Joining a Network

New sites that wish to join a National Atmospheric Deposition Program (NADP) network must complete the Site Information Worksheet (SIW). The completed SIW, site sketch, and site photos should be submitted to the Program Office via email at

General Criteria For Site Selection

Selection of monitoring sites within the NADP is based on the site’s potential to: provide insight into changing atmospheric chemistry, help assess the contributions to sensitive ecosystems, and help validate atmospheric models. Of particular interest are major physiographic, agricultural, aquatic, and forested areas within states, regions, and ecoregions. Siting criteria were established to meet the goal of having regionally representative measurements, and comparability between network sites.

A site should be accessible year round, and in normal weather conditions. It should be secure against vandalism, and from animals, both wild (e.g., bears) and domestic (e.g., cows). When a fence is used to secure a site, the Siting Criteria Rules must be considered. Placement of the NADP instrumentation relative to the fence, in terms of both horizontal and vertical proximity, and the type of fence (e.g., chain link, wood post) are important. In some instances, the fence material may be a concern as well.

Wet-deposition equipment (i.e., collectors and raingages), AMoN samplers, AMNet equipment, and Litterfall samplers should be located such that they cannot be impacted by irrigation sources. Wind speed and wind direction should be considered when assessing potential impact from nearby irrigation sources.

Collocation of an NADP site with other long-term monitoring networks is encouraged. Established sites have a data archive that can be evaluated. Such sites have documentation that may be reviewed as well. Data must not be compromised when monitoring sites are collocated. This is true whether multiple NADP networks are collocated, or whether an NADP network is collocated with another network (e.g., CASTNET, IMPROVE). Local site conditions should be evaluated to ensure that there is appropriate space to operate the networks, and that site activities will not impact sample collection or site operations.



David Gay