BACKYARDS ON THE BAY  A yard care guide for the coastal homeowner

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• TABLE OF CONTENTS
  
• INTRODUCTION
  

• SECTION 1: Diagram of good vs. bad backyard on the bay

• SECTION 1A: Salt Marsh Diagram

• SECTION 2: Evaluation of your yard's impact on the Bay.

• SECTION 3: Bay friendly yard care tips

• SECTION 4: Coastal Erosion and Seawalls

• SECTION 5: Septic Systems

• SECTION 6: How to create a buffer of Native Plants

• SECTION 7: How to determine if you need a permit

• APPENDIX 1: Coastal Buffer
  Site Plan
• APPENDIX 2: 
  Native Plant List
• APPENDIX 3: Invasive Plants
• APPENDIX 4: Planting Guidelines
• APPENDIX 5: Sources of Native Plants
• APPENDIX 6: Technical Assistance
• APPENDIX 7: References and Sources of Information

Section 4: Coastal Erosion and Seawalls

Shoreline and beach erosion is a natural phenomenon that occurs at different rates all along the Rhode Island and Narragansett Bay coastline dependent upon the exposure to the ocean and the geology of the region. Typically, the more exposed a shoreline is to the ocean tides and to coastal storms, the higher the natural erosion rates. As a result, South County and other south facing shorelines have much higher erosion rates than Narragansett Bay waterfront areas. Other factors such as soil type, vegetation cover and the direction of long shore currents also will affect the natural erosion rate. Coastal erosion is also affected by the amount of sea level rise ­ estimated at three to four millimeters per year along Rhode Island’ coastline.

• A buffer of native plants prevents coastal erosion by stabilizing and holding the soil in place more effectively than lawns that have shallow root systems and are more prone to erosion. Waves and storms can eat away at your property if there is no buffer of vegetation. Salt marshes that fringe the shoreline also act as natural shoreline protection by dissipating wave energy and stabilizing the sediments.

• Erosion can be magnified by indiscriminately removing shoreline vegetation by increasing the speed of stormwater. This increased runoff can quickly create gullies and washouts, undermine other landscaped areas and generally create more problems than you had when you started. If you do not want to lose your land, do not remove coastal plants.

• Even narrow buffers of shrubs, trees and deep-rooted grasses can help stop and slow shoreline erosion. If planting a buffer, always choose native, locally produced plant stock. See local sources of native plant material on in Appendix 2.

Many shoreline areas around Narragansett Bay have been altered by shore protection structures such as concrete seawalls, rock revetments and riprap. It is estimated that structural shoreline protection features border more than a quarter of Narragansett Bay’s shoreline. Erosion is usually increased on adjacent property when a single property owner chooses to armor their shoreline. The wave energy is diverted along the seawall and focused on the edges of adjoining property, undermining the shoreline and causing a rapid increase in erosion. The cost of building, obtaining permits for and maintaining a seawall can be an enormous financial drain for property owners. If not properly constructed or maintained, seawalls can break apart and cause greater damage to inland property during coastal storms and hurricanes. Armored shorelines can also have a profound effect on the coastal environment by replacing, filling, altering the shoreline and preventing marshes from moving inland as sea level rises.

The Coastal Resources Management Council does not allow "structural" shoreline protection in many areas of the Rhode Island coast and where it is allowed, Council policy requires the property owner to explore all other methods of shoreline stabilization prior to granting a permit.

1) If you have a seawall that is in excellent condition:

Create a maintenance-free zone of native coastal plants at the landward edge of the seawall

2) If you have a seawall in need of repair or in need of replacement:

Remove the seawall, regrade the shoreline and reestablish a planted sloping shoreline. It is often less expensive to remove a seawall than to repair an existing seawall. For any repair of a seawall or work in the coastal buffer zone, consult the Coastal Resources Management Council at 222-2476.

3) If you do not have an existing shoreline protection structure and you need to control erosion:

Consult the CRMC about options for shoreline erosion control. Dependent upon the severity of the erosion, non-structural or bioengineering alternatives such as planting the slope with coastal shrubs may be feasible. Using plants to control erosion is often more cost effective than structural shoreline erosion control such as riprap or sea walls. Employing non-structural erosion control techniques will enhance access to the shoreline, where a typical riprap revetment will restrict access to the water’s edge. Consider using new bioengineering methods such as coconut fibers and other geotextile products. These fabrics and mats not only act as temporary erosion control devices before vegetation takes hold but also become a seed germination area that can be directly planted.

| TABLE OF CONTENTS | INTRODUCTION | SECTION 1 | SECTION 2 | SECTION 3 | SECTION 4 | SECTION 5 | SECTION 6 |
SECTION 7 | APPENDIX 1 | APPENDIX 2 | APPENDIX 3 | APPENDIX 4 | APPENDIX 5 | APPENDIX 6 | APPENDIX 7 |