Environmental Monitoring & Assessment Program

Phil Trowbridge

New Hampshire Estuaries Project, New Hampshire Department of Environmental Services, Concord, New Hampshire

The National Coastal Assessment in New Hampshire has resulted in a rich spatial dataset because of the small study area. Between 2000 and 2006, the New Hampshire Department of Environmental Services (DES) and the University of New Hampshire (UNH) collected the same number of samples in a 18 square mile estuary as were collected in other states with large coast lines. Analysis of the dataset for New Hampshire revealed strengths and weaknesses for conducting probabilistic monitoring in small estuaries. Probabilistic monitoring has been a cost effective method to document spatial heterogeneity of some parameters and for assessing attainment of water quality standards for 305(b) reporting. However, even with the high spatial density of sites, probabilistic monitoring designs were not able to capture transient events. Autocorrelation of stations was a concern and certain national parameters could not be measured accurately. Despite these limitations, the National Coastal Assessment in New Hampshire has demonstrated that probabilistic monitoring is a useful and cost-effective method for assessing the condition of small estuaries.