LONG-TERM OBSERVATIONS OF THE WATER CYCLE – ONGOING MONITORING PROGRAMS AT THE MAINE GEOLOGICAL SURVEY

Several ongoing monitoring programs at the Maine Geological Survey (MGS) focus on the hydrologic cycle. These include snowpack surveys and groundwater level monitoring. These programs support societal needs by aiding forecasts of flood and drought conditions, as well as characterizing the impacts of droughts on groundwater resources. Since the mid-1980s, the Maine Cooperative Snow Survey has been a joint effort between MGS, the US Geological Survey (USGS), the National Weather Service (NWS), and many other contributors. Snowpack depth and water content data are collected at established sites each winter, compiled, reviewed, and analyzed, then used to produce statewide maps and datasets that help inform flood risk through NWS communications and at meetings of the Maine River Flow Advisory Commission. Snow data are now also being used to define and identify periods of snow drought in Maine. Prior to 2017, the most readily available information about long-term groundwater levels in Maine was from a network of 19 wells maintained by the USGS. In 2017, MGS began providing data for an additional 32 groundwater wells as a contributor to the National Groundwater Monitoring Network (NGWMN). MGS’s contribution to the NGWMN now consists of 27 wells with long-term records and 10 wells that have recently initiated monitoring. Future efforts at MGS will focus on characterizing and monitoring the ongoing threat of saltwater intrusion into coastal drinking water aquifers. Statistics derived from both snow and groundwater data are used to quantify extremes in near-real time and eventually will show trends driven by climate change.