The objective of this project was to maintain the function of the Regional Groundwater Monitoring Wells (RGMWs) continuously and to keep the best condition of the RGMWs, which based on the experience of the previous projects of 2004 to 2007. On the other hand, the basic well information was corrected in order to establish the integrity of the network of the RGMWs. According to the maintenance records of the wells inspected from 8/2007 to 1/2008, the 40 wells were screened to proceed the evaluation of well condition in this project through the five criteria of the “unusual well depth”, “groundwater recovery slowly”, “obvious turbidity in well”, “unusual color of groundwater”, and “the odor of retention groundwater”. The project results of the major tasks were described as below: 1. Providing periodical cleaning to the RGMWs (1)The 40 wells conditions were evaluated by down-hole video inspection and slug test. Among that, the well located in Yu-Yin Elementary School, Yun-Lin County, was replaced by the well of Er-Chong Elementary School, Hsin-Chu County due to the shortage of water in well while the down-hole video inspected. (2)The 32 wells redeveloped were completed and executed the slug test and down-hole video inspection. Among 32 wells included that the results of well conditions evaluated suggested that 22 wells should be redeveloped preferentially, and 2 wells (Zhao-Nan Elementary School, Miao-Li County, and Xiang-Tan Elementary School, Ping-Tung County) which were blocked by uncertain objects and therefore cleared according to the directive of the EPA, and 6 wells from the previous projects. (3)The hydraulic conductivity analysis of the 3 wells was completed. Due to the records of geography and the analysis of hydraulic conductivity were different. (4)The groundwater sampling and water quality measurement of the 30 wells were completed. Meanwhile, the trend of the water quality had been analyzed by using the Stiff and Piper diagrams. 2. Verification and correction of the basic well information (1)The altitude of 90 wells was examined. Generally, the altitude recorded in the basic well information showed significant difference (-6.583m ~ +30.994m) and all were corrected. (2)The screen depth and length of the selected 41 wells was examined by the down-hole video inspection. Among that, 20 wells were error in screen depth and length. (3)The variations of environmental data of the 41 wells were analyzed. Among that, the water level of the 22 wells was located between the up and bottom of the screen depth in the history. Other 18 wells were above the screen up or below the screen bottom. A well located in Yu-Yin Elementary School, Yun-Lin County, appeared the shortage water in the low water period due to the short interval of the well screen. (4)The data base of the RGMWs information was established. The system involved the functions of the multiple search, systematical maintenance and statistical analysis et al., so that the system operation shown more convenience and friendly. 3. Renew the equipments of the well (1)To renew the 90 wells of the bulletin boards. (2)To remove the uncertain objects completely from 5 wells located in Zhao-Nan Elementary School, Miao-Li County and so on. (3)To built 2 wells structures completely from the flat formation to the unapparent one. (4)To construct 6 wells water-repellent cover. (5)To set up 2 new wells of the RGMWs and to abolish 2 wells.

Regional ,Groundwater, Monitoring Well