VTechWorks staff will be away for the Thanksgiving holiday beginning at noon on Wednesday, November 27, through Friday, November 29. We will resume normal operations on Monday, December 2. Thank you for your patience.

Browsing by Author "Brendel, Conrad E."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Catchment-scale Phosphorus Export through Surface and Drainage Pathways
    Brendel, Conrad E.; Soupir, Michelle L.; Long, Leigh Ann M.; Helmers, Matthew J.; Ikenberry, Charles D.; Kaleita, Amy L. (2019-01)
    The site-specific nature of P fate and transport in drained areas exemplifies the need for additional data to guide implementation of conservation practices at the catchment scale. Total P (TP), dissolved reactive P (DRP), and total suspended solids (TSS) were monitored at five sites-two streams, two tile outlets, and a grassed waterway-in three agricultural subwatersheds (221.2-822.5 ha) draining to Black Hawk Lake in western Iowa. Median TP concentrations ranged from 0.034 to 1.490 and 0.008 to 0.055 mg P L-1 for event and baseflow samples, respectively. The majority of P and TSS export occurred during precipitation events and high-flow conditions with greater than 75% of DRP, 66% of TP, and 59% of TSS export occurring during the top 25% of flows from all sites. In one subwatershed, a single event (annual recurrence interval < 1 yr) was responsible for 46.6, 84.0, and 81.0% of the annual export of TP, DRP, and TSS, respectively, indicating that frequent, small storms have the potential to result in extreme losses. Isolated monitoring of surface and drainage transport pathways indicated significant P and TSS losses occurring through drainage; over the 2-yr study period, the drainage pathway was responsible for 69.8, 59.2, and 82.6% of the cumulative TP, DRP, and TSS export, respectively. Finally, the results provided evidence that particulate P losses in drainage were greater than dissolved P losses. Understanding relationships between flow, precipitation, transport pathway, and P fraction at the catchment scale is needed for effective conservation practice implementation.
  • Thumbnail Image
    Roanoke Urban Stormwater Research: Lick Run / Trout Run Phase V Final Report
    Dymond, Randel L.; Brendel, Conrad E.; Woodson, David (2018-12-19)
    Effective management and restoration of urban watersheds requires considerable information describing the watershed’s land surface, drainage system, and receiving streams, in order to understand the important hydrologic and ecologic processes, and to make informed decisions about how to allocate resources for watershed improvements. Previous research has focused on the creation of Watershed Master Plans to provide recommendations for maintaining and improving the function of City of Roanoke watersheds. This year, research has focused on the creation of tools to assist the City in making informed decisions pertaining to land development and stormwater best management practice (BMP) design. This report outlines 1) the development of web apps to assist the City with data synthesis and analysis, 2) the creation of a hydrology and hydraulics model to simulate watershed hydrology under existing conditions and a variety of development and/or stormwater BMP implementation scenarios, and 3) the review of stormwater management design manuals for various states and municipalities. This report is submitted in tandem with a literature review of stormwater management design manuals that is generally organized according to the tasks outlined in the 2018 Phase V Scope of Research. Section 1 is an Introduction that describes the ongoing relationship between the City and the Virginia Tech Via Department of Civil and Environmental Engineering that made this work possible, and also describes the layout of subsequent sections. Section 2 describes the Stream Hydrology and Rainfall Knowledge System (SHARKS) web app that was developed to provide the City with a platform to rapidly synthesize, visualize, and analyze data from various meteorological and hydrologic data sources. Section 3 describes the library of storm event precipitation and runoff data contained in Appendix II. This section also presents the MINNOWS web app that was developed to complement the SHARKS app and to provide an interactive platform to identify spatial and temporal trends in the storm event library. Section 4 describes the development of the hydrologic and hydraulic model for the combined Lick Run/Trout Run watersheds and Section 5 provides an overview of the stormwater management design manual review. Section 6 provides the references used in this report. Finally, Appendix I contains the relative flow/depth rating curves created for the nine Roanoke storm sewer depth sensors and Appendix II contains a library of storm event precipitation and runoff data for each 2018 event. Although the submittal of this report marks the end of the 2018 Scope of Research, the work performed during this period has continued the development of a long-term collaboration between the City and VT for expansion of the science of urban stormwater management, and its application to the City’s watersheds.