Seadrift Lagoon Bulkhead Inspection and Assessment
Stinson Beach, CA
In December 2001 NCI and the Seadrift Association performed a visual inspection by boat of the entire 12,000 plus lineal feet of the Seadrift Lagoon existing timber bulkhead. A ranking system was developed and utilized to assess the existing bulkhead’s condition fronting each of the 203 lagoon properties. The original existing bulkhead is of timber construction, and was installed in about the year 1965; therefore its life of over 35 years at the time of inspection already had exceeded an expected lifespan for a structure of this type that is located in a saltwater environment.
Based on our visual survey assessment, the following findings were noted: severest signs of deterioration and failure located in second horizontal plank from top and in vertical posts near the mudline location for all lots with the original bulkhead in place; there were numerous areas throughout the lagoon that were losing landside sediments into the lagoon due to gaps between the horizontal planks, gaps between the bottom plank and mudline, sections of severely deteriorated and missing planks, and/or failed wall conditions; deterioration and rotting of timber bulkhead members had accelerated due to the saltwater environment, weather conditions, change in water level, and extended life of the bulkhead; and there were very few lots with the horizontal bulkhead planking extending below the mudline.