Annual Channel Geomorphology Cross-Section Surveys 2005-2012 in Roanoke, Virginia

Geomorphology monitoring sites at 15 locations along the Roanoke River in Salem and Roanoke, Virginia, represented riffle or pool habitats and were designed to facilitate repeated measuring at the same cross section over time. Local bench marks were installed at each site to provide both horizontal and vertical control. At a minimum, each site had two bench marks (designated BM) and two transect control marks (designated TC) that were tied together through a static survey-grade Global Positioning System (GPS) survey to establish control to the nearest centimeter. Annual cross-section topographic surveys were conducted during summer low-flow periods at the 15 geomorphology monitoring sites using a total station from 2005 to 2012 at each site. Floodplains, banks, channels, and water-surface elevations were surveyed, with each survey beginning on the floodplain a minimum of 50 ft from the active channel. Floodplain features were surveyed on 5-10-ft intervals and at major breaks in slope, channel banks were surveyed on 1-5-ft intervals, and the active channel was surveyed on 1-2-ft intervals to document channel changes with greater resolution. Most sites had one bank that was steeper and more vegetated than the other; bank steepness occasionally prevented complete surveying of the banks, in which case the survey was continued up the bank as far as possible. Pools were surveyed from a canoe when depths prohibited wading. Water-surface slope within 10 meters upstream and downstream of the cross section was surveyed most years for evaluation of changes in gradient.

本数据集包含沿弗吉尼亚州塞勒姆与罗阿诺克境内罗阿诺克河布设的15处地貌监测站点，涵盖浅滩（riffle）与深潭（pool）生境，旨在支持长期在同一河道断面开展重复测量工作。各站点均布设本地水准基点（bench mark），以提供水平与垂直控制基准。每个站点至少设置2个水准基点（编号为BM）与2条断面控制标记（编号为TC），通过静态测量级全球定位系统（GPS，Global Positioning System）联测，将其纳入厘米级精度的控制网中。2005至2012年，每年夏季枯水期，研究人员均使用全站仪对15处地貌监测站点开展断面地形测绘工作。本次测绘涵盖河漫滩、岸坡、河道与水面高程，每次测绘均从距离主槽（active channel）至少50英尺的河漫滩区域起始。河漫滩地形要素以5-10英尺的间隔布设测点，并在主要坡度转折处加密测点；岸坡测绘采用1-5英尺的测点间隔；主槽测绘则采用1-2英尺的测点间隔，以更高分辨率记录河道变化情况。多数站点的两岸中，一侧岸坡更为陡峭且植被更茂密；部分站点因岸坡过陡无法完成全岸坡测绘时，测绘工作将尽可能沿岸坡向上推进。当水深不允许涉水作业时，深潭的测绘工作将通过独木舟完成。多数年份，研究人员还会测绘断面上下游10米范围内的水面坡度，以评估河道纵比降的变化情况。