Ridge to Reefs, Inc.

Guidance for reducing the impact of dirt roads on Culebra reefs

2015

Eldersburg, MD; Yauco, Puerto Rico

Ridge to Reefs, Inc.; Protectores de Cuencas, Inc.

15

Final Report

"The goal of this short document is to recommend general standards for dirt road construction, maintenance and retrofitting in Culebra, P.R. to minimize their impact on the nearshore marine environment. Also, this guide will provide the tools to minimize any additional construction and long-term maintenance costs. Dirt roads and bare soils transport sediments at a rate of 10 to 1000 times the natural transport rate from undisturbed hillslopes and forested areas. Once transported to the coast, sediment can reduce the quality and abundance of coral reef and sea grass habitats important for marine turtles, juvenile fish and shellfish. In adopting this guidance an individual or corporation is helping protect the nearshore ecosystems, reducing their own long-term maintenance costs and helping protect Culebras natural beauty, economy and ecosystems for future generations. This document is intended to be a living document and refined as practices are improved and more detailed specifications developed; it is not intended to be used as an engineering guide for road building as this subject matter is handled more thoroughly but with less focus on green infrastructure by other resources including FAO (1998). This document is more about how to minimize sediment transport from areas with dirt roads. When larger drainage areas and stream and channel crossings come into play particularly with new construction; we recommend consulting with a firm and contractors experienced in watershed engineering/ hydrology and construction. However, the vast majority of unpaved road building, management and maintenance are in small drainages, subdivision roads, driveways, road extensions and already built dirt roads particularly in areas such as Culebra. This document begins with a summary of a series of practices for reducing flow and erosion from dirt roads including: 1) Diversion Practices and 2) Flow and Erosion Reduction Practices. The document next reviews several dirt road management scenarios including road grading and ditching scenarios; 3) Example Management Scenarios for Dirt Roads. The scenarios are intended to help establish a practical set of recommendations for sites but each site will have its own unique characteristics. Finally the document provides some guidance for maintenance 4) General Recommendations for the Maintenance of Dirt Roads; in order to provide tips for effective operation and maintenance of practices. Finally, though not comprehensive, a number of design specifications from other successful projects are contained in Appendix I."

FY2013 CRCP Project ID 411; Project Title: Reduction and Prevention of Land-Based Sources of Pollution from Highly Erodible Bare Soils and Unpaved Roads on Culebra, PR; Principal Investigator: Lisa Vandiver