HARLINGEN — Spurred by memories of last June’s record rains, and the looming hurricane season, city officials from across the Valley met this week with the top official of the International Boundary and Water Commission to discuss rising concerns about flood control.
IBWC Commissioner Jayne Harkins and principal engineer Daniel Avila were in Harlingen to discuss a regional response to recent agency proposals for dredging the Arroyo Colorado and slashing vegetation choking its banks.
“The June flood that we experienced was such that we had several cities — Weslaco, Mercedes, us here in Harlingen — that had water damage in homes, we had several roads that were flooded causing damage to the roads, and it was extensive,” Harlingen City Manager Dan Serna told IBWC officials.
Serna said the damages totaled in the million of dollars, and pointed out that the arroyo was carrying 5,000 cubic feet per second and hit an elevation just below 24 feet at the flood gauge in Harlingen. IBWC engineers say the arroyo should be currently able to carry off 85 percent of its 21,000 cfs capacity.
“The improvements that were done in 2014, 2017, to remove some vegetation, was supposed to bring it back up to an acceptable level, about 85 percent (of capacity) I believe,” Serna added. “But what we experienced in 2018 with the flood was that at 5,000 (cfs) we were underwater in several areas at an elevation of 24. I believe the study from (IBWC engineer Apurba Borah) indicated that at 85 percent we can get to an elevation of what, almost 29 feet?
“At 29 feet, I don’t even want to imagine what that looks like,” he said.
The record rainfall of 16.85 inches in just 72 hours last summer in Harlingen has added urgency to efforts to find answers to what many say is a deteriorating flood-control system in the Valley.
The IBWC’s Harkin was appointed commissioner in November by President Trump. An engineer, she is former director of the Colorado River Commission of Nevada and is experienced on water and hydropower issues.
City officials doubt the Arroyo Colorado can reach 85 percent of its 21,000 cfs capacity IBWC engineers say it can. Years of siltation and vegetation growth have severely restricted flow rates along what is a crucial flood-control pathway for the Valley.
This month, the IBWC announced a plan to carve a 50-foot vegetation-free buffer along the arroyo banks beginning at 77 Sunshine Strip/U.S. 77 and extending downstream nine miles to the Port of Harlingen. Flood-plain vegetation would be trimmed back from 77 Sunshine Strip/U.S. 77 to the Union Pacific rail bridge No. 2 downstream.
The channel also would be dredged to a depth of three feet from 77 Sunshine Strip/U.S. 77 to Cemetery Road Bridge near the Port of Harlingen.
“What I didn’t like when we met two weeks ago at the IBWC office in Mercedes, when we asked about organizing the city and working alongside IBWC to improve what we’re just discussing today, we were told no, that’s something y’all have to do,” said Mercedes Mayor Henry Hinojosa. “I find that very disappointing. You would think that the feds would take the lead but they literally washed their hands. … That was very disturbing to us.”
IBWC Commissioner Harkins said she appreciated the mayor’s candid assessment of the meeting.
“I appreciate your comments, I wasn’t there,” she said. “I’m here trying to figure out what this is.”
City disputes plan
Harlingen officials disputed the claims IBWC engineers made at the meeting this month in Mercedes.
In a written rebuttal presented to Harkins and IBWC officials yesterday, city officials said clearing and removing choking vegetation along the arroyo will not provide the flow rate needed.
“The City of Harlingen questions the practicality of being able to implement the mitigation plan,” the document said. “Reduced rights of way, terrain with steep slopes and environmental protection regulations are a few factors that would restrict clearing the arroyo.”
The city document further stated that, while clearing vegetation and dredging the arroyo channel is well and good, the proposal by the IBWC doesn’t go far enough.
“The city supports a reduction of flows being routed through the arroyo by diverting waters to the North Main Drain and creating regional detention facilities at strategic locations throughout the arroyo,” the document concluded.