Thesis (M.S.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

Thesis (Ph. D.)--Michigan State University. Dept. of Geological Sciences, 2008. / David Hyndman, dissertation advisor--From acknowledgments. Title from PDF t.p. (viewed on Aug. 20, 2009) Includes bibliographical references (p. 148-150). Also issued in print.

Thesis (Ph.D. in civil engineering)--Washington State University, December 2005. / Includes bibliographical references.

Thesis (M.S.)--Washington State University, August 2006. / Includes bibliographical references (p. 29-31).

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xvii, 180 p.; also includes graphics (some col.). Includes bibliographical references (p. 156-171). Available online via OhioLINK's ETD Center

A literature survey indicated that little was known about the effects of commercial clearcutting on stream and watershed solution chemistry. To investigate these effects, five small watersheds were studied in the University of B.C. Research Forest. Three of the watersheds were equiped with weirs, stream height recorders, and soil-air-water thermographs. Soil pits were dug in the three calibrated watersheds and equiped with surface runoff collectors and hanging water column tension lysimeters. Samples of - precipitation above the forest, throughfall (through forest and slash), surface runoff, forest floor leachate, mineral soil leachate near the bottom of the rooting zone, groundwater, and streamwater - were collected at regular intervals and analyzed for pH, electrical conductivity, alkalinity as bicarbonate, K, Na, Mg, Ca, Fe, Mn, Al, Cl, P, N, S, and Si for periods of up to three years prior to clear-cutting and two years after clearcutting. Streamwater was also analyzed for dissolved oxygen and suspended sediment. Sampling was carried out for periods of up to three years prior to clearcutting and up to two years following clear-cutting. The streams were characterized by high discharges from late autumn until early summer and low discharges from May until October, with almost no contribution from snowmelt runoff. Response to precipitation was fairly rapid and it was hypothesized that stormflow arose mainly from flow of water through macrochannels in the soil. Visual observations and chemical data were consistent with this hypothesis. Evapotranspiration from the gauged watersheds was estimated to be about 85 cm per year by subtracting streamflow outputs from precipitation inputs and 65 cm per year using theoretical methods. The discrepancy between these two values was attributed to an unmeasured leakage of water, particularly from the untreated control watershed which rendered too low the streamflow outputs. There was an increase of 30.8 cm in runoff from one watershed, and 27.6 cm from another during the first six months of the dormant season immediately following clearcutting. During this period runoff from the control watershed was 141.5 cm. Stream temperatures underwent annual cycles with winter minima close to 0°C and summer maxima close to 17°C. Diurnal temperature fluctuations were slight and usually less than a few degrees. Clearcutting caused an increase in both maximum and minimum stream temperatures during the first dormant season following clearcutting. The few measurements which were made of suspended sediment, together with visual observations, indicated that concentrations were usually negligible in the streams. Dissolved oxygen concentrations in streams were usually close to 100% saturation and underwent annual cycles with maximum values in winter and minimum values in late summer and early autumn. Clearcutting had little effect on dissolved oxygen values during the cooler wetter months but caused very pronounced decreases during summer and early autumn. This was attributed to the biological and chemical oxygen demands of decaying slash in the streams. Stream chemistry exhibited little diurnal variation but considerable variation with discharge. Sodium, calcium, magnesium, dissolved silica, and bicarbonate concentrations, and electrical conductivity and pH decreased with increasing discharge, whereas potassium and nitrate concentrations exhibited some increases and some decreases. Chloride and sulphate concentrations were generally not significantly related to discharge. In the undisturbed ecosystems, chemical concentrations, pH, and electrical conductivity throughout the systems were generally highest in late summer and early autumn and lowest in winter and early spring. This was attributed to seasonal cycles of geological and biological activity with accumulation of weathering and decomposition products occurring during dry, warm summers. These were flushed through the system in autumn, with solutions becoming progressively more dilute throughout the winter until the onset of warmer weather. Nitrate concentrations tended to be higher in winter than in summer which was attributed to greater nitrogen uptake by organisms in summer. The most abundant ions in precipitation and throughfall were hydrogen, sulphate, and chloride, while calcium, bicarbonate, and sulphate were dominant in all the other types of water samples. There was a general increase in chemical concentrations to maximum values in forest floor leachate followed by a decrease to minimum values in groundwater, and a slight increase again in streamwater. The lowest pH values were in throughfall (4.0-4.5) followed by a steady increase through the system to maximum values in stream-water (6.5-7.0). Clearcutting increased the pH of water reaching the forest floor and surface runoff but decreased the pH of mineral soil leachate, groundwater, and streamwater. It generally decreased chemical concentrations in water reaching the forest floor and in surface runoff, and, to a lesser extent, in forest floor and mineral soil leachates, but it increased concentrations in groundwater and, to a lesser extent, in streamwater. A most notable increase throughout the system was in the concentration of potassium which was attributed to the relative ease with which potassium is leached from decaying vegetation. Increases in nitrate concentrations were particularly high in groundwater. Streamwater concentrations of potassium, iron, calcium, dissolved oxygen, and probably manganese, were significantly affected by clearcutting; concentrations of all these chemicals increased, except dissolved oxygen which decreased. Slight increases in magnesium, nitrate, sulphate, and chloride concentrations, and electrical conductivity, and decreases in pH and bicarbonate concentrations were also observed. All changes were most noticeable during the low flow periods of late summer and early autumn. There were no obvious effects on sodium, aluminium, ammonium, dissolved silica, and phosphate concentrations. In terms of chemical budgets, there was a general net loss of calcium, sodium, magnesium, potassium, and sulphur from all the watersheds, in their undisturbed state, while nitrogen was accumulated and phosphorus underwent very little change. The chloride balance changed from year to year with losses one year and gains the next. Chemical outputs increased relative to inputs with increasing precipitation so that net losses were greater in winter than in summer. Chemical budgets and stream chemistry at Haney were compared to the results of other studies, particularly one in the nearby Seymour watershed (Zeman, 1973). At Haney, clearcutting significantly increased potassium losses and decreased nitrogen gains in one watershed and significantly increased potassium, sodium, magnesium, and chloride losses in another watershed. From the nutrient viewpoint, it appears that clearcutting has not impaired the mechanisms for nutrient retention in the ecosystems of the type present in the study area. This may not be the case for all ecosystems in coastal B.C., or for other forestry practices, such as slashburning. The study has pointed out the need for further work to quantify the role of macrochannels in soils with respect to hydrologic and chemical behaviour of watersheds. It has also pointed out the danger of extrapolating to larger ecosystems the results of lysimeter studies. Chemical analysis of groundwater may offer a more accurate means of estimating chemical losses from soils than do lysimeters. / Forestry, Faculty of / Graduate

This thesis is comprised of four self contained chapters that report the results of a study on the stormflow hydrology of small forested watersheds in the Coast Mountains of southwestern British Columbia. The chapters discuss the general characteristics of the study watersheds and their instrumentation, the generation of stormflows from small forested watersheds, the stormflow (channel-phase) characteristics of one study watershed with steep topography, and the evaluation of initial changes in peak stormflow following logging of another study watershed. Chapter I. The characteristics of the study watersheds with respect to regional climate, physiography, soil hydrologic characteristics and forest cover were evaluated and summarized from available information. Emphasis is placed on the hydrologic characteristics of the watershed soils. The instrumentation of the study watersheds pertinent to the present study is also described. Due to the highly permeable nature of the watershed soils, the physical setting of the study watersheds favor a Rapid response of streamflow to rainstorms. On one study watershed this rapid response characteristic is reinforced by its steep topography and high drainage density. Chapter II. The problem of stormflow generation from small forested watersheds is dealt with by analyzing results from studies completed by the author and other workers in Jamieson Creek watershed and vicinity and by making field examinations in the same study area. A review is made of stormflow generation models, followed by analyses of rainfall intensity, saturated soil hydraulic conductivity and depression storage of the study area. These analyses revealed that overland flow rarely, if ever, occurs on coastal watersheds with hydro-logic environments similar to that of the study area. Instead, rain water takes alternate subsurface pathways through the soil to the stream channel. Observations made by the author in the study area and in other watersheds in this coastal region confirmed the existence of these alternate routes of water flow. Two types of subsurface stormflow pathways have been identified by earlier workers: (1) the matrix of forest floor and mineral soil beneath and (2) channels within or passing through the mineral soil. In the study area most soil channels were developed from dead or decaying roots. After passing through these two types of pathways, subsurface stormflows feed the expanding stream channel system laterally while rainfall is feeding the system from above. Subsurface stormflows are mainly in the form of saturated return flow from the ground and seepage flow through saturated stream banks. The stream channel system expansion during, and contraction after, a storm was measured in a small sub-watershed in the study area. It was found that the rate of stormflow from a watershed was closely related to the rate at which the stream channel expanded in response to the storm. From theestudy it is concluded that the model of subsurface stormflow from a variable source area is more appropriate than the other two models in describing stormflow generation in this coastal region. Chapter III. Stormflow characteristics of Jamieson Creek watershed, a small, steep, and forested watershed in the Coast Mountains of southwestern British Columbia, were evaluated by the analysis of 41 storm hydrographs from 1970-1974. During the study period, the rainfall amount per storm event varied from 5 to 330 mm, with the majority of the storm durations ranging from 20 to 60 hours. On the average, the fraction of storm rainfall that appeared as stormflow was 44 percent, varying from 2.5 to 81 percent. A significant number of major storms produced stormflow that accounted for more than 60 percent of the storm rainfall. Instantaneous peak flows varied considerably with storms, ranging from about 10 to 1,370 -1-2 1 s km and appeared to be mainly affected by the rainfall amount and distribution before the occurrence of the peak flow. Rising time (time to the peak) was short, usually within 30 hours, depending upon the rainfall distribution before the occurrence of the peak flow. Lag time was found to be relatively constant and short, ranging from 5 to 15 hours with an average of 8.5 hours. It is suggested that to derive lag time from characteristics of small watersheds, soil hydrologic properties should also be included with those parameters that are generally used. Stormflow amount was highly correlated with rainfall amount with 92 percent of its variance being accounted for. Antecedent base-flow rate was proposed as an index of watershed soil water storage prior to the storm hydrograph rise. One set of data from Jamieson Creek watershed and four additional data sets from two small steep watersheds in the Coweeta Hydrologic Laboratory were used to assess, through multiple regression analysis, the usefulness of antecedent baseflow rate in improving stormflow-rainfal1 relations. For all data sets, the inclusion of antecedent baseflow as a second independent variable significantly improved the stormflow estimate in comparison to that when rainfall amount was the only independent variable. Recession limbs of storm hydrographs varied with individual storms, depending on the degree of recharge to the watershed storage by the storm and the spatial distribution of such storage over the watershed. The stormflow characteristics of Jamieson Creek watershed reflect the influence of not only climatic conditions but also watershed characteristics: (1) shallow but highly permeable soils, (2) steep watershed slopes and stream channels, and (3) high drariinage density. The stormflow characteristics can be interpreted in terms of the generation of stormflow from a variable source area of the watershed. A comparison of the stormflow characteristics of Jamieson Creek watershed and the adjacent Elbow Creek watershed indicated that stormflow from the former usually has a sharper peak, higher peak flow ratio and steeper recession than stormflow from the latter, but both have very similar rising times. Differences in the streamflow response of the two watersheds could be caused by their differences in some topographical features. However, these differences also suggest that leakage from Elbow Creek, revealed in a preliminary field investigation, may deserve more detailed study. Chapter IV. This chapter provides the first quantitative Canadian information with respect to the impact of logging on peak stormflow. The paired-watershed technique was used to evaluate the initial changes in peak streamflow during storm periods following logging of a small watershed in the U.B.C. Research Forest, near Haney, B.C. Contrary to the majority of similar studies elsewhere, the analysis indicates that significant peak flow changes after logging occurred as follows: (1) an increase in the time to the peak, and (2) a decrease in the magnitude of the peak. The changes can be explained by (1) the degree of ground surface disturbance associated with the logging and (2) the stormflow generation mechanisms of the study area. Visual examination after the logging indicated that ground surface disturbance did not reduce the soil infiltration capacity to the extent that overland flow resulted. Workers in an earlier study speculated that forest floor disturbance could result in closure of some of the entrances to soil channels, thus increasing temporary water storage in the soil matrix. This, they further speculated, would result in reduced subsurface stormflow and, consequently, lower peak flow. The results of the present study tend to support the speculations, that the closure of some soil channel entrances is responsible for lower peak flow after logging. However, this study indicated that peak flow magnitude decreased mainly because of the flattening out of the hydrograph as a result of increased time to the peak (delayed peak rather than earlier hydrograph rise,). It is suggested that a lower rate of stormflow transmission through the soil matrix caused this increased time to the peak and, consequently, lower peak flow magnitude. Implications of this study for better water management are suggested. / Graduate and Postdoctoral Studies / Graduate

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In order to ensure clean drinking water for all, it is crucial to understand potential upland stressors that compromise the quality of source waters treated by local community water systems (CWSs). Contamination associated with specific types of land cover can result in downstream water quality degradation, which may reduce the effectiveness of treatment by CWSs. Surface mining has been hypothesized as a source of drinking water degradation within the Central Appalachian region, which may result in adverse exposures and health disparities. The purpose of this study was to identify potential correlations between land cover and adverse birth outcomes (ABOs) through the application of watershed epidemiology, an emerging environmental health paradigm. Birth records for the Central Appalachian region were acquired from their respective state health departments from 2001 to 2015: each record contained the mother's street address, outcome variables, and covariates. Records were included in later analyses if they fell within an approximated CWS service area. Contributing land cover to each CWS was determined via previously delineated watersheds that relied on CWS intake points. A binomial generalized linear model was used to compare low birth weight (LBW), term low birth rate (tLBW), and preterm birth (PTB) incidence to CWS source watershed land cover, Safe Drinking Water Act (SDWA) violations, CWS size, and covariates related to the birth records. Source watershed mining and SDWA health based (HB) violations were significantly associated with greater risks for preterm birth (PTB) and low birth weight (LBW). Future work should be conducted to explore upstream flow impacts, address missing data in the birth records, and to more accurately represent CWS service areas to better characterize exposure. / Master of Science / Millions of individuals throughout the world are sickened by waterborne exposures every year. To ensure clean drinking water long-term, it is crucial to understand how human land cover might change the water quality of source watersheds, as this may impact the effectiveness of water treatment and increase adverse human health exposures. The goal of this effort is to understand whether land cover is linked to downstream adverse birth outcomes (ABOs) in Central Appalachia, a region of the United States previously associated with high disease incidence suspected to be partially linked to environmental exposure. Birth records were acquired for the years of 2001 to 2015 from four (VA, WV, TN, KY) respective state health departments. Each record contained the mother's address, outcome variables, and covariates (e.g., race, ethnicity). Births were located within approximate service areas for 140 surface water dependent community water systems (CWS) within the region. Data from each CWS, including weighted land cover proportions for their source watershed, were merged with the birth records according to approximate service areas. Statistical analysis suggested that higher source watershed levels of mining and urban development were associated with higher risks of preterm birth (PTB) and low birth weight (LBW). The number of health based (HB) violations associated with each CWS was also associated with both of these outcomes. Major limitations of this work include birth record data gaps and the lack of publicly available CWS service areas and/or water consumption rates, which does increase the risk of exposure misclassification.