BAUE Middle Reef Project

May 14-16, 2010

BAUE conducts an annual project with a focused objective that utilizes and challenges members' skill and training in an effort to “give back” to the local dive community. These projects create a shared learning experience and build teamwork among members. Additionally, the projects provide valuable information about the local underwater ecosystem to the dive community.

BAUE’s 2010 Project took place at Whalers Cove within the Point Lobos Marine Reserve at a common dive site known as the Middle Reef. Over three months of planning, one day of setup and two days of survey works were conducted for the purpose of collecting data about the site. Results of the project were then compiled to produce a web page for the state park and BAUE.

All dives were conducted within recreational limits. Although the diving occurred within recreational depths, this project was broad in scope and required divers to endure long exposures in cold water conducting arduous dives. An average of four hours of in water time per diver per day was required to safely and successfully complete this effort.

Objective

Collect survey and mapping data for the purpose of creating an accurate, detailed map of the underwater terrain and structures within Whalers Cove. Foster unit cohesion, team building and improve dive skills among members of BAUE while working towards a shared objective.

Specific Goals:

• Collect survey data points sufficient to make a 2-D and 3-D rendering of the Middle Reef structure.

• Integrate Middle Reef survey into an overlay that correlates existing available hydrographic data in the deeper sections.

• Mentor and train new divers in the use of survey, reel and compass techniques throughout an objective oriented dive.

Special Tools Utilized:

• GPS (waterproof)

• SMB marker bouys (multiple)/Sand anchors

• Global Mapper / spreadsheet software

Project Location

Middle Reef is located within Whaler’s Cove at the Point Lobos State Natural Reserve. The project designated a 750’ x 125’ section that encompassed the reef. Two reference transect lines, 750’ long, would run the length of Middle Reef marked every 10’. Divers would conduct a survey, measuring depths every 5’ between identical markers on the two reference lines, a total distance of 125’. This data would then be utilized to generate a 3 dimensional matrix that represented Middle Reef. Area of interest was located:

Primary N-S Reference line (1-2):

#1 36 31.248N, 121 56.347W

#2 36 31.369N, 121 56.385W

3-4 Reference Line:

#3 36 31.254N, 121 56.321W

#4 36 31.375N, 121 56.360W

Special Project Support

BAUE received special permission from officials at Point Lobos to conduct an underwater survey within the marine reserve at the state park. Members were given exclusive use of Whalers Cove for the purpose of executing the survey during the project weekend. State Park Ranger Chuck Bancroft was instrumental in securing the required permits and final permission for this project.

BAUE chartered Phil Sammet’s RHIB to assist in the project setup. His surface assistance and guidance was invaluable in ensuring the project area was set up accurately and efficiently. Permission and access for the boat to launch and operate in the protected waters of the marine preserve was granted through Point Lobos State Park.

Overview

Project planning began in February 2010 when a group of six BAUE members sat down to determine the best method to accurately survey the Middle Reef structure. The proposed method was designed to simplify the survey process to allow divers of varying levels of experience to fully participate in the collection of data. Several practice and training dives were conducted in March and April to prepare all project participants for their assigned tasks on the project weekend. An extensive setup day was required prior to the project weekend, to ensure that the activities on the two designated project days could be executed efficiently.

Preliminary Project Setup (Day #1):

On Friday 14 May 2010, several BAUE members conducted a series of set-up dives to prepare the site for the survey. As site preparation was imperative to the success of the project, a great deal of effort was expended to ensure the accurate placement and marking of the transect lines. A surface team of Phil Sammet and Allison Lee marked the locations designating the northern and southern points of the survey, and also provided surface support to project divers. Two teams, one consisting of Joakim Linde and Harry Babicka and the other of Rob Lee, Kevin Dow, and Susan Bird placed anchors and set surface markers to delineate and mark the survey area. Karl Haywood and Beto Nava placed the two 750’ transect lines running parallel to the reef structure. Finally a team of Rob Lee, Kevin Dow and Susan Bird positioned marker arrows every ten feet on the transect lines as points of reference for the survey teams to follow.

Project Survey (Day #2):

On Saturday 15 May, nineteen BAUE members assembled at 8:00 at the park to begin the project. After listening to a quick briefing that explained the survey procedure and defined goals for the day, individual teams performed dry runs to develop comfort and confidence in their line-laying skills, survey procedures, and underwater communication. Following the dry runs, each team was assigned several lines to survey and teams began splashing into the cove at 9:30. By late afternoon, dive surveys had been completed on 43 of 76 transect lines.

Project Survey and Clean-Up (Day #3):

On Sunday 16 May, eighteen BAUE members arrived early in the morning to begin the final day of the project. Dry runs were conducted for participants who did not partake in Saturday’s efforts so that they could develop familiarity with the survey techniques. At 9:30 teams entered the water to survey the remaining 33 transect lines. By 12:30 data had been collected on all but 4 lines, and in the afternoon two teams completed the project objective. Once all lines were surveyed Susan Bird and Kevin Dow worked together to collect all the markers from the reference lines. Beto Nava, Joakim Linde and Rob Lee removed anchors and one reference line while Karl Haywood, Mark Lloyd, and Gary Banta removed the remaining reference line.

Project Verification:

Following the diving phase of the project, several weeks were required to mathematically analyze, manipulate, and correct the raw data in order to produce the final product. Under the guidance of project manager Karl Haywood, Rob Lee and Joakim Linde worked diligently to create renderings of the underwater structure. Once there was an agreement between the two independent attempts, the differences were reconciled into a draft version of the map for subsequent verification. On June 15th, Karl Haywood and Joakim Linde conducted a verification dive to fortify assumptions made during data processing and to ensure accuracy of the two- and three-dimensional maps.

Results

The 95,000 sqft area that encompasses the Middle Reef structure was accurately surveyed. Several images were produced from the project data. Figure 1 shows a two-dimensional view from top of the Middle Reef structure while Figure 2 shows the same image on top of the Whaler’s Cover Imagery. Figures 3, 4, and 5 show three-dimensional imagery looking South into Whalers Cove.

Lessons Learned

Accurate Area Setup:

The setup of the survey area was critical to the success of the project. Any error in placing the transect lines would skew the results of the survey, thereby rendering much of the data unusable. Particular care and attention was exercised to ensure proper placement of the sand anchors and the transect lines, and to measure and place markers along the transect lines.

Utilizing a small boat, a GPS device, and two teams of divers the boat would drop a shot line where the anchors were to be placed. Once the shot line was dropped at the appropriate location and marked on the surface with a buoy, one dive team would then drop down the line and place an anchor to mark the location. Due to only having one shot line, the boat was required to stay on station with the dive team before marking the next location.

The efficiency of site preparation could have been improved with multiple shot lines allowing the boat to service both dive teams simultaneously, minimizing set-up time and reducing cold-water exposure times for the dive teams.

Size/Scope of the project area:

The initial project plan covered twice the area we actually surveyed. Due to time constraints and the fact that the majority of the contour data resided within the first two transects, the decision was made to focus our efforts on the first of the two areas. Even with the modified project plan, it was challenging to ensure that the entire area was properly surveyed. The cold water temperature limited the amount of time that we could reasonably expose divers to the elements. Even with the reduced survey area, divers were spending an average of 3-4 hours per day in 46-48 degree water.

We recommend that future projects target a smaller survey area for data collection during the two-day time frame that is typically allotted for BAUE group activities. Based on this project, a reasonable approximation would be a survey area less than 500ft x 125ft, assuming ten teams of divers.

Additionally the project coordinator should implement a time limit for dive teams of no more than 90 minutes to avoid unnecessarily long exposures in 46-48 degree water. Team leaders will be required to inform the project manager of their dive plans and intended time of return, to ensure that safety divers are in place to assist in the event of an emergency.

Accuracy of distance markings:

Teams were required to knot/mark the line on their reels (every 5 feet), so that they could take depth measurements at 5ft increments between the transect lines. However, upon collection of the data, it became evident that the 5 ft distance between marks varied from team to team (between 3.5 and 5.5ft).

We recommend that all marking of lines be done consistently, perhaps by a designated team, to ensure that there is a known distance between marks to improve accuracy and ease the data processing procedure.

Noting Location of Intersects: Due to the unique nature of Middle Reef and the amount of relief within the structure, the data processing required the use of complex algorithms to ensure that the spacing between data points was accurately reflected. The data processors were required to make assumptions about the geometry of the line in order to properly adjust the data.

These calculations would have been greatly simplified if the surveyors noted the starting depth (tie-off), the ending depth of the line (2nd tie-off), and any point where the line intersected the reef structure. A few additional notations on standardized wetnotes could have negated the need for assumptions.

Experience and Teamwork:

The BAUE organization is filled with divers of various levels of experience. The project format offers a great opportunity for less experienced divers to team up with more experienced divers to gain exposure to unique skill sets. Even though data collection was important, the priority of the project was to foster and encourage teamwork and develop skills to be utilized in future efforts. Throughout this project we utilized experienced divers to mentor newer divers with great success, with the new divers quickly adapting and building solid skills to complete the required tasks.

In the future every effort should be made to continue offering solid mentorship for new members, enabling us to fully incorporate all members into the project.

Conclusions

The 2010 BAUE project was a challenging endeavor that provided a valuable learning experience to all participants. The project proved to be a success on multiple levels and firmly established a building block that will further the development of this unique organization. BAUE members were able to refine a team-based approach that allows for accurate and timely three-dimensional surveys in areas with unique underwater topography.

Sections of the Point Lobos marine reserve that were inaccessible or unable to be surveyed by other survey means (such as sidescan sonar) are now able to be accurately surveyed by a team of BAUE divers. During this project, divers of all experience levels within the organization were able to form a cohesive team that was able to focus on, as well as complete a common goal. Lastly, the data gained through this extensive group effort has provided the local diving community with an accurate map of the Middle Reef structure in the Point Lobos State Park.