Table 1.
Summary of trend results by constituent. The number of stations with the specified trend result are listed along with the median change 1992–2012 and the 25th to 75th percentile of change. Magnitude of change (Δ) is mg L− 1 for chloride and change in ratio for CSMR and LR.
| Δ chloride (n = 141) | Δ CSMR (n = 74) | Δ LR (n = 76) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Trend result |  |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
| # of stations | 49 | 6 | 13 | 9 | 64 | 16 | 3 | 6 | 4 | 45 | 28 | 6 | 6 | 4 | 32 |
| Land use | Median (25th–75th pctile) | Median (25th–75th pctile) | Median (25th–75th pctile) | ||||||||||||
| All sites | 0.9 | (− 2.9–5.9) | 0.08 | (− 0.01–0.29) | 0.01 | (− 0.20–0.23) | |||||||||
| Undeveloped | − 0.4 | (− 2.6–2.5) | 0.03 | (0.05–0.10) | − 0.10 | (− 0.33–0.04) | |||||||||
| Agricultural | 0.5 | (− 3.3–3.7) | 0.03 | (− 0.04–0.10) | 0.03 | (− 0.03–0.31) | |||||||||
| Mixed | 1.4 | (− 6.7–5.7) | 0.03 | (− 0.09–0.27) | 0.04 | (− 0.11–0.15) | |||||||||
| Urban | 46.9 | (24.2–53.8) | 2.50 | (1.84–3.29) | 0.53 | (0.37–0.82) | |||||||||
- Decreasing, high likelihood.
- Decreasing, some likelihood.
- Trend not likely.
- Increasing, high likelihood.
- Increasing, some likelihood.