WRRC Special Reports

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    WRRCSR No. 97-02 Technologies and Strategies Used in Okinawa: Third Symposium on Hawiai/Okinawa Water Resources
    (Water Resources Research Center, University of Hawaii at Manoa, 1997-08)
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    WRRCSR No. 96-01 Assessment of Groundwater Models: 1994
    (Water Resources Research Center, University of Hawaii at Manoa, 1995-07)
    Assessment of groundwater models was the focus of the Pacific Northwest/Oceania conference held on March 21-23, 1994, at the Turtle Bay Hilton, Oahu, Hawaii. This conference differed from other modeling meetings by focusing on critical assessment-to what extent models have been adequate to address water, land, and environmental problems and have been able to advance scientific understanding of groundwater systems. These needs have been made acute by the very popular use and sometimes misuse of computational (numerical) models in recent years. Consequently, the crucial issue is, what is needed in the next generation of models in light of the critiques?
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    WRRCSR No. 9:23:83 Rainfall Frequency Study for Oahu: Option 1--Preparation of Rainfall Frequency Maps
    (Water Resources Research Center, University of Hawaii at Manoa, 1983-09) Giambelluca, Thomas W. ; Lau, L. Stephen ; Fok, Yu-Si ; Schroeder, Thomas A.
    Annual maximum rainfall series at 157 gages were used to evaluate extreme value rainfall. Daily fixed-interval data were adjusted by a factor of 1.143 to represent true maxima. Records of short-term stations were extrapolated by regional analysis. Gumbel extreme value, log-Pearson Type III, and log-normal distributions were tested for applicability and found to have approximately equal goodness-of-fit. The Gumbel distribution was used, fitted by the method of moments. A topographically based interstation interpolation model was developed as an aid in mapping maximum rainfall for durations of 1-, 6-, and 24-hr and return periods of 2-, 10-, 50-, and 100 years.
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    WRRCSR No. 9:19:86 Rotating Biological Contactor Pilot Study: Fort Kamehameha Wastewater Treatment Plant, Pearl Harbor, Hawaii
    (Water Resources Research Center, University of Hawaii at Manoa, 1986-09) Dugan, Gordon L. ; Takiguchi, Dean K.
    A self-contained pilot unit (including primary and secondary sedimentation) complete with electric motor driven plastic discs (surface area approximately 500 ft2), located at the U.S. Navy's 7.5 mgd Fort Kamehameha Wastewater Treatment Plant (WWTP) at Pearl Harbor, O‘ahu, Hawaii, was operated from July 1985 to July 1986 at four different operating modes: hydraulic loadings of 1.5, 3.0, and 5.0 gpd/ft2 (flat disc area) with discs exposed; and 5.0 gpd/ft2 with discs covered. The influent for the RBC unit was primary clarifier effluent, which was very brackish for wastewater (4000-5000 mg/l chloride). In addition, wastewater from industrial-type operations that use and discharge controlled/treated concentrations of heavy metals were received at the WWTP. The median effluent BCDs concentrations for the first two hydraulic loading rates (1.5 and 3.0 gpd/ft2) were respectively 2.0 and 8.0 mg/l, with corresponding respective median suspended solids values of 8.0 and 7.5 mg/l. These values were comparable with the present WWTP operation utilizing the activated sludge process. Hydraulic loadings at 5.0 gpd/ft2 provided median effluent BOD5 concentrations in the 30 to 35 mg/l range. Heavy metal concentrations in the wastewater flows of the WWTP and RBC unit were considerably below the level of concern, while some accumulation of heavy metals was noted for the higher concentrations of suspended and settled solids--the mixed liquor suspended solids and the raw and digested sludge. Replacing the existing activated sludge component with an RBC component being hydraulically loaded at 3.0 gpd/ft2 would require an estimated capital cost of approximately $2,500,000, which would require nearly 20 years to repay in electrical cost savings, based on a 10¢/kWh electrical cost, that increases in cost at an annual rate of 5%, and an interest rate of 8% compounded annually.
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    WRRCSR No. 7:85 Subsurface Water and Soil Quality Data Base for State of Hawai'i, Part 1
    (Water Resources Research Center, University of Hawaii at Manoa, 1985-07) Oki, Delwyn S. ; Giambelluca, Thomas W.
    In recent years, various chemical contaminants have been detected in Hawai'i’s groundwater sources. Several agencies in Hawai'i have been monitoring the groundwater quality for the contaminants, dibromochloropropane (DBCP), ethylene dibromide (EDB), and trichloropropane (TCP). In addition, several agencies have investigated the movement of these compounds in the soil at various sites on O'ahu and Maui. The Data Base which accompanies this report represents an effort to compile all available results from these agencies and to organize than into a uniform, computer-readable system in order to facilitate research on the extent, movement, and persistence of contaminants in the soil and groundwater of Hawai'i. Results from analyses performed on water samples taken from wells, springs, and from points within various water distribution systems throughout the state, as well as results from analyses performed on soil samples taken at sites on O'ahu and Maui are included herein. The primary emphasis of the Data Base is on the compounds DBCP, EDB, and TCP, but other pertinent compounds are also included. A data summary table of the maximum concentrations of these three compounds present in well and spring water samples is included as a part of this report.