Water Resources Research Center

WRRCTR No.41 Electrodialysis for Desalting Hawaiian Brackish Ground Water: A Field Study

Lau, L Stephen; Chou, James CS — Wed, 01 Jul 1970 00:00:00 GMT

A field study was made to evaluate the applicability and problems of desalting brackish ground water from basaltic and reef limestone aquifers in Honolulu, Hawaii with the electrodialysis process. The three-week study indicated that the brackish water at both sites was upgraded to potable quality and the rejection of ionized salts was above 80 percent. No pretreatment was necessary. Both the average production and rejection rates were about 420 gpd. An economic evaluation was not determinable from the short-term results.

WRRCTR No.42 Instantaneous Unit Hydrograph Analysis of Hawaiian Small Watersheds

Wang, Ru-Yih; Wu, I-Pai; Lau, L Stephen — Sat, 01 Aug 1970 00:00:00 GMT

The analysis of about 240 flood hydrographs of 29 small watersheds on the island of Oahu, Hawaii, shows some unique hydrologic characteristics. A typical Hawaiian small watershed has a small area, flash peak, short time to peak, and small recession constant. Most of the hydrographs have the typical shape of a steep triangle. Based on statistical analysis of the observed flood hydrographs, a linear relationship has been found between peak discharge and the volume of runoff for each watershed. Because of the similar shape of the semi-dimensionless hydrographs, a unit-hydrograph with uncertain duration can be developed for each small watershed. The duration of such unit hydrographs can be determined by using the S-hydrograph technique with the equilibrium discharge as a criterion and the trial-and-error method utilizing a digital computer. The durations of the unit hydrograph, or the effective rainfall durations for Hawaiian small watersheds, were found to range from 5 minutes ot one hour. A good correlation has been found to exist between effective rainfall duration and the watershed area. Such a short duration unit hydrograph can be used to develop an instantaneous unit hydrograph by using Nash's conceptual model and the method of moments, assuming the effective rainfall is uniformly distributed with respect to time and space. The instantaneous unit hydrgraph for each watershed can then be solved by a computer. The two instantaneous unit hydrograph parameters, Gamma function argument, N, and reservoir storage constant, K, were found to correlate with areas of small watersheds. The instantaneous unit hydrograph of a given ungaged area can be determined by knowing the area of the watershed. The flood hydrograph with a given duration can also be solved by applying the incomplete Gamma function. The superposition characteristics of a linear model can be applied for hydrograph analysis of Hawaiian small watersheds. Hence, the design discharge with certain recurrence years for different engineering purposes can be directly multiplied with the design runoff, which may be obtained with the reference of the rainfall depth-frequency-duration charts and soil conditions for certain areas. A hydrograph study using an instantaneous unit hydrograph provides a good approach for hydrologic research since the short duration of effective rainfall is close to the duration caused by an instantaneous burst of rainfall. The study also synthesizes the parametric hydrograph which simplifies hydrograph analysis.

WRRCTR No.44 Identification of Irrigation Return Water in the Sub-surface, Phase III: Kahuku, Oahu and Kahului and Lahaina, Maui

Tenorio, Pedro A; Young, Reginald HF; Burbank, Nathan C Jr; Lau, L Stephen — Tue, 01 Dec 1970 00:00:00 GMT

This study continued the joint research effort undertaken by the Water Resources Research Center and the Honolulu Board of Water Supply in 1967 to investigate the physical and chemical characteristics of irrigation return water. Initial work concentrated on the Pearl Harbor-Waipahu area of Oahu. The phases reported herein included both Kahuku Plantation on Oahu and the sugar cane cultivation areas of central and West Maui (Pioneer Mill Co. and Hawaiian Commercail and Sugar Co.). Composite well, spring, and stream samples were taken and analyzed in the laboratory for the following constituents: bicarbonate, calcium, magnesium, phosphate, silica, boron, chloride, nitrate, sodium, potassium, bromide, flouride, sulfate, and total hardness. On the basis of increased index constituents over uncontaminated ground-water sources used to identify the presence of irrigation return water, it is evident, as previously concluded by Visher and Mink (1964), such irrigation return water, is definitely present in the basal water bodies underlying the three study areas. Considerable increases in the nitrate and sulfate indices, especially, and in the bicarbonate and silica indices, as shown by various methods of interpretation of water quality data obtained over a period of approximately two years or exceeding one complete cycle of plainting and harvesting of sugarcane, verify the strong influence of irrigation agricultural practices in altering the overall quality of the basal water sources in the three areas. The basal water quality of the HC&S aquifer is most affected regionally, as well as locally, by the prevailing agricultural practices. The deterioration of the water is dues in part to fertilization and to a greater exten to heavy pumping and recycling of the basal water. Water quality in the Pioneer Mill area parallels that of HC&S, although on a regional basis, the basal water quality, unlike that of the Pioneer Mill area, is not as deteriorated. Local effects of pumping are also especially noticeable in the Pioneer Mill area. Ground-water quality in the Kahuku area shows the obvious presence of irrigation return water indices, but, unlike the two plantations on Maui, the magnitude of the increases relative to uncontaminated water sources is considerably smaller. The effect of fertilization on Kahuku may be considered to be a principal factor in the regional distribution of index constituents with a relatively uniform nitrate distribution throughout. Local effects of pumping are quite pronounced and influence overall increases of indices, indicating that where heavy pumping takes place for irrigation, the increase in index constituents are correspondingly greater.

Grey's Beach Infauna Study of Source Dredge Sand Off Waikiki

Bailey-Brock, Julie H; Krause, Emily R — Fri, 01 Aug 2008 00:00:00 GMT

A diverse assemblage of infaunal polychaetes and invertebrates was collected in three replicate sand samples from three locations off Grey’s Beach, Waikīkī, O’ahu, Hawai’i. Infauna were extracted over 0.5 mm and 0.25 mm sieves. Specimens from the 0.5 mm fraction were identified and enumerated while those from the 0.25 fraction were qualitatively assessed. Nematodes were the most numerous specimens collected, followed by oligochaetes and harpacticoid copepods. Polychaetes ranked fourth in abundance followed by lesser abundances of thirteen other taxa. The 45 polychaetes were assigned to 15 taxa. The outside station had the highest taxonomic richness compared to both stations within the source-sand area. Polychaetes were predominantly motile, free-living taxa with an omnivorous feeding mode. The second-most-collected taxa were detritivores. Tube-dwelling species were not collected in these samples. Reproduction was evident in only two polychaete individuals of different species. None of the invertebrates collected were unusual or rare in their distribution in shallow Hawaiian sands.

Hydraulic Parameter Estimation Using Aquifer Tests, Specific Capacity, Ocean Tides, and Wave Setup for Hawai'i Aquifers

Rotzoll, Kolja — Sat, 01 Dec 2007 00:00:00 GMT

The islands of Hawaii face increasing ground-water demands due to population growth in the last decades. Analytical and numerical models are essential tools for managing sustainable ground-water resources. The models require estimates of hydraulic properties, such as hydraulic conductivity and storage parameters. Four methods were evaluated to estimate hydraulic properties for basalts on the island of Maui. First, unconventional step-drawdown tests were evaluated. The results compare favorably with those from classical aquifer tests with a correlation of 0.81. Hydraulic conductivity is log-normally distributed and ranges from 1 to 2,500 m/d with a geometric mean of 276 m/d and a median of 370 m/d. The second approach developed a simplified parameter-estimation scheme through an empirical relationship between specific capacity and hydraulic parameters that utilized Hawaii's state well database. For Maui's basalts, the analysis yields a geometric-mean and median hydraulic conductivity of 423 and 493 m/d, respectively. Results from aquifer tests and specific-capacity relationships were used to generate island-wide hydraulic-conductivity maps using kriging. The maps are expected to be of great benefit in absence of site-specific field assessments. In the third approach, ocean-tide responses in the central Maui aquifer were used to estimate an effective hydraulic diffusivity of 2.3 x 10^7 m^2/d. The position of the study area necessitated refining the existing analytical solution that considers asynchronous and asymmetric tidal influence from two sides in an aquifer. Finally, measured ground-water responses to wave setup were used to estimate hydraulic parameters. Setup responses were significant as far as 5 km inland and dominated barometric-pressure effects during times of energetic swell events. The effective diffusivity estimated from setup was 2.3 x 10^7 m^2/d, matching that based on tides. Additionally, simple numerical ground-water flow models were developed to assess the accuracy of results from analytical solutions for step-drawdown tests, dual-tides and wave setup, and to evaluate sediment-damping effects on tidal propagation. The estimated mean hydraulic conductivities of the four methods range between 300 and 500 m/d for basalts in Maui. The results of different methods are consistent among each other and match previous estimates for basalts.

Benthic Infaunal Communities Adjacent to the Sewage Outfalls at Agana and Northern District, Guam, Northern Mariana Islands, 2005-2007

Bailey-Brock, Julie H; Krause, Emily R — Sun, 01 Jul 2007 00:00:00 GMT

Taxa richness and abundance are given for benthic infauna collected from sediments adjacent to ocean outfalls of the Northern District and Agana (Hagatna) Sewage Treatment Plants, Guam, Northern Mariana Islands. This addresses U.S. Environmental Protection Agency requirements of 301(h) waiver permits for baseline data prior to the construction of two new outfalls to replace those currently in operation. Living infauna and sediment-surface-dwelling epifauna were collected with a remote sampler from stations off the Agana and Northern District outfalls. Samplings were done in August 2005, March 2006, and January 2007 at depths of 40 to 92 m. A total of 21,058 invertebrates were collected from both outfall areas over the three sampling years. Polychaetes were the most diverse and abundant component in the three sets of samples, with 9,068 individuals belonging to 229 taxa. Overall, polychaetes were more abundant off Northern District (5,489 individuals) than off Agana (3,579 individuals). Thirty-nine taxa (totaling 11,990 individuals) of other invertebrates were recorded: Anthozoa, Acari, Bryozoa, Cephalochordata, Chaetognatha, Crustacea (9 taxa), Echinodermata (4 taxa), Hemichordata, Hydrozoa, Insecta, Kinorhyncha, Mollusca (5 taxa), Nematoda, Nemertea, Oligochaeta, Phoronida, Platyhelminthes, Porifera, Priapula, Pycnogonida, Sipuncula, Urochordata, and Osteichthyes (a vertebrate chordate). Nematodes were abundant at both sites in the three samplings (4,605 individuals), but the Northern District locality had twice the number (3,053 individuals) of the Agana locality (1,552 individuals). Patterns of polychaete adundance and taxa richness were similar at both sites. Comparing the results of the three samplings revealed that both sites have diverse infaunal communities and that many species are common to both areas. Small differences between stations and samplings may be due to a number of factors, including reproductive events and the additional habitat provided to carbonate borers by coral rubble, shell fragments, and calcareous algae (Halimeda spp.).

Fate and Transport of Selected Endocrine Disrupting Chemicals in Recycled Water Through a Tropical Soil

Mohanty, Sanjay K — Tue, 01 Aug 2006 00:00:00 GMT

Endocrine disrupting chemicals (EDCs) are a group of synthetic and natural chemicals that have the potential to mimic the hormone-like activities in the human body. This study was conducted to recognize whether recycled water (a source of EDCs) has the potential to contaminate the environment when such water is used for irrigation purposes. Batch sorption and miscible displacement experiments were conducted to elucidate the fate and transport of four EDCs including estrone, 17β estradiol, octylphenol and nonylphenol in a soil from Hawaii. The sorption capacity of the soil from two depths (2 ft as topsoil and 15 ft as saprolite) was estimated using recycled water and deionized water as the mobile phases. The transport parameters of these contaminants were obtained by using the inverse modeling approaches as provided in the HYDRUS 1D code. All four EDCs sorbed significantly on the soil. Octylphenol and Nonylphenol rapidly degraded during sorption. The Freundlich model was suitable to describe the sorption isotherm. The sorption nonlinearity was relatively higher for saprolite compared to topsoil. Both physical and chemical non-equilibrium processes were found to affect the mobility of the EDCs in the soil. The migration of EDCs in the soil was enhanced in recycled water due to the presence of dissolved organic carbon and elevated salt concentration. The ambient pH had little effect on sorption of EDCs on the soil from either depth.

Development and Implementation of a Water Monitoring Plan to Prepare for Criminal and Terroristic Contamination of a Drinking Water System

Fujioka, Roger S; Asahina, Audrey Y; Sato, Dayna M; Yoneyama, Bunnie S — Wed, 01 Feb 2006 00:00:00 GMT

Performance Evaluation of a CBT 0.8KF-210 Wastewater Treatment Unit

Sun, 01 Jan 2006 00:00:00 GMT

Assessing the Source of Fecal Contamination in Streams on Kaua'i Based on Concentration and Genotypes of FRNA Bacteriophages

Vithanage, Gayatri — Mon, 01 Aug 2005 00:00:00 GMT

Extensive data from O'ahu indicate that all streams on this island consistently exceed the USEPA standards (200 fecal coliform/100 ml, 33 enterococci/100 ml) for water quality. Soil was determined to be the source of the elevated counts of these bacteria. In tropical areas, as Hawai'i, these bacteria are able to survive and multiply in the soil. Thus, these bacteria can end up in nearby streams after heavy rains or due to erosion. As a result, the USEPA recommended indicator bacteria (fecal coliform, enterococci) cannot be used to reliably determine when waters in tropical areas are fecally contaminated. Several alternative indicators have been proposed for such areas such as C. perfringens and FRNA coliphages. Extensive monitoring data does not exist for the other islands of Hawai'i. Kaua'i differs from O'ahu in that it is older, wetter and contains an abundance of cesspools. The Nawiliwili Watershed, on the island of Kaua'i, was chosen for this study. Sampling was conducted over a period of one year, and all samples were assayed for the traditional USEPA indicators (fecal, coliform, enterococci) as well as two alternative indicators (C. perfringens, FRNA coliphages). Of the 14 sites sampled, 12 contained levels of fecal coliform and enterococci that exceeded the USEPA standards (200 fecal coliform/100 ml and 33 enterococci/100 ml. This is similar to what has been documented in O'ahu streams. Based on the concentrations of these indicator bacteria, the USEPA would deem these sites as sewage contaminated. However, monitoring of these same sites for C. perfringens indicated that there was no sewage contamination (geometric mean values fell below the proposed standard of 50 CFU/100 ml). FRNA coliphage data indicate that cesspools may be leaching into nearby streams. Two streams (Nawiliwili, Papakōlea) had geometric mean levels greater than the 50 PFU/100 ml (based on O'ahu streams). Other streams in the watershed may be sporadically contaminated by cesspool because elevated FRNA coliphage levels were detected on occasion. Genotyping these FRNA coliphage isolates furthered supported the theory that cesspools were contaminating these sites because 98% of the FRNA isolates were typed as human while only 2% were typed as of animal origin. Current USEPA standards (fecal coliform, enterococci) are not reliable indicators of sewage pollution in tropical areas, thus, alternative indicators such as C. perfringens and FRNA coliphages may prove to be better indicators in these areas.

Are Fecal Sterols a Possible Alternative Indicator of Human Waste Contamination in Hawaiian Recreational Waters?

Brostrom, Kathleen A — Mon, 01 Aug 2005 00:00:00 GMT

Many of Hawaii’s recreational streams and beaches contain high fecal indicator bacteria levels that are not indicative of sewage pollution. Instead, this pollution is due to environmental sources of fecal bacteria which reside and multiply in tropical soils. Current EPA fecal indicator bacteria are no longer representative of human fecal contamination in tropical waters. Fecal sterols have been used as chemical indicators of fecal pollution in many parts of the world. The primary sterol found in human feces is coprostanol. Detection and quantification of coprostanol and related sterols using GCMS analysis provides a fingerprint that can be used to characterize fecal contamination. The objective of this study was to assay for fecal sterols as an independent method to determine whether streams in Hawaii are contaminated with sewage. This method was applied to ambient streams, a stream recently contaminated by a sewage spill, and a stream suspected to be affected by a sewage line leak. The results of this study showed that some ambient streams in Hawaii contain high levels of fecal indicator bacteria, but low concentrations of coprostanol (<10 ng/L). A stream contaminated with sewage during a sewage spill event contained high concentrations of coprostanol (18,000 ng/L) in the first 24 hours after contamination, but this level dropped to ≤ 60 mg/L after 72 hours. A stream suspected to be contaminated with sewage contained significant levels of coprostanol (>1000 ng/L) when fecal indicators were also high, confirming a possible sewage line leak. This study demonstrated that coprostanol is a useful and independent measurement of sewage pollution. It is best used in conjunction with other fecal indicators and human fecal markers if confirmation of human fecal pollution is sought.

Column Study of the Transport of Selected Contaminants in a Hawaii Soil Treated With Recycled Water

Thu, 01 Sep 2005 00:00:00 GMT

Assessing the Microbial Quality of Potable Water Sources on the Island of Hawaii

Fujioka, Roger S; Sato, Dayna M; Vithanage, Gayatri; Yoneyama, Bunnie S — Fri, 01 Apr 2005 00:00:00 GMT

Schofield Barracks Wastewater Treatment Plant: Optimize Aeration, Secondary Clarifier, and Disinfection Processes

Moreland, Victor — Thu, 01 Jul 2004 00:00:00 GMT

Assessing the Treatment of Cooling Tower Water Using the Electrocel Technology System (ETS) Phase I

Fujioka, Roger; Asahina, Audrey — Mon, 01 Mar 2004 00:00:00 GMT

Assessment and Protection Plan for the Nawiliwili Watershed: Phase 2--Assessment of Contaminant Levels

Wed, 01 Oct 2003 00:00:00 GMT

Economic Impacts of Providing Secondary Treatment at the Sand Island Wastewater Treatment Plant, Oahu, Hawaii

Moncur, James ET — Wed, 01 Oct 2003 00:00:00 GMT

Assessment and Protection Plan for the Nawiliwili Watershed: Phase 1-Validation and Documentation of Existing Environmental Data

Furness, Monika; El-Kadi, Aly I; Fujioka, Roger S; Moravcik, Philip S — Tue, 01 Oct 2002 00:00:00 GMT

This report documents the findings for Phase 1 of a three-phase study that is aimed at assessing the status of the Nawiliwili Watershed on Kaua’i and developing a plan for its future protection. The objectives of this phase include utilizing sources of existing information to assess current land use in the area and identifying sources and levels of pollutants believed to be present in the watershed based on past studies relevant to the project area. Sources of information included available documents, persons who are familiar with the area, and questionnaires mailed to concerned individuals. Letters mailed to landowners and operators in the watershed area asked for their input. Information was also obtained at community meetings. The study also benefited from a local advisory committee that included government individuals and environmental groups. Data concurrently collected by the Nawiliwili Bay Watershed Council are also used here. The study concluded that little hard scientific data exist for the Nawiliwili Watershed, especially baseline data. The Hawai’i Department of Health’s current Total Maximum Daily Load (TDML) studies may provide public information that could be useful in assessing the health of the watershed. Since more baseline data are being made available, there is a chance to systematically define changes and trends in the watershed. The study identified sediment, nutrient, and bacterial-contamination problems in the Nawiliwili watershed and bay. Sediment sources include agricultural lands, construction sites, channel alteration, stream erosion, a quarry, and urban runoff. Nutrients originate from agriculture practices, golf courses, cesspools, frosted areas, urban runoff, and wastewater treatment spills. Bacterial contamination originates from cesspools, frosted areas, urban runoff, and wastewater treatment spills. There is, however, a chance that chemicals from other sources are also present. The absence of data has created great uncertainties regarding quantification and assessment of such contaminants. Only the levels of bacterial contamination are defined based on available measurements. Additional studies are needed to assess the existence of other chemicals in the watershed and their respective concentration. There is also a need to assess the various sources of bacterial contamination to define the level of contaminant caused by each. A fairly extensive list of potential sources of pollution has been identified which can provide a base for choosing sites for data collection and for sampling-scheme design. There is a need for new data to confirm these findings. The study used the state of Hawai’i’s web site on the Internet to identify relevant geographic information system maps of the area. There is a need, however, to update land-use information, which has changed in recent years. Finally, there is a need to increase or improve on the availability of public and private information about the watershed and to maintain strong ties and full cooperation between environmental groups and landowners/operators. With availability of information and full cooperation of all parties involved, a better understanding of the various processes will be gained. Developing sound approaches to remediate and protect the watershed is a goal that should be easy to reach. Scientific research can provide methods and approaches to maximize economic benefits from the watershed without negatively affecting the environmental quality.

Polyacrylamide (PAM) Effects on Viruses and Bacteria Transport in an Unsaturated Oxisol

Wong, Tiow P — Tue, 01 May 2001 00:00:00 GMT

Experiments were to study the effects of anionic polyacrylamide (PAM) on viruses and bacteria movement in soil. A water pollution problem which affects all areas with significant rainfall is soil erosion and subsequent transport of soil and all land-based pollutants. In recent year, high molecular weight polymers, such as anionic polyacrylamides (PAMs), have been used for soil erosion control and subsequent environmental problems. PAM is found to enhance infiltration. Land application of manure, sludge, and wastewater is common in many areas of the world, including the United States. Bacteria, viruses and other pathogens can be found in these waste materials. Studies must be conducts to evaluate if the use of polymers will allow water pollution constituents such as chemicals, pesticides, and microbial pathogens to reach groundwater in aquifer.

Effects of Reclaimed Water on Two Golf Courses Located Over a Potable Aquifer in Central Oahu

Zhou, Zhijun; Babcock, Roger W — Sat, 01 Dec 2001 00:00:00 GMT

This study set out to evaluate the biological, chemical and agronomic effects of reclaimed water for irrigation on two golf courses (KGC and LGC) located over a potable aquifer in Central Oahu. Percolate water and grass samples were collected on two soils at background sited (potable water irrigation) and pilot-scale test plots (reclaimed water irrigation) at both golf courses with different managements during the two-year pilot-scale study. The variations in chemical characteristics of percolate samples and the relationships of these changes to soil characteristics (pH, CEC, clay content, etc) and the golf course managements were determined in a general way based on the results of this study. Great differences in soil water content were observed between the soil at LGC (wet) and the soil at KGC (dry), and between the two years of the pilot-test. Fecal contamination will be caused due to reclaimed water irrigation is still in doubt after this study. Significant percolate chloride and sodium concentration increases were found at the LGC test plot but not at the KGC test plot. Nitrate leaching was found to mainly relate to fertilization, irrigation method (amount and schedule), and soil pH. All the percolate samples with nitrate concentrations higher 20 mg/l were found at background sites with high pH. High and constant irrigation rates caused a similar degree leaching at the LGC test plot using reclaimed water as that at the background sites with fertilization and historic irrigation methods. TDS in percolates is not expected to increase significantly with the reclaimed water using the irrigation method applied at the test plots of both golf courses in this study. However, whether or not harmful agronomic effects will occur cannot be determined in this study without samples from the dry season and at the soil surface layer. Suction lysimeters are good for monitoring most of chemical parameters measured and work best at high soil water content, but are not suitable for bacteria monitoring.