Learn About Your Watershed

Southeast Coast - Biscayne Bay Watershed

Image of The Miami skyline on Biscayne Bay
The Miami skyline on Biscayne Bay

Watershed Stats

Size of Basin: 1,200 square miles

Major Cities and Towns: Tamarac, Coral Springs, Margate, North Lauderdale, Pompano Beach, Sunrise, Lauderhill, Lauderdale Lakes, Oakland Park, Wilton Manors, Plantation, Weston, Ft. Lauderdale, Davie, Cooper City, Hollywood, Dania, Pembroke Pines, North Miami Beach, North Miami, Hialeah, Miami, Medley, Miami Springs, Coral Gables, and Homestead

Counties: Three-fourths of the watershed lies within Miami-Dade County and a smaller area lies within Broward County.

Major Water Features: Biscayne Bay, Miami River, New River, Pompano Canal, Taylor Slough, Atlantic Intracoastal Waterway (AICW), and nearshore coastal waters of the Atlantic Ocean

Overview

The Biscayne Bay-Southeast Coast Basins encompass much of the lower east coast region of the state, extending from the Everglades Water Conservation Areas 2 and 3 and Everglades National Park on the western side, to the Atlantic Ocean on the eastern side. They include Biscayne Bay, the New River, Pompano Canal, Taylor Slough, the Atlantic Intracoastal Waterway (AICW), and the nearshore coastal waters of the Atlantic Ocean.

Biscayne Bay
Biscayne Bay is an estuary located in Miami-Dade and Monroe Counties. The bay is 55 miles long and varies from one to 10 miles in width. It is one to 10 feet in depth and as much as 30 to 40 feet in depth in some areas where dredging has occurred. The bay is divided into three major regions: northern, central, and southern. Northern Biscayne Bay extends from the Broward/Miami-Dade County line south to the Rickenbacker Causeway. This area of the bay is surrounded by urban development and influenced by the Oleta River and the major drainage canals in northern Miami-Dade County. Central Biscayne Bay extends from Rickenbacker Causeway south to Black Point. Several major canals also influence this segment; however, urban development is less dense. Southern Biscayne Bay extends southward from Black Point to Barnes Sound and includes Biscayne National Park. Several canals that were constructed as part of the 1948 Central and Southern Florida (C&SF) Project for Flood Control drain discharge from both agricultural and urban areas to southern Biscayne Bay. Despite these impacts, Biscayne Bay overall remains highly productive. It supports extensive seagrass beds and diverse fisheries resources, and provides habitat for a variety of endangered or threatened species.

Biscayne Bay remains highly productive and supports extensive seagrass beds that provide habitat for a variety of endangered or threatened species.

Image of Vitally important mangroves fringe the shoreline of Biscayne National Park.
Vitally important mangroves fringe the shoreline of Biscayne National Park.

New River
The New River, nearly 30 miles long, flows throughout urban Broward County and is a significant cultural and ecological resource. The North Fork, a shallow, meandering tributary, extends through the northwest section of the city of Ft. Lauderdale, while the Las Olas Isles area is a series of human-made islands located along Las Olas Boulevard in east-central Ft. Lauderdale. The South Fork is composed of two drainage tributaries that join and converge with the North Fork.

Atlantic Intracoastal Waterway
The AICW, a navigable shipping route along the Atlantic coast in the southern and eastern United States, is made up of numerous sounds, bays, lagoons, rivers, and canals, and is usable in many portions by deep-draft vessels. The route, which is maintained in Florida by the Florida Inland Navigation District, is connected to inland waterways in many places.

The AICW extends along the Biscayne Bay-Southeast Coast Basins and is influenced by the watersheds and canals in the area. The AICW in Broward County is a high-traffic shipping channel and is used for recreational boating. It lies primarily within Biscayne Bay in Miami-Dade County, as it runs down the west side of northern Biscayne Bay and extends down the middle of central and southern Biscayne Bay.

Human Impacts

Image of Stormwater runoff from intensively developed properties and roadways, hydrologic modifications, and pollution from septic systems pose the greatest threats to water quality in the bay and Atlantic Intracoastal Waterway.
Stormwater runoff from intensively developed properties and roadways, hydrologic modifications, and pollution from septic systems pose the greatest threats to water quality in the bay and Atlantic Intracoastal Waterway.

The Biscayne Bay-Southeast Coast region includes the coastal ridge and an area that would naturally exist as flatwoods and lowlands to the west. Most of the lower southeast coast of Florida is nearly level and was subject to severe flooding prior to the drainage modifications that led to development. Under the C&SF Project, the U.S. Congress authorized the U.S. Army Corps of Engineers (USACOE) to implement a major regional drainage and flood control program. The C&SF Project and accompanying smaller-scale drainage projects significantly altered the region's hydrology and landscape, as wetlands were drained, natural drainage features were modified, and land was converted to the urban/residential and agricultural land uses of today.

The coastal areas of Broward and Miami-Dade Counties were the first to be developed because of the natural coastal ridge, which historically existed as well-drained, habitable land. These areas, constituting a band that extends from the northern Broward County line to south Miami, remain the most densely developed in the Biscayne Bay-Southeast Coast Basins. Over the years, new networks of drainage canals made land to the west of the coastal ridge suitable for development.

Eastern Broward County and northeastern and east-central Miami-Dade County include the most heavily developed urban areas of these counties and contain some of the more heavily urbanized areas in the state. Over the 1990-2000 U.S. Census period, the population of Broward County grew by approximately 29 percent, and Miami-Dade County by approximately 16 percent.

Stormwater runoff from intensively developed properties and roadways and pollution from septic systems pose the greatest threats to water quality.

Excluding coastal areas, urban development in Broward County and the northern part of Miami-Dade County constitutes approximately 49 percent of the total land area, and has a significant impact on surface water quality. In many of the coastal areas in the region, the infrastructure to convey stormwater and sewage is outdated. Stormwater runoff from intensively developed properties and roadways, hydrologic modifications, and pollution from septic systems pose the greatest threats to water quality in the AICW and Biscayne Bay.

South of urban Miami-Dade County, agriculture is a significant land use (approximately 14 percent of the total land area), although urban sprawl is beginning to encroach and take over. Most runoff from these urban/residential and agricultural lands enters the canal systems and is ultimately conveyed to the AICW or Biscayne Bay. Some of these canals also discharge to the Water Conservation Areas to the west. Control structures and pumping stations are used to maintain water levels and to regulate and divert flow within canals for flood control, irrigation, and ground water recharge to prevent saltwater intrusion.

Most agricultural lands in western Broward County have transitioned to urban/residential development, and agriculture is no longer a significant land use. Fertilizer and agrichemical applications and eroded sediment that are conveyed into canals in this region constitute the greatest concerns to surface water quality in the canals and receiving estuary.

In recognition of these impacts, DEP, the South Florida Water Management District (SFWMD), and local governmental, scientific, educational, and citizen organizations are working to develop strategies for protecting and restoring water quality and quantity in the Biscayne Bay-Southeastern Coast Basins.

Interesting Facts:

  • Part of Biscayne Bay is a state Aquatic Preserve and a state Critical Wildlife Area, and almost all of it is an Outstanding Florida Water (OFW). As such, these areas are subject to some of the most stringent water quality and submerged lands regulations in the state.
  • Nearly 90 percent of all municipal water supply withdrawals in the basins are from the Biscayne aquifer, which also supplies 200 million gallons per day for agriculture, irrigation, industry, mining, and recreational purposes.
  • The Everglades Construction Project (ECP) forms the foundation for the largest ecosystem restoration program in the history of Florida, and possibly the nation.
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