Sebastian, Florida Environment Guide

Sebastian's environment section holds 25 guides, and the table below sends each common question about the lagoon, the inlet and the city's drainage to the one that answers it.

The rest of the Sebastian environment section fills in the background: the Indian River Lagoon guide explains where the lagoon's water comes from, the muck dredging guide covers the black sediment on the lagoon floor, and the low impact development and integrated pest management guides cover what the City of Sebastian does on its own land and canals.

The lagoon off Sebastian is recovering but not yet clean: the Marine Resources Council's 2025 report moved the Central Indian River Lagoon basin from poor to okay (Marine Resources Council), the stretch from Rockledge to Sebastian (WQCS, November 2025).

The basin off Sebastian was the only one of the lagoon's five basins whose overall health rating changed in 2025. Lower algae levels and new seagrass coverage drove the upgrade, yet the council rated water quality in that Central basin the poorest of all five basins (Marine Resources Council).

Indian River County counts more than 4,300 species that depend on the lagoon for some part of their life cycle, 50 of them listed as endangered or threatened (Indian River County). Its Lagoon Division works from a Lagoon Management Plan adopted on September 26, 2023, and lists two derelict vessels pulled from the lagoon in winter 2026 and a pump out vessel program launching in 2026.

Seagrass is the clearest yardstick near Sebastian Inlet. In 2024 the Sebastian Inlet District mapped 115.38 acres on its six monitored flood shoals, about 1.4 percent below the 117.02 acres of 2022 (Sebastian Inlet District). Persistent poor water clarity and bad weather meant no usable aerial images for a 2023 acreage estimate, so the district compared 2024 with 2022. Shoal grass and Johnson's seagrass dominate those shoals.

The Sebastian lagoon water quality guide goes through the pollution sources, the lagoon seagrass guide follows the inlet shoals year by year, and the algae blooms and fish kills guide covers the past bloom events near Sebastian and Vero Beach.

Pelican Island, in the Indian River Lagoon off Sebastian, became the first federal bird reservation on March 14, 1903, and its public trails sit on the barrier island along the Historic Jungle Trail (U.S. Fish and Wildlife Service).

President Theodore Roosevelt set Pelican Island aside with the encouragement of Frank Chapman and the Florida Audubon Society, and Congress made it a wilderness area in 1970 (U.S. Fish and Wildlife Service). The island measured 5.5 acres in 1970 and is roughly 3 acres now, worn down by boat wakes and sea level rise, and the Pelican Island Wilderness is the smallest unit of the national wilderness system.

The refuge public use areas are on the Historic Jungle Trail in Indian River County off A1A, 3.3 miles south of Sebastian Inlet and 3.7 miles north of Wabasso Beach Road (CR 510); the Centennial Trail address is 11455 Jungle Trail, Vero Beach (refuge visitor page). The refuge manages about seven miles of trails, including the three quarter mile Centennial Trail built to ADA standards, and bicycles are not allowed on the trails.

Hours deserve a check before an early start at Pelican Island: the same Fish and Wildlife Service page says the public use areas open daily from 7:30 a.m. until sunset, while its contact block lists refuge hours as sunrise to sunset (U.S. Fish and Wildlife Service). The 7:30 a.m. opening is the one to plan around for the Jungle Trail parking lots.

The Sebastian mangroves guide covers the red, black and white mangroves on the refuge and city shorelines, and the invasive plants guide covers the Brazilian pepper and other invaders managed around Pelican Island.

The Sebastian Inlet District, an independent special taxing district created by the Florida Legislature in 1919, maintains the inlet channel, its sand trap and the sand bypass to the beaches south of the inlet (Sebastian Inlet District).

Sebastian Inlet is one of only five navigable channels linking the Indian River Lagoon to the Atlantic Ocean (Sebastian Inlet District). The district credits that ocean connection with the tidal flushing that has kept the seagrass on its monitored inlet flood shoals in better shape than many other parts of the lagoon (2024 seagrass report).

Sand drifting along the coast collects in a 42 acre submerged sand trap west of the inlet, which the district dredges every 4 to 5 years once it holds roughly 150,000 to 200,000 cubic yards (district FAQ). The renourishment interval for beach Sectors 1 and 2, the three miles of beach just south of Sebastian Inlet, is also every 4 to 5 years.

Freshly pumped sand on the beaches south of Sebastian Inlet looks darker than normal because it comes off the bottom of the sand trap; the district says it lightens once it dries and bleaches in the sun (Sebastian Inlet District).

The Sebastian Inlet guide lists the district's key numbers, the sand bypass, beach renourishment and State of the Inlet reports guides follow the sand, and the tides and currents, worm rock reefs, coquina geology, fish nursery and sargassum guides cover what moves and lives in the inlet.

The lagoon off Sebastian lies inside the Indian River-Malabar to Vero Beach Aquatic Preserve, a 28,000 acre state preserve in Brevard and Indian River counties established in 1970 (Florida DEP).

The preserve was folded into the Aquatic Preserves Act of 1975 and designated Outstanding Florida Waters in 1979 (Florida DEP). The Florida Department of Environmental Protection lists Main Street Boat Ramp, Dale Wimbrow Park and Sebastian Inlet State Park among the preserve's public access points.

The small islands scattered through the preserve off Sebastian are spoil islands built from sand, shell, muck and limestone rubble dredged for the Intracoastal Waterway; Florida DEP calls them an important biological and recreational part of the Indian River Lagoon even though they are not a natural community (Florida DEP).

Indian River County's Living Docks program with FIT has installed 21 docks (Indian River County).

For land, the Indian River County commission passed Resolution 2022-016 on March 8, 2022, calling a referendum on up to $50,000,000 in general obligation bonds to buy environmentally significant lands, and on June 18, 2024 it approved the program guide and created the Environmental Lands Acquisition Panel to rank nominated parcels (Indian River County).

The aquatic preserve, oyster reefs, spoil islands, county conservation lands and derelict vessels guides each go deeper on one of these Sebastian protections.

Most rain that falls on Sebastian runs through city canals, ditches and swales into the St. Sebastian River and from there into the Indian River Lagoon (City of Sebastian).

The city lines nearly 9 miles of the lower eastern and southern banks of the St. Sebastian River and covers about 9,000 of the 100,000 acres in the Sebastian River watershed (City of Sebastian). General Development Corporation built the street and drainage grid in the late 1950s for about 15,000 single family home sites, and the city says that 1950s system lacks the storage and water quality treatment present day standards require.

Sebastian adopted Ordinance No. O-13-11 to run its federal NPDES stormwater program, and engineering inspectors in the Stormwater Department respond to complaints of illicit discharge into the city system (City of Sebastian Clean Water Program). The city reports illicit discharge violations to the Florida Department of Environmental Protection every year.

The Sebastian stormwater pollution prevention guide, the low impact development guide, the integrated pest management guide and the St. Sebastian River guide cover the city programs and the river itself.

Fish kills and discolored water off Sebastian go to the FWC Fish Kill Hotline at 1-800-636-0511, and dumping into city swales or canals goes to the City of Sebastian Citizens Request Line at (772) 581-0111 (FWC; City of Sebastian).

A report from the Sebastian waterfront should give FWC the location, ideally the nearest street address or GPS coordinates, and the number of fish involved; about 2,000 people submit fish kill and disease reports to the hotline each year statewide (FWC).

Last verified: October 14, 2026, on the City of Sebastian website, the Indian River County website and the FWC site.