U.S. ARMY CORPS OF ENGINEER PERMIT NUMBER 960100004
SPECIAL CONDITION 3
This document is the third of a series of monitoring reports required by the USCOE permit which was issued to IOTA Partners for the archeological excavation of the SANTA MARRGARITA, a Spanish galleon which sank on Rota's fringing reef in 1601, According to IOTA Partner's on-site archeologist, Mr. Robert Reedy, this particular wreck has historical significance as it is one of the few "early" Manila wrecks that have been, or are in the process of being excavated.
The initial compliance report(dated 19 June 1999) addressed the turbidity component of Special Condition 3, as well as containing the initial photographs of corals found in the reference sites. The turbidity issue is more completely detailed in the Section 401 Water Quality Certification (Section 401 WQC) which the DEQ issued on 5 February 1999. In keeping with the sampling scheme developed by the DEQ, turbidity data is collected daily from two predetermined sampling sites whenever excavation occurs and FAXed to DEQ that same day. The turbidometer and field personnel who obtain the water samples have all been previously approved by the DEQ. Compliance with the Section 401 WQC is based on the results of this turbidity data.
As previously discussed in the initial report, four coral reference sites were identified and marked with rebar: two sites were positioned up-current from the "project site area" (ie., sand pit) while two sites were situated down-current, These sites were further delineated into shallow and deep water. Coral colonies at each site were photodocumented for future comparison of coral health. Results from the October survey were qualitatively compared with those from the initial and July reports. The reference coral photographs included in this report were taken between 6-9 October 1999, approximately 145 days after the initial photographs were obtained (14 May 1999) and 81 days after the second report (16-17 July 1999). The reference coral photographs taken for this report are shown in Figures 1, 2, 3 and 4.
The following qualitative assessment is based on visual observations, followed up by photographic documentation, and discussion on the probable cause of any observed impacts.
UP-CURRENT SHALLOW:
Photographs of the corals at this reference site are shown in Figure 1. It appears that no project related impacts have occurred to these corals or the general surrounding reef area.
UP-CURRENT DEEP:
Photographs of the corals at this reference site are shown in Figure 2. It appears that no project related impacts have occurred to these corals or the general surrounding reef area.
DOWN-CURRENT SHALLOW:
Photographs of the corals at this reference site are shown in Figure 3. It appears that no project related impacts have occurred to these corals. The general surrounding reef area appears to be in good condition despite the closeness of the excavation site.
DOWN-CURRENT DEEP:
Photographs of the corals at this reference site are shown in Figure 4. The July Compliance report detailed the impacts of project related sedimentation to corals in the reference site and surrounding area. General observations made during this survey indicated that no further noticeable impacts had occurred to the corals included in the reference site.
In addition to the various mitigative measures employed during the excavation process and previously discussed in the July Compliance report, the IOTA field crew developed another variation which proved to be successful in further decreasing sediment plumes. The discharge ends of the 3" eductor hoses were placed in the coral rubble piles created from excavating the fore reef area. These rubble discard piles had created new "reef habitat" in the previously barren sand pit. The coral rubble and boulders decreased water velocity and much of the heavier sediment settled out immediately. The rubble pile was then covered by a parachute which acted to contain the finer sediments. Although I was not able to actually observe this measure in action, the field crew were pleased about its efficiency and the design appeared to be very functional.
Though this issue is not directly related to the monitoring of corals in the four established reference sites, IOTA Partners wished to include an assessment of reef impacts which occurred when the Jack-up barge was being positioned and stabilized on 5 October 1999. The jack-up barge and associated equipment was leased from McConnell Smith - Guam, Inc. (674 Harmon Loop Road, Suite I 11, Box 333, Guam 96912). According to the contract, McConnell Smith was responsible for positioning and placement of the jack-up barge to IOTA's specifications while IOTA Partners assumed responsibility after the jack-up barge and associated equipment was in place.
Positioning of the barge and the four support spuds was accomplished with the assistance of a snorkler in the water guiding the barge operators. Due to the danger of personal safety, only one diver was allowed in the water to assist with barge placement. As required by permit conditions, footprints for the four spuds were situated Within the sand pit area, in a previously excavated area, or on a rubble discard pile created from excavation activities. Once the jackup barge was stabilized approximately three feet above sea level, barge impacts (or chances of impacts) to adjacent coral resources ceased.
While the Jack-up barge was being positioned, a comer spud grazed the fore reef in several areas which resulted in the breaking up of benthic substrate, including live corals. Seven areas were identified as being impacted before the barge was stabilized over the sand pit area. To quantify the impact, the length and width were measured for each impacted area and the resulting data are shown in Table 1 below. Pictures of some of the impact areas are shown in Figure 5 below.
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The area of impact for the seven identified impact sites totaled approximately 270 sqft. To mitigate for the damage, broken pieces of live coral were repositioned in an upright manner within the area of impact, For example, the dark colored (live) coral head in Figure 5 - photo B which is situated in the light colored impact area was reoriented. Most (estimated 90%) of the impacted coral appeared to be encrusting or massive forms while a few soft corals (Sarcophyton) were impacted. Additionally, many of the coralline fragments were repositioned in their original orientation. Impacts to the fore reef are considered minimal and will likely have no far reaching consequences.
The IOTA field crew met informally and developed a plan of action which would hopefully minimize any further impacts to the fore reef area when the Jack-up barge is demobilized. The IOTA Field Supervisor will be coordinating with the McConnell Smith crew in implementing the plan.
Special Condition 3 (USCOE 4960100004) established a monitoring plan to examine the health of adjacent corals throughout the duration of the project. The purpose of this condition was to be able to identify early on, impacts to reference corals and thus provide the opportunity for specific data collection to determine whether the impacts were originating from project related activities. If further research correlates coral impacts to project activities, then additional mitigative measures would be developed and implemented.
Results from the July survey indicated that impacts to corals in the down-current deep reference site were related to the sediment plume generated from the archeological excavation. Controlling the magnitude and extent of sediment plumes to the previously affected area (down-current deep) was a top priority. Observations made during the October survey indicate that no further (noticeable) impacts were occurring. This can be attributable to the effort that went into developing and maintaining the sediment controlling devices and also partly due to the change in substrate and the decreased volume of sediment which the eductors were moving. Since the July report, the excavation progress had slowed and was focused more on the fore reef area which contained primarily boulders and rocks.
