WRRC Project Reports

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    WRRCPR No.94-07 Impact of Kawainui Canal on the Recreational Water Quality of Kailua Bay (KB-4)
    (Water Resources Research Center, University of Hawaii at Manoa, 1993-10) Ahuna, Lina ; Fujioka, Roger
    The microbiological criteria for recreational water quality have been directed toward the protection of water users from possible microbial pollution which may pose public health hazards. In Hawaii, all streams are classified as recreational waters. Elevated concentrations of indicator bacteria recovered in Oahu's streams that do not receive sewage or other wastewater effluents and discharges indicate, by present standards, that they are polluted with sewage and pose public health hazards. However, environmental sources of fecal bacteria, such as soils and plants, and fecal sources of non-human origins, such as animals, commonly occur in the environment and appear to be responsible for the elevated concentrations of bacteria found in streams, during both wet and dry weather conditions. High concentrations of bacteria recovered in the upper watershed of Maunawili and the Kawainui Marsh and Canal suggest that bacterial nonpoint source pollution has a significant impact on the recreational water quality of Kailua Bay. Salinity changes at sites compared to the concentrations of fecal indicator bacteria indicate that dilution alone could not account for the reductions in bacterial number; reductions were also affected by other factors such as sunlight. These bacteria in stream recreational waters ultimately impact the ocean receiving waters, suggesting a need for the further studies to assess the origins of environmental sources of bacteria, as well as their impact on the health and well-being of the user population.
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    WRRCPR No.94-08 Kailua Bay Circulation (KB-5)
    (Water Resources Research Center, University of Hawaii at Manoa, 1993-10) Krock, Hans-Jurgen ; Sundararaghavan, Hari
    The objective of this study is to describe the transport characteristics of Kailua Bay, Oahu, Hawaii. This will allow a comparison of the relative importance of the wastewater discharged through the Mokapu Ocean Outfall with land-derived discharges on the bacteriological conditions in the recreational area of Kailua Bay. Measurements were made with current meters and drogues and dye. The results show that land-derived discharges have a much greater influence on the bacteriological water quality off Kailua Beach than does the Mokapu outfall discharge. The outfall discharge transport is primarily in the northerly direction and away from Kailua Bay. However, when the wind is directly from the north or from north by northeast, a portion of the surface layer from the Mokapu diffuser area can be transported to the reef area off south Kailua Beach and off Lanikai. Even under these conditions, the resulting bacteriological effect on the waters is less than 1% of that from land-derived discharges.
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    WRRCPR No.94-05 Assessing The Impact of Mokapu Sewage Outfall on the Shoreline Water Quality of Kailua Bay (KB-2)
    (Water Resources Research Center, University of Hawaii at Manoa, 1993-10) Fujioka, Roger S. ; Wu, Chunmei ; Fujioka, Carrie K.
    The discharge of secondary treated sewage effluent from the Mokapu Ocean Outfall into Kailua Bay, Oahu, Hawaii, represents a point source of pollution to the bay. Public health considerations are therefore of significant importance due to bodily contact and the possible ingestion of recreational water. The impact of the Mokapu outfall on the shoreline water quality at Kailua Bay was assessed in 1990 and 1991. The concentrations of fecal indicator bacteria (E. coli, enterococci, C. perfringens) were determined in sewage effluent samples and in water samples collected from the zone of mixing (ZOM) sites, offshore sites, nearshore sites, and shoreline sites of Kailua Bay. The indicator bacterial loads discharged from the outfall were on the orders of 106 E. coli/100 ml, 105 enterococci/100 ml, and 104 C. perfringens/ 100 ml. Within the ZOM, some of the sewage surfaced, however most of it was transported submerged and in a northerly direction. The sewage was also transported submerged to the two offshore sites located north and south of the ZOM but preferentially north. The nearshore data also suggested the movement of sewage in a direction north-northwest of the outfall. The absence or recoveries of only very low numbers of bacteria from the nearshore sites closest to the Kailua shoreline did not provide evidence that sewage from the outfall was possibly impacting the quality of the shoreline recreational waters. The geometric means of the seven true shoreline sites all met Hawaii's marine recreational water quality standard. The two other shoreline sites which equaled or exceeded the standard are actually the mouths of land-based fresh water sources which are known to contain high concentrations of indicator bacteria. The overall results suggested that the quality of shoreline water is more likely impacted by land-based sources such as rainfall events which increase surface runoff.
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    WRRCPR No.94-06 Microbiological Assessment of Kaelepulu Stream and the Impact of Discharge in Kailua Bay (KB-3)
    (Water Resources Research Center, University of Hawaii at Manoa, 1993-10) Roll, Bruce M. ; Fujioka, Roger S.
    Kaelepulu Pond is an inland brackish water pond (20 ppt salinity) which is under tidal influence and is fed by rainfall. Water from this pond flows via canals and streams (Kaelepulu Stream) for approximately 2 miles through a residential community (Kailua) and discharges into the ocean at Kailua Beach, the most popular beach on the windward side of Oahu, Hawaii. Water in the Kaelepulu pond and stream system has been classified for recreational use and must meet the State standard of 200 fecal coliform/100 ml. A sewage pumping station located next to this stream has been documented to occasionally discharge untreated sewage into the stream. The bacterial quality of the water in this stream system has been previously determined to be poor, and citizens of this community have concluded that the sewage from the pumping station is responsible for the poor water quality. The objective of this study was to determine the sources of fecal indicator bacteria entering the Kaelepulu Stream system and to assess the impact of this stream on the water quality of water at Kailua Beach. Water from throughout the stream system, soil, and duck feces were analyzed for indicator bacteria (fecal coliform, enterococci, E. coli, and C. perfringens). Storm drains and tributary streams (especially during rainfall, soil, and duck feces) were the major sources of fecal indicator bacteria Kaelepulu Stream. Analysis of stream water samples showed the, of the three recreational water quality standards, the enterococci standard was exceeded most frequently, followed by the E. coli and the fecal coliform standard.
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    WRRCTR No. 94 Water Recycling of Sewage Effluent by Irrigation: A Field Study on Oahu
    (Water Resources Research Center, University of Hawaii at Manoa, 1975-03) Lau, L. Stephen ; Ekern, Paul C. ; Loh, Philip C.S. ; Young, Reginald H.F. ; Burbank, Jr. ; Nathan C. ; Dugan, Gordon L.
    The specific project objectives were to: (1) evaluate by field lysimeters and pilot plots and augment by laboratory studies the feasibility of utilizing water reclaimed from sewage for irrigation under Hawaiian conditions; (2) assess the probable effects of surface-applied reclaimed water on groundwater quality particularly in terms of potential viral transmission and long-term buildup of solids; (3) evaluate the effects of various water quality parameters on the soil, percolation, and vegetative growth when grassland or sugarcane is irrigated with sewage effluents; (4) explore any problem in sugarcane culture, either in technology or in crop quality that might be involved in the irrigation of sugarcane with water reclaimed from sewage. The central Oahu project site area is located near the Mililani Sewage Treatment Plant (STP) which, in 1975, received approximately 3217 m3/ day (0.85 mgd) of essentially domestic sewage from the nearby expanding Mililani Town development. The STP utilizes the Rapid Bloc activated sludge process (secondary treatment) that achieves a suspended solids and BOD5 removal rate that averages 90%. The location of the project site was chosen in part because the adjacent field soils are of the Oxisol order similar to that on which approximately 90% of the sugarcane cultivated under irrigated conditions on Oahu is grown. The general project site area receives an average annual rainfall of approximately 102 cm (40 in.), and is situated at an elevation approaching 152 m (500 ft). The research activities were grouped into three major areas: soils and irrigation, viral analysis, and water quality analysis. In general, the values of guideline chemical parameters for the Mililani STP effluent are below the maximum value for irrigation of sensitive crops. Pesticides and heavy metal concentrations were either below the level of concern or level of detectability. Nitrogen was given special emphasis for several reasons: its use as a major component of most fertilizers; its known adverse effect (lowered sugar yields) on matured sugarcane; its essential solubility in the nitrite and nitrate form; its relationship in concentrations above 10 mg/l as N to methomoglobinemia, the disease of infants; and its potential rote in the eutrophication of open bodies of water receiving excessive nitrogen loads. Commencing in August 1971, the project activities consisted of: the installation of field grass-sod, bare soil, and field lysimeters at the Mililani STP; coordinating laboratory facilities and analytical capabilities for determining the constituents in water, waste water, and soils; development of virus culturing and assaying techniques under field conditions, and studying the application of secondary effluent to maturing sugarcane in OSC Field No. 240, located approximately 3.2 km (2 miles) from the Mililani STP. The results of these studies helped establish procedures and guidelines for the principal focus of the project, the sequential application of sewage effluent, ditch water, and combinations thereof, to sugarcane in 30 test plots with uniform areas of 0.04 ha (0.1 acre) each in the newly planted (February 1973) OSC Field No. 246, located approximately 1.6 km (1 mile) from the Mililani STP. The test plots were divided into three basic irrigation schemes of ten plots each: A, B, and C. Plots "A" were scheduled to received only ditch water for the 2-yr growth cycle, "B" plots to receive secondary effluent for the first half of the growth cycle and ditch water thereafter, and "C" plots to have only effluent irrigation applications for the full growth cycle. Fifty ceramic point samplers were installed in representative "A", "B", and "C" plots at depths of 23 to 30 cm and 46 to 53 cm (9 to 12 in. and 18 to 21 in.). which resulted in the shallower points being positioned in the tillage zone and the deeper points being positioned approximately 15 cm (6 in.) below the tillage zone. Thus leachate collected by the shallower points represented liquid available to the sugarcane root zones whereas, leachate collected from the deeper points is assumed to be generally unavailable to the sugarcane and potentially may percolate to the groundwater table. Two 1.52-m (5 ft) deep field lysimeters were also installed in a furrow row adjacent to the test plot. The sugarcane growing on one lysimeter was irrigated with ditch water while sugarcane on the other lysimeter received secondary effluent. Sugarcane parameters were monitored periodically throughout the culture cycle. Field No. 246 was harvested in March 1975 and the associated laboratory analysis of the yields was completed and evaluated in April 1975. The Mililani STP secondary treated and chlorinated domestic and municipal sewage effluents containing insignificant amounts of toxic chemicals represent a generally usable irrigation supply for sugarcane and grasslands in central Oahu. Application of sewage effluent for the first year of a 2-yr cane crop cycle increased the sugar yield by about 6% compared with the control plots. However, when sewage effluent was applied for the entire 2-yr crop cycle, sugar yield was reduced by about 6% and the cane quality by about 16% even though the total cane yield increased by about 11%. There was no apparent evidence of significant surface clogging of the soil or of soil chemical properties impairment resulting from sewage effluent irrigation during the first full 2-yr sugarcane crop cycle. Under a no moisture stress condition, a 1-mgd supply is sufficient to irrigate 61 to 81 ha (150 to 200 acres) of sugarcane by the furrow method. The quality of percolate from the effluent-irrigated sugarcane-cultured soil was of acceptable concentration from the standpoint of groundwater quality protection: the only possible concern was for nitrogen which sporadically exceeded the 10 mg/l limit for drinking water during the first 6 to 7 months of cane growth. However, similar exceedance occurred in the ditch water-irrigated sugarcane plots and the plots irrigated with effluent during the first year and with ditch water during the second year. Furthermore, there was no major difference in the total quantity of nitrogen produced in the percolate among the three different treatments. Phosphorus, potassium, suspended solids, biochemical oxygen demand, total organic carbon, and boron were removed effectively from the applied effluent by means of irrigation; however, chloride in the percolate was essentially unaffected except for a transient increase during fertilization. Both total dissolved solids and chloride in the percolates met drinking water standards. Human enteric viruses have been shown to be present in the majority of effluent samples examined and hence, can be assumed to be present in the effluent applied to the irrigated field. However, the absence of these viruses in all sugarcane and grass percolates sampled over a 2-yr period, plus other project virus studies conducted, suggest strongly that the possibility of contaminating deep underground water sources is extremely remote. Survival of poliovirus was minimal in an open field area which was exposed to direct sunlight, high temperature, and dessication. In contrast, the viability of the virus was maintained for up to two months in a field of mature sugarcane where the virus was protected from the physical elements. Bermudagrass, with periodic cutting and harvesting, proved to be an excellent utilizer of sewage effluent applied nitrogen and, thus, excelled sugarcane from the standpoint of groundwater protection. Essentially no nitrogen was recovered from the percolate at the 1.52-m (5 ft) depth below the grassed surface, whereas nearly 25% of the total nitrogen applied from chemical fertilizers and sewage effluent was recovered at the same depth in sugarcane percolate. Up to 40.47 ha (100 acres) of grassland may be irrigated with 1 mil gal/day of effluent under a no moisture stress condition. However, it has been demonstrated that fallow or bare soil appears incapable of removing significant amounts of nitrogen from the applied effluent. Disinfected sewage effluent, similar in composition to that used in the Mililani study, may be used for irrigation of sugarcane in the first year followed by irrigation with surface water in the second year, however, when used for the entire 2-yr crop cycle without added treatment, poorer sugar yield will result. Establishing a virus monitoring and quality control program for the treated sewage effluent before application is an essential part of an irrigation recycling program. Furthermore, development of more effective methods of virus inactivation prior to recycling is highly recommended. Precautionary sanitation measures for field workers should be practiced. Further research on the use of effluent for irrigation sugarcane would be desirable, specifically: 1. Repeat test plot studies for a ratoon crop cycle to confirm the yield and to assess Long-term effects on the soil 2. Test with various dilutions of sewage effluent and with chemical ripeners to improve the yield 3. Investigate plugging of drip orifices in irrigation tubings in anticipation of extensive future use.
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    WRRCTR No. 85 Methodological Approaches in Hawaiian Fog Research
    (Water Resources Research Center, University of Hawaii at Manoa, 1975-03) McKnight, James H. ; Juvik, James O.
    Recent studies have demonstrated the important moisture contribution from fog precipitation in mountain areas on the island of Hawaii. The present study investigates research methodologies useful in the study of Hawaiian upslope fog, including: (1) development of an improved fog gage; (2) development of indirect approximation methods for estimating average droplet sizes during precipitation episodes and separating fog and rainfall components; (3) establishment of an extensive fog sampling network on the island of Hawaii employing continuous recording equipment, for both rain, fog, and wind; (4) development of an original computer program for detailed temporal and spatial analysis of rain, fog, and wind parameters.
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    WRRCTR No. 84 An economic analysis of the patterns and trends of water consumption within the service areas of the Honolulu Board of Water Supply.
    (Water Resources Research Center, University of Hawaii at Manoa, 1974-12) Oh, Ho-Sung ; Yamauchi, Hiroshi
    The objectives of this study are to construct and analyze the patterns and trends of water demand in the service areas of the Honolulu Board of Water Supply, and to identify factors affecting water demand with the intent of deriving useful policy implications as well as improving on urban water demand research. To accomplish the objectives, a thorough review of the literature was conducted and some suggestions for methodological improvement were developed. Classical univariate time series analysis, data disaggregation methods, and trend analysis were used to construct the patterns and trends of water consumption. Significant variables, which affect increasing per capita water consumption, were identified through a logical sequence of data processing and reasoning. The results were confirmed by the methods of sample survey and regression analyses. Most of the data used in this study were compiled from water consumption records obtained from the Board of Water Supply. During the period of 1960-1971, the average daily per capita water consumption increased by about 27 percent from 139 gal to 177 gal. When per capita consumption was estimated by nine service areas per capita consumption figures depicted not only a wide dispersion in absolute value but also revealed different rates of growth. The seasonal patterns of water consumption were examined on a monthly basis. There is a steadily widening seasonal fluctuation in water use over time with summer consumption increasing faster than that for winter use. The trend of sprinkling demand was estimated from maximum and minimum day water consumption's trend equations. There is a difference in per capita consumption's between single and multiple family dwellings, which is attributable mainly to outdoor sprinkling by households occupying single family dwellings. The water consumption's level in established residential areas has remained essentially constant over time. The overall increase in per capita consumption results from water use for other than indoor domestic purposes. Water consumption's has been expanding most noticeably where there is significant construction activity. Per capita water consumption's data were fitted by linear regression to value of construction completed and annual changes in rainfall. The equation explained 96 percent of the total variation of per capita consumption's and the two independent variables were statistically significant. There is no evidence that residential water users have been responsive to price changes in the past. Large industrial water users appear to respond to price increase but commercial users do not. Existence of price responsiveness in industrial demand seems to have a close relationship with alternative water supply sources and nonexistence of price responsiveness in commercial demand may be associated with an incidence structure of water bill payments, which also has an important meaning in measuring the price elasticity of residential demand. The demand approach for projection of water use is advocated by most urban water studies. Major implications of this study are that: (1) the requirement approach is still a practical means of forecasting future water need., (2) there are serious institutional limitations in the use of price as a means to promote conservation but peak load pricing may be an effective way of reducing the inequitable distribution of water supply costs, and (3) the complex economic forces that have been operating through the existing institutional framework call for some form of unified management of groundwater resource for the purpose of conservation.
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    WRRCTR No. 83 Dynamic Programming Optimization: A Water Distribution System Design
    (Water Resources Research Center, University of Hawaii at Manoa, 1974-09) Liang, Tung ; Yang, Kwang-Ping ; Wu, I-Pai
    A computation technique based on the dynamic programming approach using the interactive Fortran language has been developed. The computerized design procedure can be used to obtain optimal design for single source water or other compressed fluid systems with a finite number of diverging branches and loops. Pumping effect on a single source system cannot be optimized, however, the developed procedure does allow quick evaluation of many alternate pumping pressures. Similarly, multiple source network with converging branches can only be evaluated by the repeated use of the computerized procedure. Dynamic programming has been proved to be very powerful for the analysis and design of a water network. From an engineer's point of view, this approach can be used to design any conceptual water network with little limitation.
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    WRRCTR No. 78 Some Characteristics of Hawaiian High-Intensity Rainfall
    (Water Resources Research Center, University of Hawaii at Manoa, 1974-08) Fullerton, Charles M. ; Wilson, S.K.
    A computer monitored network of rapid response Raymond-Wilson rainfall intensity gauges has been established at the Cloud Physics Observatory (CPO), on the windward coast of the island of Hawaii, to record the passage of both warm and cold showers. These showers are characterized by high intensity rainfall (50 to 300 mm/hr) and an associated increase in atmospheric pressure, a change in wind velocity, and a reversal of the electric potential gradient. The showers often occur at night, during the maximum of the diurnal pressure oscillation, and frequently in groups of two to four with an interval of 10 3 to 10 4 seconds between separate showers. A relationship between the height of the base of the trade wind inversion and the total amount of rainfall was observed, indicating that almost no rainfall occurs if the inversion base is less than 2 km. A drop-size instrument (DSI) was developed and used to measure the raindrop-size spectrum. From this measurement and the rainfall intensity, an estimation of the liquid water content (LWC) of precipitating clouds was derived. The LWC (2.0 to 8.0 g/m3) was found to be larger than that generally assumed for trade wind showers.
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    WRRCTR No. 77 The Quality of Coastal Waters: Second Annual Progress Report
    (Water Resources Research Center, University of Hawaii at Manoa, 1973-09) Lau, L. Stephen
    This report summarizes the results of the second year of investigative and evaluative work of the University of Hawaii's Sea Grant Program project, "Quality of Coastal Waters" The general objectives of this multidisciplinary project are to identify, develop, and evaluate the critical physical, biological, and rational parameters needed in formulating effective policies, institutions, and systems for protecting the quality of coastal waters in Hawaii. To this end, the attainment of eight specific objectives is assigned to faculty specialists participating in the 14 activities which comprise the Project. These specialists also assist the Principal Investigator in planning the work and in interpreting the results. Research activities for the project year consisted principally of field and laboratory studies of coastal waters initiated in the first project year but with increased emphasis on biota and sediment. Assistance was rendered to the State Department of Health in the revision and updating of the State Water Quality Standards. Kahana Bay was selected for study as a coastal water area under the influence of relatively undeveloped land. Land contribution of nutrients to the bay via Kahana Stream and all nonpoint routes was found to be small despite the perennial nature of the surface and subsurface discharges. However, the nitrogen and phosphorus levels measured for Kahana Bay waters and in the contiguous open ocean water exceeded the levels allowed under its state Class AA water classification. Coliform organism concentrations met the Class A rather than Class AA standards. Thus, the Kahana Bay water quality tends to satisfy the Class A standard rather than the Class AA standard. Heavy metals, especially lead, copper, zinc, chromium, and nickel, appeared consistently and within a range of a few to a few hundred ppm in the bay sediments, stream sediments, and watershed soils. The ubiquitous nature of their presence is related to the parent rocks from which the soils and sediment are derived. However, mercury and cadmium were only occasionally detected in the sediments and when detected, occurred at only within a range of a fraction of to a few parts per million. DDT was detected in the range of a few parts per trillion in the Kahana Bay sediment together with only periodically detected and very low levels of dieldrin, DDE, a and y chlordane. In the Kahana Bay water both heavy metals and DDT were detected but only at levels similar to open ocean water, i.e., a fraction of, or a few parts per billion for the heavy metals, and only a few parts per trillion for DDT. The project's approach to revealing the effects of urban land development is selection of single predominant type of urbanization of land to reveal the cause-effect relation. Recreational use of coastal land and water in and domestic urban use of water and the abutting land in Hawaii Kai Marina and east Maunalua Bay furnish such situations. Domestic sewage is collected and removed from the areas. Investigative results for the Hawaii Kai area and Maunalua Bay showed a general trend to improvement in water quality from the marina to the near-ocean bay waters. Nitrogen levels in the bay and only the near-ocean station were within the Class A state standard by which the water bodies are classified but phosphorus levels exceeded the standard elsewhere. All heavy metals were consistently present in the coastal sediments in the parts per million level. The levels of the ubiquitous pesticides analyzed, DDT, dieldrin, and PCP, (the latter is used primarily for termite control in house construction), were at least one order of magnitude higher than in the Kahana Bay sediments, thus reflecting intensive urban activities associated with a relatively new and growing residential development. In the Hawaii Kai Marina and coastal waters, heavy metals were detected in the usual minimal parts per billion level as in open ocean water, and DDT, dieldrin and PCP were in the usual parts per trillion range. A turbid water plume in Maunalua Bay was occasionally identified and apparently was related to currents and roiling bottom sediments rather than any liquid discharge. A biota study of the bay waters was completed and detailed. Coastal water quality data obtained for the Mamala Bay waters off in support of a conjunctive study by Chave for the Corps of Engineers and coliform monitoring by the Department of Health are reported. in general the data satisfied state requirements for Class A waters except for phosphorus. Coral abundance was generally less toward Diamond Head than toward Ala Wai Canal. which is the only major drainage canal intercepting the surface runoff from the valleys and discharging into coastal waters. From the findings, there is little evidence which would attribute any specific water quality effect solely to the presence of intense recreational activity at Sandy Beach represents a rather complex situation and departs from the project approach: the open ocean coast beach being popular, the land use changing from rural and undeveloped to residential urban development, and above all, the coastal water receiving treated domestic effluent. Shoreline water quality data were obtained to complement the studies undertaken by the consulting firm of Sunn, Low, Tom, and Hara, and the routine monitoring by the State Health Department. Results for the project area showed clear shoreline water similar to but with higher nutrients than Kahana Bay water and the state Class A standard Levels. However, the study by the consulting firm of the offshore condition adjacent to the Hawaii Kai sewer outfall showed that there is little significant effect to the coastal water and benthos from the discharge of treated wastewater off Sandy Beach. A baseline survey of benthic biota, particularly coral and micromollusc abundance and diversity, and fish was performed for Kailua Bay, the proposed Mokapu outfall site, and the existing Kailua sewer outfall. While the greatest abundance and species diversity of the fish were not near the outfall, the highest standing crop of micromolluscs is near the outfall. The occurrence of micromolluscs is comparable with the patterns in other areas of similar depth and substrate. Nonpoint discharge studies of sugarcane production and milling wastes were continued but at a reduced scale on Kauai. Observations of mill waste discharge and coastal water, sediments, and biota were made both before and after the 90-year old Kilauea Sugar Company closed down its operations in north Kauai in 1971. Untreated mill wastes were found to be the major contributing factor to the presence of coliforms, sediments, trash, and bagasse. The effect was largely an extensive visible plume in the coastal waters and debris in both the water and on the beach. Sediments, rather than water, harbored most of the nutrients, heavy metals, and pesticides in the ocean. DDT, although not used by the sugarcane industry, was present in small amounts in all wastes and sediments. Herbicides used in sugarcane culture did not appear in coastal waters. A striking aesthetic improvement of the coastal water and the beach quickly followed the cessation of mill waste discharge. Coastal water qualities continued to improve: phosphorus decreased to better than Class AA standards, DDT and PCP were detectable only at parts per trillion level. The rapid improvement is attributed to both the cessation of mill waste discharge and the heavy sea. Beach and ocean sediments continue to harbor about the same level of heavy metals but contain a much decreased amount of nutrients. Fish have reappeared rapidly since 1973. No apparent changes in micromolluscs have been observed since the cessation of mill operation. Tentative conclusions of the continued Kilauea investigative studies are: no evidence of eutrophication in coastal water, adverse effects of discharge mostly transitory, and epibenthic communities more influenced by waves, currents, and coastal topography than by mill waste discharge. Studies were continued in south Kauai to assess the effect of changed operation practices by the McBryde Sugar Company subsequent to an EPA survey of coastal waters of the area in 1968. Company practices demonstrate that it is possibze to operate milzing operations without discharge to the ocean, and to prevent irrigation tailwater overflows except flooding due to intense rainfall. At the time of reporting, the coastal waters of Wahiawa Bay showed an anomalously high nitrogen content while no pesticide residues were found in the offshore water except for the one to two parts per trillion DDT which seems to be present everywhere. Evaluative summaries were detailed for several key quality parameters in water and sediment. Heavy metals were ubiquitous and in parts per million range in coastal sediment in Hawaii. This suggests that if standards for the level of heavy metals in dredge spoil were to be set, care should be taken not to fix unrealistic levels that cannot possibly be attained. In the coastal waters, heavy metals also occur but only in the parts per billion range, a level quite comparable to the level in ocean water. Conjunctive studies of mercury uptake in an aquatic food chain from the water and sediment were continued and detailed. Of the insecticides, the presence of DDT in sediments is ubiquitous. In Maunalua Bay and Hawaii Kai sediments, dieldrin, and a and y chlordane are found frequently and with highest concentration in the Low parts per billion range. Their occurrence may be attributed to prior and current continous use of these chemicals in the abutting land area and the poor sediment circulation within the Hawaii Kai Marina. In coastal waters insecticides were generally undetectable or at only a few parts per trillion. PCP, like DDT, seems to occur ubiquitously. Herbicide residues in West Loch of Pearl Harbor and Kaiaka Bay were studied. Atrazine and ametryne do not appear to be a problem, however, because of its persistence in soils, diuron can be found in coastal sediments because eroded agricultural soils are transported with storm runoff. Kahana Bay water contains about the lowest amounts of nutrients in coastal waters. The state standards for nitrogen and phosphorus were exceeded in all areas except for Kilauea, in the case of nitrogen, and McBryde, in the case of phosphorus. The use of mircomolluscs as an indicator organism was reported with a differentiation noted in species between coastal areas affected primarily by silting compared to areas affected primarily by nutrient input. In the former situation Bittium zebrum becomes the major fauna component and standing crops and diversity values are conspicuously depressed. In the latter case, the community changes towards dominance by suspension feeding forms which depend on primary productivity of the water columns. Also associated strongly with silted reef flats is Obtortio pupoides. The responses of an ecosystem to land-generated effects are changes in structure from a grazing herbivore environment with associated frondose algae to either a rubble associated ecosystem with few species or to a eutrophic state with many suspension feeders and Low diversity. The principal changes in institutional arrangements noted in the project year are those resulting from the passage of the Federal Water Pollution Control Act Amendments PL 92-500. The effects of this legislation will be far-reaching and result in changes which include: new discharge permit requirements, reporting of operating and monitoring results for wastewater treatment facilities, a minimum requirement level of secondary treatment for municipal wastewaters, and industrial waste treatment effluent guidelines. The full impact of these and other changes is not yet apparent although some delays have incurred in regulatory actions and attempts to implement legislation.