Self-draining parking lots topic of workshop


HARLINGEN — An educational workshop on redesigning parking lots to collect, filter and redirect stormwater will be held June 25, according to program organizers.

Municipalities and all others interested are invited to attend the free workshop, according to Jaime Flores, Texas A&M AgriLife Extension Service program coordinator for the Texas Water Resources Institute in Weslaco.

The workshop will be from 8 a.m.- noon at the Hugh Ramsey Nature Park, 1001 S. Loop 400 in Harlingen. It will be presented by the Arroyo Colorado Watershed Partnership and the Texas Water Resources Institute in collaboration with the city of Harlingen, Texas A&M University-Kingsville and the Texas General Land Office.

He said the workshop will have a 30-minute presentation on the construction of the new parking lot and bioretention basin at Ramsey Park. Volunteers will then plant native plants, shrubs and trees to complete construction of the project

“Cities throughout the Rio Grande Valley will be interested in this type project because it treats and stores stormwater instead of it going directly into the nearby Arroyo Colorado without any treatment,” he said. “Storing the water can also help alleviate flooding.”

Flores said a similar project was constructed at the South Texas College campus parking lot in McAllen.

“In the case at STC, during a good rain, the parking lot runoff would flood surrounding neighborhoods,” he said. “In Harlingen, the flooding resulted in the pooling of water, creating pot holes and eventually ruining the parking lot.”

At Ramsey Park, an entire parking lot was ripped up, a bioretention basin was dug into the middle of the area and the parking lot reconstructed around it so that stormwater would flow to the basin, Flores said. As part of the project, a five-acre wetland system was expanded at the park.

“Native plants and trees planted in the basin will remove nutrients from the runoff, and as the runoff percolates through the underlying layers of sand and rock in the basin, sediment and additional pollutants will be filtered out,” he said. “The treated water will then be channeled into the expanded wetland system where it will evaporate over time.”

Flores said the basin and wetlands are located on the banks of the Arroyo Colorado and will keep untreated urban nonpoint source runoff from entering it.

He said the wetlands provide a habitat for fish and wildlife and serve as a demonstration project for other municipalities and counties that may be interested in using this type of technology to treat urban stormwater.

“The Arroyo Colorado Watershed Partnership will provide the plants and tools to volunteers,” Flores said. “All of the plants are from Heep’s Native Plant Nursery and nursery owner Mike Heep will provide information on the plants.”

“We are excited to finally see the completion of the bioretention basin portion of the project,” said Javier Mendez, Harlingen parks director. “The last phase is to fill the rest of the basin with a compost layer and plant the native plants, shrubs and trees and install a drip line to keep the plants alive during the hot summer months and in case of drought.”

Construction of the project began in 2014 and involved the collaboration of TWRI with the city of Harlingen, Texas A&M University-Kingsville and Cameron County, Flores said.

“This was a big effort and one that we had discussed for several years,” he said. “The Texas General Land Office made all this possible by awarding TWRI the Coastal Impact Assistance Program grant to complete the project. All project partners brought their expertise to the table and worked together beautifully to make it a success. The city of Harlingen’s engineering department did a great job designing the basin, Cameron County’s public works department excelled in building the basin and Cameron County did their part by tearing out the old parking lot and constructing a new one.”

The workshop June 25 is part of the Arroyo Colorado Watershed Partnership’s Ramsey Park Wetland Project, funded by the Coastal Impact Assistance Program through the Texas General Land Office, Flores said.

Flores said the partnership, representing federal, state and private organizations, works to improve the water quality of the Arroyo Colorado and identifies projects that will help improve water quality.

The Rio Grande Valley Texas Master Naturalist and the Arroyo Colorado Audubon Society will provide refreshments for volunteers attending the workshop.

Rod Santa Ana III is a Texas A&M AgriLife communications specialist.