Wetland Monitoring
Smithtown, NY
Roux Associates was commissioned to complete extensive wetland monitoring activities of wetlands located adjacent to a groundwater pump and treat system. The principal objective of the wetland-monitoring plan was to determine what affects, if any, operation of a proposed groundwater recovery system will have on the wetland.
Key investigative elements included:
Establishment of vegetation and hydrologic monitoring plots in wetland areas potentially
impacted by the groundwater pump and treat system- Establishment of representative background monitoring stations
- Completion of a baseline assessment
- Collection and analysis of hydrologic and vegetation monitoring data
Water levels were monitored through the installation of a hydrologic monitoring network that consisted of surface water and groundwater monitoring locations. The locations and number of monitoring wells were designed to monitor and evaluate changes in the wetland water table elevations in response to natural (i.e., seasonal) and potentially induced hydrologic fluctuations (i.e., pump and treat system). Precipitation data provided by the National Climate Data Center were comparatively evaluated to the surface water and groundwater response to identify natural verses induced trends in the wetland hydrology.
In accordance with the methods described in the U.S. Army Corps of Engineers (USCOE) Wetland Delineation Manual; Section E, Steps 8 through 20-Comprehensive Determination, a survey of vegetation, soils, and hydrology was performed at each monitoring location.
Potential effects of the groundwater pump and treatment system were evaluated based the completion of comparative analyses of quarterly hydrologic, precipitation, and vegetation monitoring data to the baseline conditions documented prior to startup of the system. Substantive shifts in the vegetative structure of the wetlands would then be an indicator of potential project related effects. The PI methodology was used throughout the monitoring program to evaluate and differentiate induced changes from those attributable to naturally occurring (seasonal) fluctuations.
No impacts hydrologic or vegetative effects were observed from the operation of the recovery system on the adjacent wetland area. PI scores recorded from each monitoring quarter reflected only natural seasonal fluctuations. Since inception of the baseline survey, the diversity, abundance and overall health of the vegetation present within the monitoring plots has remained constant. In addition, no new upland species or invasive species were recorded in the monitoring plots since the baseline survey period.