Bard’s Real-Time 水的质量 Monitoring System


Annandale Dam on the campus of Bard College in June 2019 (photo by E. 白色).

When evaluating a site for the potential installation of micro hydropower system, 重要的是要考虑现有的水质在拟议的地点,以确定如何安装可能影响水质. 锯杀项目, 巴德在安南代尔大坝蓄水区安装了一个多参数水质监测探测仪. With help from Robin Moore and Spike Pagano (Buildings and Grounds), 找到了一个沉积物深度足够的位置,可以支撑支撑探测仪的结构和传输采集数据所需的设备.


巴德的水质监测系统部署在Annandale大坝上方的蓄水池中(图片由E. 白色).

的 real-time water quality monitoring system consists of a YSI EXO2 多参数探头, housed in a protective PVC pipe that is fastened to one leg of the support structure. 的 sonde is connected by cable to a YSI风暴3数据记录器, contained in an all-weather enclosure. In addition to the data logger, this box holds a cellular modem and antenna for transmitting collected data, a desiccant canister to keep the cable dry, a 12 Volt battery to power the system. 的 battery is recharged by the solar panel mounted on top of the support structure. 的 system is programmed to “wake up” and collect data every 15 minutes. 的 data 然后通过cell modem从数据记录器推送到YSI 水LOGⓇStorm中央云数据收集服务.

Data logging/transmission equipment


该传感器是定制的传感器,测量一系列的水质参数,包括: 温度, 导电率, pH, 浊度, 溶解氧, 藻类总. 该仪器还有一个气压传感器,用来确定水深. 该传感器是为长期部署而设计的,并配备了一个雨刷,以保持传感器的清洁. To ensure data accuracy, the instrument must be routinely serviced (i.e.,清洗和校准).

的 sonde sensors (pre-deployment).

温度 因为它控制着自然水体中发生的化学和生物过程的速率. Temperature affects the solubility of 化学s. For example, the oxygen content of water increases as 温度 decreases. 的 survival of aquatic organisms (e.g., 微生物, 大型无脊椎动物, 鱼)也取决于水温,不同的物种有不同的最佳温度. Temperature can be measured with a thermometer but the sonde uses a thermistor. 热敏电阻的电阻随温度的变化而变化,利用一种算法将测量电阻转换为温度. Temperature is measured by the sonde with an accuracy of ±0.02°C.

天然水含有溶解的无机固体,它们携带正电荷和负电荷. 这些溶解离子, which come from rocks and minerals as well as anthropogenic inputs,  导电. 导电率 是一种测量电流在两个浸在水中的金属板(电极)之间流动的能力的方法. 在电极之间施加电压,由水的电阻引起的测量电压降被转换成电导率, in units of micro- or millisiemens per centimeter (µS/cm or mS/cm), 通过电导率计. A water that contains more dissolved ions will have a higher 导电率. 非离子的化合物(e.g., oil) do not 导电 and therefore will not contribute to 导电率.

的 solubility of ionic compounds is influenced by 温度, which affects the measured 导电率. 在更高的温度下, water contains a higher concentration of dissolved ions, resulting in higher 导电率. 为了消除温度对测量电导率的影响(以便观察到的差异可以归因于离子的浓度)电导率报告为25°C或 电导率. 这种温度补偿是由传感器自动完成的,使用测量的温度. This allows data collected at different 温度s to be directly compared. 的 sonde’s accuracy for 电导率 is ±1% of the reading.

pH of a natural water describes the acidic or basic characteristics of the water. pH is reported on a scale of 1 to 14, with lower values indicating more acidic water. A pH of 7 is considered neutral. 与温度, pH值影响自然水体中发生的许多生物和化学过程. When pH falls outside of the range of 6.5-8, aquatic organisms are physiologically stressed. 在低pH (i.e., 酸性条件), the mobility of some contaminants can also be enhanced, resulting in increased uptake by aquatic organisms. pH计的工作原理是测量浸入水中电极的电势. 的 sonde is capable of measuring pH with an accuracy of ±0.1 pH值单位. When data quality is less important (i.e.,较低的精度是可以接受的),可以更便宜地测量pH值使用颜色比较器.

浊度 is the measurement of light scattering by suspended particles in a natural water. It serves as an indirect measure of the concentration of suspended solids (e.g., clay, silt, sand, 藻类, organic matter), which influences water clarity. 因此,浊度是监测由雨水和其他径流来源引起的变化的有用工具. 浊度 is measured using a turbidimeter, 一种将光照射在水样上并测量样品中粒子散射光强度的仪器(用浊度单位或NTU表示)。. 的 sonde uses a submersible turbidimeter, an optical sensor that uses an infrared light source, which measures 浊度 in formazin nephelometric units (FNU). 这两种方法都是测量浑浊度的有效方法,但重要的是要认识到,用仪表和传感器收集的浑浊度数据是不同的. 浊度 is measured by the sonde with an accuracy of ±0.3 FNU. 比浊度测量更便宜的替代方法是使用塞奇圆盘或透明管来确定水的透明度.

溶解氧 is essential to aquatic organisms including fish, invertebrates, bacteria and plants. 天然水从大气中吸收氧气(通过扩散和通气),并通过浮游植物的光合作用, 藻类, 和其他植物. Oxygen is consumed by respiration, the decomposition of organic material by 微生物, some 化学 reactions (e.g., involving 化学 pollutants). DO is measured in either milligrams per liter (mg/L) or percent saturation, 当水与大气处于平衡状态时,相对于水所含的氧气总量,一升水的含氧量是多少. Dissolved oxygen is dependent on 温度 and barometric pressure. 氧的溶解度随着温度的升高和海拔的升高而降低. In addition, solubility is lower in higher salinity water (e.g., seawater) compared to freshwater. 的re are several ways that DO can be measured. 该探头使用光学溶解氧传感器来测量氧和发光染料之间的相互作用. Dissolved oxygen is measured by the sonde with an accuracy of ±1% of the reading.

探空仪配备有 藻类总 传感器,提供半定量的信息,通过测量数量的光合色素存在的水的藻类种群. 这个传感器是光学的, 双通道传感器,使用荧光以相对荧光单位(RFU)测定叶绿素(来自浮游植物)和藻青素(来自蓝藻)的浓度.


包含传感器的多参数仪器(用于测量特定的物理参数, 化学, 或生物特性),捆绑在一个单一的住房(探测仪)提供了许多优势监测365体育备用水. Compared to the alternatives of making readings in the field, 收集离散样本, conducting multiple analyses; the time required is significantly reduced. In addition, In situ measurements are likely to be more accurate and precise. Data can be collected with high frequency over long time periods, making it possible to observe trends on environmentally relevant time scales (e.g.,每日及季节变化). Instrument software allows for quick data visualization but for most applications, 需要进行数据处理.

由多参数探测仪在安嫩代尔大坝上方的蓄水池中收集的水质数据几乎是实时的,可以在 YSI 水LOGⓇ Storm Central website, which is displayed in the screenshot below.

您可以通过选择您感兴趣的日期范围来定制图形显示(数据从6月28日开始可用), 2019),并通过选择/取消选择参数(在图右侧的图例中)来逐个查看每个参数. 值显示为-99.99 indicate that data are not available.


http://stormcentral.涝灾.com/SiteDetails.php?a=437&网站= 3305&pa = 吟游诗人water

To request access to downloaded data or any additional information, please contact 艾米丽白.