Why Miami Conservancy District Uses Turf 

Maintaining the levee embankments is essential to reducing flood risk. Properly managing turf and other vegetation plays a critical role in protecting the integrity of dams, levees, and flood channels. With over 1,500 acres to inspect and maintain, grass is both an effective and affordable solution to prevent erosion and provide a stable, easy-to-manage surface.

The roots of grass hold soil together, while the stems trap fine particles, creating a protective layer against erosion. Smooth, even turf also helps our team spot potential problems, like sinkholes or unstable areas, before they become serious threats. Plus, well-kept levees deter burrowing animals that could weaken the flood control system.

Let’s take a closer look at some of the key benefits of turf maintenance:

#1 Damage from burrowing animals

Sorry buddy. You gotta go.

Burrowing animals, such as groundhogs, can cause serious damage to the structural integrity and proper performance of the flood protection system. Keeping grass mowed and trees and shrubs cut away from the levees discourages groundhogs from digging; Well-kept levees make it easier to detect holes of burrowing animals.

• Damage from just one hole can lead to levee failure during a high-water event. Burrows weaken the levee and provide conduits for seepage through the embankment.
• Damage to the levee is compounded where multiple burrowing animals construct their tunnels near each other.

#2 Sinkholes

Sinkholes can be a hazard both for worker safety and dam or levee integrity. Potential sinkholes can be difficult to identify, because they develop slowly beneath the land surface. Internal damage may be extensive before it is visible to the naked eye. Public and private sewer pipes and water mains cross through and under MCD’s levees. When a pipe leaks or fails and soil washes away, it can become a sinkhole.

• Water under pressure can erode and wash away the earthen material deep underground.
• Broken or leaking underground water or sanitary sewer lines may create an environmental and public health hazard.
• If a sinkhole opens up, water can enter the hole from the land’s surface, causing additional erosion.
• If a sinkhole opens under a wall, revetment, pavement, or other structure, the structure could collapse into the hole.
• A sinkhole can be an imminent threat to dam or levee integrity and public safety.

Keeping grass mowed and trees and shrubs cut away from the levees makes it easier to detect developing sinkholes when they are small.

#3 Embankment Instability

A smooth embankment reduces accumulation of debris and maintains proper flow direction. Maintaining a healthy turf cover is the primary way to maintain embankment shape. Well-managed turf makes it easier to detect embankment problems in the early stages. Embankment instability can rapidly result in complete dam or levee failure. 

Internal voids and openings may exist before external signs are visible. Exposed soil increases the possibility of erosion at the surface. 

#4 Erosion

The normal process of a flowing river includes erosion and deposition. The best way to prevent erosion problems is to keep water’s erosive forces from making contact with bare earth. Well-established turf provides effective and inexpensive protection of earthen levees against erosion.

• Erosion could affect maintenance or access to the flood protection structures
• Erosion could cause an embankment, floodwall, bridge, bikeway, maintenance ramp, stairway, or other structure to move, settle, or collapse.
• If erosion is left unchecked, it could cause dam or levee failure.
  
  

#5 Gravel & Sediment Deposits

After high-water, sediment is often deposited on levees and dams, on the maintained beach area and on recreation amenities. Storm sewer outlets and floodgates can become clogged with sediment. Sediment is often co-mingled with trash, recyclables, and other debris. Gravel bars in the river may appear, move, or grow as the natural forces of erosion and deposition occurs. 

Maintaining turf properly and not allowing brush to grow on the beach areas will keep the flow of water smooth and consistent so silt is less likely to slow down and deposit.

If left unmanaged, gravel and silt can:

• Leave recreation amenities muddy and unusable.
• Disrupt drainage from storm sewers, beach areas, and recreation amenities.
• Block maintenance access and damage turf.
• Cause the flow of water to be directed toward the levee and other structures.
• Reduce channel flow capacity.
• Extreme situations may also impact levee, dam or bridge integrity.

By managing turf effectively, the Miami Conservancy District protects the flood control system, maintains public safety, and ensures recreational spaces remain usable. It’s all part of our commitment to safeguarding the region from flooding.