Caring for Backyard Streams

Fairfax County has about 980 miles of streams, many of which pass through homeowners’ backyards. Sadly, many of these streams suffer from bed and bank erosion due to upstream development, which results in excess stormwater entering the streams. The Northern Virginia Soil and Water Conservation District receives several calls each month from homeowners about these degraded streams. Callers typically are looking for a quick, low cost fix to stop the erosion that may damage their property or trees.

Homeowners often believe that if inadequate stormwater management is the cause, then the County will assume responsibility for the solution. Unfortunately, this is not the case. The County has very limited resources for doing work on private property. The County sets priorities that are based on threat to life and personal property, in that order. Most erosion in backyard streams does not qualify for County assistance.

Some homeowners believe that a local landscape company can fix stream erosion problems. However, landscapers may not be familiar with the specific causes of the stream erosion. Their solutions generally involve conventional measures such as dumping rip rap (specifically sized stones) and building gabion (wire baskets of stones) walls. Long term monitoring of streams using these methods shows that instead of solving the problem, they aggravate it. These structures narrow the stream, which increases the velocity of the flow and thus its erosiveness. Inappropriate solutions may cause more long-term damage than doing nothing at all.

The Northern Virginia Soil and Water Conservation District and other agencies such as the Virginia Department of Forestry can assess the erosion problem and suggest solutions. In the majority of cases, the complexity of the problem, the extent of the damage, and the time it takes to collect appropriate data will require that a homeowner hire a consultant to deal with the problem. NVSWCD can provide a list of consultants who are experts in stream stabilization techniques.

There are other issues about which homeowners may not be aware:

• Permitting
  Activities inside perennial streams may need federal and local permits depending on the size of the project and the type of equipment needed.
  
  
• Accessibility
  If part of the solution requires heavy equipment, you will need an access road. This is a particular problem if you need to run the access road through a park or a neighbor’s property.
  
  
• Trees
  Sometimes dealing with stream problems requires removing healthy trees, particularly if the stream banks need to be re-graded or if the trees stand in the way of heavy equipment.
  
  
• Cost
  The cost of stabilizing a stream significantly varies with the amount of damage and the size of the stream. A stream with limited damage may be fixed with bioengineering practices where the banks are re-graded and vegetated. Materials may include biologs, shrubs, live stakes, and grass seed. If the Conservation District prepares the plan (no charge), the project may cost between $50-100 per linear foot. For extremely degraded streams, a project can cost up to $350-$400 per linear foot because the entire channel might need to be restructured. If the stream is on a homeowner’s property, this may not be practical because the restructuring may take land from the yard by bringing meanders close to the house.
  
  
• Funding
  There might be a small amount of funding available for stream stabilization if the project is used to educate others about the design and construction or if it serves as a demonstration project for others to view and assess. In other words, more than just the homeowner has to benefit from the project. Potential sources of funding include grants from Fairfax Water or the Chesapeake Bay Restoration Fund. But in most cases, the homeowner pays for the materials, equipment, and labor.

In sum, we highly recommend that stream erosion be handled with care. Otherwise, inadequate remedies might worsen rather solve the problem.

If funding is minimal and access to the stream for heavy equipment is limited by buildings, trees or steep slopes, there are some techniques available for a do-it-yourself-project. While a simple fix might not solve the problem over the long run, it can slow down the effects of erosion. If you would like more information, e-mail NVSWCD’s Asad Rouhi or call him at 703-324-1427.