Corals are frequently exposed to elevated turbidity and deposited sediment caused from coastal construction, dredging, and/or beach renourishment. This study addresses the effects of turbidity and deposited sediment on the survival and growth of newly settled and 6-week-old Orbicella faveolata recruits and disentangles the effects of turbidity and deposited sediment. We conducted two experiments in which newly settled coral recruits were reared in one of ten different turbidity and deposited sediment treatments for five weeks (0 NTU/ 0 mg cm-2, 3.4 NTU/ 0 mg cm-2, 8.2 NTU/ 0 mg cm-2, 16 NTU/ 0 mg cm-2, 29.1 NTU/ 0 mg cm-2, 0 NTU/ 0 mg cm-2, 3.4 NTU/ 27.7 mg cm-2, 8.2 NTU/ 50 mg cm-2, 16 NTU/ 101 mg cm-2, 29.1 NTU/ 220 mg cm-2). The highest turbidity treatment in the absence of deposited sediment (29.1 NTU/ 0 mg cm-2) had the best survival, suggesting that turbidity in the absence of sediment is beneficial to coral recruits, as it decreases harmful light levels. However, when recruits were exposed to both turbidity and deposited sediment, representative of normal coastal construction conditions, high turbidity when coupled with deposited sediment (16 NTU/ 101 mg cm-2 and 29.1 NTU/ 220 mg cm-2) had negative effects on coral recruits. Based on the results from the first experiment, the experiment was repeated with six-week-old symbiotic recruits for two weeks to determine if the sensitivity to light and benefits of high turbidity were related to the presence of symbionts. Six-week-old recruits also had the highest survival in the highest turbidity treatment, suggesting that light sensitivity by coral recruits is not dependent on the presence of symbionts within the first six weeks post-settlement. While the low light associated with turbidity increases recruit survival, turbidity is a proxy for deposited sediment, which has negative effects on coral recruits. Based on the results from this study, regulations should prevent turbidity from exceeding 8.2 NTU to prevent excessive deposited sediment on coral reefs, and its deleterious effects on corals.

Thesis (S.M.)--Joint Program in Marine Geology and Geophysics (Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering; and the Woods Hole Oceanographic Institution), 2012. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 77-79). / This study describes the spatial distribution of sediment deposition in the wake of a circular patch of model vegetation and the effect of the patch on turbulence and mean flow. Two difference types pf vegetation were used along with two different stem densities totaling four different case studies. The spatial location of enhanced deposition correlated with the steady wake zone, which has length, L1. The steady wake zone only occurred downstream of the rigid emergent patches of vegetation and was not seen downstream of the flexible submerged patches of vegetation. The enhanced deposition occurred when both turbulence and mean velocity was below the upstream, initial values. The enhanced deposition occurred when the mean velocity was less than or equal to half of the initial velocity. For the four cases studied, theses parameters of low velocity and low turbulence were primarily met within the steady wake region immediately downstram of the two rigid emergent patches of vegetation. In all four cases, large coherent structures are created in the flow due to the patch. Lateral vortices are formed downstream of the patch in a von-Karman vortex street that meets at the center of the flow a distance, Lw, downstream of the patch. For the flexible submerged cases, streamlines reattach to the bed of the flume a distance, Lv, downstream of the patch. In addition, for the flexible submerged cases, a secondary circulation is generated with flow moving laterally away from the patch at the surface and toward the centerline of the patch at the bed. / by Alejandra C. Ortiz. / S.M.

The general aim of Master’s thesis was to analyze a water supply network in the village Klobouky u Brna using the WaterRisk software through the simple and complex methodology. It was performed a measurement of turbidity on water supply network as practical support of undesirable states. Also it was accomplished detailed exploration of the village Klobouky u Brna. Added value of Master’s thesis was a consultation related to a water supply and a water treatment system with technician working for the Vodovody a kanalizace Hodonín company wherefrom water is bought for the village Klobouky u Brna.

The goal of this study was to demonstrate the application of aerial imagery as a tool in detecting water quality indicators in a three mile segment of Tibbee Creek in, Clay County, Mississippi. Water samples from 10 transects were collected per sampling date over two periods in 2010 and 2011. Temperature and dissolved oxygen (DO) were measured at each point, and water samples were tested for turbidity and total suspended solids (TSS). Relative reflectance was extracted from high resolution (0.5 meter) multispectral aerial images. A regression model was developed for turbidity and TSS as a function of values for specific sampling dates. The best model was used to predict turbidity and TSS using datasets outside the original model date. The development of an appropriate predictive model for water quality assessment based on the relative reflectance of aerial imagery is affected by the quality of imagery and time of sampling.

No description available.

Construction sites are frequently cited as major sources of pollution that degrade the quality of surface water. The highly erodible topsoil is transported off site by stormwater runoff causing negative effects downstream. Research has shown that the small particles, which are the most susceptible to erosive forces, have more pollutants associated with them than larger soil particles. Currently, in the state of Florida, it is not permissible to discharge water to a receiving water body if the turbidity is more than 29 Nephelometric Turbidity Units (NTUs) above background or higher than background for an outstanding Florida water body. The removal of fine suspended sediment from water can be achieved by filtration, settling, and the use of chemical coagulants. Polyacrylamide (PAM), a coagulant, has been shown to be effective in removing fine suspended particles from water via coagulation and flocculation. The Stormwater Management Academy at the University of Central Florida has researched the use of PAM and collection mats in a treatment channel to meet state discharge requirements. In this study, turbid water using sediment from typical Florida soils was simulated and passed through a channel. The channel contained polymer blocks in a configuration previously determined to be the most effective. An important component of the treatment system is the floc collection. This research examined three types of collection mats, namely jute, coconut fiber and polypropylene mix to collect the flocs. This thesis presents the results of this investigation. The results for the sandy soil tests showed an average removal efficiency prior to the collection mat starting at 71% and decreasing to 44% at the end of the tests. The 20-foot coconut mat maintained an average removal efficiency of 90%. The turbidity due to silty-sandy soil was decreased with an average removal efficiency prior to the collection mat ranging from 50% to 65%. The average removal efficiency for the 20-foot coconut mat started at 85%and decreased to 60% during the tests. The turbidity due to crushed limestone showed an average removal efficiency prior to the collection mat ranging from 81% down to 69% over time. The average results from the 20-foot coconut mat ranged from 65% to 80%. Turbidity was tested on the samples under two conditions, a 30 second settling time and completely mixed. Statistical results show a significant decrease (?=0.05) in turbidity between the mixed and settled samples. Statistical analyses were performed on the collected data, which concluded that the capability of the mat to reduce turbidity can be repeated with a 95% confidence interval. The 20-foot length coconut mat had the highest turbidity removal efficiency for every soil type examined. Further statistical analysis showed that the achieved turbidity reduction was significantly different (?=0.05) for the various materials. It was observed that generally, each type of mat clogged during testing indicating that longer collection mats be used, possibly lining the entire channel. Recommendations from this study are to provide a settling area after the collection mats and line the entire length of the channel with the collection mat selected.

Yes / Water scarcity is a huge problem in Africa, and hence rainwater becomes a crucial water source for fulfilling basic human needs. However, less attention has been given by African countries to the effectiveness of common rainwater treatments to ensure the population's health. This study investigates the impact of different household treatment techniques (HHTTs), i.e. treatments by chlorine, boiling, alum, and a combination of alum and chlorine, on its storage system using a case study at the Ikorodu area of Lagos state, which is a rural area in Nigeria. The first-flush quality has been particularly studied here, where the microbial reduction through its practice has been examined from five different roofs. One of the investigated roofs was from a residential building, and four were constructed for the purpose of this study. In this study, the physical parameters (i.e. total suspended solids and turbidity) and the microbial parameters (i.e. total coliform and Escherichia coli) of the collected rainwater have been investigated. From the results, it has been observed that: (1) the water quality at the free phase zone is better than that at the tank's bottom; (2) the combination of chlorine and alum gives the best rainwater quality after comparing the application of different HHTTs; and (3) a reduction of about 40% from the original contaminant load occurs in every 1 mm diversion. / Hidden Histories of Environmental Science Grant Project (at Seed-grant Stage), funded by the Natural Environment Research Council (NERC) and Arts and Humanities Research Council (AHRC), part of UK Research and Innovation (UKRI)

<p> Sedimentary structures, textures and fabric were studied in detail in eight turbidite greywacke beds from the Cloridorme Formation (Middle Ordovician), Gaspe, Quebec. The beds are exposed on the wave-cut platform near Grande Vallee and were traced for about two miles along the strike (276 degrees), which is parallel to the average current direction (274 degrees) as indicated by sole mark directions. </p> <p> The beds under study show the following systematic downcurrent changes along the strike from east to west: (i) Sole mark types show the following changes: (1) tool marks such as grooves, prod marks and isolated flute marks, to (2) longitudinal ridges, longitudinal ridges with overlapping flute, closely spaced flutes, to (3) poorly developed, shallow longitudinal ridges with occasional cuspate crossing bars, to (4) smooth bottom with occasional grooves. (ii) There is an increase in variance of sole mark directions without a large change in the mean direction in most beds, but the sole mark direction changes by nearly 90° as one of the beds is traced from east to west along the strike. (iii) Most of the beds are massive and are divided into two parts by a bedding joint. However, in the proximal region, if a bed is unusually thin, the bedding joint is absent and the bed shows slightly wavy, plane-laminated structure at places. (iv) Grain orientations are generally statistically non-significant in the upper massive part of the bed in the proximal region and significant in the rest of the bed. Significant grain orientations and graptolite orientations show large deviations from the sole in the distal region. Deviations increase towards the top of the bed. (v) The beds show a change from good grading to poor grading or slight reverse grading from the proximal to distal region. It is considered that the beds were deposited by low concentration, highly turbulent currents. Deposition of the beds took place in two distinct phases. First a 'quick' bed separated from the current was sheared extensively by the overflowing current and on consolidation formed the lower part of the bed. Later deposition in the proximal region from the upper part of the current and the part close to the tail was by settling of individual particles from the suspension. Separation and consolidation of another 'quick' bed in some cases formed the upper part of the beds in the distal region. </p> <p> The depositing currents produced a good vertical and lateral grain size grading in the proximal region, but poor vertical grading in the distal region due to the loss of coarse grains and possibly increased concentration of flocculated clay. Also, the turbidity currents tended to "meander" greatly on slowing down in the distal region. </p> / Thesis / Doctor of Philosophy (PhD)

Inland water has for a long time showed vast stress due to eutrophication, mainly caused by increased levels of phosphorus. Applying remote sensing as a tool for monitoring water parameters has long been used. In the past, inland watercourses measurements have proven to be challenging, often due to the limitations of satellite missions' spectral resolution or difficulties in implementing the appropriate methodology. This project investigates the potential to use a high-resolution satellite mission, Sentinel 2, to monitor phosphorus with the proxies total suspended matter (TSM) and turbidity in two smaller watercourses, Fyrisån and Sävjaån, in Uppsala, Sweden. From April to November, a period spanning three years (2018, 2019, and 2021), empirical modeling was employed to conduct investigations. The three years all represent different weather patterns and discharge velocities. The bands 2 to 8 were investigated individually and together to see if there was a potential using a single band correlation or multiple to correlate with turbidity or TSM. The two optically active water parameters are known to have a high correlation with the non-optically active phosphorus. There was no correlation found between the proxies and each band individually for any of the years investigated. Using a multi regression analysis both 2018 and 2019 showed high correlation for TSM, and 2019 for turbidity. While the results for 2021 were not significant for any of the proxies. The conclusion indicates that with right surrounding factors it’s possible to use TSM and turbidity as a proxy for phosphorus when using Sentinel 2 in these smaller watercourses. Nevertheless, further studies are needed to investigate how the proxy and the nutrient acts together with satellite data for peaks etc. before using Sentinel 2 results as a direct interpretation.

No description available.