HARLINGEN — The city’s new subdivision developers’ guide is putting its upgraded drainage standards down in writing.
Meanwhile, city officials plan multimillion-dollar projects aimed at curbing flooding.
After months of debate, a split City Commission this month approved the Harlingen Subdivision Development Guide, a 131-page manual specifying engineering standards developers will follow as they plan the city’s new subdivisions.
“The intent behind the manual is to bring the engineering standards into a document that facilitates access for the developers and engineering community to know the standards and how to follow them,” Assistant City Manager Carlos Sanchez, a hydraulic engineer, said during an interview.
But Commissioners Frank Puente and Richard Uribe voted against the manual’s approval for the same reason a citizens’ group opposed it.
The city’s new ordinance upgraded its drainage standards from five-year storm designs to 25-year plans aimed at protecting homes from so-called 25-year storms, or storms expected to occur every 25 years.
“This ordinance is a step forward and it strengthens our building codes and ordinances and guidelines to mitigate against further flooding,” Mayor Chris Boswell said.
But Puente and Uribe along with the group Reinvent Harlingen Drainage believe the city’s new drainage standards don’t go far enough.
For months, they called for 50-year storm designs such as those adopted in Weslaco, McAllen and Hidalgo County requiring developers to design subdivisions to better protect against flooding stemming from storms such as those in June 2018 and 2019.
Across town, hundreds of homes flooded during the two so-called 100-year storms.
During public comment periods, residents called for 50-year storm designs featuring expanded drainage ditches and wider storm sewer pipes along with bigger retention ponds to protect new subdivisions.
“What everyone’s upset about is the flooding that’s happening to homes and the cost to the citizens and insurance companies,” Uribe said.
Cost of 50-year storm design plans
For weeks, resident J.V. Garcia, a civil engineer who founded the group Reinvent Harlingen Drainage, has claimed the city held back on upgrading its standards to 50-year storm plans because that would tack an additional $200 to the cost of a subdivision lot.
“We need to improve the drainage system — get bigger pipes,” resident Eddie Rocha told commissioners during the Oct. 7 meeting. “The city has to go out and get this funding to help the citizens of Harlingen.”
Meanwhile, Puente requested City Engineer Andy Vigstol estimate the 50-year storm design’s additional costs.
But Vigstol said costs depend on project variables.
Under the new manual, developers are required to upgrade standards from five-year storm designs to 25-year plans.
Now, the new 25-year storm designs calls for bigger detention ponds.
“The current requirement, or post requirement, is a 25-year storm event design, and so what that means is that the developer is going to be required to detain the amount of water that a 25-year storm would create prior to the development,” Sanchez told commissioners during the meeting.
“A difference between a 25-and 50-year event, by my calculations, quick calculations, was anywhere between around 30-, 35-percent increase in volume created by a 50-year storm.”
The city also requires developers to design subdivisions’ drainage plans to prevent runoff from flooding nearby neighborhoods.
“The new system needs to be designed primarily to provide a functional system for the development itself,” Sanchez told commissioners.
“Obviously, the developer should not build a system that’s not going to protect the property of those owners or buyers of land who are going to reside in that subdivision. Our part as a community, as a city, is to protect that but at the same time protect those who are around and for that reason we mitigate — we require developers to mitigate the impact to the connections to the outfall points where these developments are going to tie into.”
Master drainage plan
Since 2008, officials have followed a master plan calling for about $70 million worth of projects aimed at curbing flooding.
“These are the drainage needs in our community and we recognize these needs,” Sanchez said during an interview. “It’s going to take millions of dollars but we’re seeking grants.”
Projects completed from 2008- 2014
From 2008 to 2014, officials launched $13.4 million worth of drainage projects, he said, adding grants funded $6.49 million. They include a $4.3 million downtown project, a $1.6 million project in the Buchanan, Hays and M Street area, a $2.3 million project to improve a drainage ditch along 32 nd Street and Jefferson Avenue, a $530,000 project to improve a drainage ditch along Third Street and a $1.6 million project to improve northwest drainage.
Projects completed last year
In August 2019, the city completed a project off Lake Drive in which crews replaced undersized curb inlets with three- and four-foot inlets, creating a bigger opening to allow floodwaters to enter storm pipes.
By December, the city had completed a project expanding a drainage ditch in the Secluded Acres and Spanish Acres subdivisions while installing flap gates to prevent floodwaters from backing into the neighborhoods.
Along Becky Lane, the city installed a 24-inch concrete pipe to carry water from a west-side inlet to an east-side pond.
Early this year, the city completed a project along Halpin Road aimed at improving a drainage ditch and resetting slopes to better direct water flow.
Then in April, the city completed a $278,891 project in which crews repaired a concrete drainage ditch along Jefferson Avenue.
As part of a partnership with Cameron County Drainage District No. 5 and Harlingen Irrigation District No. 1, the city launched a $157,374 project to improve a drainage ditch along 13 th Street.
Last year, the same partnership undertook a $494,584 project to improve a drainage ditch along Dixieland Road.
This year’s projects
Next month, the city plans to launch a $2.59 million project to widen storm sewer pipes in the Ninth and 13 th Street area.
A grant application could lead to a $1.5 million federal reimbursement, Sanchez said.
Now, officials are planning $11.2 million worth of projects aimed at improving the city’s storm sewer system, while requesting $8.4 million in grant funding. They include a $2.4 million project along Jefferson Street, a $3.8 million project in the Business 77 and 13 th Street area, a $2.6 million project in the Fifth and Seventh Street area, a $1.59 million project in the 21 st Street area and a $690,836 project in the Treasure Hills and 25 th Street area.