Characteristics of Water Quality in Anchialine Ponds of the Kona , Hawaii , Coast

A study of the water quality characteristics of anchialine ponds of the Kona, Hawaii, coast suggests that groundwater is a major source of dissolved nutrients for these systems. These groundwater sources apparently show high spatial and temporal variability with respect to dissolved nutrients. Changes are apparent in the water quality characteristics of one anchialine pond system that has been subjected to considerable surrounding development. These changes are within the range of natural variability suggesting that this perturbation, at least over the short term (ca. 9 years), is not damaging since these nutrients frequently occur naturally in excess of concentrations which would control biological proce sses. Within an anchialine pond system that we have studied, spatial variability in water quality may be explained by a simple model of groundwater diluti on with proximity to the sea. In the Ha waiian Islands, anchialine ponds are found in the geologicall y young lava flows on Maui and Hawaii islands . More than 70% of the estimated 520 Hawaii Island anchialine ponds occur in a 53 km contiguous section of the Kona coast. The lands surrounding many of these Kona coast anchialine ponds have been proposed for or are undergoing resort and residential development. As a result, much of what is known regarding these anchialine systems is found not in the published literature, but rather in impact assessments written to fulfill environmental regulations. One recently initiated development at the Waikoloa, Kona, area (between Waiulua and Anaehoomalu Bays) destroyed more than 130 anchialine ponds in late 1985; approximately 66 adjacent ponds with a combined water surface area of 1.4 ha were set aside in a 4.9 ha preserve (the Waikoloa Anchialine Pond Preservation Areasee Figure 1). Since the ear ly 1970's, selected ponds in this Waiulua-Anaehoomalu complex (some of which are now in the preserve) were occasionally sampled for organism abundance or water quality characteristic s. The literature on water quality characteristics of anchialine ponds is scant, and there are no comprehensive studies. Cox et al. (1969) reported nitrate, phosphate, and sili-