## 5 Discussion and Conclusions  
The RWMS designed in this paper has the following advantages over other similar water-level monitoring systems available at home and abroad, shown in Table 1: (1) The software and the hardware are researched and developed independently. They can not only tremendously ensure a stable, expansible and reliable system, but also reduce the expenses. The cost is half that of the similar products available in China and one-sixth of the similar overseas products with a conservative estimation. The hardware is designed independently to ensure reasonable hardware settings and a strong anti-jamming system, especially for the unattended and changeable environments. (2) The system possess good real time performance and synchronicity. The data obtained from this system's sensor modules are written into the memory of the base station, which are transmitted to the data center immediately realize the real-time, fast, and wireless remote acquisition of data. The system will obtain a better synchronization when the data have been transmitted through the satellite and multiple sites orderly. (3) The system has several methods to release and process the data. They can be released through the mobile mode, the WEB mode and the web page browsing. Besides, the trend analysis can be realized through the data center.  
The RWMS can be further improved on the following aspects: (1) Combination of more nodes. Users can obtain the data in large-scale by placing the nodes orderly and optimizing the structure of the sensor network. (2) Intelligent power management. The current system uses storage batteries to provide power, but this method has its limitations in inaccessible places. The self-developed embedded intelligent power management is based on a low-temperature rechargeable battery, solar energy and wind power generation, as shown in Figure 11.  
This intelligent power management system can work in gear without wind and solar. It can take certain actions to protect the system, such as reducing the sampling frequency or cutting off the high energy sensors and so on. (3) Integration of the system with RS (remote sensing). RS is the  
\begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline \multirow{2}{*}{**System**} & \multirow{2}{*}{**Cost**} & \multirow{2}{*}{**Real-time**} & \multirow{2}{*}{**Synchronicity**} & \multicolumn{2}{c}{**Remote Upgrade**} & \multirow{2}{*}{**Expandability**} & \multirow{2}{*}{**Customizability**} & \multicolumn{1}{c}{**Giving an alarm**} \\ \hline Water Environment & & & & & & & \\ Monitoring System[6] & & L & Y & Y & N & Y & U & N \\ Micro-environmental & & & & & & & \\ monitoring system[7] & U & Y & U & N & U & U & U \\ JWR-SJ[11] & H & U & N & N & U & N & N \\ HG35-QSW[12] & H & N & N & N & U & N & N \\ DATA86[33] & H & Y & N & Y & U & U & U \\ RWMS & L & Y & Y & Y & Y & Y & Y \\ \hline \hline \end{tabular} Notes: L-Low, H-High, Y-Yes, N-No, U-Unknown  
\end{table}
Table 1: Comparation of different systems.  
Figure 11: Embedded intelligent power management system.  
macroscopic method to study Nature. Integrating the RS with the real-time data is an important direction in the future and has important theoretic value and practical significance.