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Article Excerpt
Abstract: Monitoring efforts indicate that Loantaka Brook contributes approximately 61% of the soluble reactive phosphate (SRP) load that enters the Great Swamp Watershed. However, previous monitoring efforts focused on one site close to the confluence of Great Brook and Loantaka Brook, and did not attempt to identify the source or upstream dynamics of the SRP loads. Potential sources in the watershed include geese, urban runoff, lawns and golf courses, and Morris County's Woodland Road Wastewater Treatment Facility. We monitored SRP concentrations and stream discharge above and below the wastewater treatment plant, and above and below Kitchell Pond. Loantaka Brook enters this pond approximately 0.85 km downstream of the treatment outfall, and resumes at the pond's outflow. These sites were sampled once a week from 6/4/04-7/16/04. Results indicated that the treatment plant contributed 100% of load (185 g/hr, sd=99), and 95% of the discharge (0.084 [m.sup.3]/sec, sd=0.006). Notably, discharge was highest at the plant, and was on average 31% lower at the entrance to Kitchell Pond, although SRP concentrations at these two sites were nearly identical. This suggests that water from the plant may be charging groundwater stores. Comparison of SRP discharge and concentrations above and below the pond indicate that the pond reduces both, although the decrease in SRP concentration appears to be the greatest effect between these two sites.
Key Words: Phosphorus, nutrients, discharge, wastewater
INTRODUCTION
The Great Swamp Watershed is a major subunit of the Upper Passaic Watershed. It contains the Great Swamp National Wildlife Refuge, a 3,078-hectare area containing a wide diversity of wildlife habitat. This area is the largest protected wetland area in the Upper Passaic Watershed, with abundant habitat for migratory birds, and receives about 350,000 visits annually for recreation, nature observation, and hunting (Caudill and Henderson, 2005). In addition to its value for wildlife habitat, recreation, and aesthetics, the swamp is well positioned in the landscape to provide ecological services by improving water quality and buffering flood flows (Figure 1).
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The Great Swamp is fed by the Upper Passaic, Primrose Brook, Great Brook, Loantaka Brook, and Black Brook. Of the five streams that feed the swamp, Loantaka Brook is the most heavily impacted. Although much of the corridor adjacent to Loantaka Brook is maintained as a park by Morris County, the impacts of development are multiple and considerable. They include runoff from impervious surface area and lawn runoff, input from the Morristown sewage treatment facility, impacts of channelization, and large numbers of Canada Geese attracted to the open fields (Figure 2).
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Large numbers of geese can be observed year round, attracted by the many open fields that are adjacent to the brook, and geese feces are a considerable nuisance in these areas. Geese feces have been shown to be important vectors of nutrient loading in several ecosystems. For example, models coupling geese movements with nutrient mass balances suggested that geese feces resulted in high loading rates into the wetlands of Bosque del Apache National Wildlife Refuge, New Mexico (Post et al., 1998). Studies of lakes in Michigan (Manny et al., 1975) and Massachusetts (Moore et al., 1998) also showed high phosphorus loading from geese feces, and geese were determined to be the primary source of phosphorus to Middle Creek Reservoir in south-eastern Pennsylvania (Olson et al.,...
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