## 3 Results and Discussions
### Empirical Orthogonal Functions  
For _L. monocytogenes_ concentrations, EOF1 (Figure 2a) and EOF2 (Figure 2b) explained 84.4% and 9.7%, respectively, of the variance of the deviations from the average. For Rain1, EOF1 explained 78.5% (Figure 2a) and EOF2 explained 19.1% (Figure 2b) of the variance of deviations from average. Similarly, EOF1 and EOF2 for Rain7 explained 79.2% and 18.7% of the variance, respectively (Figure 2). Figure 2: First (EOF1) and second (EOF2) spatial patterns of _L. monocytogenes_ and _Salmonella_ and cumulative rain fall over one (Rain1) and seven (Rain 7) days before sampling; (**a**) _L. monocytogenes_ EOF1; (**b**) _L. monocytogenes_ EOF2; (**c**) _Salmonella_ EOF 1; (**d**) _Salmonella_ EOF2. Solid (red) lines indicate EOF values of the pathogens; striped (turquoise) lines indicate EOF values of Rain1 (diagonal to the left) or Rain7 (diagonal to the right). The EOF1 values of Rain1 and Rain7 had the same signs at each of the four sites (Figure 2). Hence, deviations of the accumulated rainfall from the average were similar over the observation time for one-day and seven-day rainfall accumulation. The MA04 site had deviations opposite to the deviations at the other three sites. The _L. monocytogenes_ EOF1 had similar signs as precipitation (Rain1, Rain7) at pond sites but was opposite to precipitation at the stream sites. These findings indicate that levels of _L. monocytogenes_ potentially could be associated with rainfall at pond sites across the study area. On the contrary, there was no similarity in signs of _L. monocytogenes_ levels and rainfall values at the stream sites MA04 and MA05. While the EOF1 value for _L. monocytogenes_ at MA05 was negative, the EOF1 value for _L. monocytogenes_ from all other sampling sites was positive. These results indicate different fate and transport mechanisms and possibly different sources of _L. monocytogenes_ at the stream site MA05 compared to stream MA04 or pond MA10 or MA11 sites. Comparison of absolute values of EOF1 shows that the levels of _L. monocytogenes_ at the MA05 sampling site were mostly greater than the average across all sampling sites and were influenced more by sampling-site specific characteristics than by rainfall. EOF1 and EOF2 values for _S. enterica_ and rainfall are presented in Figure 2. EOF1 (Figure 2c) and EOF2 (Figure 2d) values for _S. enterica_ explained 50.8% and 45.0% of the spatial variance of deviations from average, respectively. _S. enterica_ concentration distributions across all the sites follow a more complex spatial pattern compared to survival patterns of _L. monocytogenes_. For _S. enterica_ levels, two equally important patterns (EOF1, EOF2) needed to account for most of the variability (95.8%). In contrast, only a single pattern described by one EOF (EOF1) accounts for the majority (84.4%) of the variance for _L. monocytogenes_ levels (Figure 2). The EOF1 value for _S. enterica_ at the stream site MA04 was positive, while EOF1 values for other sampling sites were all negative (Figure 2c), indicating that MA04 had higher _Salmonella_ levels than stream site MA05 and pond sites MA10 and MA11. EOF1 values for rainfall (Rain1, Rain7) showed the opposite pattern to _S. enterica_ values across all sampling sites. Interpretation of all these results indicates that at least 50% of the concentration deviations variance may not be rainfall related. However, the remaining deviation variance explained by EOF2 appears to be associated with rainfall. _S. enterica_ and rainfall EOF2 values have the same signs at MA04 (negative), MA05 (positive), and MA11 (positive) (Figure 2c). Spatial patterns of deviations from average values were different for _S. enterica_ and _L. monocytogenes_, implying that sources of the two pathogens and potentially dominant processes of their fate, transport, and survival in the studied water bodies are different. Aside from inherent differences in ecophysiology between the two taxa, the possible reasons for different EOF patterns between _L. monocytogenes_ and _S.