Level II Pollutant Loading
Level II load monitoring is essential for small watersheds with high peak flows,
and in situations where a continuous record of discharge and automatic sampling
of pollutant concentration is needed. Level II load monitoring requires a complex
and typically expensive sampling protocol to measure discharge and pollutant
concentration. However, there are good references for measuring loads, such as
Brakensiek et al.
and Wedepohl et al. (1990). The US
Geological Survey is a direct source of information on stream discharge measure-
Continuous discharge measurements for level II require instruments to record
stage upstream from either a natural control or a structural control such as a weir
or flume. Automatic samplers are used to collect concentration samples at a
regular interval (e.g., eight or 24 hours).