Monday, April 21, 2014  

More than a Silly Word  

Those of us who live in waterfront communities know all to well the environmental importance of riprap. For those that have never heard such an odd word, let us explain the value and necessity of riprap to protect our property and environment from erosion.

The use of riprap goes way back. Not only was it one of the very first means of erosion control, riprap was also used in the building of the dams in the Panama Canal. Though the completion of the canal was in 1914, construction actually began in the early 1800s, so its usefulness has been known for many years.

Riprap is also environmentally friendly and creates a habitat for sea life and wildlife. During low tide it may be home to a multitude of insects, snakes, lizards, frogs, etc. During high tide when the riprap is covered in water for long periods of time, it becomes a safe haven to all sorts of sea life seeking shelter—all of which will vary depending on the body of water, i.e. ocean, bay, river, creek and so on. The Virginia Institute of Marine Science (VIMS) recommends using riprap over bulkheads because it helps create a habitat for small creatures. So it, in turn, is a valuable asset to our ecosystem.

Riprap consists of many materials, including rock, stone, or concrete. It is used to prevent water erosion on the shoreline, or anywhere that may erode due to the movement of water or runoff. Proper installation is of utmost importance. You should always consult a professional to make sure it is installed properly. A professional will be able to guide you to the correct way to provide the highest amount of erosion control for your property. They will also be able to estimate what size of stone will be strong enough to stay in place and do it’s job, and what will be the most beneficial to the environment and to your needs.

The need for riprap on the shoreline of a body of water is to absorb the waves to prevent erosion and runoff. Seawalls and other types of barriers will only deflect the waves and send them to other areas along the shoreline. But when riprap is used, the wave is dampened as it crashes into the riprap. Therefore it doesn’t deflect to other areas and destroy the shorelines. Riprap can also be placed in front of seawalls or bulkheads that have a high rate of erosion. Putting riprap in front of a barrier keeps the dirt or sand from eroding away at the bottom and helps absorb the waves. Thus further protecting the shoreline and the environment from damage. This is highly recommended in areas that have extreme erosion issues, such as inlets, marinas and properties that have very little beach available.

Riprap is also very important in protecting marshlands. It can be installed in creeks and backwaters to preserve our natural habitat and prevent destruction of the marsh grasses. This is done by placing the rocks or other materials well in front of the marsh grasses so as not to disturb them. It is vital not to cause any disturbances to the natural growth of marshland so you must seek the opinion of an environmental specialist before attempting to do this yourself. There are most likely laws in place to protect against damage to marshlands. You must also check with your county for any restrictions. In many instances, if there is any destruction of marshlands, you will be required to offset the damage and create additional marshland to replace what has been damaged. This is a huge environmental concern. In an ideal scenario, if there is to be work around marsh grasses, the riprap is placed well in front of the grasses so as not to disturb them at all.

Riprap must be installed properly to control erosion damage. What many do-it-yourselfers do not know is that there must be a trench dug out at the bottom, called a toe, below the mean low water mark to properly hold the riprap. It is essential that this toe be laid correctly or the entire project may collapse, or worse, it may all wash away with the tide itself. Every scenario will have a different method of installing riprap, but in general, it starts with grading the area or embankment to a 1.5:1 ratio and then covering the area with a filter cloth followed by the proper sized riprap. The size of riprap depends on the amount of erosion damage and the type of water causing the damage. Hence largely exposed areas on strong waterways would use a heavier, larger type of riprap than creeks or even hillsides or cliffs that suffer water runoff damage. This is so the riprap doesn’t get carried away with the tides or wash away during a storm. Typically Class 2 rocks (300-500 lbs.) will be used to treat erosion problems on the shorelines of rivers and bays and Class 1 rocks (80-150 lbs.) are more proficient for use on creek and backwater properties.

Some contractors use a barge to deliver the riprap so as not to destroy your property by having the riprap delivered in large trucks. This is an option if you are concerned about the additional destruction incurred of possibly having to fill, regrade and re-seed your surroundings, straw the yard, replace plants and shrubbery, etc., creating yet another possible area for runoff damage. Barge delivery also doesn’t disturb the environment leading up to the shoreline, and protects your landscaping and the potential destruction of any large trees that may prevent a drive up delivery. Depending on where your property is located, a barge may be necessary due to the Resource Protection Area (RPA) which is a buffer of 50-100 feet, depending on the work area, developed to protect the Chesapeake Bay and it’s tributaries. In some areas, the Chesapeake Bay Act makes the use of barge delivery mandatory, so check with your local officials or contractors before making any decisions on how to have your riprap delivered. But generally speaking, it is more cost effective to have riprap delivered by land. The inconvenience or damage to your landscape may be a smaller price to pay when comparing it with the cost of using of a barge for delivery.

As always, when hiring a professional make sure they are licensed and insured, check their references, view their previous work, and make sure the contract states the type of work to be performed. You should also have in writing exactly what kind of warranty there is to guarantee the workmanship.

Riprap is the most cost effective way to protect our environment against erosion and to protect your property for future generations. As you can see, riprap plays an important role in conserving our natural beauty, preventing shoreline destruction and is invaluable to our environment and our future. That about “raps” it up.

By Melissa Cleaton Shearwood
Special thanks to Blake Slusser for contributing to this article.