Three monitoring stations were established: stations U1 and D1
in the receiving river were set at the upstream and downstream of
A10 site, respectively; station A1 in the drainage canal was set at
the outlet of A10 site (Fig. 1b and c). Drainage from small agricultural watersheds with intensive livestock production as well as A10 flows into the river at a few points between stations U1 and
D1.
The amounts of rainfall and the water levels in the drainage
were recorded at A1 at 5-min intervals with a self-registering rain
gauge (Model 674; Isco Inc., Lincoln, NE, USA) and with a self-registering pressure-type water gauge system (MC1100W; Sensor Technik Sirnach AG, Sirnach, Switzerland), respectively. Water
depths and velocities were measured once a week.