Maine Department of Environment Protection lake monitoring and assessment, 1970s-2011, compiled all ME DEP programs for metadata unpublished data

Much of the lake monitoring in the state is done to assess "trophic state" or the productivity of the water. Our 30 year record includes data on over 1000 of our 5785 lakes, including parameters such as transparency, conductivity, alkalinity, total phosphorus and chlorophyll-a. These, along with extensive data sets from the University of Maine and clarity readings from volunteers, have produced one of the most comprehensive lake data sets in the country. DEP regular monitoring includes annual Baseline Sampling Program and special projects of one or more years’ duration. Each year between August 10 and September 10, we visit over 100 lakes and take a number of types of data. The timing coincides with the period when lakes usually show their worst water quality: lowest dissolved oxygen, lowest transparency and highest algae and phosphorus levels. Besides these measures, we sample for conductivity, alkalinity and acid neutralizing capacity (ANC), true and apparent color, and a variety of cations and anions. Lakes sampled generally include TMDL lakes, 33-50 lakes in the VLMP, lakes of special concern (e.g., anecdotal report of algal bloom), long-term monitoring lakes in ecoreserves and special project lakes.本州绝大多数湖泊监测工作均围绕评估水体营养状态（trophic state）或水体生产力展开。本数据集拥有长达30年的监测记录，覆盖全州5785个湖泊中的1000余个，监测参数涵盖透明度、电导率、碱度、总磷与叶绿素a等指标。结合缅因大学提供的海量数据集与志愿者采集的透明度观测数据，本数据集已成为全美覆盖最为全面的湖泊监测数据集之一。 DEP常规监测工作包含年度基线采样计划（Baseline Sampling Program）与持续时长1年及以上的专项项目。每年8月10日至9月10日期间，项目团队会走访100余个湖泊并采集多类监测数据。该时段恰好对应湖泊水质最差的时期：此时水体溶解氧含量最低、透明度最差，同时藻类与磷浓度达到峰值。除上述指标外，团队还会采集电导率、碱度、酸中和容量（ANC）、真色与表观色度，以及多种阳离子与阴离子样本。本次采样覆盖的湖泊通常包括：TMDL相关湖泊、VLMP项目下的33至50个湖泊、受特别关注的湖泊（如收到藻华传闻的湖泊）、生态保护区内的长期监测湖泊，以及专项项目涉及的湖泊。