Methodology for Groundwater Monitoring Network Assessment and Design, Part 1: Observation-Wells Condition Evaluation; Case Study: Shirvan Aquifer, North Khorasan, Iran

Groundwater level monitoring networks already exist in most alluvial aquifers in Iran. A question needs to be answered as to what extent networks are able to provide proper information about the groundwater resources to meet the water resources management objectives. Therefore, it is necessary to evaluate the efficiency of the existing monitoring network and redesign it if necessary.  This study has attempted to assess the condition of existing observation wells and the relationship between the wells and the aquifer by combining hydrogeological information and the results of a well-video inspection. Hydrogeological studies can reveal that the observation wells were drilled in which hydro-geological sequence (hydrofacies) and the external factors influence water level fluctuations. Moreover, observation well's video inspection operations, performed for the first time in Iran, can show the condition of the well casing and screen and the water-column length. The proposed framework was applied to evaluate the groundwater-level observation  well's efficiency in Shirvan alluvial aquifer in North Khorasan province, Iran. The results showed that out of 17 observation wells in the aquifer, one well is not placed into the main aquifer, six observation wells need to be rehabilitated due to screen clogging and three observation wells are at risk of going dry.