Look at Table 1, which shows selected hydrological and climatological indicators for four sub-catchments in the Valdivia River Basin, Chile.
Table 1
| Sub-catchment | Mean annual runoff (mm) | Forest cover (%) | Peak discharge (m3 s−1m^3\ s^{-1}m3 s−1) |
|---|---|---|---|
| Calle-Calle | 1 450 | 72 | 180 |
| Cruces | 1 120 | 58 | 125 |
| Futa | 980 | 84 | 95 |
| Angachilla | 650 | 45 | 40 |
Calculate the mean "Mean annual runoff" across these four sub-catchments.