Measuring Public Access to the Shoreline: The Boat-Based Offset Survey Method

Abstract

As cities redevelop underutilized waterfronts, opportunities exist to promote public access to the shoreline. However, planning for access is hampered by a lack of reliable data on how people utilize a specific shoreline. The boat-based offset transect survey (B-BOTS) method allows researchers to accurately record, map, and analyze shoreline access. This article discusses the use of B-BOTS along the northern part Narragansett Bay, RI. Using B-BOTS, on 52 randomly selected days over a two-season period, researchers developed a geodatabase that included the position of all shoreline users and the activity in which they were engaging. Using this geodatabase, the article demonstrates that the amount and type of shoreline use varied dramatically throughout the study area and varied in ways that would not have been predictable using conventional sources of data. The article also demonstrates that the availability of parking not only influenced the amount of shoreline use, but also the manner in which different user types distributed themselves along the shore. The article discusses the importance of such findings for developing plans for waterfront redevelopment and public access.

Keywords:

• coastal access
• GIS
• GPS
• waterfront redevelopment

Acknowledgments

We thank Tiffany Smythe, Michelle Armsby, Emily Pysh, Danielle Boudreau, David Conover, Liz Hansel, Beth McArdle, and Sara Schroeder for assisting with data collection. This research was funded by the Rhode Island Sea Grant with additional support from the URI College of Environment and Life Sciences.

Notes

1. While the federal legislation includes access as a fundamental goal, § 309 of the 1990 Coastal Zone Amendments and Reauthorization Act does not establish any required minimum public shoreline access standards.

2. Observation points have been similarly used to study vessel activity. For example, researchers have counted vessels within geographically defined areas to study fishing activities around a marine reserve in California (Wilcox & Pomeroy, 2003), boater compliance with speed restrictions in Florida (Gorzelany, 2004), recreational boating patterns in Sydney Harbor, Australia (Widmer & Underwood, 2004), and changes in boating activities over almost two decades in Scotland (Adams et al., 2006).

3. See Valdemoro and Jimenez (2006) and the sourced cited therein for examples of using aerial photographs to study the spatial distribution of recreational beach users.

4. The shoreline length was calculated by modifying a polyline shapefile of the shoreline that is available from Rhode Island GIS (http://www.edc.uri.edu/rigis/data/). The shoreline was digitized 1:5000 orthophotographs. We modified the shapefile by eliminating polylines that represented the shorelines of smaller semi-enclosed waters that were not on the main part of the Bay and that were not visible from the boat.

5. Rather than spread the sample days throughout the year, the researchers chose to concentrate limited resources on the warmer months which were believed to be the busiest.

6. The Laser Locator can theoretically obtain measurements for objects up to 2500 meters away and is rated for +/- 1 meter accuracy up to 1500 meters at 10 kilometers visibility. The researchers utilized the binoculars over much shorter distances along the transects.

7. The CRMC dataset does contain attributes that could suggest the purposes for which people might access the shoreline at a given access point, including such information as whether there is a boat ramp and the geology of the nearby shoreline, e.g., whether the shore is sand, cobble, or armored.

8. http://www.eastprovidencewaterfront.com/index.php, last accessed on December 8th, 2008.

9. Every record in the database for a person accessing the shoreline was assigned to the nearest access point. Of course, while this is not an unreasonable assumption, a person may have accessed the shore from an access point other than the closest one.

10. A half mile was chosen because it is often used in as a maximum walking distance in the urban planning literature when designing pedestrian oriented development (Song & Knaap, 2004; Thompson et al., 2006). Certainly people take walks along the shore that are longer than a one mile round trip. Still, if people are carrying fishing equipment, beach toys, coolers, and so forth, they will not be willing to walk long distances. In fact, when approving beach renourishment projects, the U.S. Corps of Engineers requires 10 parking spaces within a quarter mile of each access point (Blizzard & Mangun, 2008).

11. Cuspate forelands are geological features found on coastlines and created by long shore drift. Made out of sand and shingle, and later stabilized by vegetation, cuspate forelands are triangular-shaped shoreline accretions (Woodroffe, 2003).