TYPE OF ACTION 2 + cont. UNAVOIOABLE ADVERSE EFFECTS 9.44. Lagoon dispasal of sail AVOIDABLE ADVERSE EFFECTS Temporary impacts to water ° column and benthic eco- MEASURES TO AVOID OR REDUCE ADVERSE EFFECTS Migration of turbidity and Locate disposal site where currents valuable ecological areas valuable ecosystems will not carry plumes toward suspended sediments toward systems Temporary water quality impacts and sedimentation Disposal in semi-confined craters Disturbance or destruction of important coral and fish habitat Aggravated shoreline ero- Minimize causeway width and length ches and along causeway Ciguatera fish paotsoning outbreaks at sites of causeway construction currents (armor rock, filter clath) Monitor toxic algae and fish and warn islanders if and when fish a potential soil disposal sites additional radioactivity ° Permanent loss of coral and subsistence fishery habitat under the causeway Loss and potential poisoning of fish Disturbance to additional reef habitat from circulation changes Ecological and water quality disturbance from heavy equipment operation and other construction activity Decreased circulation and degraded water quality in * eastern Bikini lagoon Reduced migration of shellfish and finfish between ocean and lagoon side of causeway Due to high volume of Proper design of shoreline of causeway to prevent erosion from sion near island approa- and quarrying paisoning is imminent Place armor rock and filter cloth ° prior to filling operations Use heavy equipment that minimizes disturbance Major turbidity and sedimentation during filling opera- tions Significant blockage of circulation and stagnation in the eastern lagoon Significant blockage of migratory routes of ° Select construction corridors and o truct a causeway between Bikini & Eneu [slands Conduct current and model studies to access points to minimize impacts estimate maqnitude of impact and need for culverts and bridges Install many culverts and large aquatic species Loss of valuable habitat at quarry sites ° armor rock requirements, loss and disturbance of reef bridge openings at reqular intervals along the causeway Locate quarry sites away from sandy areas and valuable coral areas Design quarry holes to enhance flat habitat at quarry sites Causeway instability during major storms, causing additional sedimentation fishery populations tilling, mixing or place- obtained (sites not yet ment of soil, fertilizers, or conditioners, that may identified) 9.8.9. Bredg- be excessive Unspecified impacts at site where soi! obtained Turbidity and sedimentation ing lagoon sediments as a source of soil Dust control measures, Measures may be needed impacts once the site techniques to collect soil are identified Oust emissions during Unspecified impacts at the site where replacement soil is sedimentation basins on land to prevent overflow and damage to causing significant ecolo.gical damage at discharge lic dredge or at clamsheil/ end af hydraulic dredge Significant damage or destruction of coral, fish and shellfish habitat at dredging sites Ciguatera fish poisoning bucket dredge site Damage and destruction of reef or lagoon floor habitat at dredge sites Loss and poisoning of fish aquatic resources Use silt curtains at dredging site Locate dredging sites away from valuable coral and fish areas Locate dredging sites where currents will not carry plumes to valuable areas 4onttor toxic alqae and fish and warn islanders if and when fish poisoning is imminent Minimize replacement fill and associated dredging requirements outbreaks at dredge and ° discharge sites 9.8.9. Dredging lagoon * Turbidity and sedimentation ° at cutterhead end of hydrau- gical damage at discharge end af hydraulic dredge bucket dredge site Damage and destruction of Significant damage or destruction of coral, reef or lagoon floor habitat * at dredge sites Loss and poisoning of fish Turbidity and sedimentation causing significant ecolo- lic dredge or at clamshell/ sediments as a source of soil a fish and shelifish habitat at dredging sites Ciguatera Fish poisoning outbreaks at dredge and discharge sites as needed to control and replacement Convey discharge sturry into Turbidity and sedimentation at cutterhead end of hydrau- o 9.B. Replacement of Soil 9.8). Off-atoll sources of soi} conditioners or fertilizers - Exposing food chain ta Dredging access ways to 9.As. Cons- such as Bravo Use turbidity curtains during disposa! operations Bag, solidify or otherwise immobilize sot! prior to disposal Locate disposal sites away from valuable coral and fish habitat, preferably over radioactive “hot spots” Chocse sites where dredging and filling for access is not required ° TABLE * Convey discharge slurry into sedimentation basins on land to prevent overflow and damage to aquatic resources Use silt curtains at dredqing site Locate dredging sites away from valuable coral and fish areas Locate dredging sites where currents will not carry olumes. to valuable areas Monitor taxic algae and fish and warn ‘islanders if and when fish poisoning i$ imtinent Minimize replacement fil} and associated dredging requirements E-2c