Download or read book The Effect of Watershed Runoff and Sediment Resuspension on Turbidity and Sediment Deposition in St John US Virgin Islands written by Stephen E. Campbell and published by . This book was released on 2017 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the US Virgin Islands (USVI), land-based (terrigenous) sedimentation has been identified as a major cause of coral stress. Development, such as the building of unpaved roads in steep coastal watersheds, has increased sediment yields and marine terrigenous sedimentation by up to an order of magnitude above background levels. When activated during storm events, ephemeral streams transport sediment from the watershed to coastal waters. Once deposited on the seafloor, resuspension of benthic sediments can further increase turbidity and deposition. However, isolating the relative contributions of runoff and resuspension to turbidity and deposition using conventional sediment trap monitoring has been challenging. Here we describe the spatial and temporal variability of marine sediment dynamics in response to runoff and resuspension events in St. John, USVI. Between late July 2013 and January 2014, nephelometers were deployed at three reef and five shoreline sites next to ephemeral stream outfalls equipped with a water level sensor (10-min resolution) and peak crest gauges (~13-day resolution). At each instrument site, benthic sediment samples were collected every ~26 days. While runoff events resulted in high-magnitude spikes in turbidity and deposition, which were up to 900 and 17,000 times background, respectively, they were short-lived (hours). Resuspension-induced spikes in turbidity and deposition were lower in magnitude but of longer duration (days-weeks), particularly at sites with finer-grained benthic sediments, and were associated with increased wave height during low tides. While the relative contribution of runoff and resuspension to turbidity and deposition were spatially variable between our study sites, resuspension contributed at least 7 times more to turbidity and 3 times more to deposition than runoff during the 2013 rainy season at one of our coastal marine monitoring sites. Though previous studies have measured marine sedimentation over months-centuries in St. John, no studies have monitored turbidity or the relative contributions to turbidity and deposition from runoff and resuspension at the time scale of minutes-days. Understanding the relative contribution of runoff vs. resuspension to marine turbidity and deposition is important to effectively manage land-based sedimentation, marine development, as well as evaluate the effectiveness of watershed restoration programs which aim to reduce marine terrigenous sedimentation.
Download or read book The Effect of Anthropogenic Development on Sediment Loading to Bays on St John U S Virgin Islands written by Helen F. McCreery and published by . This book was released on 2007 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to assess the impact of anthropogenic development on sediment delivery rates to bays on St. John, U.S.V.I., I developed a sediment loading prediction model. Based on the modified universal soil loss equation, this model predicts sediment loading using watershed parameters, including the soil type, topography, and land use of the watershed, and also storm based parameters, including the total storm runoff and peak discharge. Sediment loads I predicted on a storm-by-storm basis, and annual sediment loads were calculated by summing the loads from each storm in a year. This was performed from historical rainfall data for three years: 1990, which had an approximately average total rainfall; 1986, which had the highest total rainfall in the period for which I had rainfall data; and 1989, which was the year of Hurricane Hugo, and therefore had the largest single storm. I calculated sediment loads for multiple bays, with varying levels of development. The sediment loads to the developed bays were as much as or even more than an order of magnitude greater than sediment loads to undeveloped bays. Additionally, I calculated the sediment loads to each bay under entirely undeveloped conditions, comparing these loads to the loads under current development conditions. Again, developed conditions often resulted in a sediment load at least ten times greater than the load under no development.
Download or read book Year 2 written by Sarah Gray and published by . This book was released on 2017 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: "We were awarded continued funding (for a 2nd year, 2014) from the DCRC (Domestic Coral Reef Conservation) Program to supplement ongoing funding (noncompetitive NOAA CRC) to support a joint terrestrial-marine sediment monitoring project to study how marine sediment dynamics are affected by watershed erosion, runoff and restoration activities in Coral Bay, St. John, USVI. In July 2013, the P.I. and Dr. Carlos Ramos-Scharrón of UT Austin in partnership with NOAA and community environmental managers, initiated a joint terrestrial-marine monitoring program to build on previous work to determine how ARRA-funded watershed restoration projects completed in Coral Bay in 2011 have impacted watershed runoff and marine sedimentation. In addition, the program initiated new monitoring approaches to evaluate the specific linkages between watershed processes and marine sedimentation in near-shore and coral reef areas. This grant funded field work for an additional season from Aug.-Nov. of 2014 and the follow-up data synthesis and interpretation. However, through cost savings, this grant has supported continued sampling through 2015 at two of our shoreline sites. Ultimately our aim was to a) understanding of the linkages between watershed processes and marine sedimentation, b) to evaluate the effectiveness of ARRA watershed restoration activities, b and c) evaluate marine sediment-monitoring protocols for coral reef areas. This report is divided into three parts, addressing each of these aims"--Introduction and Project Objectives."
Download or read book Sedimentation in Coastal Bays with Coral Reefs written by Megan LaDonna Kolupski and published by . This book was released on 2011 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measuring and Predicting Erosion and Sediment Yields on St John U S Virgin Islands written by Carlos E. Ramos-Scharrón and published by . This book was released on 2004 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Man s Long term Impact on Sedimentation written by Maynard M. Nichols and published by . This book was released on 1988 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coastal ecosystems of the Virgin Islands Biosphere Reserve, St. John, are subject to stress of sedimentation from watershed erosion, both natural and man-induced. A pilot study was initiated at Mandal Pond and Reef Bay mangrove swamp on the southern coast of St. John to determine sedimentation rates and to discover if the rates have changed in response to man's historical activity in the watershed. The results reveal the deposits are ordered in time, display horizons and preserve components produced in the pond/swamp or derived from the watershed. Radiocarbon ages of intertidal peat indicate that both sites have submerged at a uniform rate of 0.08 cm/yr. Submergence exceeds sediment infilling at Mandal Pond whereas infilling exceeds submergence at Reef Bay. Consequently, the swamp size at Reef Bay and water depth increase with time, depositional units change and watershed-derived alluvium encroaches on the swamp. Despite man's activity, no massive effect of sedimentation on the swamp is observed. man's effects are relatively small in comparison to the long-term natural evolution of the system.
Download or read book Cruise Ship Induced Sediment Resuspension Characteristics in Charlotte Amalie Harbor and the West Gregerie Channel St Thomas U S Virgin Islands written by Jennifer K. Kisabeth and published by . This book was released on 2014 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cruise ship port activities are one of the largest potential sources of sediment resuspension in the marine environment of St. Thomas, United States Virgin Islands. The two cruise ships ports of St. Thomas were examined from September 2013 to May 2014 to better understand the extent of sediment resuspension and dispersal. To establish cruise ship effects on the water column a conductivity-temperature-depth (CTD) sensor package was used to collect water quality variables, including turbidity, on a daily basis directly before and after the passage of inbound cruise ships to each port. Water samples were taken simultaneously for total suspended solids (TSS) analyses. SedPods that mimic coral surfaces were deployed for one day at a time to determine deposition rates of particles in a transect running perpendicularly away from the ship docks for ship days and no ship days. Gross sediment accumulation rates were measured on a monthly basis by sediment traps at the same sites as SedPods.
Download or read book Modeling the Fate and Transport of Nitrogen and Sediment Within Coastal Embayments on St John U S Virgin Islands written by Jeffrey Douglas Walker and published by . This book was released on 2007 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) A mass balance model for nitrogen was also developed accounting for input fluxes by groundwater discharge, atmospheric deposition, and nitrogen fixation and output fluxes by tidal flushing and denitrification. The biological fluxes of nitrogen were orders of magnitude greater than the physical fluxes suggesting that nitrogen availability in these ecosystems may be controlled mainly by microbial processes and not by external inputs. Accounting only for the physical fluxes, steady-state inorganic nitrogen concentrations agreed with historical measurements of inorganic nitrogen collected by the National Park Service. The model results indicated elevated levels of sediment and nitrogen in bays with watersheds that are more developed and have larger areas. Overall, this study provides strong evidence that both watershed development and watershed size are closely related to deteriorating water quality in coastal bays around St. John, and further studies of nitrogen and sediment pollution are warranted.
Download or read book Grain Size Analysis of the Watershed and Nearshore Coastal Sediments in Coral Bay St John U S Virgin Islands written by Thomas A. Copeland and published by . This book was released on 2016 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Affects sic of Sediment Resuspension on Recreational Water Quality written by Jack David Doyle and published by . This book was released on 1985 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The specific purpose of the study was to quantify the microbial impact of experimental sediment resuspension over overlying waters"--Page 5
Download or read book Inorganic Sediment Source Flux and Composition with Bays in St John USVI written by Kimbrie Lynn Gobbi and published by . This book was released on 2009 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Review of the St Johns River Water Supply Impact Study written by National Research Council and published by National Academies Press. This book was released on 2009-10-08 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: The St. Johns River is the longest river in Florida, containing extensive freshwater wetlands, numerous large lakes, a wide estuarine channel, and a correspondingly diverse array of native flora and fauna. Water resource management in the river's watershed is the responsibility of the St. Johns River Water Management District (the District). The District must provide water for the region's 4.4 million residents as well as numerous industrial and agricultural users, all while protecting natural systems within the river basin. With population growth in the watershed expected to surpass 7.2 million in 2030, the District, through its water resources planning process, has begun to identify alternative sources of water beyond its traditional groundwater sources, including the potential withdrawal of 262 million gallons per day from the St. Johns River. To more comprehensively evaluate the environmental impacts of withdrawing this water from the river, the District embarked on a two-year Water Supply Impact Study (WSIS), and requested the involvement of the National Research Council. The present volume reviews the Phase I work of the WSIS and provides recommendations for improving Phase II.
Download or read book Effects of Erosion Sediment and Runoff on Coastal and Marine Resources written by United States. Virgin Islands National Park and published by . This book was released on 1996 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Environmental Characteristics Upon Storm Runoff and Sediment Production in Selected Middle Atlantic Watersheds written by John Ray Ratzlaff and published by . This book was released on 1974 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Sediment on the Aquatic Environment written by Janine Castro and published by . This book was released on 1995 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sediment Removal as a Lake Restoration Technique written by Spencer A. Peterson and published by . This book was released on 1981 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis and Modeling of Erosion Hazards and Sediment Delivery on St John U S Virgin Islands written by Donald M. Anderson and published by . This book was released on 1994 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:
