Hedonic models are used to estimate implicit prices for water quality in housing markets. Recent studies aggregate sales across large spatial areas in scaled-up models leading to a concern that these models may overlook regional heterogeneity in water-quality preferences. We estimate scaled-up hedonic models comprised of multiple states and individual states and investigate how observations from subregions can differ. We find that the scaled-up model results are driven by select subregions. The results of this study call into question hedonic models using data for large geographic regions where substantial differences may arise across housing markets. / M.S. / Water quality in lakes impacts the prices people pay for lakefront properties. However, these effects can vary across different housing markets. We study whether owners of lakefront properties throughout the northeast and upper Midwest are willing to pay the same amount for water in lakes. We find that in multi-state housing markets, the effects from one state can dominate the overall results and there is likely heterogeneity in preferences across housing markets.

This study compares the sensitivity of biological and chemical parameters for monitoring water quality, examines several methods of analyzing diversity of the aquatic organisms and attempts to assess water quality in the three streams investigated. The Cairns-Dickson DI_T diversity index was applied to two trophic levels of aquatic organisms and the results were compared to ascertain whether this diversity index is applicable to all levels of the trophic\structure or of greater use for a particular level. Two diversity indices, Cairns-Dickson DI_T and Wilhm-Dorris d̅, were used to analyze the same component of the biological community and the results of these two indices were compared. A correlation test was performed among chemical and biological data and among chemical parameters. / Master of Science

The distribution system is the primary cause of taste and odor complaints in drinking water. This research examined the ability of small diameter pipes used in home plumbing to affect drinking water quality. The properties of the materials were investigated in the absence of disinfectant and the presence of either chlorine or chloramines. A panel was trained in flavor profile analysis (FPA) according to Standard Methods 2170B and used to assess the sensory properties of all samples. Chemical analyses were performed to determine disinfectants, total organic carbon (TOC), pH and specific organic contaminants. The first part of this study investigated PEX pipes manufactured by the silane (PEX-b) and peroxide (PEX-a) cross-linking technology, using the utility quick test (UQT) method. Silane PEX-b had a greater effect on water quality properties such as odor, TOC and residual disinfectant demand than peroxide-linked PEX-a. Chemical analysis revealed that PEX pipes can contribute fuel oxygenates such as ETBE (PEX-b) and possibly MTBE (PEX-a) to drinking water. PEX pipes did not contribute any significant trihalomethanes to drinking water. This study showed that the type of PEX used in homes will determine the extent to which drinking water quality is affected. The second part of this study used simulated plumbing rigs to investigate seven different materials under low flow and stagnant conditions; chlorinated polyvinyl chloride, cross-linked polyethylene, polyethylene, epoxy-lined copper, copper, stainless steel, galvanized iron and glass (control). Results showed that these plumbing materials have the potential to affect water quality characteristics such as TOC concentrations, residual disinfectant and odor when newly installed in homes. A high TOC concentration was consistent with the presence of a distinct odor or a high FPA intensity rating. Galvanized iron produced the worst odors that were consistently described as "motor oil". Polyethylene generated more intense plumbing associated odors than PEX or cPVC plastic material. cPVC and copper generated the least odors. Both copper pipe and epoxy-lined copper consumed residual chlorine and chloramines. / Master of Science

Corrosion of iron and copper pipes can produce leaks and loss of efficiency in the water distribution system, elevate levels of contaminants at the tap, and cost billions of dollars annually in pipe replacement or rehabilitation. In situ pipe rehabilitation using cement mortar, polyurethane, and epoxy is a commonly employed method of dealing with aging yet structurally sound pipes because it is less expensive and less invasive than replacing pipe infrastructure. Although epoxy has been shown to be an effective solution to pipe corrosion, little research has been conducted regarding its impact on a comprehensive list of water quality parameters. This research addressed that gap in the literature by conducting short-term immersion tests in which new epoxy linings were exposed to reference tap waters containing one of three disinfectant treatments: no disinfectant, free chlorine, or chloramines. As a comparison, an aged epoxy-lined field sample was also tested. Water exposed to the liners under stagnant conditions was analyzed for the following water quality parameters: pH, ammonia, alkalinity, hardness, metals, disinfectant consumption, total organic carbon (TOC), semi-volatile organic compounds (SVOCs), disinfectant byproduct (DBP) formation, and odor. Results of the study showed relatively low impacts on water quality, as all USEPA drinking water regulations were met. Impacts were highest during the first 24 hour exposure period during which time significant disinfectant consumption was shown (> 90% free chlorine consumed, 13% chloramines consumed), high TOC was leached (2.6-6.2 mg/L), trihalomethanes and haloacetic acids were formed (both < 15 ug/L), Bisphenol-A, an endocrine disrupter, was detected (< 35 ug/L), and odor was reported by panelists at a moderate intensity and described as sweet/chemical/burning/chlorinous. Impacts were much less after the initial 24 hours, although odor remained noticeable throughout the 30 day study. Overall, water quality impacts were greatest in chlorinated waters and both new and aged epoxy showed slight differences in results. / Master of Science

The purpose of this problem was to determine the cause of tastes and odors in the Breckenridge water supply and to isolate and culture the organisms responsible for the offensive chemicals.

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

The Lesotho Highlands Development Authority routinely uses the South African Scoring System version 4 (SASS4) in conjunction with water chemistry to monitor water quality of rivers in the Lesotho Highlands Water Project areas. The objective of this study was to test the efficiency of SASS4 in these areas.

<p>The Eerste River is a river system which has, over the years, been subjected to human interference. The purpose of this study was to investigatge temporal and spatial trends in the water quality of the Eerste River between 1990 and 2005. The study results revealed that the major trends in the water quality of the Eerste River are more spatial than temporal.</p>

Vandens tarša išlieka viena pagrindinių aplinkosaugos problemų. Upių ir ežerų vandens kokybė Lietuvoje yra nuolat stebima, vykdomas valstybinis monitoringas. Siekiant išaiškinti Šventosios baseino upių vandens kokybę ir jų kaitą, darbe buvo pritaikytas vandens kokybės indeksas. Šiam tikslui buvo panaudoti Šventosios baseino valstybinio monitoringo 1992 – 2012 m duomenys. Vandens kokybės indekso įvertinimui panaudoti šie parametrai: skendinčių medžiagų kiekis, pH, ištirpęs O2, BDS7, NO3-N, N bendras, P04-P, P bendras, Ca, Mg, SO4, Pb, Hg ir koliforminės bakterijos. Nustatyta, kad praeityje Šventosios upę ir jos intakus daugiausia teršė koliforminės bakterijos, tuo tarpu pastaruoju metu vyrauja fosforo ir azoto junginių tarša. Blogiausi vandens kokybės indeksų vidurkis nustatytas Vyžuonos upėje žemiau Utenos – 53,1 balo, o geriausias Šventojoje ties Sabaliūnais - 83,5 balai. / Water pollution is one of the most important problems in environmental protection. Water quality of Lithuanian rivers and lakes is constantly observed and national monitoring is being performed. In order to find out the Šventoji river basin water quality and its long-term changes, water quality index was applied in the work. To reach this goal, the Šventoji river basin national monitoring data of 1992-2012 years were used. To evaluate water quality index, the following parameters were applied: suspended substance, pH, dissolved O2, BDS7, NO3-N, N total, PO4-P, P total, Ca, Mg, SO4, Pb, Hg and coliform bacterias. Results of the research revealed that the Šventoji river and its tributaries had been polluted with coliform bacterias in the past, while recently pollution of phosphorus and nitrogen have dominated. The worst water quality indexes average determined in the Vyžuona below Utena – 53,1 points, and the best is in the Šventoji at Sabaliūnai – 83,5 points.