General Development Corporation and Sebastian Highlands — Sebastian, Florida

General Development Corporation, the company that grew out of the Miami-based Mackle Brothers, built Sebastian Highlands after buying 1,345 acres in Sebastian in 1957 (Congressional Record).

Sebastian Highlands, the grid of curving streets, swales and canals that fills most of Sebastian between U.S. 1 and the St. Sebastian River, was a General Development Corporation project. In a Congressional Record statement entered on November 13, 2024, for the city's centennial, Rep. Bill Posey wrote that the Mackle Brothers, a developer based in Miami, which later became General Development Corporation, bought land throughout Florida for planned communities, including 1,345 acres in Sebastian in 1957 to develop Sebastian Highlands.

The purchase came when Sebastian was still a small river town. Vero Beach Magazine records that commercial fishing families ran fish houses that dotted the riverfront along Indian River Drive, and that the population numbered fewer than 400 some 70 years before its 2024 article. The Highlands changed the shape of the place: an old town on the lagoon, and then a platted subdivision many times its size spread west and south toward the river. By the 2000 census, according to the same Posey statement, Sebastian had become the most populous city in Indian River County, a position it still holds.

Sebastian Highlands took shape over about four decades, from the 1957 land purchase to a mostly built-out subdivision by the late 1990s (Congressional Record).

Before any houses went up, General Development built the Sebastian Highlands street grid and an open drainage network of canals, ditches and swales sized for about 15,000 home sites (City of Sebastian).

GDC built the roads and the drainage first and sold the lots afterward. The City of Sebastian's drainage system history states that in the late 1950s, General Development Corporation (GDC) designed and constructed the street and drainage infrastructure to support development of approximately 15,000 single-family home sites. The Sebastian Highlands system was installed during the early phases of the land development to the 1950's standards, which means open channels that move water quickly rather than hold and clean it.

The scale explains why Sebastian's stormwater network is so large for a city of its population. The same city page places Sebastian along nearly 9 miles of the lower eastern and southern banks of the St. Sebastian River, covering about 9,000 acres of the 100,000 acre Sebastian River Watershed. The majority of the City's storm water run-off is delivered by a system of canals, ditches and swales to the St. Sebastian River, which drains to the Indian River Lagoon.

Today the city's Stormwater Utility lists what GDC left behind: a collection and treatment system of swales, ditches, culverts, catch basins, baffle boxes and the 8.15 mile Elkcam Canal/Collier Creek Canal. Collier Creek and the Elkcam waterway run through the middle of the Highlands, and the roadside swale in front of nearly every Highlands lot is part of the same GDC design.

General Development sold Sebastian Highlands lots through advertising, offering quarter-acre lots for $500 to buyers across the Northeast during the 1970s (Vero Beach Magazine).

General Development sold Sebastian by mail and advertisement to buyers who often had never seen the land. Vero Beach Magazine reported in July 2024 that growth in Sebastian was slow until the 1970s, when GDC, which it describes as a major developer in Florida, platted some 1,345 acres and advertised its quarter-acre, $500 lots throughout the Northeast. The magazine writes that the lots attracted retirees looking for affordable housing and warm weather, and that the affordable housing also drew people who worked in Vero Beach.

Selling lots far ahead of building meant the Highlands filled in over decades rather than years. The City of Sebastian states that most of the roughly 15,000 home sites have been developed by the late 1990s, about forty years after the street grid went in. The result is the pattern still visible along Highlands streets off Barber Street and Schumann Drive: houses of many decades side by side on lots of the same size, each fronted by its own swale and driveway culvert, with vacant lots in between.

The population record reflects that slow fill. Rep. Posey's 2024 statement puts Sebastian's 2023 population at 26,825 and notes that 35 percent of the population is 65 or older, the retirement profile GDC's northeastern advertising first drew.

When General Development filed for bankruptcy in 1990, the City of Sebastian acquired vacant Highlands lots that it still held in 2024 (Sebastian Daily).

General Development's collapse left the City of Sebastian holding land. Sebastian Daily reported in December 2024 that a group of vacant parcels owned by the city were acquired when General Development Corporation filed for bankruptcy in 1990, and that the company's bankruptcy was considered one of the most complicated in the state's history.

Those GDC-era lots resurfaced in 2024. The Sebastian City Council partnered with Indian River Habitat for Humanity and proposed donating 12 acres of the former GDC land for single-family homes, with city employees given priority. Residents of Concha Drive, Adams Street and Acorn Terrace objected at a council meeting, saying they had not been properly notified; Mayor Bob McPartlan said the homes would be single-family houses bought through sweat equity and mortgage payments. Sebastian Daily reported that zoning changes were still necessary and that the first house could take years.

The City of Sebastian Stormwater Utility maintains the GDC canals, ditches and baffle boxes, while each Highlands homeowner keeps up the front yard swale and driveway culvert (City of Sebastian).

The city does, with help from every Highlands homeowner. The City of Sebastian's stormwater FAQ states that each homeowner is responsible for maintaining his/her own front yard swale and driveway culvert, a rule that comes straight from the GDC design of roadside swales instead of curbs and storm sewers. City Stormwater Utility staff clean all City of Sebastian baffle boxes quarterly, and Ordinance O-13-11 set up Sebastian's stormwater quality and discharge control program under the federal Clean Water Act.

Water quality is the gap the city is closing. The city's drainage history says the GDC system does not provide the storm water storage or water quality treatment required by present day development standards. The city has 9 baffle boxes installed at outfall points, and its stormwater website reports that monthly sampling of discharges for nitrogen and phosphorus began in 2014. Sebastian's 2023 Stormwater Master Plan adds a sea level rise assessment and a capital improvement plan, and the council followed with Resolution R-24-41, a stormwater impact fee increase.

The city record of what GDC built in Sebastian lists streets and drainage but no sewer system, so central sewer has come later through Indian River County and city projects (City of Sebastian).

The City of Sebastian's account of what GDC built lists streets and drainage; it does not list a sewer system. Connecting Sebastian homes and businesses to central sewer has since become a long-running Indian River County and City of Sebastian effort. In 2017, House Bill 4281 requested a $2,500,000 state appropriation for Indian River County-Sebastian Septic to Sewer; it died in the Appropriations Committee on May 8, 2017.

The current approach is an interlocal agreement. WQCS reported on September 12, 2025, that Indian River County Utility Services would install public sewer pipes so residents and businesses in Sebastian's Community Redevelopment Area could connect, and that the county had another grant project planned for north Sebastian. The Highlands, the largest piece of GDC's 1957 purchase, is the area that future phases would have to reach.