The conversion factor was the calculated as

the ratio of weight (kg) to volume (m3) for each core ( Fig. 8 and Table selleck 2). These values were imported into ArcGIS and gridded using the nearest-neighbor-gridding algorithm to provide a surface for a spatially integrated volume–weight calculation. Additional correction factors were taken into consideration: (1) core compaction (Cc), which was recorded during coring, and (2) inorganic sediment fraction (Co), which was determined from the LOI analysis. The methodology of applying correction factors is outlined in Fig. 8 with values for each core shown in Table 2. Interpolated and gridded values were multiplied as raster layers in ArcGIS and generated an estimate of dry sediment weight for the pond. An envelope of inferred minimum and maximum values for sediment weight in the pond was provided by using uniform values for the conversion and correction

factors based on min/max values of the empirical data, respectively. The resulting weight estimates serve as bounding values for internal error assessment. Regardless of C-factors used and resulting min/max pixel values the USLE model of the Lily Pond watershed shows erosion-rate variations that mimic LS-factor variations; this is particularly noticeable along the find more steep pond-proximal slopes ( Fig. 4). C-factor values of 0.001 and 0.42 provide an envelope of erosion estimates representing end-members of forested land-cover types described in the literature ( Table 1). Each metric was used as a constant C-value in repeated model runs. Using a C-factor of 0.001 produced an estimated total soil loss from 1974 to 2012 of 1087 kg while a C-factor of 0.42 yielded a total of 456,368 kg over the same time duration; the highest value possible for the C-factor ( Wischmeier and Smith, 1965) is 1 for bare soil; running the model using this C-factor generated an estimated total soil loss of 1,086,590 kg ( Table 3). The USLE models show that 60% of the estimated erosion is focused on the steep slopes

surrounding the pond, which make up only ∼10% of the watershed extent ( Fig. 1). The high-gradient hillslopes surrounding the pond to the north have the highest R-values while the more gently sloping terrain has values approximating PFKL ‘0’ ( Table 3 and Fig. 4F). Collected pond cores range in length from 14 to 46 cm with compaction averaging ∼30% (Table 2). Depths to bedrock or till with respect to pond level were checked during the coring process and found in agreement with the 1974 excavation-survey maps, which detail a 1.5-m uniform pond depth and 2:1 aspect ratio along the sides (Fig. 7A). Sediment cores all contain low percentages of organic matter with near-surface intervals containing slightly higher weight percentages; organic-matter contributions to the sediment budget rarely exceed 2% in weight percent and are always below 5.5% (Table 2).