數位分佈式水位感測元件與擷取系統開發

Abstract

臺灣由於近來天候極端變化，降雨強度集中（時間域與地域），臺灣之淹水問題頻 率增加，然而藉由既有雨量站之降雨特性推算可能淹水區，無法有效的對淹水區域發 出即時預警。因此提升分佈式水文監測功能，如雨水下水道、地表慢地流以及區域排 水內之水位，可對易淹水地區提供更準確的淹水檢核，以降低淹水損失。另外降雨問 題也使邊坡坍崩問題頻傳，邊坡破壞經常也涉及地下水壓變化，因此若能同時監測地 下水壓剖面則更能有效反應地層之破壞潛能，藉以提早預警。 有鑑於此，本計畫所提出之數位分佈式水位感測元件與擷取系統開發，主要配合微 機電電阻元件引用，而組裝開發本土化水位感測元件；另外以穩定傳輸以及經濟成本 為考量，提出利用 RS485 模式進行感測元件溝通與串接，包含其擷取系統與軟體，其 特色在於可多點串接以及長距離有線傳輸。基於上述感測系統開發以及其優勢，應可 提供一接近分佈式的水位感測方案，如淹水檢核所需之橫向空間多點水位資料分佈， 以及邊坡坍崩所需之縱向地下水壓剖面。另外本系統也兼容傳統設備（如電阻式或振 弦式）以及先進量測系統（如時域反射量測技術），因此配合本計畫開發之軟硬體介面， 應可大幅提昇現有工程監測人員應用便利性。

Since the weather changes dramatically recently, torrential rainfall events lead the flooding frequently in Taiwan. However, by characterizing the rainfall type via rainfall station data, it is not an effective and accurate approach to predict the possible flooding areas for pre-warning. It is suggested cooperate the measured water level data from the streams, pipelines, and surface runoff simultaneously. Furthermore, the rainfall events also yield landslide problems. The slope failures highly correspond to the ground water pressure increases. The ground water pressure profile can improve the interpretations of land sliding in advance. Based upon the aforementioned requirements, the study proposes the digitized distributed water level sensors and correlated data acquisition system. The first step of the study is using micro electromechanical systems (MEMS) module as the main transducer of the water level sensor. Second, using the RS485 protocol to achieve the multi-sensor connection and long distance communication purposes. Thus the development includes the acquisition system and software. This system can provide the distributed water level sensors that covers the water level measurements in horizontal spatial scale for the flooding prediction, and also the vertical ground water pressure profile for the land sliding interpretation. Moreover, the system is design to has the compatibility with the traditional sensors (e.g. resistance or vibrating wire types) and advanced measurement techniques (e.g. time domain reflectometry, TDR). Therefore, the development with system hardware and software would increase the operation efficiency in practice.