AIMS Talladega Field Discharge Data (AIMS_SE_TAL_DISL)

This study was conducted in the Talladega research watershed (outlet location: 33.76219799, -85.59550775) in the Talladega National Forest (Cleburne County, AL, USA). The watershed drains a non-perennial unnamed tributary of Pendergrass Creek, and contains 0.92 km^2 of mixed coniferous and deciduous forest in the Piedmont Upland physiographic section. Located near Anniston, AL, the watershed spans an elevation range from 345 to 456 m above sea level and is a tributary to the Coosa River (within the larger Mobile-Tombigbee basin). The region has a humid subtropical climate, with mean daily January and July air temperatures of 5.3°C and 25.3°C respectively, and mean annual precipitation of 1,400 mm/yr. These samples were collected in support of the core sampling goals of the Aquatic Intermittency effects on Microbiomes in Streams (AIMS) Project. Between 7 October 2021 and 7 October 2024, we conducted pulse additions of NaCl (i.e., \"salt slugs\") to estimate discharge (Q; liters per second) and velocity (v; meters per second) at the watershed outlet (TLM01) every 3 weeks during routine sensor maintenance (AIMS Approach 1), seasonally at seven distributed, long term monitoring sites (AIMS Approach 2), and during a large synoptic sampling efforts concentrated across the watershed (AIMS Approach 3). Briefly, discharge and velocity were estimated by adding a known mass of NaCl dissolved in approximately 1 liter of stream water to an upstream \"addition\" site and measuring changes in conductivity using a Solinst Conductivity Sensor (at 2 second intervals) at a downstream \"logging\" site. Discharge (in liters per second) was estimated using the mass of salt added and the area under the background conductivity-corrected \"breakthrough curve\" (e.g., change in conductivity over time at the logging site from the arrival of the salt tracer until conductivity returns to pre-salt slug background levels). Velocity (in meters per second) was estimated using nominal travel time (time for 50% of salt mass to pass the logging site) and the reach length between the addition and logging site. Salt slugs were only conducted if the reach upstream of the sample site was fully connected and flowing continuously for a distance of at least ten wetted widths. For R scripts and individual tracer breakthrough curves used to estimate discharge and travel time, please contact Stephen Plont ([e-mail]).本研究开展于美国阿拉巴马州克莱本县塔拉迪加国家森林内的塔拉迪加研究流域（出水口坐标：33.76219799, -85.59550775）。该流域汇水区域为彭德格拉斯溪一条无正式名称的非常年流动支流，流域面积0.92平方千米，地貌上属于皮埃蒙特台地地貌区，覆盖针阔混交林。该流域临近阿拉巴马州安尼斯顿市，海拔范围介于345米至456米之间，是库萨河的支流（隶属于更大的莫比尔-汤比格比流域）。本区域属于亚热带湿润气候，1月与7月的日均气温分别为5.3℃与25.3℃，年平均降水量为1400毫米/年。 这些样本采集工作旨在支撑“溪流微生物组的间歇性水文效应（Aquatic Intermittency effects on Microbiomes in Streams, AIMS）”项目的核心采样目标。2021年10月7日至2024年10月7日期间，我们开展了氯化钠（NaCl）脉冲投加实验（即“盐脉冲”），以估算流域出水口（TLM01）的径流量（Q，单位：升/秒）与流速（v，单位：米/秒）：具体采样方式包括每3周配合常规传感器维护开展1次采样（AIMS方法1）、在7个分布式长期监测点位按季节开展采样（AIMS方法2），以及在覆盖全流域的大型同步采样工作期间开展采样（AIMS方法3）。 简言之，径流量与流速的估算原理如下：将溶解于约1升溪流水中的已知质量氯化钠投加至上游“投加点位”，并在下游“监测点位”使用Solinst电导率传感器以2秒的间隔记录电导率变化。径流量（单位：升/秒）通过投加的盐质量与背景电导率校正后的“穿透曲线”——即从盐示踪剂抵达监测点位至电导率恢复至盐脉冲前背景水平期间，监测点位的电导率随时间变化的曲线——下方面积估算得出。流速（单位：米/秒）通过名义行进时间（即50%盐质量通过监测点位的时间）与投加点位至监测点位的河段长度估算得出。仅当采样点位上游河段完全连通且连续流动的距离至少达到10倍湿润宽度时，方可开展盐脉冲实验。如需获取用于估算径流量与行进时间的R脚本及单条示踪剂穿透曲线，请联系斯蒂芬·普隆特（Stephen Plont，邮箱：[e-mail]）。