HECO annually conducts and reports results of a biological monitoring program for waters receiving effluent from the Kahe Generating Station, O'ahu, Hawai'i from 1977 to 1996 (NODC Accession 9900012)

The volume of sand and silt entrained and circulated by operation of the Kahe Generating Station is an environmental parameter of considerable geological and biological importance. Wave-suspended sediments are carried in cooling water through the station's condensers and discharged from the station's outfall. Sediment entrainment represents a potential loss of sand from the littoral system which consequently affects the supply of sand available to maintain beach configurations in the area. Biologically, deposition of entrained sand off the outfall and the distribution of silt suspended in the thermal plume represent potential stressors for benthic (bottom-dwelling) organisms, which may have no mechanisms for ridding themselves of sediments, or must expend energy to do so. Burial of hard reef surfaces by sand and silt diminishes the surface area available for recruitment of sessile benthic organisms and eliminates habitat of motile benthos and demersal fishes.

HECO has monitored sediment entrainment and throughput related to the station's circulating cooling water system since 1977. The startup of Kahe Unit 6 resulted in a noticeable increase of annual sediment entrainment rates. However, Hurricane Iwa reduced sand levels along the entire Kahe reef front in late 1982, and sediment entrainment values have been steadily declining since. This is because less sand has been available near the intake to be entrained. The following study presents the eighteenth year of sediment entrainment monitoring with six Kahe units in operation.

卡赫发电站（Kahe Generating Station）运行过程中裹挟并循环的沙与粉砂体量，是一项兼具重要地质与生物学意义的环境参数。波浪悬浮沉积物随冷却水流经电站冷凝器，并从电站排污口排出。沉积物裹挟作用会造成沿岸系统（littoral system）的沙量潜在流失，进而影响该区域维持海滩形态所需的沙源供给。从生物学角度而言，排污口外裹挟泥沙的沉积，以及热羽流（thermal plume）中悬浮粉砂的分布，均会对底栖生物（benthic (bottom-dwelling) organisms）构成潜在胁迫因子——这类生物要么缺乏清除沉积物的生理机制，要么需消耗额外能量才能完成该过程。沙与粉砂对硬质礁体表面的掩埋，会缩减固着底栖生物（sessile benthic organisms）可用于附着定居的表面积，并摧毁移动底栖生物与底层鱼类（demersal fishes）的栖息生境。

HECO自1977年起便对该电站循环冷却水系统相关的沉积物裹挟与输送量开展监测。卡赫6号机组投运后，年度沉积物裹挟速率出现显著提升。但1982年末的伊瓦飓风（Hurricane Iwa）导致整个卡赫礁滩沿线的沙量锐减，此后沉积物裹挟量便持续走低，究其原因是取水口附近可供裹挟的沙量有所减少。本研究呈现了卡赫6台机组全负荷运行情况下第18个年度的沉积物裹挟监测结果。