional staking methods with motorgraders, dozers and one excavator to make the balanced cut and fill operation.
"The deepest cuts were approximately 7 feet," stated Ruben Cazares with A.T.S.S. "A layer of hard caliche with rock slowed progress for a time, requiring the teeth on the shank of the dozer ripper to be replaced every other day." To generate sufficient pulling force, only one ripper tine could be used instead of twoor three.
The city Parks Dept. issued its own challenge as well. They wanted the ball fields relatively flat so that rainwater would stay on the fields for the sake of the grass instead on running off into the detention ponds. A.T.S.S. achieved this leveling as well, with a finished compaction of 95 percent with rollers, according to Cazares.
Water conservation was a primary design issue, so SRA developed a xeric (sustainable) plan to work with the desert environment, according to Baxter. Martinez Irrigation and Landscape, Inc. extended El Paso's system of non-potable sewerage effluent to this facility.
El Paso has developed an extensive system of non-potable water lines from water treatment plants primarily in the western, central and northeastern parts of the city. The lines — all color-coded in purple — serve landscaping irrigation needs for many city parks, golf courses, commercial developments, and schools. The non-potable effluent tends to have a high salinity rate, so analysis of soil in each park helps determine if the effluent is a viable option, according to Jose Ortiz of the El Paso Parks and Recreation Dept. If the soil in a particular area is naturally high in salinity, effluent lines are not extended to that area. Here at Westside, the effluent was determined to be an acceptable for irrigation.
Martinez Irrigation and Landscape, Inc. installed over 10,000 lineal feet of landscaping irrigation throughout the areas of Westside Recreation Center to be landscaped, according to Lalo Martinez.
The turfgrass used for the ball field is a special hybrid, Princess 77 Bermudagrass, which is both water-conserving and salt-tolerant. Turfgrass and irrigation is limited to ballfields and a few key high-use areas. All other landscaping is planned to be sustainable and to naturalize into the site with little or no irrigation.
"We put in about 2,500 plants," said Martinez. "They were established desert plants in one-gallon and five-gallon containers that require very little maintenance."
"Native bunch grasses and plants, such as sage, creosote, agave, yucca, and sotol were used in strategically planted landscaping and accented with boulders," explained Clint Wofford, RLA, landscape architect with SRA. "Areas outside the footprint of the recreation center were left native."
Beyond the site constraints, an additional constraint was found off-site. Off-site drainage that enters the site from the surrounding neighborhood required not only erosion control measures to stop its velocity as it entered the site but also the opportunity to filter the water before entering the drainage basin. This led to the design of a dry waterfall biofilter that slows the water down as it passes through a series of filters before it is introduced to the existing drainage channels that had been carved naturally. Because flash flooding is common in the Chihuahuan Desert, early warning devises were placed upstream to give park users time to climb to safety.
Amid what is still a natural setting, this community of about 100,000 residents can enjoy team sports, children's playground equipment and hiking trails. Extensive use of crushed granite surfacing ties the park's venues together visually and marries the project with its desert surroundings. The recreation center's combination of subtle and bright colors reflects sunset's glow on the Franklin Mountains to the north. Westside Community Park settles gracefully into its rugged basin setting, demonstrating that with thoughtful planning and design a utilitarian site can live a second life as an attractive, sustainable and popular community park.
|General Contractor||SamCorp General Contractors|
|Landscape Architect||Schrickel, Rollins and Associates, Inc. (SRA)|
|Architect||Parkhill, Smith and Cooper, Inc. (PSC)|
|Irrigation system||Martinez Irrigation & Landscape, Inc.|
|Landscaping planting||Martinez Irrigation & Landscape, Inc.|
|Concrete curb/gutter||Mlee Corp.|
|Concrete cast tilt wall||Mlee Corp.|
|Tilt wall erection||Alliance Riggers and Constructors|
|Masonry||Manuel and Jerry Construction, Inc.|
|Glazing||Canyon Glass Co.|